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Date: Thu, 9 Nov 2017 18:22:09 +0100
From: Juergen Fitschen <me@....yt>
To: Ludovic Desroches <ludovic.desroches@...rochip.com>,
Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] i2c: at91: split driver into core and master file
The single file i2c-at91.c has been split into core code (i2c-at91-core.c)
and master mode specific code (i2c-at91-master.c). This should enhance
maintainability and reduce ifdeffery for slave mode related code.
The code itself hasn't been touched. Shared functions only had to be made
non-static. Furthermore, includes have been cleaned up.
Acked-by: Ludovic Desroches <ludovic.desroches@...rochip.com>
Signed-off-by: Juergen Fitschen <me@....yt>
---
MAINTAINERS | 3 +-
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-at91-core.c | 373 ++++++++++
drivers/i2c/busses/i2c-at91-master.c | 806 ++++++++++++++++++++++
drivers/i2c/busses/i2c-at91.c | 1265 ----------------------------------
drivers/i2c/busses/i2c-at91.h | 151 ++++
6 files changed, 1333 insertions(+), 1266 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-at91-core.c
create mode 100644 drivers/i2c/busses/i2c-at91-master.c
delete mode 100644 drivers/i2c/busses/i2c-at91.c
create mode 100644 drivers/i2c/busses/i2c-at91.h
diff --git a/MAINTAINERS b/MAINTAINERS
index e021587..c15cccd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2341,7 +2341,8 @@ ATMEL I2C DRIVER
M: Ludovic Desroches <ludovic.desroches@...rochip.com>
L: linux-i2c@...r.kernel.org
S: Supported
-F: drivers/i2c/busses/i2c-at91.c
+F: drivers/i2c/busses/i2c-at91.h
+F: drivers/i2c/busses/i2c-at91-*.c
ATMEL ISI DRIVER
M: Ludovic Desroches <ludovic.desroches@...rochip.com>
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 47f3ac9..2a79c3d 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
obj-$(CONFIG_I2C_ALTERA) += i2c-altera.o
obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o
obj-$(CONFIG_I2C_AT91) += i2c-at91.o
+i2c-at91-objs := i2c-at91-core.o i2c-at91-master.o
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o
diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
new file mode 100644
index 0000000..4fed72d
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -0,0 +1,373 @@
+/*
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2011 Weinmann Medical GmbH
+ * Author: Nikolaus Voss <n.voss@...nmann.de>
+ *
+ * Evolved from original work by:
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor <andrew@...people.com>
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock <phil@...mpy.netroedge.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pinctrl/consumer.h>
+
+#include "i2c-at91.h"
+
+unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
+{
+ return readl_relaxed(dev->base + reg);
+}
+
+void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
+{
+ writel_relaxed(val, dev->base + reg);
+}
+
+void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
+{
+ at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK);
+}
+
+void at91_twi_irq_save(struct at91_twi_dev *dev)
+{
+ dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
+ at91_disable_twi_interrupts(dev);
+}
+
+void at91_twi_irq_restore(struct at91_twi_dev *dev)
+{
+ at91_twi_write(dev, AT91_TWI_IER, dev->imr);
+}
+
+void at91_init_twi_bus(struct at91_twi_dev *dev)
+{
+ at91_disable_twi_interrupts(dev);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
+
+ at91_init_twi_bus_master(dev);
+}
+
+static struct at91_twi_pdata at91rm9200_config = {
+ .clk_max_div = 5,
+ .clk_offset = 3,
+ .has_unre_flag = true,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static struct at91_twi_pdata at91sam9261_config = {
+ .clk_max_div = 5,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static struct at91_twi_pdata at91sam9260_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static struct at91_twi_pdata at91sam9g20_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static struct at91_twi_pdata at91sam9g10_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static const struct platform_device_id at91_twi_devtypes[] = {
+ {
+ .name = "i2c-at91rm9200",
+ .driver_data = (unsigned long) &at91rm9200_config,
+ }, {
+ .name = "i2c-at91sam9261",
+ .driver_data = (unsigned long) &at91sam9261_config,
+ }, {
+ .name = "i2c-at91sam9260",
+ .driver_data = (unsigned long) &at91sam9260_config,
+ }, {
+ .name = "i2c-at91sam9g20",
+ .driver_data = (unsigned long) &at91sam9g20_config,
+ }, {
+ .name = "i2c-at91sam9g10",
+ .driver_data = (unsigned long) &at91sam9g10_config,
+ }, {
+ /* sentinel */
+ }
+};
+
+#if defined(CONFIG_OF)
+static struct at91_twi_pdata at91sam9x5_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = false,
+};
+
+static struct at91_twi_pdata sama5d4_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+ .has_alt_cmd = false,
+ .has_hold_field = true,
+};
+
+static struct at91_twi_pdata sama5d2_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = true,
+ .has_alt_cmd = true,
+ .has_hold_field = true,
+};
+
+static const struct of_device_id atmel_twi_dt_ids[] = {
+ {
+ .compatible = "atmel,at91rm9200-i2c",
+ .data = &at91rm9200_config,
+ } , {
+ .compatible = "atmel,at91sam9260-i2c",
+ .data = &at91sam9260_config,
+ } , {
+ .compatible = "atmel,at91sam9261-i2c",
+ .data = &at91sam9261_config,
+ } , {
+ .compatible = "atmel,at91sam9g20-i2c",
+ .data = &at91sam9g20_config,
+ } , {
+ .compatible = "atmel,at91sam9g10-i2c",
+ .data = &at91sam9g10_config,
+ }, {
+ .compatible = "atmel,at91sam9x5-i2c",
+ .data = &at91sam9x5_config,
+ }, {
+ .compatible = "atmel,sama5d4-i2c",
+ .data = &sama5d4_config,
+ }, {
+ .compatible = "atmel,sama5d2-i2c",
+ .data = &sama5d2_config,
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
+#endif
+
+static struct at91_twi_pdata *at91_twi_get_driver_data(
+ struct platform_device *pdev)
+{
+ if (pdev->dev.of_node) {
+ const struct of_device_id *match;
+ match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
+ if (!match)
+ return NULL;
+ return (struct at91_twi_pdata *)match->data;
+ }
+ return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
+}
+
+static int at91_twi_probe(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev;
+ struct resource *mem;
+ int rc;
+ u32 phy_addr;
+
+ dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->dev = &pdev->dev;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!mem)
+ return -ENODEV;
+ phy_addr = mem->start;
+
+ dev->pdata = at91_twi_get_driver_data(pdev);
+ if (!dev->pdata)
+ return -ENODEV;
+
+ dev->base = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(dev->base))
+ return PTR_ERR(dev->base);
+
+ dev->irq = platform_get_irq(pdev, 0);
+ if (dev->irq < 0)
+ return dev->irq;
+
+ platform_set_drvdata(pdev, dev);
+
+ dev->clk = devm_clk_get(dev->dev, NULL);
+ if (IS_ERR(dev->clk)) {
+ dev_err(dev->dev, "no clock defined\n");
+ return -ENODEV;
+ }
+ clk_prepare_enable(dev->clk);
+
+ snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
+ i2c_set_adapdata(&dev->adapter, dev);
+ dev->adapter.owner = THIS_MODULE;
+ dev->adapter.class = I2C_CLASS_DEPRECATED;
+ dev->adapter.dev.parent = dev->dev;
+ dev->adapter.nr = pdev->id;
+ dev->adapter.timeout = AT91_I2C_TIMEOUT;
+ dev->adapter.dev.of_node = pdev->dev.of_node;
+
+ rc = at91_twi_probe_master(pdev, phy_addr, dev);
+ if (rc)
+ return rc;
+
+ at91_init_twi_bus(dev);
+
+ pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
+ pm_runtime_use_autosuspend(dev->dev);
+ pm_runtime_set_active(dev->dev);
+ pm_runtime_enable(dev->dev);
+
+ rc = i2c_add_numbered_adapter(&dev->adapter);
+ if (rc) {
+ clk_disable_unprepare(dev->clk);
+
+ pm_runtime_disable(dev->dev);
+ pm_runtime_set_suspended(dev->dev);
+
+ return rc;
+ }
+
+ dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
+ at91_twi_read(dev, AT91_TWI_VER));
+ return 0;
+}
+
+static int at91_twi_remove(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&dev->adapter);
+ clk_disable_unprepare(dev->clk);
+
+ pm_runtime_disable(dev->dev);
+ pm_runtime_set_suspended(dev->dev);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int at91_twi_runtime_suspend(struct device *dev)
+{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(twi_dev->clk);
+
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static int at91_twi_runtime_resume(struct device *dev)
+{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+
+ pinctrl_pm_select_default_state(dev);
+
+ return clk_prepare_enable(twi_dev->clk);
+}
+
+static int at91_twi_suspend_noirq(struct device *dev)
+{
+ if (!pm_runtime_status_suspended(dev))
+ at91_twi_runtime_suspend(dev);
+
+ return 0;
+}
+
+static int at91_twi_resume_noirq(struct device *dev)
+{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+ int ret;
+
+ if (!pm_runtime_status_suspended(dev)) {
+ ret = at91_twi_runtime_resume(dev);
+ if (ret)
+ return ret;
+ }
+
+ pm_runtime_mark_last_busy(dev);
+ pm_request_autosuspend(dev);
+
+ at91_init_twi_bus(twi_dev);
+
+ return 0;
+}
+
+static const struct dev_pm_ops at91_twi_pm = {
+ .suspend_noirq = at91_twi_suspend_noirq,
+ .resume_noirq = at91_twi_resume_noirq,
+ .runtime_suspend = at91_twi_runtime_suspend,
+ .runtime_resume = at91_twi_runtime_resume,
+};
+
+#define at91_twi_pm_ops (&at91_twi_pm)
+#else
+#define at91_twi_pm_ops NULL
+#endif
+
+static struct platform_driver at91_twi_driver = {
+ .probe = at91_twi_probe,
+ .remove = at91_twi_remove,
+ .id_table = at91_twi_devtypes,
+ .driver = {
+ .name = "at91_i2c",
+ .of_match_table = of_match_ptr(atmel_twi_dt_ids),
+ .pm = at91_twi_pm_ops,
+ },
+};
+
+static int __init at91_twi_init(void)
+{
+ return platform_driver_register(&at91_twi_driver);
+}
+
+static void __exit at91_twi_exit(void)
+{
+ platform_driver_unregister(&at91_twi_driver);
+}
+
+subsys_initcall(at91_twi_init);
+module_exit(at91_twi_exit);
+
+MODULE_AUTHOR("Nikolaus Voss <n.voss@...nmann.de>");
+MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:at91_i2c");
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
new file mode 100644
index 0000000..81a072f
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -0,0 +1,806 @@
+/*
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2011 Weinmann Medical GmbH
+ * Author: Nikolaus Voss <n.voss@...nmann.de>
+ *
+ * Evolved from original work by:
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor <andrew@...people.com>
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock <phil@...mpy.netroedge.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/dma-atmel.h>
+#include <linux/pm_runtime.h>
+
+#include "i2c-at91.h"
+
+void at91_init_twi_bus_master(struct at91_twi_dev *dev)
+{
+ /* FIFO should be enabled immediately after the software reset */
+ if (dev->fifo_size)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
+ at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
+}
+
+/*
+ * Calculate symmetric clock as stated in datasheet:
+ * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
+ */
+static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
+{
+ int ckdiv, cdiv, div, hold = 0;
+ struct at91_twi_pdata *pdata = dev->pdata;
+ int offset = pdata->clk_offset;
+ int max_ckdiv = pdata->clk_max_div;
+ u32 twd_hold_time_ns = 0;
+
+ div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
+ 2 * twi_clk) - offset);
+ ckdiv = fls(div >> 8);
+ cdiv = div >> ckdiv;
+
+ if (ckdiv > max_ckdiv) {
+ dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
+ ckdiv, max_ckdiv);
+ ckdiv = max_ckdiv;
+ cdiv = 255;
+ }
+
+ if (pdata->has_hold_field) {
+ of_property_read_u32(dev->dev->of_node, "i2c-sda-hold-time-ns",
+ &twd_hold_time_ns);
+
+ /*
+ * hold time = HOLD + 3 x T_peripheral_clock
+ * Use clk rate in kHz to prevent overflows when computing
+ * hold.
+ */
+ hold = DIV_ROUND_UP(twd_hold_time_ns
+ * (clk_get_rate(dev->clk) / 1000), 1000000);
+ hold -= 3;
+ if (hold < 0)
+ hold = 0;
+ if (hold > AT91_TWI_CWGR_HOLD_MAX) {
+ dev_warn(dev->dev,
+ "HOLD field set to its maximum value (%d instead of %d)\n",
+ AT91_TWI_CWGR_HOLD_MAX, hold);
+ hold = AT91_TWI_CWGR_HOLD_MAX;
+ }
+ }
+
+ dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
+ | AT91_TWI_CWGR_HOLD(hold);
+
+ dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns)\n",
+ cdiv, ckdiv, hold, twd_hold_time_ns);
+}
+
+static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
+{
+ struct at91_twi_dma *dma = &dev->dma;
+
+ at91_twi_irq_save(dev);
+
+ if (dma->xfer_in_progress) {
+ if (dma->direction == DMA_FROM_DEVICE)
+ dmaengine_terminate_all(dma->chan_rx);
+ else
+ dmaengine_terminate_all(dma->chan_tx);
+ dma->xfer_in_progress = false;
+ }
+ if (dma->buf_mapped) {
+ dma_unmap_single(dev->dev, sg_dma_address(&dma->sg[0]),
+ dev->buf_len, dma->direction);
+ dma->buf_mapped = false;
+ }
+
+ at91_twi_irq_restore(dev);
+}
+
+static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
+{
+ if (!dev->buf_len)
+ return;
+
+ /* 8bit write works with and without FIFO */
+ writeb_relaxed(*dev->buf, dev->base + AT91_TWI_THR);
+
+ /* send stop when last byte has been written */
+ if (--dev->buf_len == 0)
+ if (!dev->use_alt_cmd)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
+
+ dev_dbg(dev->dev, "wrote 0x%x, to go %zu\n", *dev->buf, dev->buf_len);
+
+ ++dev->buf;
+}
+
+static void at91_twi_write_data_dma_callback(void *data)
+{
+ struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
+
+ dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]),
+ dev->buf_len, DMA_TO_DEVICE);
+
+ /*
+ * When this callback is called, THR/TX FIFO is likely not to be empty
+ * yet. So we have to wait for TXCOMP or NACK bits to be set into the
+ * Status Register to be sure that the STOP bit has been sent and the
+ * transfer is completed. The NACK interrupt has already been enabled,
+ * we just have to enable TXCOMP one.
+ */
+ at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
+ if (!dev->use_alt_cmd)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
+}
+
+static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
+{
+ dma_addr_t dma_addr;
+ struct dma_async_tx_descriptor *txdesc;
+ struct at91_twi_dma *dma = &dev->dma;
+ struct dma_chan *chan_tx = dma->chan_tx;
+ unsigned int sg_len = 1;
+
+ if (!dev->buf_len)
+ return;
+
+ dma->direction = DMA_TO_DEVICE;
+
+ at91_twi_irq_save(dev);
+ dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
+ DMA_TO_DEVICE);
+ if (dma_mapping_error(dev->dev, dma_addr)) {
+ dev_err(dev->dev, "dma map failed\n");
+ return;
+ }
+ dma->buf_mapped = true;
+ at91_twi_irq_restore(dev);
+
+ if (dev->fifo_size) {
+ size_t part1_len, part2_len;
+ struct scatterlist *sg;
+ unsigned fifo_mr;
+
+ sg_len = 0;
+
+ part1_len = dev->buf_len & ~0x3;
+ if (part1_len) {
+ sg = &dma->sg[sg_len++];
+ sg_dma_len(sg) = part1_len;
+ sg_dma_address(sg) = dma_addr;
+ }
+
+ part2_len = dev->buf_len & 0x3;
+ if (part2_len) {
+ sg = &dma->sg[sg_len++];
+ sg_dma_len(sg) = part2_len;
+ sg_dma_address(sg) = dma_addr + part1_len;
+ }
+
+ /*
+ * DMA controller is triggered when at least 4 data can be
+ * written into the TX FIFO
+ */
+ fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
+ fifo_mr &= ~AT91_TWI_FMR_TXRDYM_MASK;
+ fifo_mr |= AT91_TWI_FMR_TXRDYM(AT91_TWI_FOUR_DATA);
+ at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
+ } else {
+ sg_dma_len(&dma->sg[0]) = dev->buf_len;
+ sg_dma_address(&dma->sg[0]) = dma_addr;
+ }
+
+ txdesc = dmaengine_prep_slave_sg(chan_tx, dma->sg, sg_len,
+ DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!txdesc) {
+ dev_err(dev->dev, "dma prep slave sg failed\n");
+ goto error;
+ }
+
+ txdesc->callback = at91_twi_write_data_dma_callback;
+ txdesc->callback_param = dev;
+
+ dma->xfer_in_progress = true;
+ dmaengine_submit(txdesc);
+ dma_async_issue_pending(chan_tx);
+
+ return;
+
+error:
+ at91_twi_dma_cleanup(dev);
+}
+
+static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
+{
+ /*
+ * If we are in this case, it means there is garbage data in RHR, so
+ * delete them.
+ */
+ if (!dev->buf_len) {
+ at91_twi_read(dev, AT91_TWI_RHR);
+ return;
+ }
+
+ /* 8bit read works with and without FIFO */
+ *dev->buf = readb_relaxed(dev->base + AT91_TWI_RHR);
+ --dev->buf_len;
+
+ /* return if aborting, we only needed to read RHR to clear RXRDY*/
+ if (dev->recv_len_abort)
+ return;
+
+ /* handle I2C_SMBUS_BLOCK_DATA */
+ if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
+ /* ensure length byte is a valid value */
+ if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
+ dev->msg->flags &= ~I2C_M_RECV_LEN;
+ dev->buf_len += *dev->buf;
+ dev->msg->len = dev->buf_len + 1;
+ dev_dbg(dev->dev, "received block length %zu\n",
+ dev->buf_len);
+ } else {
+ /* abort and send the stop by reading one more byte */
+ dev->recv_len_abort = true;
+ dev->buf_len = 1;
+ }
+ }
+
+ /* send stop if second but last byte has been read */
+ if (!dev->use_alt_cmd && dev->buf_len == 1)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
+
+ dev_dbg(dev->dev, "read 0x%x, to go %zu\n", *dev->buf, dev->buf_len);
+
+ ++dev->buf;
+}
+
+static void at91_twi_read_data_dma_callback(void *data)
+{
+ struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
+ unsigned ier = AT91_TWI_TXCOMP;
+
+ dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]),
+ dev->buf_len, DMA_FROM_DEVICE);
+
+ if (!dev->use_alt_cmd) {
+ /* The last two bytes have to be read without using dma */
+ dev->buf += dev->buf_len - 2;
+ dev->buf_len = 2;
+ ier |= AT91_TWI_RXRDY;
+ }
+ at91_twi_write(dev, AT91_TWI_IER, ier);
+}
+
+static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
+{
+ dma_addr_t dma_addr;
+ struct dma_async_tx_descriptor *rxdesc;
+ struct at91_twi_dma *dma = &dev->dma;
+ struct dma_chan *chan_rx = dma->chan_rx;
+ size_t buf_len;
+
+ buf_len = (dev->use_alt_cmd) ? dev->buf_len : dev->buf_len - 2;
+ dma->direction = DMA_FROM_DEVICE;
+
+ /* Keep in mind that we won't use dma to read the last two bytes */
+ at91_twi_irq_save(dev);
+ dma_addr = dma_map_single(dev->dev, dev->buf, buf_len, DMA_FROM_DEVICE);
+ if (dma_mapping_error(dev->dev, dma_addr)) {
+ dev_err(dev->dev, "dma map failed\n");
+ return;
+ }
+ dma->buf_mapped = true;
+ at91_twi_irq_restore(dev);
+
+ if (dev->fifo_size && IS_ALIGNED(buf_len, 4)) {
+ unsigned fifo_mr;
+
+ /*
+ * DMA controller is triggered when at least 4 data can be
+ * read from the RX FIFO
+ */
+ fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
+ fifo_mr &= ~AT91_TWI_FMR_RXRDYM_MASK;
+ fifo_mr |= AT91_TWI_FMR_RXRDYM(AT91_TWI_FOUR_DATA);
+ at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
+ }
+
+ sg_dma_len(&dma->sg[0]) = buf_len;
+ sg_dma_address(&dma->sg[0]) = dma_addr;
+
+ rxdesc = dmaengine_prep_slave_sg(chan_rx, dma->sg, 1, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!rxdesc) {
+ dev_err(dev->dev, "dma prep slave sg failed\n");
+ goto error;
+ }
+
+ rxdesc->callback = at91_twi_read_data_dma_callback;
+ rxdesc->callback_param = dev;
+
+ dma->xfer_in_progress = true;
+ dmaengine_submit(rxdesc);
+ dma_async_issue_pending(dma->chan_rx);
+
+ return;
+
+error:
+ at91_twi_dma_cleanup(dev);
+}
+
+static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
+{
+ struct at91_twi_dev *dev = dev_id;
+ const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
+ const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
+
+ if (!irqstatus)
+ return IRQ_NONE;
+ /*
+ * In reception, the behavior of the twi device (before sama5d2) is
+ * weird. There is some magic about RXRDY flag! When a data has been
+ * almost received, the reception of a new one is anticipated if there
+ * is no stop command to send. That is the reason why ask for sending
+ * the stop command not on the last data but on the second last one.
+ *
+ * Unfortunately, we could still have the RXRDY flag set even if the
+ * transfer is done and we have read the last data. It might happen
+ * when the i2c slave device sends too quickly data after receiving the
+ * ack from the master. The data has been almost received before having
+ * the order to send stop. In this case, sending the stop command could
+ * cause a RXRDY interrupt with a TXCOMP one. It is better to manage
+ * the RXRDY interrupt first in order to not keep garbage data in the
+ * Receive Holding Register for the next transfer.
+ */
+ if (irqstatus & AT91_TWI_RXRDY)
+ at91_twi_read_next_byte(dev);
+
+ /*
+ * When a NACK condition is detected, the I2C controller sets the NACK,
+ * TXCOMP and TXRDY bits all together in the Status Register (SR).
+ *
+ * 1 - Handling NACK errors with CPU write transfer.
+ *
+ * In such case, we should not write the next byte into the Transmit
+ * Holding Register (THR) otherwise the I2C controller would start a new
+ * transfer and the I2C slave is likely to reply by another NACK.
+ *
+ * 2 - Handling NACK errors with DMA write transfer.
+ *
+ * By setting the TXRDY bit in the SR, the I2C controller also triggers
+ * the DMA controller to write the next data into the THR. Then the
+ * result depends on the hardware version of the I2C controller.
+ *
+ * 2a - Without support of the Alternative Command mode.
+ *
+ * This is the worst case: the DMA controller is triggered to write the
+ * next data into the THR, hence starting a new transfer: the I2C slave
+ * is likely to reply by another NACK.
+ * Concurrently, this interrupt handler is likely to be called to manage
+ * the first NACK before the I2C controller detects the second NACK and
+ * sets once again the NACK bit into the SR.
+ * When handling the first NACK, this interrupt handler disables the I2C
+ * controller interruptions, especially the NACK interrupt.
+ * Hence, the NACK bit is pending into the SR. This is why we should
+ * read the SR to clear all pending interrupts at the beginning of
+ * at91_do_twi_transfer() before actually starting a new transfer.
+ *
+ * 2b - With support of the Alternative Command mode.
+ *
+ * When a NACK condition is detected, the I2C controller also locks the
+ * THR (and sets the LOCK bit in the SR): even though the DMA controller
+ * is triggered by the TXRDY bit to write the next data into the THR,
+ * this data actually won't go on the I2C bus hence a second NACK is not
+ * generated.
+ */
+ if (irqstatus & (AT91_TWI_TXCOMP | AT91_TWI_NACK)) {
+ at91_disable_twi_interrupts(dev);
+ complete(&dev->cmd_complete);
+ } else if (irqstatus & AT91_TWI_TXRDY) {
+ at91_twi_write_next_byte(dev);
+ }
+
+ /* catch error flags */
+ dev->transfer_status |= status;
+
+ return IRQ_HANDLED;
+}
+
+static int at91_do_twi_transfer(struct at91_twi_dev *dev)
+{
+ int ret;
+ unsigned long time_left;
+ bool has_unre_flag = dev->pdata->has_unre_flag;
+ bool has_alt_cmd = dev->pdata->has_alt_cmd;
+
+ /*
+ * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
+ * read flag but shows the state of the transmission at the time the
+ * Status Register is read. According to the programmer datasheet,
+ * TXCOMP is set when both holding register and internal shifter are
+ * empty and STOP condition has been sent.
+ * Consequently, we should enable NACK interrupt rather than TXCOMP to
+ * detect transmission failure.
+ * Indeed let's take the case of an i2c write command using DMA.
+ * Whenever the slave doesn't acknowledge a byte, the LOCK, NACK and
+ * TXCOMP bits are set together into the Status Register.
+ * LOCK is a clear on write bit, which is set to prevent the DMA
+ * controller from sending new data on the i2c bus after a NACK
+ * condition has happened. Once locked, this i2c peripheral stops
+ * triggering the DMA controller for new data but it is more than
+ * likely that a new DMA transaction is already in progress, writing
+ * into the Transmit Holding Register. Since the peripheral is locked,
+ * these new data won't be sent to the i2c bus but they will remain
+ * into the Transmit Holding Register, so TXCOMP bit is cleared.
+ * Then when the interrupt handler is called, the Status Register is
+ * read: the TXCOMP bit is clear but NACK bit is still set. The driver
+ * manage the error properly, without waiting for timeout.
+ * This case can be reproduced easyly when writing into an at24 eeprom.
+ *
+ * Besides, the TXCOMP bit is already set before the i2c transaction
+ * has been started. For read transactions, this bit is cleared when
+ * writing the START bit into the Control Register. So the
+ * corresponding interrupt can safely be enabled just after.
+ * However for write transactions managed by the CPU, we first write
+ * into THR, so TXCOMP is cleared. Then we can safely enable TXCOMP
+ * interrupt. If TXCOMP interrupt were enabled before writing into THR,
+ * the interrupt handler would be called immediately and the i2c command
+ * would be reported as completed.
+ * Also when a write transaction is managed by the DMA controller,
+ * enabling the TXCOMP interrupt in this function may lead to a race
+ * condition since we don't know whether the TXCOMP interrupt is enabled
+ * before or after the DMA has started to write into THR. So the TXCOMP
+ * interrupt is enabled later by at91_twi_write_data_dma_callback().
+ * Immediately after in that DMA callback, if the alternative command
+ * mode is not used, we still need to send the STOP condition manually
+ * writing the corresponding bit into the Control Register.
+ */
+
+ dev_dbg(dev->dev, "transfer: %s %zu bytes.\n",
+ (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
+
+ reinit_completion(&dev->cmd_complete);
+ dev->transfer_status = 0;
+
+ /* Clear pending interrupts, such as NACK. */
+ at91_twi_read(dev, AT91_TWI_SR);
+
+ if (dev->fifo_size) {
+ unsigned fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
+
+ /* Reset FIFO mode register */
+ fifo_mr &= ~(AT91_TWI_FMR_TXRDYM_MASK |
+ AT91_TWI_FMR_RXRDYM_MASK);
+ fifo_mr |= AT91_TWI_FMR_TXRDYM(AT91_TWI_ONE_DATA);
+ fifo_mr |= AT91_TWI_FMR_RXRDYM(AT91_TWI_ONE_DATA);
+ at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
+
+ /* Flush FIFOs */
+ at91_twi_write(dev, AT91_TWI_CR,
+ AT91_TWI_THRCLR | AT91_TWI_RHRCLR);
+ }
+
+ if (!dev->buf_len) {
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
+ at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
+ } else if (dev->msg->flags & I2C_M_RD) {
+ unsigned start_flags = AT91_TWI_START;
+
+ /* if only one byte is to be read, immediately stop transfer */
+ if (!dev->use_alt_cmd && dev->buf_len <= 1 &&
+ !(dev->msg->flags & I2C_M_RECV_LEN))
+ start_flags |= AT91_TWI_STOP;
+ at91_twi_write(dev, AT91_TWI_CR, start_flags);
+ /*
+ * When using dma without alternative command mode, the last
+ * byte has to be read manually in order to not send the stop
+ * command too late and then to receive extra data.
+ * In practice, there are some issues if you use the dma to
+ * read n-1 bytes because of latency.
+ * Reading n-2 bytes with dma and the two last ones manually
+ * seems to be the best solution.
+ */
+ if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
+ at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK);
+ at91_twi_read_data_dma(dev);
+ } else {
+ at91_twi_write(dev, AT91_TWI_IER,
+ AT91_TWI_TXCOMP |
+ AT91_TWI_NACK |
+ AT91_TWI_RXRDY);
+ }
+ } else {
+ if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
+ at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK);
+ at91_twi_write_data_dma(dev);
+ } else {
+ at91_twi_write_next_byte(dev);
+ at91_twi_write(dev, AT91_TWI_IER,
+ AT91_TWI_TXCOMP |
+ AT91_TWI_NACK |
+ AT91_TWI_TXRDY);
+ }
+ }
+
+ time_left = wait_for_completion_timeout(&dev->cmd_complete,
+ dev->adapter.timeout);
+ if (time_left == 0) {
+ dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR);
+ dev_err(dev->dev, "controller timed out\n");
+ at91_init_twi_bus(dev);
+ ret = -ETIMEDOUT;
+ goto error;
+ }
+ if (dev->transfer_status & AT91_TWI_NACK) {
+ dev_dbg(dev->dev, "received nack\n");
+ ret = -EREMOTEIO;
+ goto error;
+ }
+ if (dev->transfer_status & AT91_TWI_OVRE) {
+ dev_err(dev->dev, "overrun while reading\n");
+ ret = -EIO;
+ goto error;
+ }
+ if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
+ dev_err(dev->dev, "underrun while writing\n");
+ ret = -EIO;
+ goto error;
+ }
+ if ((has_alt_cmd || dev->fifo_size) &&
+ (dev->transfer_status & AT91_TWI_LOCK)) {
+ dev_err(dev->dev, "tx locked\n");
+ ret = -EIO;
+ goto error;
+ }
+ if (dev->recv_len_abort) {
+ dev_err(dev->dev, "invalid smbus block length recvd\n");
+ ret = -EPROTO;
+ goto error;
+ }
+
+ dev_dbg(dev->dev, "transfer complete\n");
+
+ return 0;
+
+error:
+ /* first stop DMA transfer if still in progress */
+ at91_twi_dma_cleanup(dev);
+ /* then flush THR/FIFO and unlock TX if locked */
+ if ((has_alt_cmd || dev->fifo_size) &&
+ (dev->transfer_status & AT91_TWI_LOCK)) {
+ dev_dbg(dev->dev, "unlock tx\n");
+ at91_twi_write(dev, AT91_TWI_CR,
+ AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
+ }
+ return ret;
+}
+
+static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
+{
+ struct at91_twi_dev *dev = i2c_get_adapdata(adap);
+ int ret;
+ unsigned int_addr_flag = 0;
+ struct i2c_msg *m_start = msg;
+ bool is_read;
+
+ dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
+
+ ret = pm_runtime_get_sync(dev->dev);
+ if (ret < 0)
+ goto out;
+
+ if (num == 2) {
+ int internal_address = 0;
+ int i;
+
+ /* 1st msg is put into the internal address, start with 2nd */
+ m_start = &msg[1];
+ for (i = 0; i < msg->len; ++i) {
+ const unsigned addr = msg->buf[msg->len - 1 - i];
+
+ internal_address |= addr << (8 * i);
+ int_addr_flag += AT91_TWI_IADRSZ_1;
+ }
+ at91_twi_write(dev, AT91_TWI_IADR, internal_address);
+ }
+
+ dev->use_alt_cmd = false;
+ is_read = (m_start->flags & I2C_M_RD);
+ if (dev->pdata->has_alt_cmd) {
+ if (m_start->len > 0 &&
+ m_start->len < AT91_I2C_MAX_ALT_CMD_DATA_SIZE) {
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMEN);
+ at91_twi_write(dev, AT91_TWI_ACR,
+ AT91_TWI_ACR_DATAL(m_start->len) |
+ ((is_read) ? AT91_TWI_ACR_DIR : 0));
+ dev->use_alt_cmd = true;
+ } else {
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMDIS);
+ }
+ }
+
+ at91_twi_write(dev, AT91_TWI_MMR,
+ (m_start->addr << 16) |
+ int_addr_flag |
+ ((!dev->use_alt_cmd && is_read) ? AT91_TWI_MREAD : 0));
+
+ dev->buf_len = m_start->len;
+ dev->buf = m_start->buf;
+ dev->msg = m_start;
+ dev->recv_len_abort = false;
+
+ ret = at91_do_twi_transfer(dev);
+
+ ret = (ret < 0) ? ret : num;
+out:
+ pm_runtime_mark_last_busy(dev->dev);
+ pm_runtime_put_autosuspend(dev->dev);
+
+ return ret;
+}
+
+/*
+ * The hardware can handle at most two messages concatenated by a
+ * repeated start via it's internal address feature.
+ */
+static const struct i2c_adapter_quirks at91_twi_quirks = {
+ .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
+ .max_comb_1st_msg_len = 3,
+};
+
+static u32 at91_twi_func(struct i2c_adapter *adapter)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
+ | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm at91_twi_algorithm = {
+ .master_xfer = at91_twi_xfer,
+ .functionality = at91_twi_func,
+};
+
+static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
+{
+ int ret = 0;
+ struct dma_slave_config slave_config;
+ struct at91_twi_dma *dma = &dev->dma;
+ enum dma_slave_buswidth addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+
+ /*
+ * The actual width of the access will be chosen in
+ * dmaengine_prep_slave_sg():
+ * for each buffer in the scatter-gather list, if its size is aligned
+ * to addr_width then addr_width accesses will be performed to transfer
+ * the buffer. On the other hand, if the buffer size is not aligned to
+ * addr_width then the buffer is transferred using single byte accesses.
+ * Please refer to the Atmel eXtended DMA controller driver.
+ * When FIFOs are used, the TXRDYM threshold can always be set to
+ * trigger the XDMAC when at least 4 data can be written into the TX
+ * FIFO, even if single byte accesses are performed.
+ * However the RXRDYM threshold must be set to fit the access width,
+ * deduced from buffer length, so the XDMAC is triggered properly to
+ * read data from the RX FIFO.
+ */
+ if (dev->fifo_size)
+ addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
+ memset(&slave_config, 0, sizeof(slave_config));
+ slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
+ slave_config.src_addr_width = addr_width;
+ slave_config.src_maxburst = 1;
+ slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
+ slave_config.dst_addr_width = addr_width;
+ slave_config.dst_maxburst = 1;
+ slave_config.device_fc = false;
+
+ dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
+ if (IS_ERR(dma->chan_tx)) {
+ ret = PTR_ERR(dma->chan_tx);
+ dma->chan_tx = NULL;
+ goto error;
+ }
+
+ dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
+ if (IS_ERR(dma->chan_rx)) {
+ ret = PTR_ERR(dma->chan_rx);
+ dma->chan_rx = NULL;
+ goto error;
+ }
+
+ slave_config.direction = DMA_MEM_TO_DEV;
+ if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
+ dev_err(dev->dev, "failed to configure tx channel\n");
+ ret = -EINVAL;
+ goto error;
+ }
+
+ slave_config.direction = DMA_DEV_TO_MEM;
+ if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
+ dev_err(dev->dev, "failed to configure rx channel\n");
+ ret = -EINVAL;
+ goto error;
+ }
+
+ sg_init_table(dma->sg, 2);
+ dma->buf_mapped = false;
+ dma->xfer_in_progress = false;
+ dev->use_dma = true;
+
+ dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
+ dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
+
+ return ret;
+
+error:
+ if (ret != -EPROBE_DEFER)
+ dev_info(dev->dev, "can't get DMA channel, continue without DMA support\n");
+ if (dma->chan_rx)
+ dma_release_channel(dma->chan_rx);
+ if (dma->chan_tx)
+ dma_release_channel(dma->chan_tx);
+ return ret;
+}
+
+int at91_twi_probe_master(struct platform_device *pdev,
+ u32 phy_addr, struct at91_twi_dev *dev)
+{
+ int rc;
+ u32 bus_clk_rate;
+
+ init_completion(&dev->cmd_complete);
+
+ rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
+ dev_name(dev->dev), dev);
+ if (rc) {
+ dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
+ return rc;
+ }
+
+ if (dev->dev->of_node) {
+ rc = at91_twi_configure_dma(dev, phy_addr);
+ if (rc == -EPROBE_DEFER) {
+ clk_disable_unprepare(dev->clk);
+ return rc;
+ }
+ }
+
+ if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
+ &dev->fifo_size)) {
+ dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
+ }
+
+ rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
+ &bus_clk_rate);
+ if (rc)
+ bus_clk_rate = DEFAULT_TWI_CLK_HZ;
+
+ at91_calc_twi_clock(dev, bus_clk_rate);
+
+ dev->adapter.algo = &at91_twi_algorithm;
+ dev->adapter.quirks = &at91_twi_quirks;
+
+ return 0;
+}
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
deleted file mode 100644
index af979b1..0000000
--- a/drivers/i2c/busses/i2c-at91.c
+++ /dev/null
@@ -1,1265 +0,0 @@
-/*
- * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
- *
- * Copyright (C) 2011 Weinmann Medical GmbH
- * Author: Nikolaus Voss <n.voss@...nmann.de>
- *
- * Evolved from original work by:
- * Copyright (C) 2004 Rick Bronson
- * Converted to 2.6 by Andrew Victor <andrew@...people.com>
- *
- * Borrowed heavily from original work by:
- * Copyright (C) 2000 Philip Edelbrock <phil@...mpy.netroedge.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- */
-
-#include <linux/clk.h>
-#include <linux/completion.h>
-#include <linux/dma-mapping.h>
-#include <linux/dmaengine.h>
-#include <linux/err.h>
-#include <linux/i2c.h>
-#include <linux/interrupt.h>
-#include <linux/io.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/platform_data/dma-atmel.h>
-#include <linux/pm_runtime.h>
-#include <linux/pinctrl/consumer.h>
-
-#define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */
-#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
-#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
-#define AUTOSUSPEND_TIMEOUT 2000
-#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
-
-/* AT91 TWI register definitions */
-#define AT91_TWI_CR 0x0000 /* Control Register */
-#define AT91_TWI_START BIT(0) /* Send a Start Condition */
-#define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */
-#define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */
-#define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */
-#define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */
-#define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */
-#define AT91_TWI_QUICK BIT(6) /* SMBus quick command */
-#define AT91_TWI_SWRST BIT(7) /* Software Reset */
-#define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */
-#define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */
-#define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */
-#define AT91_TWI_RHRCLR BIT(25) /* Receive Holding Register Clear */
-#define AT91_TWI_LOCKCLR BIT(26) /* Lock Clear */
-#define AT91_TWI_FIFOEN BIT(28) /* FIFO Enable */
-#define AT91_TWI_FIFODIS BIT(29) /* FIFO Disable */
-
-#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
-#define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
-#define AT91_TWI_MREAD BIT(12) /* Master Read Direction */
-
-#define AT91_TWI_IADR 0x000c /* Internal Address Register */
-
-#define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
-#define AT91_TWI_CWGR_HOLD_MAX 0x1f
-#define AT91_TWI_CWGR_HOLD(x) (((x) & AT91_TWI_CWGR_HOLD_MAX) << 24)
-
-#define AT91_TWI_SR 0x0020 /* Status Register */
-#define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */
-#define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */
-#define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */
-#define AT91_TWI_OVRE BIT(6) /* Overrun Error */
-#define AT91_TWI_UNRE BIT(7) /* Underrun Error */
-#define AT91_TWI_NACK BIT(8) /* Not Acknowledged */
-#define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */
-
-#define AT91_TWI_INT_MASK \
- (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK)
-
-#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
-#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
-#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
-#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
-#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
-
-#define AT91_TWI_ACR 0x0040 /* Alternative Command Register */
-#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff)
-#define AT91_TWI_ACR_DIR BIT(8)
-
-#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
-#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
-#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
-#define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4)
-#define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4)
-#define AT91_TWI_ONE_DATA 0x0
-#define AT91_TWI_TWO_DATA 0x1
-#define AT91_TWI_FOUR_DATA 0x2
-
-#define AT91_TWI_FLR 0x0054 /* FIFO Level Register */
-
-#define AT91_TWI_FSR 0x0060 /* FIFO Status Register */
-#define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */
-#define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */
-#define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */
-
-#define AT91_TWI_VER 0x00fc /* Version Register */
-
-struct at91_twi_pdata {
- unsigned clk_max_div;
- unsigned clk_offset;
- bool has_unre_flag;
- bool has_alt_cmd;
- bool has_hold_field;
- struct at_dma_slave dma_slave;
-};
-
-struct at91_twi_dma {
- struct dma_chan *chan_rx;
- struct dma_chan *chan_tx;
- struct scatterlist sg[2];
- struct dma_async_tx_descriptor *data_desc;
- enum dma_data_direction direction;
- bool buf_mapped;
- bool xfer_in_progress;
-};
-
-struct at91_twi_dev {
- struct device *dev;
- void __iomem *base;
- struct completion cmd_complete;
- struct clk *clk;
- u8 *buf;
- size_t buf_len;
- struct i2c_msg *msg;
- int irq;
- unsigned imr;
- unsigned transfer_status;
- struct i2c_adapter adapter;
- unsigned twi_cwgr_reg;
- struct at91_twi_pdata *pdata;
- bool use_dma;
- bool use_alt_cmd;
- bool recv_len_abort;
- u32 fifo_size;
- struct at91_twi_dma dma;
-};
-
-static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
-{
- return readl_relaxed(dev->base + reg);
-}
-
-static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
-{
- writel_relaxed(val, dev->base + reg);
-}
-
-static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
-{
- at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK);
-}
-
-static void at91_twi_irq_save(struct at91_twi_dev *dev)
-{
- dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
- at91_disable_twi_interrupts(dev);
-}
-
-static void at91_twi_irq_restore(struct at91_twi_dev *dev)
-{
- at91_twi_write(dev, AT91_TWI_IER, dev->imr);
-}
-
-static void at91_init_twi_bus_master(struct at91_twi_dev *dev)
-{
- /* FIFO should be enabled immediately after the software reset */
- if (dev->fifo_size)
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
- at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
-}
-
-static void at91_init_twi_bus(struct at91_twi_dev *dev)
-{
- at91_disable_twi_interrupts(dev);
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
-
- at91_init_twi_bus_master(dev);
-}
-
-/*
- * Calculate symmetric clock as stated in datasheet:
- * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
- */
-static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
-{
- int ckdiv, cdiv, div, hold = 0;
- struct at91_twi_pdata *pdata = dev->pdata;
- int offset = pdata->clk_offset;
- int max_ckdiv = pdata->clk_max_div;
- u32 twd_hold_time_ns = 0;
-
- div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
- 2 * twi_clk) - offset);
- ckdiv = fls(div >> 8);
- cdiv = div >> ckdiv;
-
- if (ckdiv > max_ckdiv) {
- dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
- ckdiv, max_ckdiv);
- ckdiv = max_ckdiv;
- cdiv = 255;
- }
-
- if (pdata->has_hold_field) {
- of_property_read_u32(dev->dev->of_node, "i2c-sda-hold-time-ns",
- &twd_hold_time_ns);
-
- /*
- * hold time = HOLD + 3 x T_peripheral_clock
- * Use clk rate in kHz to prevent overflows when computing
- * hold.
- */
- hold = DIV_ROUND_UP(twd_hold_time_ns
- * (clk_get_rate(dev->clk) / 1000), 1000000);
- hold -= 3;
- if (hold < 0)
- hold = 0;
- if (hold > AT91_TWI_CWGR_HOLD_MAX) {
- dev_warn(dev->dev,
- "HOLD field set to its maximum value (%d instead of %d)\n",
- AT91_TWI_CWGR_HOLD_MAX, hold);
- hold = AT91_TWI_CWGR_HOLD_MAX;
- }
- }
-
- dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
- | AT91_TWI_CWGR_HOLD(hold);
-
- dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns)\n",
- cdiv, ckdiv, hold, twd_hold_time_ns);
-}
-
-static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
-{
- struct at91_twi_dma *dma = &dev->dma;
-
- at91_twi_irq_save(dev);
-
- if (dma->xfer_in_progress) {
- if (dma->direction == DMA_FROM_DEVICE)
- dmaengine_terminate_all(dma->chan_rx);
- else
- dmaengine_terminate_all(dma->chan_tx);
- dma->xfer_in_progress = false;
- }
- if (dma->buf_mapped) {
- dma_unmap_single(dev->dev, sg_dma_address(&dma->sg[0]),
- dev->buf_len, dma->direction);
- dma->buf_mapped = false;
- }
-
- at91_twi_irq_restore(dev);
-}
-
-static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
-{
- if (!dev->buf_len)
- return;
-
- /* 8bit write works with and without FIFO */
- writeb_relaxed(*dev->buf, dev->base + AT91_TWI_THR);
-
- /* send stop when last byte has been written */
- if (--dev->buf_len == 0)
- if (!dev->use_alt_cmd)
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
-
- dev_dbg(dev->dev, "wrote 0x%x, to go %zu\n", *dev->buf, dev->buf_len);
-
- ++dev->buf;
-}
-
-static void at91_twi_write_data_dma_callback(void *data)
-{
- struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
-
- dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]),
- dev->buf_len, DMA_TO_DEVICE);
-
- /*
- * When this callback is called, THR/TX FIFO is likely not to be empty
- * yet. So we have to wait for TXCOMP or NACK bits to be set into the
- * Status Register to be sure that the STOP bit has been sent and the
- * transfer is completed. The NACK interrupt has already been enabled,
- * we just have to enable TXCOMP one.
- */
- at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
- if (!dev->use_alt_cmd)
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
-}
-
-static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
-{
- dma_addr_t dma_addr;
- struct dma_async_tx_descriptor *txdesc;
- struct at91_twi_dma *dma = &dev->dma;
- struct dma_chan *chan_tx = dma->chan_tx;
- unsigned int sg_len = 1;
-
- if (!dev->buf_len)
- return;
-
- dma->direction = DMA_TO_DEVICE;
-
- at91_twi_irq_save(dev);
- dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
- DMA_TO_DEVICE);
- if (dma_mapping_error(dev->dev, dma_addr)) {
- dev_err(dev->dev, "dma map failed\n");
- return;
- }
- dma->buf_mapped = true;
- at91_twi_irq_restore(dev);
-
- if (dev->fifo_size) {
- size_t part1_len, part2_len;
- struct scatterlist *sg;
- unsigned fifo_mr;
-
- sg_len = 0;
-
- part1_len = dev->buf_len & ~0x3;
- if (part1_len) {
- sg = &dma->sg[sg_len++];
- sg_dma_len(sg) = part1_len;
- sg_dma_address(sg) = dma_addr;
- }
-
- part2_len = dev->buf_len & 0x3;
- if (part2_len) {
- sg = &dma->sg[sg_len++];
- sg_dma_len(sg) = part2_len;
- sg_dma_address(sg) = dma_addr + part1_len;
- }
-
- /*
- * DMA controller is triggered when at least 4 data can be
- * written into the TX FIFO
- */
- fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
- fifo_mr &= ~AT91_TWI_FMR_TXRDYM_MASK;
- fifo_mr |= AT91_TWI_FMR_TXRDYM(AT91_TWI_FOUR_DATA);
- at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
- } else {
- sg_dma_len(&dma->sg[0]) = dev->buf_len;
- sg_dma_address(&dma->sg[0]) = dma_addr;
- }
-
- txdesc = dmaengine_prep_slave_sg(chan_tx, dma->sg, sg_len,
- DMA_MEM_TO_DEV,
- DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
- if (!txdesc) {
- dev_err(dev->dev, "dma prep slave sg failed\n");
- goto error;
- }
-
- txdesc->callback = at91_twi_write_data_dma_callback;
- txdesc->callback_param = dev;
-
- dma->xfer_in_progress = true;
- dmaengine_submit(txdesc);
- dma_async_issue_pending(chan_tx);
-
- return;
-
-error:
- at91_twi_dma_cleanup(dev);
-}
-
-static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
-{
- /*
- * If we are in this case, it means there is garbage data in RHR, so
- * delete them.
- */
- if (!dev->buf_len) {
- at91_twi_read(dev, AT91_TWI_RHR);
- return;
- }
-
- /* 8bit read works with and without FIFO */
- *dev->buf = readb_relaxed(dev->base + AT91_TWI_RHR);
- --dev->buf_len;
-
- /* return if aborting, we only needed to read RHR to clear RXRDY*/
- if (dev->recv_len_abort)
- return;
-
- /* handle I2C_SMBUS_BLOCK_DATA */
- if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
- /* ensure length byte is a valid value */
- if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
- dev->msg->flags &= ~I2C_M_RECV_LEN;
- dev->buf_len += *dev->buf;
- dev->msg->len = dev->buf_len + 1;
- dev_dbg(dev->dev, "received block length %zu\n",
- dev->buf_len);
- } else {
- /* abort and send the stop by reading one more byte */
- dev->recv_len_abort = true;
- dev->buf_len = 1;
- }
- }
-
- /* send stop if second but last byte has been read */
- if (!dev->use_alt_cmd && dev->buf_len == 1)
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
-
- dev_dbg(dev->dev, "read 0x%x, to go %zu\n", *dev->buf, dev->buf_len);
-
- ++dev->buf;
-}
-
-static void at91_twi_read_data_dma_callback(void *data)
-{
- struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
- unsigned ier = AT91_TWI_TXCOMP;
-
- dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]),
- dev->buf_len, DMA_FROM_DEVICE);
-
- if (!dev->use_alt_cmd) {
- /* The last two bytes have to be read without using dma */
- dev->buf += dev->buf_len - 2;
- dev->buf_len = 2;
- ier |= AT91_TWI_RXRDY;
- }
- at91_twi_write(dev, AT91_TWI_IER, ier);
-}
-
-static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
-{
- dma_addr_t dma_addr;
- struct dma_async_tx_descriptor *rxdesc;
- struct at91_twi_dma *dma = &dev->dma;
- struct dma_chan *chan_rx = dma->chan_rx;
- size_t buf_len;
-
- buf_len = (dev->use_alt_cmd) ? dev->buf_len : dev->buf_len - 2;
- dma->direction = DMA_FROM_DEVICE;
-
- /* Keep in mind that we won't use dma to read the last two bytes */
- at91_twi_irq_save(dev);
- dma_addr = dma_map_single(dev->dev, dev->buf, buf_len, DMA_FROM_DEVICE);
- if (dma_mapping_error(dev->dev, dma_addr)) {
- dev_err(dev->dev, "dma map failed\n");
- return;
- }
- dma->buf_mapped = true;
- at91_twi_irq_restore(dev);
-
- if (dev->fifo_size && IS_ALIGNED(buf_len, 4)) {
- unsigned fifo_mr;
-
- /*
- * DMA controller is triggered when at least 4 data can be
- * read from the RX FIFO
- */
- fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
- fifo_mr &= ~AT91_TWI_FMR_RXRDYM_MASK;
- fifo_mr |= AT91_TWI_FMR_RXRDYM(AT91_TWI_FOUR_DATA);
- at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
- }
-
- sg_dma_len(&dma->sg[0]) = buf_len;
- sg_dma_address(&dma->sg[0]) = dma_addr;
-
- rxdesc = dmaengine_prep_slave_sg(chan_rx, dma->sg, 1, DMA_DEV_TO_MEM,
- DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
- if (!rxdesc) {
- dev_err(dev->dev, "dma prep slave sg failed\n");
- goto error;
- }
-
- rxdesc->callback = at91_twi_read_data_dma_callback;
- rxdesc->callback_param = dev;
-
- dma->xfer_in_progress = true;
- dmaengine_submit(rxdesc);
- dma_async_issue_pending(dma->chan_rx);
-
- return;
-
-error:
- at91_twi_dma_cleanup(dev);
-}
-
-static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
-{
- struct at91_twi_dev *dev = dev_id;
- const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
- const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
-
- if (!irqstatus)
- return IRQ_NONE;
- /*
- * In reception, the behavior of the twi device (before sama5d2) is
- * weird. There is some magic about RXRDY flag! When a data has been
- * almost received, the reception of a new one is anticipated if there
- * is no stop command to send. That is the reason why ask for sending
- * the stop command not on the last data but on the second last one.
- *
- * Unfortunately, we could still have the RXRDY flag set even if the
- * transfer is done and we have read the last data. It might happen
- * when the i2c slave device sends too quickly data after receiving the
- * ack from the master. The data has been almost received before having
- * the order to send stop. In this case, sending the stop command could
- * cause a RXRDY interrupt with a TXCOMP one. It is better to manage
- * the RXRDY interrupt first in order to not keep garbage data in the
- * Receive Holding Register for the next transfer.
- */
- if (irqstatus & AT91_TWI_RXRDY)
- at91_twi_read_next_byte(dev);
-
- /*
- * When a NACK condition is detected, the I2C controller sets the NACK,
- * TXCOMP and TXRDY bits all together in the Status Register (SR).
- *
- * 1 - Handling NACK errors with CPU write transfer.
- *
- * In such case, we should not write the next byte into the Transmit
- * Holding Register (THR) otherwise the I2C controller would start a new
- * transfer and the I2C slave is likely to reply by another NACK.
- *
- * 2 - Handling NACK errors with DMA write transfer.
- *
- * By setting the TXRDY bit in the SR, the I2C controller also triggers
- * the DMA controller to write the next data into the THR. Then the
- * result depends on the hardware version of the I2C controller.
- *
- * 2a - Without support of the Alternative Command mode.
- *
- * This is the worst case: the DMA controller is triggered to write the
- * next data into the THR, hence starting a new transfer: the I2C slave
- * is likely to reply by another NACK.
- * Concurrently, this interrupt handler is likely to be called to manage
- * the first NACK before the I2C controller detects the second NACK and
- * sets once again the NACK bit into the SR.
- * When handling the first NACK, this interrupt handler disables the I2C
- * controller interruptions, especially the NACK interrupt.
- * Hence, the NACK bit is pending into the SR. This is why we should
- * read the SR to clear all pending interrupts at the beginning of
- * at91_do_twi_transfer() before actually starting a new transfer.
- *
- * 2b - With support of the Alternative Command mode.
- *
- * When a NACK condition is detected, the I2C controller also locks the
- * THR (and sets the LOCK bit in the SR): even though the DMA controller
- * is triggered by the TXRDY bit to write the next data into the THR,
- * this data actually won't go on the I2C bus hence a second NACK is not
- * generated.
- */
- if (irqstatus & (AT91_TWI_TXCOMP | AT91_TWI_NACK)) {
- at91_disable_twi_interrupts(dev);
- complete(&dev->cmd_complete);
- } else if (irqstatus & AT91_TWI_TXRDY) {
- at91_twi_write_next_byte(dev);
- }
-
- /* catch error flags */
- dev->transfer_status |= status;
-
- return IRQ_HANDLED;
-}
-
-static int at91_do_twi_transfer(struct at91_twi_dev *dev)
-{
- int ret;
- unsigned long time_left;
- bool has_unre_flag = dev->pdata->has_unre_flag;
- bool has_alt_cmd = dev->pdata->has_alt_cmd;
-
- /*
- * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
- * read flag but shows the state of the transmission at the time the
- * Status Register is read. According to the programmer datasheet,
- * TXCOMP is set when both holding register and internal shifter are
- * empty and STOP condition has been sent.
- * Consequently, we should enable NACK interrupt rather than TXCOMP to
- * detect transmission failure.
- * Indeed let's take the case of an i2c write command using DMA.
- * Whenever the slave doesn't acknowledge a byte, the LOCK, NACK and
- * TXCOMP bits are set together into the Status Register.
- * LOCK is a clear on write bit, which is set to prevent the DMA
- * controller from sending new data on the i2c bus after a NACK
- * condition has happened. Once locked, this i2c peripheral stops
- * triggering the DMA controller for new data but it is more than
- * likely that a new DMA transaction is already in progress, writing
- * into the Transmit Holding Register. Since the peripheral is locked,
- * these new data won't be sent to the i2c bus but they will remain
- * into the Transmit Holding Register, so TXCOMP bit is cleared.
- * Then when the interrupt handler is called, the Status Register is
- * read: the TXCOMP bit is clear but NACK bit is still set. The driver
- * manage the error properly, without waiting for timeout.
- * This case can be reproduced easyly when writing into an at24 eeprom.
- *
- * Besides, the TXCOMP bit is already set before the i2c transaction
- * has been started. For read transactions, this bit is cleared when
- * writing the START bit into the Control Register. So the
- * corresponding interrupt can safely be enabled just after.
- * However for write transactions managed by the CPU, we first write
- * into THR, so TXCOMP is cleared. Then we can safely enable TXCOMP
- * interrupt. If TXCOMP interrupt were enabled before writing into THR,
- * the interrupt handler would be called immediately and the i2c command
- * would be reported as completed.
- * Also when a write transaction is managed by the DMA controller,
- * enabling the TXCOMP interrupt in this function may lead to a race
- * condition since we don't know whether the TXCOMP interrupt is enabled
- * before or after the DMA has started to write into THR. So the TXCOMP
- * interrupt is enabled later by at91_twi_write_data_dma_callback().
- * Immediately after in that DMA callback, if the alternative command
- * mode is not used, we still need to send the STOP condition manually
- * writing the corresponding bit into the Control Register.
- */
-
- dev_dbg(dev->dev, "transfer: %s %zu bytes.\n",
- (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
-
- reinit_completion(&dev->cmd_complete);
- dev->transfer_status = 0;
-
- /* Clear pending interrupts, such as NACK. */
- at91_twi_read(dev, AT91_TWI_SR);
-
- if (dev->fifo_size) {
- unsigned fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
-
- /* Reset FIFO mode register */
- fifo_mr &= ~(AT91_TWI_FMR_TXRDYM_MASK |
- AT91_TWI_FMR_RXRDYM_MASK);
- fifo_mr |= AT91_TWI_FMR_TXRDYM(AT91_TWI_ONE_DATA);
- fifo_mr |= AT91_TWI_FMR_RXRDYM(AT91_TWI_ONE_DATA);
- at91_twi_write(dev, AT91_TWI_FMR, fifo_mr);
-
- /* Flush FIFOs */
- at91_twi_write(dev, AT91_TWI_CR,
- AT91_TWI_THRCLR | AT91_TWI_RHRCLR);
- }
-
- if (!dev->buf_len) {
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
- at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
- } else if (dev->msg->flags & I2C_M_RD) {
- unsigned start_flags = AT91_TWI_START;
-
- /* if only one byte is to be read, immediately stop transfer */
- if (!dev->use_alt_cmd && dev->buf_len <= 1 &&
- !(dev->msg->flags & I2C_M_RECV_LEN))
- start_flags |= AT91_TWI_STOP;
- at91_twi_write(dev, AT91_TWI_CR, start_flags);
- /*
- * When using dma without alternative command mode, the last
- * byte has to be read manually in order to not send the stop
- * command too late and then to receive extra data.
- * In practice, there are some issues if you use the dma to
- * read n-1 bytes because of latency.
- * Reading n-2 bytes with dma and the two last ones manually
- * seems to be the best solution.
- */
- if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
- at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK);
- at91_twi_read_data_dma(dev);
- } else {
- at91_twi_write(dev, AT91_TWI_IER,
- AT91_TWI_TXCOMP |
- AT91_TWI_NACK |
- AT91_TWI_RXRDY);
- }
- } else {
- if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
- at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK);
- at91_twi_write_data_dma(dev);
- } else {
- at91_twi_write_next_byte(dev);
- at91_twi_write(dev, AT91_TWI_IER,
- AT91_TWI_TXCOMP |
- AT91_TWI_NACK |
- AT91_TWI_TXRDY);
- }
- }
-
- time_left = wait_for_completion_timeout(&dev->cmd_complete,
- dev->adapter.timeout);
- if (time_left == 0) {
- dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR);
- dev_err(dev->dev, "controller timed out\n");
- at91_init_twi_bus(dev);
- ret = -ETIMEDOUT;
- goto error;
- }
- if (dev->transfer_status & AT91_TWI_NACK) {
- dev_dbg(dev->dev, "received nack\n");
- ret = -EREMOTEIO;
- goto error;
- }
- if (dev->transfer_status & AT91_TWI_OVRE) {
- dev_err(dev->dev, "overrun while reading\n");
- ret = -EIO;
- goto error;
- }
- if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
- dev_err(dev->dev, "underrun while writing\n");
- ret = -EIO;
- goto error;
- }
- if ((has_alt_cmd || dev->fifo_size) &&
- (dev->transfer_status & AT91_TWI_LOCK)) {
- dev_err(dev->dev, "tx locked\n");
- ret = -EIO;
- goto error;
- }
- if (dev->recv_len_abort) {
- dev_err(dev->dev, "invalid smbus block length recvd\n");
- ret = -EPROTO;
- goto error;
- }
-
- dev_dbg(dev->dev, "transfer complete\n");
-
- return 0;
-
-error:
- /* first stop DMA transfer if still in progress */
- at91_twi_dma_cleanup(dev);
- /* then flush THR/FIFO and unlock TX if locked */
- if ((has_alt_cmd || dev->fifo_size) &&
- (dev->transfer_status & AT91_TWI_LOCK)) {
- dev_dbg(dev->dev, "unlock tx\n");
- at91_twi_write(dev, AT91_TWI_CR,
- AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
- }
- return ret;
-}
-
-static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
-{
- struct at91_twi_dev *dev = i2c_get_adapdata(adap);
- int ret;
- unsigned int_addr_flag = 0;
- struct i2c_msg *m_start = msg;
- bool is_read;
-
- dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
-
- ret = pm_runtime_get_sync(dev->dev);
- if (ret < 0)
- goto out;
-
- if (num == 2) {
- int internal_address = 0;
- int i;
-
- /* 1st msg is put into the internal address, start with 2nd */
- m_start = &msg[1];
- for (i = 0; i < msg->len; ++i) {
- const unsigned addr = msg->buf[msg->len - 1 - i];
-
- internal_address |= addr << (8 * i);
- int_addr_flag += AT91_TWI_IADRSZ_1;
- }
- at91_twi_write(dev, AT91_TWI_IADR, internal_address);
- }
-
- dev->use_alt_cmd = false;
- is_read = (m_start->flags & I2C_M_RD);
- if (dev->pdata->has_alt_cmd) {
- if (m_start->len > 0 &&
- m_start->len < AT91_I2C_MAX_ALT_CMD_DATA_SIZE) {
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMEN);
- at91_twi_write(dev, AT91_TWI_ACR,
- AT91_TWI_ACR_DATAL(m_start->len) |
- ((is_read) ? AT91_TWI_ACR_DIR : 0));
- dev->use_alt_cmd = true;
- } else {
- at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMDIS);
- }
- }
-
- at91_twi_write(dev, AT91_TWI_MMR,
- (m_start->addr << 16) |
- int_addr_flag |
- ((!dev->use_alt_cmd && is_read) ? AT91_TWI_MREAD : 0));
-
- dev->buf_len = m_start->len;
- dev->buf = m_start->buf;
- dev->msg = m_start;
- dev->recv_len_abort = false;
-
- ret = at91_do_twi_transfer(dev);
-
- ret = (ret < 0) ? ret : num;
-out:
- pm_runtime_mark_last_busy(dev->dev);
- pm_runtime_put_autosuspend(dev->dev);
-
- return ret;
-}
-
-/*
- * The hardware can handle at most two messages concatenated by a
- * repeated start via it's internal address feature.
- */
-static const struct i2c_adapter_quirks at91_twi_quirks = {
- .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
- .max_comb_1st_msg_len = 3,
-};
-
-static u32 at91_twi_func(struct i2c_adapter *adapter)
-{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
- | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
-}
-
-static const struct i2c_algorithm at91_twi_algorithm = {
- .master_xfer = at91_twi_xfer,
- .functionality = at91_twi_func,
-};
-
-static struct at91_twi_pdata at91rm9200_config = {
- .clk_max_div = 5,
- .clk_offset = 3,
- .has_unre_flag = true,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static struct at91_twi_pdata at91sam9261_config = {
- .clk_max_div = 5,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static struct at91_twi_pdata at91sam9260_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static struct at91_twi_pdata at91sam9g20_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static struct at91_twi_pdata at91sam9g10_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static const struct platform_device_id at91_twi_devtypes[] = {
- {
- .name = "i2c-at91rm9200",
- .driver_data = (unsigned long) &at91rm9200_config,
- }, {
- .name = "i2c-at91sam9261",
- .driver_data = (unsigned long) &at91sam9261_config,
- }, {
- .name = "i2c-at91sam9260",
- .driver_data = (unsigned long) &at91sam9260_config,
- }, {
- .name = "i2c-at91sam9g20",
- .driver_data = (unsigned long) &at91sam9g20_config,
- }, {
- .name = "i2c-at91sam9g10",
- .driver_data = (unsigned long) &at91sam9g10_config,
- }, {
- /* sentinel */
- }
-};
-
-#if defined(CONFIG_OF)
-static struct at91_twi_pdata at91sam9x5_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = false,
-};
-
-static struct at91_twi_pdata sama5d4_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = false,
- .has_alt_cmd = false,
- .has_hold_field = true,
-};
-
-static struct at91_twi_pdata sama5d2_config = {
- .clk_max_div = 7,
- .clk_offset = 4,
- .has_unre_flag = true,
- .has_alt_cmd = true,
- .has_hold_field = true,
-};
-
-static const struct of_device_id atmel_twi_dt_ids[] = {
- {
- .compatible = "atmel,at91rm9200-i2c",
- .data = &at91rm9200_config,
- } , {
- .compatible = "atmel,at91sam9260-i2c",
- .data = &at91sam9260_config,
- } , {
- .compatible = "atmel,at91sam9261-i2c",
- .data = &at91sam9261_config,
- } , {
- .compatible = "atmel,at91sam9g20-i2c",
- .data = &at91sam9g20_config,
- } , {
- .compatible = "atmel,at91sam9g10-i2c",
- .data = &at91sam9g10_config,
- }, {
- .compatible = "atmel,at91sam9x5-i2c",
- .data = &at91sam9x5_config,
- }, {
- .compatible = "atmel,sama5d4-i2c",
- .data = &sama5d4_config,
- }, {
- .compatible = "atmel,sama5d2-i2c",
- .data = &sama5d2_config,
- }, {
- /* sentinel */
- }
-};
-MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
-#endif
-
-static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
-{
- int ret = 0;
- struct dma_slave_config slave_config;
- struct at91_twi_dma *dma = &dev->dma;
- enum dma_slave_buswidth addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-
- /*
- * The actual width of the access will be chosen in
- * dmaengine_prep_slave_sg():
- * for each buffer in the scatter-gather list, if its size is aligned
- * to addr_width then addr_width accesses will be performed to transfer
- * the buffer. On the other hand, if the buffer size is not aligned to
- * addr_width then the buffer is transferred using single byte accesses.
- * Please refer to the Atmel eXtended DMA controller driver.
- * When FIFOs are used, the TXRDYM threshold can always be set to
- * trigger the XDMAC when at least 4 data can be written into the TX
- * FIFO, even if single byte accesses are performed.
- * However the RXRDYM threshold must be set to fit the access width,
- * deduced from buffer length, so the XDMAC is triggered properly to
- * read data from the RX FIFO.
- */
- if (dev->fifo_size)
- addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-
- memset(&slave_config, 0, sizeof(slave_config));
- slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
- slave_config.src_addr_width = addr_width;
- slave_config.src_maxburst = 1;
- slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
- slave_config.dst_addr_width = addr_width;
- slave_config.dst_maxburst = 1;
- slave_config.device_fc = false;
-
- dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
- if (IS_ERR(dma->chan_tx)) {
- ret = PTR_ERR(dma->chan_tx);
- dma->chan_tx = NULL;
- goto error;
- }
-
- dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
- if (IS_ERR(dma->chan_rx)) {
- ret = PTR_ERR(dma->chan_rx);
- dma->chan_rx = NULL;
- goto error;
- }
-
- slave_config.direction = DMA_MEM_TO_DEV;
- if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
- dev_err(dev->dev, "failed to configure tx channel\n");
- ret = -EINVAL;
- goto error;
- }
-
- slave_config.direction = DMA_DEV_TO_MEM;
- if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
- dev_err(dev->dev, "failed to configure rx channel\n");
- ret = -EINVAL;
- goto error;
- }
-
- sg_init_table(dma->sg, 2);
- dma->buf_mapped = false;
- dma->xfer_in_progress = false;
- dev->use_dma = true;
-
- dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
- dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
-
- return ret;
-
-error:
- if (ret != -EPROBE_DEFER)
- dev_info(dev->dev, "can't get DMA channel, continue without DMA support\n");
- if (dma->chan_rx)
- dma_release_channel(dma->chan_rx);
- if (dma->chan_tx)
- dma_release_channel(dma->chan_tx);
- return ret;
-}
-
-static struct at91_twi_pdata *at91_twi_get_driver_data(
- struct platform_device *pdev)
-{
- if (pdev->dev.of_node) {
- const struct of_device_id *match;
- match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
- if (!match)
- return NULL;
- return (struct at91_twi_pdata *)match->data;
- }
- return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
-}
-
-static int at91_twi_probe_master(struct platform_device *pdev,
- u32 phy_addr, struct at91_twi_dev *dev)
-{
- int rc;
- u32 bus_clk_rate;
-
- init_completion(&dev->cmd_complete);
-
- rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
- dev_name(dev->dev), dev);
- if (rc) {
- dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
- return rc;
- }
-
- if (dev->dev->of_node) {
- rc = at91_twi_configure_dma(dev, phy_addr);
- if (rc == -EPROBE_DEFER) {
- clk_disable_unprepare(dev->clk);
- return rc;
- }
- }
-
- if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
- &dev->fifo_size)) {
- dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
- }
-
- rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
- &bus_clk_rate);
- if (rc)
- bus_clk_rate = DEFAULT_TWI_CLK_HZ;
-
- at91_calc_twi_clock(dev, bus_clk_rate);
-
- dev->adapter.algo = &at91_twi_algorithm;
- dev->adapter.quirks = &at91_twi_quirks;
-
- return 0;
-}
-
-static int at91_twi_probe(struct platform_device *pdev)
-{
- struct at91_twi_dev *dev;
- struct resource *mem;
- int rc;
- u32 phy_addr;
-
- dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
- if (!dev)
- return -ENOMEM;
-
- dev->dev = &pdev->dev;
-
- mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!mem)
- return -ENODEV;
- phy_addr = mem->start;
-
- dev->pdata = at91_twi_get_driver_data(pdev);
- if (!dev->pdata)
- return -ENODEV;
-
- dev->base = devm_ioremap_resource(&pdev->dev, mem);
- if (IS_ERR(dev->base))
- return PTR_ERR(dev->base);
-
- dev->irq = platform_get_irq(pdev, 0);
- if (dev->irq < 0)
- return dev->irq;
-
- platform_set_drvdata(pdev, dev);
-
- dev->clk = devm_clk_get(dev->dev, NULL);
- if (IS_ERR(dev->clk)) {
- dev_err(dev->dev, "no clock defined\n");
- return -ENODEV;
- }
- rc = clk_prepare_enable(dev->clk);
- if (rc)
- return rc;
-
- snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
- i2c_set_adapdata(&dev->adapter, dev);
- dev->adapter.owner = THIS_MODULE;
- dev->adapter.class = I2C_CLASS_DEPRECATED;
- dev->adapter.dev.parent = dev->dev;
- dev->adapter.nr = pdev->id;
- dev->adapter.timeout = AT91_I2C_TIMEOUT;
- dev->adapter.dev.of_node = pdev->dev.of_node;
-
- rc = at91_twi_probe_master(pdev, phy_addr, dev);
- if (rc)
- return rc;
-
- at91_init_twi_bus(dev);
-
- pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
- pm_runtime_use_autosuspend(dev->dev);
- pm_runtime_set_active(dev->dev);
- pm_runtime_enable(dev->dev);
-
- rc = i2c_add_numbered_adapter(&dev->adapter);
- if (rc) {
- clk_disable_unprepare(dev->clk);
-
- pm_runtime_disable(dev->dev);
- pm_runtime_set_suspended(dev->dev);
-
- return rc;
- }
-
- dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
- at91_twi_read(dev, AT91_TWI_VER));
- return 0;
-}
-
-static int at91_twi_remove(struct platform_device *pdev)
-{
- struct at91_twi_dev *dev = platform_get_drvdata(pdev);
-
- i2c_del_adapter(&dev->adapter);
- clk_disable_unprepare(dev->clk);
-
- pm_runtime_disable(dev->dev);
- pm_runtime_set_suspended(dev->dev);
-
- return 0;
-}
-
-#ifdef CONFIG_PM
-
-static int at91_twi_runtime_suspend(struct device *dev)
-{
- struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
-
- clk_disable_unprepare(twi_dev->clk);
-
- pinctrl_pm_select_sleep_state(dev);
-
- return 0;
-}
-
-static int at91_twi_runtime_resume(struct device *dev)
-{
- struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
-
- pinctrl_pm_select_default_state(dev);
-
- return clk_prepare_enable(twi_dev->clk);
-}
-
-static int at91_twi_suspend_noirq(struct device *dev)
-{
- if (!pm_runtime_status_suspended(dev))
- at91_twi_runtime_suspend(dev);
-
- return 0;
-}
-
-static int at91_twi_resume_noirq(struct device *dev)
-{
- struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
- int ret;
-
- if (!pm_runtime_status_suspended(dev)) {
- ret = at91_twi_runtime_resume(dev);
- if (ret)
- return ret;
- }
-
- pm_runtime_mark_last_busy(dev);
- pm_request_autosuspend(dev);
-
- at91_init_twi_bus(twi_dev);
-
- return 0;
-}
-
-static const struct dev_pm_ops at91_twi_pm = {
- .suspend_noirq = at91_twi_suspend_noirq,
- .resume_noirq = at91_twi_resume_noirq,
- .runtime_suspend = at91_twi_runtime_suspend,
- .runtime_resume = at91_twi_runtime_resume,
-};
-
-#define at91_twi_pm_ops (&at91_twi_pm)
-#else
-#define at91_twi_pm_ops NULL
-#endif
-
-static struct platform_driver at91_twi_driver = {
- .probe = at91_twi_probe,
- .remove = at91_twi_remove,
- .id_table = at91_twi_devtypes,
- .driver = {
- .name = "at91_i2c",
- .of_match_table = of_match_ptr(atmel_twi_dt_ids),
- .pm = at91_twi_pm_ops,
- },
-};
-
-static int __init at91_twi_init(void)
-{
- return platform_driver_register(&at91_twi_driver);
-}
-
-static void __exit at91_twi_exit(void)
-{
- platform_driver_unregister(&at91_twi_driver);
-}
-
-subsys_initcall(at91_twi_init);
-module_exit(at91_twi_exit);
-
-MODULE_AUTHOR("Nikolaus Voss <n.voss@...nmann.de>");
-MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:at91_i2c");
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
new file mode 100644
index 0000000..555b167
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -0,0 +1,151 @@
+/*
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2011 Weinmann Medical GmbH
+ * Author: Nikolaus Voss <n.voss@...nmann.de>
+ *
+ * Evolved from original work by:
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor <andrew@...people.com>
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock <phil@...mpy.netroedge.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/i2c.h>
+#include <linux/platform_data/dma-atmel.h>
+#include <linux/platform_device.h>
+
+#define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */
+#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
+#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
+#define AUTOSUSPEND_TIMEOUT 2000
+#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
+
+/* AT91 TWI register definitions */
+#define AT91_TWI_CR 0x0000 /* Control Register */
+#define AT91_TWI_START BIT(0) /* Send a Start Condition */
+#define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */
+#define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */
+#define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */
+#define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */
+#define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */
+#define AT91_TWI_QUICK BIT(6) /* SMBus quick command */
+#define AT91_TWI_SWRST BIT(7) /* Software Reset */
+#define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */
+#define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */
+#define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */
+#define AT91_TWI_RHRCLR BIT(25) /* Receive Holding Register Clear */
+#define AT91_TWI_LOCKCLR BIT(26) /* Lock Clear */
+#define AT91_TWI_FIFOEN BIT(28) /* FIFO Enable */
+#define AT91_TWI_FIFODIS BIT(29) /* FIFO Disable */
+
+#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
+#define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
+#define AT91_TWI_MREAD BIT(12) /* Master Read Direction */
+
+#define AT91_TWI_IADR 0x000c /* Internal Address Register */
+
+#define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
+#define AT91_TWI_CWGR_HOLD_MAX 0x1f
+#define AT91_TWI_CWGR_HOLD(x) (((x) & AT91_TWI_CWGR_HOLD_MAX) << 24)
+
+#define AT91_TWI_SR 0x0020 /* Status Register */
+#define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */
+#define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */
+#define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */
+#define AT91_TWI_OVRE BIT(6) /* Overrun Error */
+#define AT91_TWI_UNRE BIT(7) /* Underrun Error */
+#define AT91_TWI_NACK BIT(8) /* Not Acknowledged */
+#define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */
+
+#define AT91_TWI_INT_MASK \
+ (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK)
+
+#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
+#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
+#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
+#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
+#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
+
+#define AT91_TWI_ACR 0x0040 /* Alternative Command Register */
+#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff)
+#define AT91_TWI_ACR_DIR BIT(8)
+
+#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
+#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
+#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
+#define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4)
+#define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4)
+#define AT91_TWI_ONE_DATA 0x0
+#define AT91_TWI_TWO_DATA 0x1
+#define AT91_TWI_FOUR_DATA 0x2
+
+#define AT91_TWI_FLR 0x0054 /* FIFO Level Register */
+
+#define AT91_TWI_FSR 0x0060 /* FIFO Status Register */
+#define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */
+#define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */
+#define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */
+
+#define AT91_TWI_VER 0x00fc /* Version Register */
+
+struct at91_twi_pdata {
+ unsigned clk_max_div;
+ unsigned clk_offset;
+ bool has_unre_flag;
+ bool has_alt_cmd;
+ bool has_hold_field;
+ struct at_dma_slave dma_slave;
+};
+
+struct at91_twi_dma {
+ struct dma_chan *chan_rx;
+ struct dma_chan *chan_tx;
+ struct scatterlist sg[2];
+ struct dma_async_tx_descriptor *data_desc;
+ enum dma_data_direction direction;
+ bool buf_mapped;
+ bool xfer_in_progress;
+};
+
+struct at91_twi_dev {
+ struct device *dev;
+ void __iomem *base;
+ struct completion cmd_complete;
+ struct clk *clk;
+ u8 *buf;
+ size_t buf_len;
+ struct i2c_msg *msg;
+ int irq;
+ unsigned imr;
+ unsigned transfer_status;
+ struct i2c_adapter adapter;
+ unsigned twi_cwgr_reg;
+ struct at91_twi_pdata *pdata;
+ bool use_dma;
+ bool use_alt_cmd;
+ bool recv_len_abort;
+ u32 fifo_size;
+ struct at91_twi_dma dma;
+};
+
+unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);
+void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val);
+void at91_disable_twi_interrupts(struct at91_twi_dev *dev);
+void at91_twi_irq_save(struct at91_twi_dev *dev);
+void at91_twi_irq_restore(struct at91_twi_dev *dev);
+void at91_init_twi_bus(struct at91_twi_dev *dev);
+
+void at91_init_twi_bus_master(struct at91_twi_dev *dev);
+int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
+ struct at91_twi_dev *dev);
--
2.7.4
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