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Message-Id: <1350052469-27802-3-git-send-email-larsi@wh2.tu-dresden.de>
Date: Fri, 12 Oct 2012 16:34:28 +0200
From: Lars Poeschel <larsi@....tu-dresden.de>
To: sameo@...ux.intel.com
Cc: linux-kernel@...r.kernel.org, jic23@....ac.uk, khali@...ux-fr.org,
ben-linux@...ff.org, w.sang@...gutronix.de,
grant.likely@...retlab.ca, linus.walleij@...aro.org,
Lars Poeschel <poeschel@...onage.de>
Subject: [PATCH v2 3/4] i2c: add viperboard i2c master driver
From: Lars Poeschel <poeschel@...onage.de>
This adds the mfd cell to use the i2c part of the Nano River Technologies
viperboard as i2c master.
Signed-off-by: Lars Poeschel <poeschel@...onage.de>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-viperboard.c | 442 +++++++++++++++++++++++++++++++++++
drivers/mfd/viperboard.c | 3 +
4 files changed, 456 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-viperboard.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 42d9fdd..48344cb 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -803,6 +803,16 @@ config I2C_TINY_USB
This driver can also be built as a module. If so, the module
will be called i2c-tiny-usb.
+config I2C_VIPERBOARD
+ tristate "Viperboard I2C master support"
+ depends on MFD_VIPERBOARD && USB
+ help
+ Say yes here to access the I2C part of the Nano River
+ Technologies Viperboard as I2C master.
+ See viperboard API specification and Nano
+ River Tech's viperboard.h for detailed meaning
+ of the module parameters.
+
comment "Other I2C/SMBus bus drivers"
config I2C_ACORN
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 37c4182..cc3a376 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o
obj-$(CONFIG_I2C_TAOS_EVM) += i2c-taos-evm.o
obj-$(CONFIG_I2C_TINY_USB) += i2c-tiny-usb.o
+obj-$(CONFIG_I2C_VIPERBOARD) += i2c-viperboard.o
# Other I2C/SMBus bus drivers
obj-$(CONFIG_I2C_ACORN) += i2c-acorn.o
diff --git a/drivers/i2c/busses/i2c-viperboard.c b/drivers/i2c/busses/i2c-viperboard.c
new file mode 100644
index 0000000..c8da2a7
--- /dev/null
+++ b/drivers/i2c/busses/i2c-viperboard.c
@@ -0,0 +1,442 @@
+/*
+ * Nano River Technologies viperboard i2c master driver
+ *
+ * (C) 2012 by Lemonage GmbH
+ * Author: Lars Poeschel <poeschel@...onage.de>
+ * All rights reserved.
+ *
+ * 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/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#include <linux/usb.h>
+#include <linux/i2c.h>
+
+#include <linux/mfd/viperboard.h>
+
+struct vprbrd_i2c {
+ struct i2c_adapter i2c;
+};
+
+/* i2c bus frequency module parameter */
+static unsigned char i2c_bus_freq = 6;
+module_param(i2c_bus_freq, byte, 0);
+MODULE_PARM_DESC(i2c_bus_freq, "i2c bus frequency (default is 6 for 100kHz)");
+
+static int vprbrd_i2c_status(struct i2c_adapter *i2c,
+ struct vprbrd_i2c_status *status, bool prev_error)
+{
+ u16 bytes_xfer;
+ int ret;
+ struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
+
+ /* check for protocol error */
+ bytes_xfer = sizeof(struct vprbrd_i2c_status);
+
+ ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
+ 0xe9, 0xc0, 0x0000, 0x0000, status, bytes_xfer, 100);
+
+ if (ret != bytes_xfer)
+ prev_error = true;
+
+ if (prev_error) {
+ dev_err(&i2c->dev, "failure in usb communication\n");
+ return -EREMOTEIO;
+ }
+
+ dev_dbg(&i2c->dev, " status = %d\n", status->status);
+ if (status->status != 0x00) {
+ dev_err(&i2c->dev, "failure: i2c protocol error\n");
+ return -EPROTO;
+ }
+ return 0;
+}
+
+static int vprbrd_i2c_receive(struct usb_device *usb_dev,
+ struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)
+{
+ int ret, bytes_actual;
+ int error = 0;
+
+ /* send the read request */
+ ret = usb_bulk_msg(usb_dev,
+ usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,
+ sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual, 100);
+
+ if ((ret < 0)
+ || (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {
+ dev_err(&usb_dev->dev, "failure transmitting usb\n");
+ error = -EREMOTEIO;
+ }
+
+ /* read the actual data */
+ ret = usb_bulk_msg(usb_dev,
+ usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,
+ bytes_xfer, &bytes_actual, 100);
+
+ if ((ret < 0) || (bytes_xfer != bytes_actual)) {
+ dev_err(&usb_dev->dev, "failure receiving usb\n");
+ error = -EREMOTEIO;
+ }
+ return error;
+}
+
+static int vprbrd_i2c_addr(struct usb_device *usb_dev,
+ struct vprbrd_i2c_addr_msg *amsg)
+{
+ int ret, bytes_actual;
+
+ ret = usb_bulk_msg(usb_dev,
+ usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,
+ sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual, 100);
+
+ if ((ret < 0) ||
+ (sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {
+ dev_err(&usb_dev->dev, "failure transmitting usb\n");
+ return -EREMOTEIO;
+ }
+ return 0;
+}
+
+static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
+{
+ int ret;
+ u16 remain_len, bytes_xfer, len1, len2,
+ start = 0x0000;
+ struct vprbrd_i2c_read_msg *rmsg =
+ (struct vprbrd_i2c_read_msg *)vb->buf;
+
+ remain_len = msg->len;
+ rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
+ while (remain_len > 0) {
+ rmsg->header.addr = cpu_to_le16(start + 0x4000);
+ if (remain_len <= 255) {
+ len1 = remain_len;
+ len2 = 0x00;
+ rmsg->header.len0 = remain_len;
+ rmsg->header.len1 = 0x00;
+ rmsg->header.len2 = 0x00;
+ rmsg->header.len3 = 0x00;
+ rmsg->header.len4 = 0x00;
+ rmsg->header.len5 = 0x00;
+ remain_len = 0;
+ } else if (remain_len <= 510) {
+ len1 = remain_len;
+ len2 = 0x00;
+ rmsg->header.len0 = remain_len - 255;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0x00;
+ rmsg->header.len3 = 0x00;
+ rmsg->header.len4 = 0x00;
+ rmsg->header.len5 = 0x00;
+ remain_len = 0;
+ } else if (remain_len <= 512) {
+ len1 = remain_len;
+ len2 = 0x00;
+ rmsg->header.len0 = remain_len - 510;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0xff;
+ rmsg->header.len3 = 0x00;
+ rmsg->header.len4 = 0x00;
+ rmsg->header.len5 = 0x00;
+ remain_len = 0;
+ } else if (remain_len <= 767) {
+ len1 = 512;
+ len2 = remain_len - 512;
+ rmsg->header.len0 = 0x02;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0xff;
+ rmsg->header.len3 = remain_len - 512;
+ rmsg->header.len4 = 0x00;
+ rmsg->header.len5 = 0x00;
+ bytes_xfer = remain_len;
+ remain_len = 0;
+ } else if (remain_len <= 1022) {
+ len1 = 512;
+ len2 = remain_len - 512;
+ rmsg->header.len0 = 0x02;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0xff;
+ rmsg->header.len3 = remain_len - 767;
+ rmsg->header.len4 = 0xff;
+ rmsg->header.len5 = 0x00;
+ remain_len = 0;
+ } else if (remain_len <= 1024) {
+ len1 = 512;
+ len2 = remain_len - 512;
+ rmsg->header.len0 = 0x02;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0xff;
+ rmsg->header.len3 = remain_len - 1022;
+ rmsg->header.len4 = 0xff;
+ rmsg->header.len5 = 0xff;
+ remain_len = 0;
+ } else {
+ len1 = 512;
+ len2 = 512;
+ rmsg->header.len0 = 0x02;
+ rmsg->header.len1 = 0xff;
+ rmsg->header.len2 = 0xff;
+ rmsg->header.len3 = 0x02;
+ rmsg->header.len4 = 0xff;
+ rmsg->header.len5 = 0xff;
+ remain_len -= 1024;
+ start += 1024;
+ }
+ rmsg->header.tf1 = cpu_to_le16(len1);
+ rmsg->header.tf2 = cpu_to_le16(len2);
+
+ /* first read transfer */
+ ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
+ if (ret < 0)
+ return ret;
+ /* copy the received data */
+ memcpy(msg->buf + start, rmsg, len1);
+
+ /* second read transfer if neccessary */
+ if (len2 > 0) {
+ ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
+ if (ret < 0)
+ return ret;
+ /* copy the received data */
+ memcpy(msg->buf + start + 512, rmsg, len2);
+ }
+ }
+ return 0;
+}
+
+static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)
+{
+ int ret, bytes_actual;
+ u16 remain_len, bytes_xfer,
+ start = 0x0000;
+ struct vprbrd_i2c_write_msg *wmsg =
+ (struct vprbrd_i2c_write_msg *)vb->buf;
+
+ remain_len = msg->len;
+ wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;
+ wmsg->header.last = 0x00;
+ wmsg->header.chan = 0x00;
+ wmsg->header.spi = 0x0000;
+ while (remain_len > 0) {
+ wmsg->header.addr = cpu_to_le16(start + 0x4000);
+ if (remain_len > 503) {
+ wmsg->header.len1 = 0xff;
+ wmsg->header.len2 = 0xf8;
+ remain_len -= 503;
+ bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);
+ start += 503;
+ } else if (remain_len > 255) {
+ wmsg->header.len1 = 0xff;
+ wmsg->header.len2 = (remain_len - 255);
+ bytes_xfer = remain_len +
+ sizeof(struct vprbrd_i2c_write_hdr);
+ remain_len = 0;
+ } else {
+ wmsg->header.len1 = remain_len;
+ wmsg->header.len2 = 0x00;
+ bytes_xfer = remain_len +
+ sizeof(struct vprbrd_i2c_write_hdr);
+ remain_len = 0;
+ }
+ memcpy(wmsg->data, msg->buf + start,
+ bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));
+
+ ret = usb_bulk_msg(vb->usb_dev,
+ usb_sndbulkpipe(vb->usb_dev,
+ VPRBRD_EP_OUT), wmsg,
+ bytes_xfer, &bytes_actual, 100);
+ if ((ret < 0) || (bytes_xfer != bytes_actual))
+ return -EREMOTEIO;
+ }
+ return 0;
+}
+
+static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
+ int num)
+{
+ struct i2c_msg *pmsg;
+ int i, ret,
+ error = 0;
+ struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
+ struct vprbrd_i2c_addr_msg *amsg =
+ (struct vprbrd_i2c_addr_msg *)vb->buf;
+ struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;
+
+ dev_dbg(&i2c->dev, "master xfer %d messages:\n", num);
+
+ for (i = 0 ; i < num ; i++) {
+ pmsg = &msgs[i];
+
+ dev_dbg(&i2c->dev,
+ " %d: %s (flags %d) %d bytes to 0x%02x\n",
+ i, pmsg->flags & I2C_M_RD ? "read" : "write",
+ pmsg->flags, pmsg->len, pmsg->addr);
+
+ /* msgs longer than 2048 bytes are not supported by adapter */
+ if (pmsg->len > 2048)
+ return -EINVAL;
+
+ mutex_lock(&vb->lock);
+ /* directly send the message */
+ if (pmsg->flags & I2C_M_RD) {
+ /* read data */
+ amsg->cmd = VPRBRD_I2C_CMD_ADDR;
+ amsg->unknown2 = 0x00;
+ amsg->unknown3 = 0x00;
+ amsg->addr = pmsg->addr;
+ amsg->unknown1 = 0x01;
+ amsg->len = cpu_to_le16(pmsg->len);
+ /* send the addr and len, we're interested to board */
+ ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
+ if (ret < 0)
+ error = ret;
+
+ ret = vprbrd_i2c_read(vb, pmsg);
+ if (ret < 0)
+ error = ret;
+
+ ret = vprbrd_i2c_status(i2c, smsg, error);
+ if (ret < 0)
+ error = ret;
+ /* in case of protocol error, return the error */
+ if (error < 0)
+ goto error;
+ } else {
+ /* write data */
+ ret = vprbrd_i2c_write(vb, pmsg);
+
+ amsg->cmd = VPRBRD_I2C_CMD_ADDR;
+ amsg->unknown2 = 0x00;
+ amsg->unknown3 = 0x00;
+ amsg->addr = pmsg->addr;
+ amsg->unknown1 = 0x00;
+ amsg->len = cpu_to_le16(pmsg->len);
+ /* send the addr, the data goes to to board */
+ ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
+ if (ret < 0)
+ error = ret;
+
+ ret = vprbrd_i2c_status(i2c, smsg, error);
+ if (ret < 0)
+ error = ret;
+
+ if (error < 0)
+ goto error;
+ }
+ mutex_unlock(&vb->lock);
+ }
+ return 0;
+error:
+ mutex_unlock(&vb->lock);
+ return error;
+}
+
+static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+/* This is the actual algorithm we define */
+static const struct i2c_algorithm vprbrd_algorithm = {
+ .master_xfer = vprbrd_i2c_xfer,
+ .functionality = vprbrd_i2c_func,
+};
+
+static int __devinit vprbrd_i2c_probe(struct platform_device *pdev)
+{
+ struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
+ struct vprbrd_i2c *vb_i2c;
+ int ret;
+ int pipe;
+
+ vb_i2c = kzalloc(sizeof(*vb_i2c), GFP_KERNEL);
+ if (vb_i2c == NULL)
+ return -ENOMEM;
+
+ /* setup i2c adapter description */
+ vb_i2c->i2c.owner = THIS_MODULE;
+ vb_i2c->i2c.class = I2C_CLASS_HWMON;
+ vb_i2c->i2c.algo = &vprbrd_algorithm;
+ vb_i2c->i2c.algo_data = vb;
+ snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),
+ "viperboard at bus %03d device %03d",
+ vb->usb_dev->bus->busnum, vb->usb_dev->devnum);
+
+ /* setting the bus frequency */
+ if ((i2c_bus_freq <= VPRBRD_I2C_FREQ_10KHZ)
+ && (i2c_bus_freq >= VPRBRD_I2C_FREQ_6MHZ)) {
+ pipe = usb_sndctrlpipe(vb->usb_dev, 0);
+ ret = usb_control_msg(vb->usb_dev, pipe, 0xe6, 0x40,
+ 0x0000, 0x0000, &i2c_bus_freq, 1, 100);
+ if (ret != 1) {
+ dev_err(&vb_i2c->i2c.dev,
+ "failure setting i2c_bus_freq to %d\n", i2c_bus_freq);
+ ret = -EIO;
+ goto error;
+ }
+ } else {
+ dev_err(&vb_i2c->i2c.dev,
+ "invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);
+ ret = -EIO;
+ goto error;
+ }
+
+ vb_i2c->i2c.dev.parent = &pdev->dev;
+
+ /* attach to i2c layer */
+ i2c_add_adapter(&vb_i2c->i2c);
+
+ platform_set_drvdata(pdev, vb_i2c);
+
+ return 0;
+
+error:
+ kfree(vb_i2c);
+ return ret;
+}
+
+static int __devexit vprbrd_i2c_remove(struct platform_device *pdev)
+{
+ struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = i2c_del_adapter(&vb_i2c->i2c);
+
+ return ret;
+}
+
+static struct platform_driver vprbrd_i2c_driver = {
+ .driver.name = "viperboard-i2c",
+ .driver.owner = THIS_MODULE,
+ .probe = vprbrd_i2c_probe,
+ .remove = __devexit_p(vprbrd_i2c_remove),
+};
+
+static int __init vprbrd_i2c_init(void)
+{
+ return platform_driver_register(&vprbrd_i2c_driver);
+}
+subsys_initcall(vprbrd_i2c_init);
+
+static void __exit vprbrd_i2c_exit(void)
+{
+ platform_driver_unregister(&vprbrd_i2c_driver);
+}
+module_exit(vprbrd_i2c_exit);
+
+MODULE_AUTHOR("Lars Poeschel <poeschel@...onage.de>");
+MODULE_DESCRIPTION("I2C master driver for Nano River Techs Viperboard");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:viperboard-i2c");
diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c
index 09558e7..a25e07e 100644
--- a/drivers/mfd/viperboard.c
+++ b/drivers/mfd/viperboard.c
@@ -52,6 +52,9 @@ static struct mfd_cell vprbrd_devs[] = {
{
.name = "viperboard-gpio",
},
+ {
+ .name = "viperboard-i2c",
+ },
};
static int vprbrd_probe(struct usb_interface *interface,
--
1.7.10.4
--
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