Date:   Fri, 15 Sep 2017 15:29:16 +0800
From:   Baolin Wang <baolin.wang@...eadtrum.com>
To:     <broonie@...nel.org>, <robh+dt@...nel.org>, <mark.rutland@....com>
CC:     <linux-spi@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <baolin.wang@...eadtrum.com>,
        <baolin.wang@...aro.org>
Subject: [PATCH v3 2/2] spi: Add ADI driver for Spreadtrum platform

This patch adds ADI driver based on SPI framework for
Spreadtrum SC9860 platform.

Signed-off-by: Baolin Wang <baolin.wang@...eadtrum.com>
---
Changes since v2:
 - Remove the MIT license.

Changes since v1:
 - Add COMPILE_TEST config as dependency.
 - Remove spi_controller_put() function when removing driver.
 - Change to module_init() level.
---
 drivers/spi/Kconfig        |    6 +
 drivers/spi/Makefile       |    1 +
 drivers/spi/spi-sprd-adi.c |  419 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 426 insertions(+)
 create mode 100644 drivers/spi/spi-sprd-adi.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 9b31351..fbdced7 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -627,6 +627,12 @@ config SPI_SIRF
 	help
 	  SPI driver for CSR SiRFprimaII SoCs
 
+config SPI_SPRD_ADI
+	tristate "Spreadtrum ADI controller"
+	depends on ARCH_SPRD || COMPILE_TEST
+	help
+	  ADI driver based on SPI for Spreadtrum SoCs.
+
 config SPI_STM32
 	tristate "STMicroelectronics STM32 SPI controller"
 	depends on ARCH_STM32 || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index a3ae2b7..de5ae2a 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -90,6 +90,7 @@ obj-$(CONFIG_SPI_SH_HSPI)		+= spi-sh-hspi.o
 obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o
 obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
+obj-$(CONFIG_SPI_SPRD_ADI)		+= spi-sprd-adi.o
 obj-$(CONFIG_SPI_STM32) 		+= spi-stm32.o
 obj-$(CONFIG_SPI_ST_SSC4)		+= spi-st-ssc4.o
 obj-$(CONFIG_SPI_SUN4I)			+= spi-sun4i.o
diff --git a/drivers/spi/spi-sprd-adi.c b/drivers/spi/spi-sprd-adi.c
new file mode 100644
index 0000000..0d481f8
--- /dev/null
+++ b/drivers/spi/spi-sprd-adi.c
@@ -0,0 +1,419 @@
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/hwspinlock.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/sizes.h>
+
+/* Registers definitions for ADI controller */
+#define REG_ADI_CTRL0			0x4
+#define REG_ADI_CHN_PRIL		0x8
+#define REG_ADI_CHN_PRIH		0xc
+#define REG_ADI_INT_EN			0x10
+#define REG_ADI_INT_RAW			0x14
+#define REG_ADI_INT_MASK		0x18
+#define REG_ADI_INT_CLR			0x1c
+#define REG_ADI_GSSI_CFG0		0x20
+#define REG_ADI_GSSI_CFG1		0x24
+#define REG_ADI_RD_CMD			0x28
+#define REG_ADI_RD_DATA			0x2c
+#define REG_ADI_ARM_FIFO_STS		0x30
+#define REG_ADI_STS			0x34
+#define REG_ADI_EVT_FIFO_STS		0x38
+#define REG_ADI_ARM_CMD_STS		0x3c
+#define REG_ADI_CHN_EN			0x40
+#define REG_ADI_CHN_ADDR(id)		(0x44 + (id - 2) * 4)
+#define REG_ADI_CHN_EN1			0x20c
+
+/* Bits definitions for register REG_ADI_GSSI_CFG0 */
+#define BIT_CLK_ALL_ON			BIT(30)
+
+/* Bits definitions for register REG_ADI_RD_DATA */
+#define BIT_RD_CMD_BUSY			BIT(31)
+#define RD_ADDR_SHIFT			16
+#define RD_VALUE_MASK			GENMASK(15, 0)
+#define RD_ADDR_MASK			GENMASK(30, 16)
+
+/* Bits definitions for register REG_ADI_ARM_FIFO_STS */
+#define BIT_FIFO_FULL			BIT(11)
+#define BIT_FIFO_EMPTY			BIT(10)
+
+/*
+ * ADI slave devices include RTC, ADC, regulator, charger, thermal and so on.
+ * The slave devices address offset is always 0x8000 and size is 4K.
+ */
+#define ADI_SLAVE_ADDR_SIZE		SZ_4K
+#define ADI_SLAVE_OFFSET		0x8000
+
+/* Timeout (ms) for the trylock of hardware spinlocks */
+#define ADI_HWSPINLOCK_TIMEOUT		5000
+/*
+ * ADI controller has 50 channels including 2 software channels
+ * and 48 hardware channels.
+ */
+#define ADI_HW_CHNS			50
+
+#define ADI_FIFO_DRAIN_TIMEOUT		1000
+#define ADI_READ_TIMEOUT		2000
+#define REG_ADDR_LOW_MASK		GENMASK(11, 0)
+
+struct sprd_adi {
+	struct spi_controller	*ctlr;
+	struct device		*dev;
+	void __iomem		*base;
+	struct hwspinlock	*hwlock;
+	unsigned long		slave_vbase;
+	unsigned long		slave_pbase;
+};
+
+static int sprd_adi_check_paddr(struct sprd_adi *sadi, u32 paddr)
+{
+	if (paddr < sadi->slave_pbase || paddr >
+	    (sadi->slave_pbase + ADI_SLAVE_ADDR_SIZE)) {
+		dev_err(sadi->dev,
+			"slave physical address is incorrect, addr = 0x%x\n",
+			paddr);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static unsigned long sprd_adi_to_vaddr(struct sprd_adi *sadi, u32 paddr)
+{
+	return (paddr - sadi->slave_pbase + sadi->slave_vbase);
+}
+
+static int sprd_adi_drain_fifo(struct sprd_adi *sadi)
+{
+	u32 timeout = ADI_FIFO_DRAIN_TIMEOUT;
+	u32 sts;
+
+	do {
+		sts = readl_relaxed(sadi->base + REG_ADI_ARM_FIFO_STS);
+		if (sts & BIT_FIFO_EMPTY)
+			break;
+
+		cpu_relax();
+	} while (--timeout);
+
+	if (timeout == 0) {
+		dev_err(sadi->dev, "drain write fifo timeout\n");
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int sprd_adi_fifo_is_full(struct sprd_adi *sadi)
+{
+	return readl_relaxed(sadi->base + REG_ADI_ARM_FIFO_STS) & BIT_FIFO_FULL;
+}
+
+static int sprd_adi_read(struct sprd_adi *sadi, u32 reg_paddr, u32 *read_val)
+{
+	int read_timeout = ADI_READ_TIMEOUT;
+	u32 val, rd_addr;
+
+	/*
+	 * Set the physical register address need to read into RD_CMD register,
+	 * then ADI controller will start to transfer automatically.
+	 */
+	writel_relaxed(reg_paddr, sadi->base + REG_ADI_RD_CMD);
+
+	/*
+	 * Wait read operation complete, the BIT_RD_CMD_BUSY will be set
+	 * simultaneously when writing read command to register, and the
+	 * BIT_RD_CMD_BUSY will be cleared after the read operation is
+	 * completed.
+	 */
+	do {
+		val = readl_relaxed(sadi->base + REG_ADI_RD_DATA);
+		if (!(val & BIT_RD_CMD_BUSY))
+			break;
+
+		cpu_relax();
+	} while (--read_timeout);
+
+	if (read_timeout == 0) {
+		dev_err(sadi->dev, "ADI read timeout\n");
+		return -EBUSY;
+	}
+
+	/*
+	 * The return value includes data and read register address, from bit 0
+	 * to bit 15 are data, and from bit 16 to bit 30 are read register
+	 * address. Then we can check the returned register address to validate
+	 * data.
+	 */
+	rd_addr = (val & RD_ADDR_MASK ) >> RD_ADDR_SHIFT;
+
+	if (rd_addr != (reg_paddr & REG_ADDR_LOW_MASK)) {
+		dev_err(sadi->dev, "read error, reg addr = 0x%x, val = 0x%x\n",
+			reg_paddr, val);
+		return -EIO;
+	}
+
+	*read_val = val & RD_VALUE_MASK;
+	return 0;
+}
+
+static int sprd_adi_write(struct sprd_adi *sadi, unsigned long reg, u32 val)
+{
+	u32 timeout = ADI_FIFO_DRAIN_TIMEOUT;
+	int ret;
+
+	ret = sprd_adi_drain_fifo(sadi);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * we should wait for write fifo is empty before writing data to PMIC
+	 * registers.
+	 */
+	do {
+		if (!sprd_adi_fifo_is_full(sadi)) {
+			writel_relaxed(val, (void __iomem *)reg);
+			break;
+		}
+
+		cpu_relax();
+	} while (--timeout);
+
+	if (timeout == 0) {
+		dev_err(sadi->dev, "write fifo is full\n");
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int sprd_adi_transfer_one(struct spi_controller *ctlr,
+				 struct spi_device *spi_dev,
+				 struct spi_transfer *t)
+{
+	struct sprd_adi *sadi = spi_controller_get_devdata(ctlr);
+	unsigned long flags, virt_reg;
+	u32 phy_reg, val;
+	int ret;
+
+	if (t->rx_buf) {
+		phy_reg = *(u32 *)t->rx_buf + sadi->slave_pbase;
+
+		ret = sprd_adi_check_paddr(sadi, phy_reg);
+		if (ret)
+			return ret;
+
+		ret = hwspin_lock_timeout_irqsave(sadi->hwlock,
+						  ADI_HWSPINLOCK_TIMEOUT,
+						  &flags);
+		if (ret) {
+			dev_err(sadi->dev, "get the hw lock failed\n");
+			return ret;
+		}
+
+		ret = sprd_adi_read(sadi, phy_reg, &val);
+		hwspin_unlock_irqrestore(sadi->hwlock, &flags);
+		if (ret)
+			return ret;
+
+		*(u32 *)t->rx_buf = val;
+	} else if (t->tx_buf) {
+		u32 *p = (u32 *)t->tx_buf;
+
+		/*
+		 * Get the physical register address need to write and convert
+		 * the physical address to virtual address. Since we need
+		 * virtual register address to write.
+		 */
+		phy_reg = *p++ + sadi->slave_pbase;
+		ret = sprd_adi_check_paddr(sadi, phy_reg);
+		if (ret)
+			return ret;
+
+		virt_reg = sprd_adi_to_vaddr(sadi, phy_reg);
+		val = *p;
+
+		ret = hwspin_lock_timeout_irqsave(sadi->hwlock,
+						  ADI_HWSPINLOCK_TIMEOUT,
+						  &flags);
+		if (ret) {
+			dev_err(sadi->dev, "get the hw lock failed\n");
+			return ret;
+		}
+
+		ret = sprd_adi_write(sadi, virt_reg, val);
+		hwspin_unlock_irqrestore(sadi->hwlock, &flags);
+		if (ret)
+			return ret;
+	} else {
+		dev_err(sadi->dev, "no buffer for transfer\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void sprd_adi_hw_init(struct sprd_adi *sadi)
+{
+	struct device_node *np = sadi->dev->of_node;
+	int i, size, chn_cnt;
+	const __be32 *list;
+	u32 tmp;
+
+	/* Address bits select default 12 bits */
+	writel_relaxed(0, sadi->base + REG_ADI_CTRL0);
+
+	/* Set all channels as default priority */
+	writel_relaxed(0, sadi->base + REG_ADI_CHN_PRIL);
+	writel_relaxed(0, sadi->base + REG_ADI_CHN_PRIH);
+
+	/* Set clock auto gate mode */
+	tmp = readl_relaxed(sadi->base + REG_ADI_GSSI_CFG0);
+	tmp &= ~BIT_CLK_ALL_ON;
+	writel_relaxed(tmp, sadi->base + REG_ADI_GSSI_CFG0);
+
+	/* Set hardware channels setting */
+	list = of_get_property(np, "sprd,hw-channels", &size);
+	if (!size || !list) {
+		dev_info(sadi->dev, "no hw channels setting in node\n");
+		return;
+	}
+
+	chn_cnt = size / 8;
+	for (i = 0; i < chn_cnt; i++) {
+		u32 value;
+		u32 chn_id = be32_to_cpu(*list++);
+		u32 chn_config = be32_to_cpu(*list++);
+
+		/* Channel 0 and 1 are software channels */
+		if (chn_id < 2)
+			continue;
+
+		writel_relaxed(chn_config, sadi->base +
+			       REG_ADI_CHN_ADDR(chn_id));
+
+		if (chn_id < 31) {
+			value = readl_relaxed(sadi->base + REG_ADI_CHN_EN);
+			value |= BIT(chn_id);
+			writel_relaxed(value, sadi->base + REG_ADI_CHN_EN);
+		} else if (chn_id < ADI_HW_CHNS) {
+			value = readl_relaxed(sadi->base + REG_ADI_CHN_EN1);
+			value |= BIT(chn_id - 32);
+			writel_relaxed(value, sadi->base + REG_ADI_CHN_EN1);
+		}
+	}
+}
+
+static int sprd_adi_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct spi_controller *ctlr;
+	struct sprd_adi *sadi;
+	struct resource *res;
+	u32 num_chipselect;
+	int ret;
+
+	if (!np) {
+		dev_err(&pdev->dev, "can not find the adi bus node\n");
+		return -ENODEV;
+	}
+
+	pdev->id = of_alias_get_id(np, "spi");
+	num_chipselect = of_get_child_count(np);
+
+	ctlr = spi_alloc_master(&pdev->dev, sizeof(struct sprd_adi));
+	if (!ctlr)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, ctlr);
+	sadi = spi_controller_get_devdata(ctlr);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sadi->base = devm_ioremap_resource(&pdev->dev, res);
+	if (!sadi->base) {
+		ret = -ENOMEM;
+		goto put_ctlr;
+	}
+
+	sadi->slave_vbase = (unsigned long)sadi->base + ADI_SLAVE_OFFSET;
+	sadi->slave_pbase = res->start + ADI_SLAVE_OFFSET;
+	sadi->ctlr = ctlr;
+	sadi->dev = &pdev->dev;
+	ret = of_hwspin_lock_get_id(np, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can not get the hardware spinlock\n");
+		goto put_ctlr;
+	}
+
+	sadi->hwlock = hwspin_lock_request_specific(ret);
+	if (!sadi->hwlock) {
+		ret = -ENXIO;
+		goto put_ctlr;
+	}
+
+	sprd_adi_hw_init(sadi);
+
+	ctlr->dev.of_node = pdev->dev.of_node;
+	ctlr->bus_num = pdev->id;
+	ctlr->num_chipselect = num_chipselect;
+	ctlr->flags = SPI_MASTER_HALF_DUPLEX;
+	ctlr->bits_per_word_mask = 0;
+	ctlr->transfer_one = sprd_adi_transfer_one;
+
+	ret = devm_spi_register_controller(&pdev->dev, ctlr);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register SPI controller\n");
+		goto free_hwlock;
+	}
+
+	return 0;
+
+free_hwlock:
+	hwspin_lock_free(sadi->hwlock);
+put_ctlr:
+	spi_controller_put(ctlr);
+	return ret;
+}
+
+static int sprd_adi_remove(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr = dev_get_drvdata(&pdev->dev);
+	struct sprd_adi *sadi = spi_controller_get_devdata(ctlr);
+
+	hwspin_lock_free(sadi->hwlock);
+	return 0;
+}
+
+static const struct of_device_id sprd_adi_of_match[] = {
+	{
+		.compatible = "sprd,sc9860-adi",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sprd_adi_of_match);
+
+static struct platform_driver sprd_adi_driver = {
+	.driver = {
+		.name = "sprd-adi",
+		.owner = THIS_MODULE,
+		.of_match_table = sprd_adi_of_match,
+	},
+	.probe = sprd_adi_probe,
+	.remove = sprd_adi_remove,
+};
+module_platform_driver(sprd_adi_driver);
+
+MODULE_DESCRIPTION("Spreadtrum ADI Controller Driver");
+MODULE_AUTHOR("Baolin Wang <Baolin.Wang@...eadtrum.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5

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