i2c: Add DaVinci I2C controller support

Signed-off-by: Vladimir Barinov <vbarinov@ru.mvista.com>
Acked-by: Trilok Soni <soni.trilok@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 586 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
new file mode 100644
index 00000000000..bd7aaff3524
--- /dev/null
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -0,0 +1,586 @@
+/*
+ * TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ *
+ * Updated by Vinod & Sudhakar Feb 2005
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ----------------------------------------------------------------------------
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include <asm/hardware.h>
+#include <asm/mach-types.h>
+
+#include <asm/arch/i2c.h>
+
+/* ----- global defines ----------------------------------------------- */
+
+#define DAVINCI_I2C_TIMEOUT	(1*HZ)
+#define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
+				 DAVINCI_I2C_IMR_SCD | \
+				 DAVINCI_I2C_IMR_ARDY | \
+				 DAVINCI_I2C_IMR_NACK | \
+				 DAVINCI_I2C_IMR_AL)
+
+#define DAVINCI_I2C_OAR_REG	0x00
+#define DAVINCI_I2C_IMR_REG	0x04
+#define DAVINCI_I2C_STR_REG	0x08
+#define DAVINCI_I2C_CLKL_REG	0x0c
+#define DAVINCI_I2C_CLKH_REG	0x10
+#define DAVINCI_I2C_CNT_REG	0x14
+#define DAVINCI_I2C_DRR_REG	0x18
+#define DAVINCI_I2C_SAR_REG	0x1c
+#define DAVINCI_I2C_DXR_REG	0x20
+#define DAVINCI_I2C_MDR_REG	0x24
+#define DAVINCI_I2C_IVR_REG	0x28
+#define DAVINCI_I2C_EMDR_REG	0x2c
+#define DAVINCI_I2C_PSC_REG	0x30
+
+#define DAVINCI_I2C_IVR_AAS	0x07
+#define DAVINCI_I2C_IVR_SCD	0x06
+#define DAVINCI_I2C_IVR_XRDY	0x05
+#define DAVINCI_I2C_IVR_RDR	0x04
+#define DAVINCI_I2C_IVR_ARDY	0x03
+#define DAVINCI_I2C_IVR_NACK	0x02
+#define DAVINCI_I2C_IVR_AL	0x01
+
+#define DAVINCI_I2C_STR_BB	(1 << 12)
+#define DAVINCI_I2C_STR_RSFULL	(1 << 11)
+#define DAVINCI_I2C_STR_SCD	(1 << 5)
+#define DAVINCI_I2C_STR_ARDY	(1 << 2)
+#define DAVINCI_I2C_STR_NACK	(1 << 1)
+#define DAVINCI_I2C_STR_AL	(1 << 0)
+
+#define DAVINCI_I2C_MDR_NACK	(1 << 15)
+#define DAVINCI_I2C_MDR_STT	(1 << 13)
+#define DAVINCI_I2C_MDR_STP	(1 << 11)
+#define DAVINCI_I2C_MDR_MST	(1 << 10)
+#define DAVINCI_I2C_MDR_TRX	(1 << 9)
+#define DAVINCI_I2C_MDR_XA	(1 << 8)
+#define DAVINCI_I2C_MDR_IRS	(1 << 5)
+
+#define DAVINCI_I2C_IMR_AAS	(1 << 6)
+#define DAVINCI_I2C_IMR_SCD	(1 << 5)
+#define DAVINCI_I2C_IMR_XRDY	(1 << 4)
+#define DAVINCI_I2C_IMR_RRDY	(1 << 3)
+#define DAVINCI_I2C_IMR_ARDY	(1 << 2)
+#define DAVINCI_I2C_IMR_NACK	(1 << 1)
+#define DAVINCI_I2C_IMR_AL	(1 << 0)
+
+#define MOD_REG_BIT(val, mask, set) do { \
+	if (set) { \
+		val |= mask; \
+	} else { \
+		val &= ~mask; \
+	} \
+} while (0)
+
+struct davinci_i2c_dev {
+	struct device           *dev;
+	void __iomem		*base;
+	struct completion	cmd_complete;
+	struct clk              *clk;
+	int			cmd_err;
+	u8			*buf;
+	size_t			buf_len;
+	int			irq;
+	struct i2c_adapter	adapter;
+};
+
+/* default platform data to use if not supplied in the platform_device */
+static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
+	.bus_freq	= 100,
+	.bus_delay	= 0,
+};
+
+static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
+					 int reg, u16 val)
+{
+	__raw_writew(val, i2c_dev->base + reg);
+}
+
+static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
+{
+	return __raw_readw(i2c_dev->base + reg);
+}
+
+/*
+ * This functions configures I2C and brings I2C out of reset.
+ * This function is called during I2C init function. This function
+ * also gets called if I2C encounters any errors.
+ */
+static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+{
+	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+	u16 psc;
+	u32 clk;
+	u32 clkh;
+	u32 clkl;
+	u32 input_clock = clk_get_rate(dev->clk);
+	u16 w;
+
+	if (!pdata)
+		pdata = &davinci_i2c_platform_data_default;
+
+	/* put I2C into reset */
+	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+
+	/* NOTE: I2C Clock divider programming info
+	 * As per I2C specs the following formulas provide prescaler
+	 * and low/high divider values
+	 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
+	 *                       module clk
+	 *
+	 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
+	 *
+	 * Thus,
+	 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
+	 *
+	 * where if PSC == 0, d = 7,
+	 *       if PSC == 1, d = 6
+	 *       if PSC > 1 , d = 5
+	 */
+
+	psc = 26; /* To get 1MHz clock */
+
+	clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - 10;
+	clkh = (50 * clk) / 100;
+	clkl = clk - clkh;
+
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
+
+	dev_dbg(dev->dev, "CLK  = %d\n", clk);
+	dev_dbg(dev->dev, "PSC  = %d\n",
+		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
+	dev_dbg(dev->dev, "CLKL = %d\n",
+		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
+	dev_dbg(dev->dev, "CLKH = %d\n",
+		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
+
+	/* Take the I2C module out of reset: */
+	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+
+	/* Enable interrupts */
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
+
+	return 0;
+}
+
+/*
+ * Waiting for bus not busy
+ */
+static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
+					 char allow_sleep)
+{
+	unsigned long timeout;
+
+	timeout = jiffies + DAVINCI_I2C_TIMEOUT;
+	while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
+	       & DAVINCI_I2C_STR_BB) {
+		if (time_after(jiffies, timeout)) {
+			dev_warn(dev->dev,
+				 "timeout waiting for bus ready\n");
+			return -ETIMEDOUT;
+		}
+		if (allow_sleep)
+			schedule_timeout(1);
+	}
+
+	return 0;
+}
+
+/*
+ * Low level master read/write transaction. This function is called
+ * from i2c_davinci_xfer.
+ */
+static int
+i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
+{
+	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+	u32 flag;
+	u32 stat;
+	u16 w;
+	int r;
+
+	if (msg->len == 0)
+		return -EINVAL;
+
+	if (!pdata)
+		pdata = &davinci_i2c_platform_data_default;
+	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
+	if (pdata->bus_delay)
+		udelay(pdata->bus_delay);
+
+	/* set the slave address */
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
+
+	dev->buf = msg->buf;
+	dev->buf_len = msg->len;
+
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
+
+	init_completion(&dev->cmd_complete);
+	dev->cmd_err = 0;
+
+	/* Clear any pending interrupts by reading the IVR */
+	stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);
+
+	/* Take I2C out of reset, configure it as master and set the
+	 * start bit */
+	flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
+
+	/* if the slave address is ten bit address, enable XA bit */
+	if (msg->flags & I2C_M_TEN)
+		flag |= DAVINCI_I2C_MDR_XA;
+	if (!(msg->flags & I2C_M_RD))
+		flag |= DAVINCI_I2C_MDR_TRX;
+	if (stop)
+		flag |= DAVINCI_I2C_MDR_STP;
+
+	/* Enable receive or transmit interrupts */
+	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
+	if (msg->flags & I2C_M_RD)
+		MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
+	else
+		MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
+
+	/* write the data into mode register */
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+
+	r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+						      DAVINCI_I2C_TIMEOUT);
+	dev->buf_len = 0;
+	if (r < 0)
+		return r;
+
+	if (r == 0) {
+		dev_err(dev->dev, "controller timed out\n");
+		i2c_davinci_init(dev);
+		return -ETIMEDOUT;
+	}
+
+	/* no error */
+	if (likely(!dev->cmd_err))
+		return msg->len;
+
+	/* We have an error */
+	if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
+		i2c_davinci_init(dev);
+		return -EIO;
+	}
+
+	if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
+		if (msg->flags & I2C_M_IGNORE_NAK)
+			return msg->len;
+		if (stop) {
+			w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+			MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
+			davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+		}
+		return -EREMOTEIO;
+	}
+	return -EIO;
+}
+
+/*
+ * Prepare controller for a transaction and call i2c_davinci_xfer_msg
+ */
+static int
+i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+	int i;
+	int ret;
+
+	dev_dbg(dev->dev, "%s: msgs: %d\n", __FUNCTION__, num);
+
+	ret = i2c_davinci_wait_bus_not_busy(dev, 1);
+	if (ret < 0) {
+		dev_warn(dev->dev, "timeout waiting for bus ready\n");
+		return ret;
+	}
+
+	for (i = 0; i < num; i++) {
+		ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+		if (ret < 0)
+			return ret;
+	}
+
+	dev_dbg(dev->dev, "%s:%d ret: %d\n", __FUNCTION__, __LINE__, ret);
+
+	return num;
+}
+
+static u32 i2c_davinci_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C interrupt
+ * occurs.
+ */
+static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
+{
+	struct davinci_i2c_dev *dev = dev_id;
+	u32 stat;
+	int count = 0;
+	u16 w;
+
+	while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
+		dev_dbg(dev->dev, "%s: stat=0x%x\n", __FUNCTION__, stat);
+		if (count++ == 100) {
+			dev_warn(dev->dev, "Too much work in one IRQ\n");
+			break;
+		}
+
+		switch (stat) {
+		case DAVINCI_I2C_IVR_AL:
+			dev->cmd_err |= DAVINCI_I2C_STR_AL;
+			complete(&dev->cmd_complete);
+			break;
+
+		case DAVINCI_I2C_IVR_NACK:
+			dev->cmd_err |= DAVINCI_I2C_STR_NACK;
+			complete(&dev->cmd_complete);
+			break;
+
+		case DAVINCI_I2C_IVR_ARDY:
+			w = davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG);
+			MOD_REG_BIT(w, DAVINCI_I2C_STR_ARDY, 1);
+			davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, w);
+			complete(&dev->cmd_complete);
+			break;
+
+		case DAVINCI_I2C_IVR_RDR:
+			if (dev->buf_len) {
+				*dev->buf++ =
+				    davinci_i2c_read_reg(dev,
+							 DAVINCI_I2C_DRR_REG);
+				dev->buf_len--;
+				if (dev->buf_len)
+					continue;
+
+				w = davinci_i2c_read_reg(dev,
+							 DAVINCI_I2C_STR_REG);
+				MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 0);
+				davinci_i2c_write_reg(dev,
+						      DAVINCI_I2C_STR_REG,
+						      w);
+			} else
+				dev_err(dev->dev, "RDR IRQ while no"
+					"data requested\n");
+			break;
+
+		case DAVINCI_I2C_IVR_XRDY:
+			if (dev->buf_len) {
+				davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
+						      *dev->buf++);
+				dev->buf_len--;
+				if (dev->buf_len)
+					continue;
+
+				w = davinci_i2c_read_reg(dev,
+							 DAVINCI_I2C_IMR_REG);
+				MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
+				davinci_i2c_write_reg(dev,
+						      DAVINCI_I2C_IMR_REG,
+						      w);
+			} else
+				dev_err(dev->dev, "TDR IRQ while no data to"
+					"send\n");
+			break;
+
+		case DAVINCI_I2C_IVR_SCD:
+			w = davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG);
+			MOD_REG_BIT(w, DAVINCI_I2C_STR_SCD, 1);
+			davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, w);
+			complete(&dev->cmd_complete);
+			break;
+
+		case DAVINCI_I2C_IVR_AAS:
+			dev_warn(dev->dev, "Address as slave interrupt\n");
+		}/* switch */
+	}/* while */
+
+	return count ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static struct i2c_algorithm i2c_davinci_algo = {
+	.master_xfer	= i2c_davinci_xfer,
+	.functionality	= i2c_davinci_func,
+};
+
+static int davinci_i2c_probe(struct platform_device *pdev)
+{
+	struct davinci_i2c_dev *dev;
+	struct i2c_adapter *adap;
+	struct resource *mem, *irq, *ioarea;
+	int r;
+
+	/* NOTE: driver uses the static register mapping */
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "no mem resource?\n");
+		return -ENODEV;
+	}
+
+	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!irq) {
+		dev_err(&pdev->dev, "no irq resource?\n");
+		return -ENODEV;
+	}
+
+	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
+				    pdev->name);
+	if (!ioarea) {
+		dev_err(&pdev->dev, "I2C region already claimed\n");
+		return -EBUSY;
+	}
+
+	dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
+	if (!dev) {
+		r = -ENOMEM;
+		goto err_release_region;
+	}
+
+	dev->dev = get_device(&pdev->dev);
+	dev->irq = irq->start;
+	platform_set_drvdata(pdev, dev);
+
+	dev->clk = clk_get(&pdev->dev, "I2CCLK");
+	if (IS_ERR(dev->clk)) {
+		r = -ENODEV;
+		goto err_free_mem;
+	}
+	clk_enable(dev->clk);
+
+	dev->base = (void __iomem *)IO_ADDRESS(mem->start);
+	i2c_davinci_init(dev);
+
+	r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
+	if (r) {
+		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
+		goto err_unuse_clocks;
+	}
+
+	adap = &dev->adapter;
+	i2c_set_adapdata(adap, dev);
+	adap->owner = THIS_MODULE;
+	adap->class = I2C_CLASS_HWMON;
+	strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
+	adap->algo = &i2c_davinci_algo;
+	adap->dev.parent = &pdev->dev;
+
+	/* FIXME */
+	adap->timeout = 1;
+	adap->retries = 1;
+
+	adap->nr = pdev->id;
+	r = i2c_add_numbered_adapter(adap);
+	if (r) {
+		dev_err(&pdev->dev, "failure adding adapter\n");
+		goto err_free_irq;
+	}
+
+	return 0;
+
+err_free_irq:
+	free_irq(dev->irq, dev);
+err_unuse_clocks:
+	clk_disable(dev->clk);
+	clk_put(dev->clk);
+	dev->clk = NULL;
+err_free_mem:
+	platform_set_drvdata(pdev, NULL);
+	put_device(&pdev->dev);
+	kfree(dev);
+err_release_region:
+	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+
+	return r;
+}
+
+static int davinci_i2c_remove(struct platform_device *pdev)
+{
+	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
+	struct resource *mem;
+
+	platform_set_drvdata(pdev, NULL);
+	i2c_del_adapter(&dev->adapter);
+	put_device(&pdev->dev);
+
+	clk_disable(dev->clk);
+	clk_put(dev->clk);
+	dev->clk = NULL;
+
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
+	free_irq(IRQ_I2C, dev);
+	kfree(dev);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+	return 0;
+}
+
+static struct platform_driver davinci_i2c_driver = {
+	.probe		= davinci_i2c_probe,
+	.remove		= davinci_i2c_remove,
+	.driver		= {
+		.name	= "i2c_davinci",
+		.owner	= THIS_MODULE,
+	},
+};
+
+/* I2C may be needed to bring up other drivers */
+static int __init davinci_i2c_init_driver(void)
+{
+	return platform_driver_register(&davinci_i2c_driver);
+}
+subsys_initcall(davinci_i2c_init_driver);
+
+static void __exit davinci_i2c_exit_driver(void)
+{
+	platform_driver_unregister(&davinci_i2c_driver);
+}
+module_exit(davinci_i2c_exit_driver);
+
+MODULE_AUTHOR("Texas Instruments India");
+MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
+MODULE_LICENSE("GPL");