--- /dev/null
+/*
+ * 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");
projects / deliverable / linux.git / commitdiff
