i2c: davinci: use bus recovery infrastructure

This patch converts Davinci I2C driver to use I2C bus recovery
infrastructure, introduced by commit 5f9296ba21b3 ("i2c: Add
bus recovery infrastructure").

The i2c_bus_recovery_info is configured for Davinci I2C adapter
only in case scl_pin is provided in platform data.

As the controller must be held in reset while doing so, the
recovery routine must re-init the controller. Since this was already
being done after each call to i2c_recover_bus, move those calls into
the recovery_prepare/unprepare routines and as well.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 36 insertions, 41 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 120a4ef36ef5..54819fb4f82e 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -129,43 +129,6 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
         return readw_relaxed(i2c_dev->base + reg);
 }
 
-/* Generate a pulse on the i2c clock pin. */
-static void davinci_i2c_clock_pulse(unsigned int scl_pin)
-{
-        u16 i;
-
-        if (scl_pin) {
-                /* Send high and low on the SCL line */
-                for (i = 0; i < 9; i++) {
-                        gpio_set_value(scl_pin, 0);
-                        udelay(20);
-                        gpio_set_value(scl_pin, 1);
-                        udelay(20);
-                }
-        }
-}
-
-/* This routine does i2c bus recovery as specified in the
- * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
- */
-static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)
-{
-        u32 flag = 0;
-        struct davinci_i2c_platform_data *pdata = dev->pdata;
-
-        dev_err(dev->dev, "initiating i2c bus recovery\n");
-        /* Send NACK to the slave */
-        flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        flag |=  DAVINCI_I2C_MDR_NACK;
-        /* write the data into mode register */
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
-        davinci_i2c_clock_pulse(pdata->scl_pin);
-        /* Send STOP */
-        flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        flag |= DAVINCI_I2C_MDR_STP;
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
-}
-
 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
                                                                 int val)
 {
@@ -263,6 +226,34 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 }
 
 /*
+ * This routine does i2c bus recovery by using i2c_generic_gpio_recovery
+ * which is provided by I2C Bus recovery infrastructure.
+ */
+static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
+{
+        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+        /* Disable interrupts */
+        davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
+
+        /* put I2C into reset */
+        davinci_i2c_reset_ctrl(dev, 0);
+}
+
+static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+        i2c_davinci_init(dev);
+}
+
+static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
+        .recover_bus = i2c_generic_gpio_recovery,
+        .prepare_recovery = davinci_i2c_prepare_recovery,
+        .unprepare_recovery = davinci_i2c_unprepare_recovery,
+};
+
+/*
  * Waiting for bus not busy
  */
 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
@@ -282,8 +273,7 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
                                 return -ETIMEDOUT;
                         } else {
                                 to_cnt = 0;
-                                davinci_i2c_recover_bus(dev);
-                                i2c_davinci_init(dev);
+                                i2c_recover_bus(&dev->adapter);
                         }
                 }
                 if (allow_sleep)
@@ -372,8 +362,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
                                                 dev->adapter.timeout);
         if (!time_left) {
                 dev_err(dev->dev, "controller timed out\n");
-                davinci_i2c_recover_bus(dev);
-                i2c_davinci_init(dev);
+                i2c_recover_bus(adap);
                 dev->buf_len = 0;
                 return -ETIMEDOUT;
         }
@@ -712,6 +701,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
         adap->timeout = DAVINCI_I2C_TIMEOUT;
         adap->dev.of_node = pdev->dev.of_node;
 
+        if (dev->pdata->scl_pin) {
+                adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;
+                adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;
+                adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;
+        }
+
         adap->nr = pdev->id;
         r = i2c_add_numbered_adapter(adap);
         if (r) {