[i2c] [PATCH] mv64xxx: Reinitialize hw and driver on I2C bus hang

[Dale Farnsworth]

Under certain conditions, the mv64xxx I2C bus can hang preventing
further operation.  To make the driver more robust, we now reset
the I2C hardware and the driver state machine when such hangs are
detected.

Signed-off-by: Dale Farnsworth <dale at farnsworth.org>
---
 i2c-mv64xxx.c |   31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 251154a..bb7bf68 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -107,6 +107,21 @@ struct mv64xxx_i2c_data {
  *
  *****************************************************************************
  */
+
+/* Reset hardware and initialize FSM */
+static void
+mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data)
+{
+	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SOFT_RESET);
+	writel((((drv_data->freq_m & 0xf) << 3) | (drv_data->freq_n & 0x7)),
+		drv_data->reg_base + MV64XXX_I2C_REG_BAUD);
+	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SLAVE_ADDR);
+	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_EXT_SLAVE_ADDR);
+	writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP,
+		drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
+	drv_data->state = MV64XXX_I2C_STATE_IDLE;
+}
+
 static void
 mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
 {
@@ -203,7 +218,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
 			 drv_data->state, status, drv_data->msg->addr,
 			 drv_data->msg->flags);
 		drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
-		drv_data->state = MV64XXX_I2C_STATE_IDLE;
+		mv64xxx_i2c_hw_init(drv_data);
 		drv_data->rc = -EIO;
 	}
 }
@@ -367,6 +382,7 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
 				"mv64xxx: I2C bus locked, block: %d, "
 				"time_left: %d\n", drv_data->block,
 				(int)time_left);
+			mv64xxx_i2c_hw_init(drv_data);
 		}
 	} else
 		spin_unlock_irqrestore(&drv_data->lock, flags);
@@ -443,19 +459,6 @@ static const struct i2c_algorithm mv64xxx_i2c_algo = {
  *
  *****************************************************************************
  */
-static void __devinit
-mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data)
-{
-	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SOFT_RESET);
-	writel((((drv_data->freq_m & 0xf) << 3) | (drv_data->freq_n & 0x7)),
-		drv_data->reg_base + MV64XXX_I2C_REG_BAUD);
-	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SLAVE_ADDR);
-	writel(0, drv_data->reg_base + MV64XXX_I2C_REG_EXT_SLAVE_ADDR);
-	writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP,
-		drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
-	drv_data->state = MV64XXX_I2C_STATE_IDLE;
-}
-
 static int __devinit
 mv64xxx_i2c_map_regs(struct platform_device *pd,
 	struct mv64xxx_i2c_data *drv_data)