Commit a07ad1cc authored by Dale Farnsworth's avatar Dale Farnsworth Committed by Jean Delvare
Browse files

i2c-mv64xxx: Reinitialize hw and driver on I2C bus hang 



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: default avatarDale Farnsworth <dale@farnsworth.org>
Acked-by: default avatarMark A. Greer <mgreer@mvista.com>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 5af0e07f

drivers/i2c/busses/i2c-mv64xxx.c

+17 −14
Original line number Diff line number Diff line
@@ -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)

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