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Commit c984319a authored by Zhiwu Song's avatar Zhiwu Song Committed by Wolfram Sang
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i2c: sirf: reset i2c controller early after we get a noack 



Due to hardware ANOMALY, we need to reset I2C earlier after
we get NOACK while accessing non-existing clients, otherwise
we will get errors even we access existing clients later

Signed-off-by: default avatarZhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 57cd1e30

drivers/i2c/busses/i2c-sirf.c

+18 −9
Original line number Diff line number Diff line
@@ -64,6 +64,8 @@ 
#define SIRFSOC_I2C_START		BIT(7)



#define SIRFSOC_I2C_DEFAULT_SPEED 100000

#define SIRFSOC_I2C_ERR_NOACK      1

#define SIRFSOC_I2C_ERR_TIMEOUT    2



struct sirfsoc_i2c {

	void __iomem *base;
@@ -142,14 +144,24 @@ static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id) 


	if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {

		/* Error conditions */

		siic->err_status = 1;

		siic->err_status = SIRFSOC_I2C_ERR_NOACK;

		writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);



		if (i2c_stat & SIRFSOC_I2C_STAT_NACK)

			dev_err(&siic->adapter.dev, "ACK not received\n");

			dev_dbg(&siic->adapter.dev, "ACK not received\n");

		else

			dev_err(&siic->adapter.dev, "I2C error\n");



		/*

		 * Due to hardware ANOMALY, we need to reset I2C earlier after

		 * we get NOACK while accessing non-existing clients, otherwise

		 * we will get errors even we access existing clients later

		 */

		writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,

				siic->base + SIRFSOC_I2C_CTRL);

		while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)

			cpu_relax();



		complete(&siic->done);

	} else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {

		/* CMD buffer execution complete */
@@ -190,7 +202,6 @@ static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg) 
	u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);

	/* timeout waiting for the xfer to finish or fail */

	int timeout = msecs_to_jiffies((msg->len + 1) * 50);

	int ret = 0;



	i2c_sirfsoc_set_address(siic, msg);
@@ -199,7 +210,7 @@ static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg) 
	i2c_sirfsoc_queue_cmd(siic);



	if (wait_for_completion_timeout(&siic->done, timeout) == 0) {

		siic->err_status = 1;

		siic->err_status = SIRFSOC_I2C_ERR_TIMEOUT;

		dev_err(&siic->adapter.dev, "Transfer timeout\n");

	}
@@ -207,16 +218,14 @@ static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg) 
		siic->base + SIRFSOC_I2C_CTRL);

	writel(0, siic->base + SIRFSOC_I2C_CMD_START);



	if (siic->err_status) {

	/* i2c control doesn't response, reset it */

	if (siic->err_status == SIRFSOC_I2C_ERR_TIMEOUT) {

		writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,

			siic->base + SIRFSOC_I2C_CTRL);

		while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)

			cpu_relax();



		ret = -EIO;

	}



	return ret;

	return siic->err_status ? -EIO : 0;

}



static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)