i2c: imx: Use correct function to write to register

The i2c-imx driver incorrectly uses readb()/writeb() to read and
write to the appropriate registers when performing a repeated start.
The appropriate imx_i2c_read_reg()/imx_i2c_write_reg() functions
should be used instead. Performing a repeated start results in
a kernel panic. The platform is imx.

Signed-off-by: Michail G Etairidis <m.etairidis@beck-ipc.com>
Fixes: ce1a78840ff7 ("i2c: imx: add DMA support for freescale i2c driver")
Fixes: 054b62d9f25c ("i2c: imx: fix the i2c bus hang issue when do repeat restart")
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-imx.c

@@ -734,9 +734,9 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
 		 * the first read operation, otherwise the first read cost
 		 * one extra clock cycle.
 		 */
-		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 		temp |= I2CR_MTX;
-		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 	}
 	msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 
@@ -857,9 +857,9 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bo
 				 * the first read operation, otherwise the first read cost
 				 * one extra clock cycle.
 				 */
-				temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+				temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 				temp |= I2CR_MTX;
-				writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+				imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 			}
 		} else if (i == (msgs->len - 2)) {
 			dev_dbg(&i2c_imx->adapter.dev,