target/linux/imx6/patches-3.10/0004-i2c-imx-retry-on-NAK.patch

   1 From: Tim Harvey <tharvey@gateworks.com>
   2 Subject: [PATCH] i2c: imx: retry on NAK
   3
   4 In case of busy i2c try again to get ACK.
   5
   6 Signed-off-by: Tim Harvey <tharvey@gateworks.com>
   7 Tested-by: Luka Perkov <luka@openwrt.org>
   8 ---
   9  drivers/i2c/busses/i2c-imx.c | 4 +++-
  10  1 file changed, 3 insertions(+), 1 deletion(-)
  11
  12 --- a/drivers/i2c/busses/i2c-imx.c
  13 +++ b/drivers/i2c/busses/i2c-imx.c
  14 @@ -62,6 +62,7 @@
  15
  16  /* Default value */
  17  #define IMX_I2C_BIT_RATE       100000  /* 100kHz */
  18 +#define IMX_I2C_MAX_RETRIES    3       /* number of retries to attempt */
  19
  20  /* IMX I2C registers */
  21  #define IMX_I2C_IADR   0x00    /* i2c slave address */
  22 @@ -198,7 +199,7 @@ static int i2c_imx_acked(struct imx_i2c_
  23  {
  24         if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
  25                 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
  26 -               return -EIO;  /* No ACK */
  27 +               return -EAGAIN; /* try again */
  28         }
  29
  30         dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
  31 @@ -533,6 +534,7 @@ static int __init i2c_imx_probe(struct p
  32         i2c_imx->adapter.dev.parent     = &pdev->dev;
  33         i2c_imx->adapter.nr             = pdev->id;
  34         i2c_imx->adapter.dev.of_node    = pdev->dev.of_node;
  35 +       i2c_imx->adapter.retries        = IMX_I2C_MAX_RETRIES;
  36         i2c_imx->base                   = base;
  37
  38         pinctrl = devm_pinctrl_get_select_default(&pdev->dev);