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

   1 From 0d1ee1f265cf9730feb214ddd18bc430c0800e8b Mon Sep 17 00:00:00 2001
   2 From: Tim Harvey <tharvey@gateworks.com>
   3 Date: Tue, 10 Sep 2013 21:42:29 +0200
   4 Subject: [PATCH] i2c: imx: retry on NAK
   5
   6 In case of busy i2c try again to get ACK.
   7
   8 Signed-off-by: Tim Harvey <tharvey@gateworks.com>
   9 Tested-by: Luka Perkov <luka@openwrt.org>
  10 ---
  11  drivers/i2c/busses/i2c-imx.c | 4 +++-
  12  1 file changed, 3 insertions(+), 1 deletion(-)
  13
  14 --- a/drivers/i2c/busses/i2c-imx.c
  15 +++ b/drivers/i2c/busses/i2c-imx.c
  16 @@ -62,6 +62,7 @@
  17
  18  /* Default value */
  19  #define IMX_I2C_BIT_RATE       100000  /* 100kHz */
  20 +#define IMX_I2C_MAX_RETRIES    3       /* number of retries to attempt */
  21
  22  /* IMX I2C registers */
  23  #define IMX_I2C_IADR   0x00    /* i2c slave address */
  24 @@ -198,7 +199,7 @@ static int i2c_imx_acked(struct imx_i2c_
  25  {
  26         if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
  27                 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
  28 -               return -EIO;  /* No ACK */
  29 +               return -EAGAIN; /* try again */
  30         }
  31
  32         dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
  33 @@ -533,6 +534,7 @@ static int __init i2c_imx_probe(struct p
  34         i2c_imx->adapter.dev.parent     = &pdev->dev;
  35         i2c_imx->adapter.nr             = pdev->id;
  36         i2c_imx->adapter.dev.of_node    = pdev->dev.of_node;
  37 +       i2c_imx->adapter.retries        = IMX_I2C_MAX_RETRIES;
  38         i2c_imx->base                   = base;
  39
  40         pinctrl = devm_pinctrl_get_select_default(&pdev->dev);