Hi Daniel,

> A recent patch refactored i2c error handling in the register read/write
> path.  This adds similar handling to the other i2c paths used in fw_update
> and bootloader state detection.
> 
> The generic i2c layer can return values indicating a partial transaction.
> From the atmel_mxt driver's perspective, this is an IO error, so we use
> some helper functions to convert these partial transfers to -EIO in a
> uniform way.  Other error codes might still be useful, though, so we pass
> them up unmodified.
> 
> Signed-off-by: Daniel Kurtz <djku...@chromium.org>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 92 
> +++++++++++++++++++-------------
>  1 file changed, 54 insertions(+), 38 deletions(-)

Nice cleanup, but some comments below.

> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c 
> b/drivers/input/touchscreen/atmel_mxt_ts.c
> index d04f810..a222bd8 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -324,16 +324,62 @@ static void mxt_dump_message(struct device *dev,
>               message->reportid, 7, message->message);
>  }
>  
> +static int mxt_i2c_recv(struct i2c_client *client, u8 *buf, size_t count)
> +{
> +     int ret;
> +
> +     ret = i2c_master_recv(client, buf, count);
> +     if (ret == count) {
> +             ret = 0;
> +     } else if (ret != count) {

Eh, implied logic. Also, no need for an else here, just return 0 above.

> +             ret = (ret < 0) ? ret : -EIO;
> +             dev_err(&client->dev, "i2c recv failed (%d)\n", ret);
> +     }
> +
> +     return ret;
> +}
> +
> +static int mxt_i2c_send(struct i2c_client *client, const u8 *buf, size_t 
> count)
> +{
> +     int ret;
> +
> +     ret = i2c_master_send(client, buf, count);
> +     if (ret == count) {
> +             ret = 0;
> +     } else if (ret != count) {

Ditto...

> +             ret = (ret < 0) ? ret : -EIO;
> +             dev_err(&client->dev, "i2c send failed (%d)\n", ret);
> +     }
> +
> +     return ret;
> +}
> +
> +static int mxt_i2c_transfer(struct i2c_client *client, struct i2c_msg *msgs,
> +             size_t count)
> +{
> +     int ret;
> +
> +     ret = i2c_transfer(client->adapter, msgs, count);
> +     if (ret == count) {
> +             ret = 0;

return 0;

> +     } else {

skip

> +             ret = (ret < 0) ? ret : -EIO;
> +             dev_err(&client->dev, "i2c transfer failed (%d)\n", ret);
> +     }
> +
> +     return ret;
> +}
> +
>  static int mxt_check_bootloader(struct i2c_client *client,
>                                    unsigned int state)
>  {
>       u8 val;
> +     int ret;
>  
>  recheck:
> -     if (i2c_master_recv(client, &val, 1) != 1) {
> -             dev_err(&client->dev, "%s: i2c recv failed\n", __func__);
> -             return -EIO;
> -     }
> +     ret = mxt_i2c_recv(client, &val, 1);
> +     if (ret)
> +             return ret;
>  
>       switch (state) {
>       case MXT_WAITING_BOOTLOAD_CMD:
> @@ -363,23 +409,13 @@ static int mxt_unlock_bootloader(struct i2c_client 
> *client)
>       buf[0] = MXT_UNLOCK_CMD_LSB;
>       buf[1] = MXT_UNLOCK_CMD_MSB;
>  
> -     if (i2c_master_send(client, buf, 2) != 2) {
> -             dev_err(&client->dev, "%s: i2c send failed\n", __func__);
> -             return -EIO;
> -     }
> -
> -     return 0;
> +     return mxt_i2c_send(client, buf, 2);
>  }
>  
>  static int mxt_fw_write(struct i2c_client *client,
>                            const u8 *data, unsigned int frame_size)
>  {
> -     if (i2c_master_send(client, data, frame_size) != frame_size) {
> -             dev_err(&client->dev, "%s: i2c send failed\n", __func__);
> -             return -EIO;
> -     }
> -
> -     return 0;
> +     return mxt_i2c_send(client, data, frame_size);
>  }
>  
>  static int __mxt_read_reg(struct i2c_client *client,
> @@ -387,7 +423,6 @@ static int __mxt_read_reg(struct i2c_client *client,
>  {
>       struct i2c_msg xfer[2];
>       u8 buf[2];
> -     int ret;
>  
>       buf[0] = reg & 0xff;
>       buf[1] = (reg >> 8) & 0xff;
> @@ -404,17 +439,7 @@ static int __mxt_read_reg(struct i2c_client *client,
>       xfer[1].len = len;
>       xfer[1].buf = val;
>  
> -     ret = i2c_transfer(client->adapter, xfer, 2);
> -     if (ret == 2) {
> -             ret = 0;
> -     } else {
> -             if (ret >= 0)
> -                     ret = -EIO;
> -             dev_err(&client->dev, "%s: i2c transfer failed (%d)\n",
> -                     __func__, ret);
> -     }
> -
> -     return ret;
> +     return mxt_i2c_transfer(client, xfer, 2);
>  }
>  
>  static int mxt_read_reg(struct i2c_client *client, u16 reg, u8 *val)
> @@ -438,16 +463,7 @@ static int __mxt_write_reg(struct i2c_client *client, 
> u16 reg, u16 len,
>       buf[1] = (reg >> 8) & 0xff;
>       memcpy(&buf[2], val, len);
>  
> -     ret = i2c_master_send(client, buf, count);
> -     if (ret == count) {
> -             ret = 0;
> -     } else {
> -             if (ret >= 0)
> -                     ret = -EIO;
> -             dev_err(&client->dev, "%s: i2c send failed (%d)\n",
> -                     __func__, ret);
> -     }
> -
> +     ret = mxt_i2c_send(client, buf, count);
>       kfree(buf);
>       return ret;
>  }
> -- 
> 1.8.1
> 

Thanks,
Henrik
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