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Date: Wed, 20 Feb 2013 21:37:35 +0100
From: "Henrik Rydberg" <rydberg@...omail.se>
To: Daniel Kurtz <djkurtz@...omium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Bill Pemberton <wfp5p@...ginia.edu>,
Nick Dyer <nick.dyer@...ev.co.uk>,
Benson Leung <bleung@...omium.org>,
linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
Yufeng Shen <miletus@...omium.org>
Subject: Re: [PATCH v2] Input: atmel_mxt_ts - refactor i2c error handling
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. Note that in the partial transfer case, we log the
> number of bytes partially transferred, and not -EIO.
>
> Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
> ---
> Changes from V1:
> - simplified implied logic (thanks Henrik!)
> - error print the partial number of bytes received, not -EIO
>
> drivers/input/touchscreen/atmel_mxt_ts.c | 83 +++++++++++++++++---------------
> 1 file changed, 45 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index d04f810..3d56d5f 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -324,16 +324,53 @@ 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)
> + return 0;
> +
> + dev_err(&client->dev, "i2c recv failed (%d)\n", ret);
> + return (ret < 0) ? ret : -EIO;
> +}
> +
> +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)
> + return 0;
> +
> + dev_err(&client->dev, "i2c send failed (%d)\n", ret);
> + return (ret < 0) ? ret : -EIO;
> +}
> +
> +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)
> + return 0;
> +
> + dev_err(&client->dev, "i2c transfer failed (%d)\n", ret);
> + return (ret < 0) ? ret : -EIO;
> +}
> +
> 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 +400,13 @@ 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 +414,6 @@ 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 +430,7 @@ 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 +454,7 @@ 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
>
Reviewed-by: Henrik Rydberg <rydberg@...omail.se>
Thanks,
Henrik
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