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SubjectRe: [PATCH v2 3/3] hwmon: tmp401: bail-out from tmp401_probe() in case of write errors
On Thu, Dec 04, 2014 at 04:22:54PM +0100, Bartosz Golaszewski wrote:
> The return value of i2c_smbus_read_byte_data() is checked in
> tmp401_init_client(), but only a warning is printed and the device is
> registered anyway. This leads to devices being registered even if they
> cannot be physically detected.
>
> Bail-out from probe in case of write errors and notify the user.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
> drivers/hwmon/tmp401.c | 29 ++++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
> index a5f0973..ce7e579 100644
> --- a/drivers/hwmon/tmp401.c
> +++ b/drivers/hwmon/tmp401.c
> @@ -618,10 +618,10 @@ static const struct attribute_group tmp432_group = {
> * Begin non sysfs callback code (aka Real code)
> */
>
> -static void tmp401_init_client(struct tmp401_data *data,
> - struct i2c_client *client)
> +static int tmp401_init_client(struct tmp401_data *data,
> + struct i2c_client *client)
> {
> - int config, config_orig;
> + int config, config_orig, status;
>
> /* Set the conversion rate to 2 Hz */
> i2c_smbus_write_byte_data(client, TMP401_CONVERSION_RATE_WRITE, 5);
> @@ -629,16 +629,21 @@ static void tmp401_init_client(struct tmp401_data *data,
>
> /* Start conversions (disable shutdown if necessary) */
> config = i2c_smbus_read_byte_data(client, TMP401_CONFIG_READ);
> - if (config < 0) {
> - dev_warn(&client->dev, "Initialization failed!\n");
> - return;
> - }
> + if (config < 0)
> + return config;
>
> config_orig = config;
> config &= ~TMP401_CONFIG_SHUTDOWN;
>
> - if (config != config_orig)
> - i2c_smbus_write_byte_data(client, TMP401_CONFIG_WRITE, config);
> + if (config != config_orig) {
> + status = i2c_smbus_write_byte_data(client,
> + TMP401_CONFIG_WRITE,
> + config);
> + if (status < 0)
> + return status;

Just pre-initialize status to 0 and return status unconditionally.

Thanks,
Guenter


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