On 12/04/2014 01:57 AM, 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 <bgolaszew...@baylibre.com>
---
  drivers/hwmon/tmp401.c | 16 ++++++++++------
  1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
index 5a72d7f..75b3210 100644
--- a/drivers/hwmon/tmp401.c
+++ b/drivers/hwmon/tmp401.c
@@ -618,8 +618,8 @@ 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;

@@ -630,8 +630,8 @@ 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;
+               dev_err(&client->dev, "Initialization failed!");
+               return config;
        }

        config_orig = config;
@@ -639,6 +639,8 @@ static void tmp401_init_client(struct tmp401_data *data,

        if (config != config_orig)
                i2c_smbus_write_byte_data(client, TMP401_CONFIG_WRITE, config);

No error check and return here ?

Guenter

+
+       return 0;
  }

  static int tmp401_detect(struct i2c_client *client,
@@ -721,7 +723,7 @@ static int tmp401_probe(struct i2c_client *client,
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct tmp401_data *data;
-       int groups = 0;
+       int groups = 0, status;

        data = devm_kzalloc(dev, sizeof(struct tmp401_data), GFP_KERNEL);
        if (!data)
@@ -732,7 +734,9 @@ static int tmp401_probe(struct i2c_client *client,
        data->kind = id->driver_data;

        /* Initialize the TMP401 chip */
-       tmp401_init_client(data, client);
+       status = tmp401_init_client(data, client);
+       if (status < 0)
+               return status;

        /* Register sysfs hooks */
        data->groups[groups++] = &tmp401_group;


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