Re: [PATCH RFC v2] media: i2c: mt9p031: add OF support

[Prabhakar Lad <prabhakar.csengg@gmail.com>]

Hi Sascha,

Thanks for the quick review.

On Thu, May 2, 2013 at 12:25 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Thu, May 02, 2013 at 11:52:34AM +0530, Prabhakar Lad wrote:
>> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
>>
>> add OF support for the mt9p031 sensor driver.
>> Alongside this patch sorts the header inclusion alphabetically.
[Snip]

>> +#if defined(CONFIG_OF)
>> +static struct mt9p031_platform_data *
>> +     mt9p031_get_pdata(struct i2c_client *client)
>> +
>> +{
>> +     if (client->dev.of_node) {
>
> By inverting the logic here and returning immediately you can safe an
> indention level for the bulk of this function.
>
OK

>> +             struct device_node *np;
>> +             struct mt9p031_platform_data *pdata;
>> +
>> +             np = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
>> +             if (!np)
>> +                     return NULL;
>> +
>> +             pdata = devm_kzalloc(&client->dev,
>> +                                  sizeof(struct mt9p031_platform_data),
>> +                                  GFP_KERNEL);
>> +             if (!pdata) {
>> +                     dev_err(&client->dev,
>> +                             "mt9p031 failed allocate memeory\n");
>> +                     return NULL;
>
> s/memeory/memory/
>
> Better drop this message completely. If you are really out of memory
> you'll notice it quite fast anyway.
>
alright I'll drop the message.

>> +             }
>> +             pdata->reset = of_get_named_gpio(client->dev.of_node,
>> +                                              "gpio-reset", 0);
>> +             if (!gpio_is_valid(pdata->reset))
>> +                     pdata->reset = -1;
>> +
>> +             if (of_property_read_u32(np, "input-clock-frequency",
>> +                                      &pdata->ext_freq))
>> +                     return NULL;
>> +
>> +             if (of_property_read_u32(np, "pixel-clock-frequency",
>> +                                      &pdata->target_freq))
>> +                     return NULL;
>
> returning NULL here means that when these properties are missing the
> driver bails out with the message "No platform data\n" which is not
> very helpful for users. How about just ignoring this here and return
> pdata? The driver will probably print a more useful message later when
> it notices that the clock params are invalid.
>
Yes would be good idea of not returning NULL.

>> +
>> +             return pdata;
>> +     }
>> +
>> +     return client->dev.platform_data;
>> +}
>> +#else
>> +static struct mt9p031_platform_data *
>> +     mt9p031_get_pdata(struct i2c_client *client)
>> +{
>> +     return client->dev.platform_data;
>> +}
>> +#endif
>> +
>>  static int mt9p031_probe(struct i2c_client *client,
>>                        const struct i2c_device_id *did)
>>  {
>> -     struct mt9p031_platform_data *pdata = client->dev.platform_data;
>> +     struct mt9p031_platform_data *pdata = mt9p031_get_pdata(client);
>>       struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
>>       struct mt9p031 *mt9p031;
>>       unsigned int i;
>> @@ -1070,8 +1120,16 @@ static const struct i2c_device_id mt9p031_id[] = {
>>  };
>>  MODULE_DEVICE_TABLE(i2c, mt9p031_id);
>>
>> +static const struct of_device_id mt9p031_of_match[] = {
>> +     { .compatible = "aptina,mt9p031", },
>> +     { .compatible = "aptina,mt9p031m", },
>> +     {},
>> +};
>
> I would have expected something like:
>
> static const struct of_device_id mt9p031_of_match[] = {
>         {
>                 .compatible = "aptina,mt9p031-sensor",
>                 .data = (void *)MT9P031_MODEL_COLOR,
>         }, {
>                 .compatible = "aptina,mt9p031m-sensor",
>                 .data = (void *)MT9P031_MODEL_MONOCHROME,
>         }, {
>                 /* sentinel */
>         },
> };
>
>         of_id = of_match_device(mt9p031_of_match, &client->dev);
>         if (of_id)
>                 mt9p031->model = (enum mt9p031_model)of_id->data;
>
> To handle monochrome sensors.
>
OK will do the same.

Regards,
--Prabhakar Lad