Re: [PATCH 7/9] media: atomisp: gc0310: Remove gc0310_s_config() function

[Hans de Goede <hdegoede@redhat.com>]

HI,

On 5/19/23 12:32, Andy Shevchenko wrote:
> On Thu, May 18, 2023 at 6:32 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> gc0310_s_config() used to call camera_sensor_platform_data.csi_cfg() back
>> when the gc0310 driver was still using the atomisp_gmin_platform code
>> for power-management.
>>
>> Now it is just a weirdly named wrapper around gc0310_detect(), drop
>> gc0310_s_config() and make probe() call gc0310_detect() directly.
> 
> ...
> 
>> -       ret = i2c_smbus_read_word_swapped(client, GC0310_SC_CMMN_CHIP_ID_H);
>> +       ret = pm_runtime_get_sync(&client->dev);
>> +       if (ret >= 0)
>> +               ret = i2c_smbus_read_word_swapped(client, GC0310_SC_CMMN_CHIP_ID_H);
>> +       pm_runtime_put(&client->dev);
>>         if (ret < 0) {
>>                 dev_err(&client->dev, "read sensor_id failed: %d\n", ret);
>>                 return -ENODEV;
> 
> Not sure if it's good to have in this patch, but above can be cleaned up to
> 
>       pm_runtime_get_sync(&client->dev);
>       ret = i2c_smbus_read_word_swapped(client, GC0310_SC_CMMN_CHIP_ID_H);
>       pm_runtime_put(&client->dev);
>       if (ret < 0) {
>                dev_err(&client->dev, "read sensor_id failed: %d\n", ret);
>                return ret;
>       }
> 
> But I don't know what will be the response on the I2C bus if the
> device is powered off.

In my experience the i2c bus tends to get stuck when using it with
the sensor powered down and unsticking it is tricky (seems to
require a full i2c-controller reset).

So it is best to not even try if the pm_runtime_get_sync() fails
for some reason.

Regards,

Hans