Re: [PATCH v3 1/4] media: i2c: ov9282: Fix reset-gpio logical state

[Krzysztof Kozlowski <krzk@kernel.org>]

On 03/12/2025 11:00, Loic Poulain wrote:
> Hi Laurent,
> 
> On Mon, Nov 17, 2025 at 6:30 PM Sakari Ailus
> <sakari.ailus@linux.intel.com> wrote:
>>
>> Hi Loic,
>>
>> On Fri, Nov 14, 2025 at 02:38:19PM +0100, Loic Poulain wrote:
>>> Ensure reset state is low in the power-on state and high in the
>>> power-off state (assert reset). Note that the polarity is abstracted
>>> by the GPIO subsystem, so the logic level reflects the intended reset
>>> behavior.
>>
>> That's an interesting approach to fix DTS gone systematically wrong.
>>
>> I was thinking of the drivers that have this issue, too, but I would have
>> introduced a new GPIO under a different name (many sensors use "enable",
>> too). Any thoughts?
>>
>> Cc Laurent.
> 
> Do you have any feedback on this change?
> 
>>
>>>
>>> To maintain backward compatibility with DTS files that use an incorrect
>>> flag, we implement a mechanism similar to:
>>>   commit 738455858a2d ("ASoC: codecs: wsa881x: Use proper shutdown GPIO polarity")

Heh, so you even found my commit which exactly points which cases are
broken, but you:

...


>>> +     /*
>>> +      * Backwards compatibility work-around.
>>> +      *
>>> +      * The reset GPIO is active-low, but the driver has always used the
>>> +      * gpiod API with inverted logic. As a result, the DTS had to
>>> +      * incorrectly mark the GPIO as active-high to compensate for this
>>> +      * behavior. Changing the flag in the driver now would break backward
>>> +      * compatibility with existing DTS configurations. To address this,
>>> +      * we add a simple value inversion so the driver works with both old
>>> +      * and new DTS.

claim everything is working fine. Please read my commit.


Best regards,
Krzysztof