linux-kernel - Re: [PATCH v2] pinctrl: samsung: Add support for pull-up and pull-down

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Date: Thu, 27 Jun 2024 17:27:49 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Vishnu Reddy <vishnu.reddy@...sung.com>,
 'Krzysztof Kozlowski' <krzysztof.kozlowski@...aro.org>,
 s.nawrocki@...sung.com, alim.akhtar@...sung.com, linus.walleij@...aro.org
Cc: linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org,
 linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
 pankaj.dubey@...sung.com, ravi.patel@...sung.com, gost.dev@...sung.com
Subject: Re: [PATCH v2] pinctrl: samsung: Add support for pull-up and
 pull-down

On 27/06/2024 17:22, Krzysztof Kozlowski wrote:
> On 27/06/2024 15:35, Vishnu Reddy wrote:
>>>
>>> I don't remember the code used here, but usually such choices are
>>> determined by driver match data (and flags or value customized per variant).
>> Hi, Thanks for suggestion.
>> I have gone through this and found that driver match data in this driver is stored in the __initconst section, which is freed up after kernel initialization. So we have two options:
>> 1: Keep this platform specific data in driver match data and then populate driver_data field in probe function. 
>> 2: Use compatible matching and set different values during set_config. 
>>
>> First approach will result in many changes, such as populating  driver match data for all platforms and then storing the same in driver_data in probe.
>>
>> In the second approach, we can handle this using simple if/else based on a compatible match. 
>>
>> IMO, second approach would be simpler and introduce less changes. Any suggestions from your end?
> 
> Please wrap your email according to mailing list style.
> 
> Both options are not the way because you introduce a new, different
> style of handling per-variant customization. The driver already parses
> match data and stores such per-variant-details in different places, like
> samsung_pin_bank or samsung_pinctrl_drv_data. This seems like a value
> fixed per entire device, so could go to samsung_pinctrl_drv_data.

... although maybe this matches your first option? Not sure.

Best regards,
Krzysztof