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Message-ID: <e1d01191-fd96-4b17-b223-7147eb427315@linux.dev>
Date: Fri, 3 May 2024 00:25:17 +0800
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Subject: Re: [v1,1/3] drm/panel: ili9341: Correct use of device property APIs
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Neil Armstrong <neil.armstrong@linaro.org>,
 Randy Dunlap <rdunlap@infradead.org>, dri-devel@lists.freedesktop.org,
 linux-kernel@vger.kernel.org, Jessica Zhang <quic_jesszhan@quicinc.com>,
 Sam Ravnborg <sam@ravnborg.org>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
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From: Sui Jingfeng <sui.jingfeng@linux.dev>
In-Reply-To: <ZjNPiBvLF3WcBftn@smile.fi.intel.com>
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Hi,


On 2024/5/2 16:32, Andy Shevchenko wrote:
> On Wed, May 01, 2024 at 12:27:14AM +0800, Sui Jingfeng wrote:
>> On 2024/4/30 22:13, Andy Shevchenko wrote:
>>> On Fri, Apr 26, 2024 at 05:13:43AM +0800, Sui Jingfeng wrote:
> ...
>
>>> the former might be subdivided to "is it swnode backed or real fwnode one?"
>>>
>> Yeah,
>> On non-DT cases, it can be subdivided to swnode backed case and ACPI fwnode backed case.
>>
>>   - For swnode backed case: the device_get_match_data() don't has a implemented backend.
>>   - For ACPI fwnode backed case: the device_get_match_data() has a implemented backend.
>>
>> But the driver has *neither* software node support
> True.
>
>> nor ACPI support,
> Not true.

Why this is not true? Are you means that the panel-ilitek-ili9341 driver has ACPI support?
I'm asking because I don't see struct acpi_device_id related stuff in that source file,
am I miss something?


> So, slow down and take your time to get into the code and understand how it works.
>
>> so that the rotation property can not get and ili9341_dpi_probe() will fails.
>> So in total, this is not a 100% correct use of device property APIs.
>>
>> But I'm fine that if you want to leave(ignore) those less frequent use cases temporarily,
>> there may have programmers want to post patches, to complete the missing in the future.
>>
>> So, there do have some gains on non-DT cases.
>>
>>   - As you make it be able to compiled on X86 with the drm-misc-defconfig.
>>   - You cleanup the code up (at least patch 2 in this series is no obvious problem).
>>   - You allow people to modprobe it, and maybe half right and half undefined.
>>
>> But you do helps moving something forward, so congratulations for the wake up.

-- 
Best regards,
Sui