linux-kernel - Re: [v1,1/3] drm/panel: ili9341: Correct use of device property APIs

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Date: Thu, 2 May 2024 11:32:08 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: Neil Armstrong <neil.armstrong@...aro.org>,
	Randy Dunlap <rdunlap@...radead.org>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	Jessica Zhang <quic_jesszhan@...cinc.com>,
	Sam Ravnborg <sam@...nborg.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>
Subject: Re: [v1,1/3] drm/panel: ili9341: Correct use of device property APIs

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.

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.

-- 
With Best Regards,
Andy Shevchenko