linux-kernel - Re: [PATCH] software node: Implement device_get_match

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Date: Wed, 20 Mar 2024 12:39:33 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	Daniel Scally <djrscally@...il.com>,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-acpi@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] software node: Implement device_get_match_data fwnode
 callback

+Cc: Vladimir

On Tue, Mar 19, 2024 at 07:42:22AM +0800, Sui Jingfeng wrote:
> This makes it possible to support (and/or test) a few drivers that
> originates from DT World on the x86-64 platform. Originally, those
> drivers using the of_device_get_match_data() function to get match
> data. For example, drivers/gpu/drm/bridge/simple-bridge.c and
> drivers/gpu/drm/bridge/display-connector.c. Those drivers works very
> well in the DT world, however, there is no counterpart to
> of_device_get_match_data() when porting them to the x86 platform,
> because x86 CPUs lack DT support.

This is not true.

First of all, there is counter part that called device_get_match_data().
Second, there *is* DT support for the _selected_ x86 based platforms.

> By replacing it with device_get_match_data() and creating a software
> graph that mimics the OF graph, everything else works fine, except that
> there isn't an out-of-box replacement for the of_device_get_match_data()
> function. Because the software node backend of the fwnode framework lacks
> an implementation for the device_get_match_data callback.

device_get_match_data

> Implement device_get_match_data fwnode callback fwnode callback to fill

device_get_match_data

> this gap. Device drivers or platform setup codes are expected to provide
> a "compatible" string property. The value of this string property is used
> to match against the compatible entries in the of_device_id table. Which
> is consistent with the original usage style.

Why do you need to implement the graph in the board file?

..

Have you seen this discussion?
https://lore.kernel.org/lkml/20230223203713.hcse3mkbq3m6sogb@skbuf/

-- 
With Best Regards,
Andy Shevchenko