linux-kernel - Re: [PATCH 5/6] platform/chrome: cros_ec_lpc: Correct ACPI name for Framework Laptop

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Date: Sun, 26 May 2024 01:26:26 +0000
From: Tzung-Bi Shih <tzungbi@...nel.org>
To: Ben Walsh <ben@...nut.com>
Cc: Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>,
	"Dustin L. Howett" <dustin@...ett.net>,
	Kieran Levin <ktl@...me.work>,
	Thomas Weißschuh <linux@...ssschuh.net>,
	Mario Limonciello <mario.limonciello@....com>,
	chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] platform/chrome: cros_ec_lpc: Correct ACPI name for
 Framework Laptop

On Fri, May 24, 2024 at 07:35:22PM +0100, Ben Walsh wrote:
> Tzung-Bi Shih <tzungbi@...nel.org> writes:
> 
> > From the context you provided, instead of matching "PNP0C09" in the driver,
> > it makes more sense to me (for Framework EC):
> >
> > * Mainly use DMI match.
> > * Add a quirk for looking up (acpi_get_devices()?) and binding
> >   (e.g. ACPI_COMPANION_SET()) the `adev` in cros_ec_lpc_probe().
> 
> Sorry, I don't think I provided enough context. There is already a
> platform device /sys/bus/platform/devices/PNP0C09:00 with a companion
> acpi device /sys/bus/acpi/devices/PNP0C09:00. I think it makes sense to
> bind the driver to the existing platform device.
> 
> I could add a new quirk which provides an alternative ACPI match table
> to be used instead of the default. In the default case the match_table
> will contain only "GOOG0004" as before. But in the Framework EC case the
> match table will be "PNP0C09".

I think it doesn't work as the current quirk is handling in
cros_ec_lpc_probe() which is after matching.

My original idea: would it be possible to get the `adev` in cros_ec_lpc_probe()
via any lookup API?  If yes, it could still use DMI match and get `adev` if
required.