linux-kernel - Re: [PATCH] spi: cs42l43: Use actual ACPI firmware node for chip selects

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Message-ID: <aR30JbIbx3MIySjM@opensource.cirrus.com>
Date: Wed, 19 Nov 2025 16:45:25 +0000
From: Charles Keepax <ckeepax@...nsource.cirrus.com>
To: broonie@...nel.org, brgl@...ev.pl, linus.walleij@...aro.org
Cc: andy@...nel.org, p.zabel@...gutronix.de, linux-gpio@...r.kernel.org,
        linux-spi@...r.kernel.org, bartosz.golaszewski@...aro.org,
        linux-kernel@...r.kernel.org, patches@...nsource.cirrus.com
Subject: Re: [PATCH] spi: cs42l43: Use actual ACPI firmware node for chip
 selects

On Wed, Nov 19, 2025 at 04:40:17PM +0000, Charles Keepax wrote:
> On some systems the cs42l43 has amplifiers attached to its SPI
> controller that are not properly defined in ACPI. Currently software
> nodes are added to support this case, however, the chip selects
> for these devices are specified using a bit of a hack. A software
> node is added with the same name as the pinctrl driver, as the look
> up was name based this caused the GPIO looks to return the pinctrl
> driver even though the swnode is not associated with the pinctrl
> driver. This was necessary as the swnodes did not support directly
> linking to real firmware nodes.
> 
> Since commit e5d527be7e69 ("gpio: swnode: don't use the
> swnode's name as the key for GPIO lookup") changed the lookup to
> be fwnode based this hack will no longer find the pinctrl driver,
> resulting in the driver not probing. But other patches also add support
> for linking a swnode to a real fwnode node [1]. As such switch over to
> just passing the real fwnode for the pinctrl property to avoid any
> issues.
> 
> [1] https://lore.kernel.org/linux-gpio/20251106-reset-gpios-swnodes-v6-0-69aa852de9e4@linaro.org/
> 
> Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> ---

Apologies this probably should have a fixes tag, or two and I
probably should have marked it RFC. Lets have some discussion and
if people like the approach I will send a v2 with the tags
included.

Thanks,
Charles