linux-kernel - Re: [PATCH RFT/RFC 2/2] mfd: cs42l43: use GPIO machine lookup for cs-gpios

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Message-ID: <CAMRc=Md4jHrHxHUOM=eFuWRSaEO9jFEoHGTjEEJLj9w6E53gOA@mail.gmail.com>
Date: Wed, 19 Nov 2025 16:35:07 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
	David Rhodes <david.rhodes@...rus.com>, Richard Fitzgerald <rf@...nsource.cirrus.com>, 
	Lee Jones <lee@...nel.org>, Mark Brown <broonie@...nel.org>, 
	Maciej Strozek <mstrozek@...nsource.cirrus.com>, 
	Charles Keepax <ckeepax@...nsource.cirrus.com>, Andy Shevchenko <andy@...nel.org>, 
	Philipp Zabel <p.zabel@...gutronix.de>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-sound@...r.kernel.org, patches@...nsource.cirrus.com, 
	linux-spi@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH RFT/RFC 2/2] mfd: cs42l43: use GPIO machine lookup for cs-gpios

On Wed, Nov 19, 2025 at 4:21 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>
> Currently the SPI driver sets up a software node referencing the GPIO
> controller exposing the chip-select GPIO but this node never gets
> attached to the actual GPIO provider. The lookup uses the weird way GPIO
> core performs the software node lookup by the swnode's name. We want to
> switch to a true firmware node lookup in GPIO core but without the true
> link, this driver will break.
>
> We can't use software nodes as only one software node per device is
> allowed and the ACPI node the MFD device uses has a secondary node
> already attached.
>
> Let's switch to GPIO machine lookup instead.
>
> Fixes: 439fbc97502a ("spi: cs42l43: Add bridged cs35l56 amplifiers")
> Reported-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> Closes: https://lore.kernel.org/all/aRyf7qDdHKABppP8@opensource.cirrus.com/
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>
> +static struct gpiod_lookup_table cs42l43_gpio_lookup = {
> +       .dev_id = "cs42l43-spi",
> +       .table = {
> +               GPIO_LOOKUP("cs42l43-pinctrl", 0, "cs", GPIO_ACTIVE_LOW),
> +               GPIO_LOOKUP(INIT_ERR_PTR(-ENOENT), 0, "cs", 0),

I sent the wrong version, sorry. This should have been:

GPIO_LOOKUP_IDX("cs42l43-pinctrl", 0, "cs", 0, GPIO_ACTIVE_LOW),
GPIO_LOOKUP_IDX(INIT_ERR_PTR(-ENOENT), 0, "cs", 1, 0),

Charles: Can you fix it up yourself before testing?

Bart