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

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Message-ID: <aR34h1H+isZQLEdk@opensource.cirrus.com>
Date: Wed, 19 Nov 2025 17:04:07 +0000
From: Charles Keepax <ckeepax@...nsource.cirrus.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: broonie@...nel.org, brgl@...ev.pl, linus.walleij@...aro.org,
        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 06:49:57PM +0200, Andy Shevchenko wrote:
> On Wed, Nov 19, 2025 at 6:40 PM Charles Keepax
> <ckeepax@...nsource.cirrus.com> 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/
> >
> 
> This can be
> 
> Link: ... [1]
> 
> actually.

Thanks will fixup for v2.

> > Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> > ---
> >
> > Ok here is what I would propose to fix this one, IMPORTANT NOTE: this
> > does depend on the first four patches of the linked chain which I don't
> > think are merged yet. But I would argue if we are removing the name
> > based look up, we should add support for fwnodes at the same time.
> 
> You mean it has functional dependency and not a compile-time one?

Apologies that wasn't clear, both.

> > +               args[0].fwnode = fwnode;
> 
> You can assign entries directly here as
> 
>   args = devm_kmalloc_array(...);
>   ...
>   args[0] = SOFTWARE_NODE_REFERENCE(...);
>   args[1] = SOFTWARE_NODE_REFERENCE(&swnode_gpio_undefined),

Yes thank you I will fix that up for v2 as well, I was a little
rushing this one out.

Thanks,
Charles