Re: [PATCH] spi: bcm2835: Restore native CS probing when pinctrl-bcm2835 is absent

[Florian Fainelli]

On 4/2/25 04:44, Bartosz Golaszewski wrote:
> On Wed, Apr 2, 2025 at 1:37 AM Florian Fainelli
> <florian.fainelli@xxxxxxxxxxxx> wrote:
> > The lookup table forces the use of the "pinctrl-bcm2835" GPIO chip
> > provider and essentially assumes that there is going to be such a
> > provider, and if not, we will fail to set-up the SPI device.
>
> Yeah, the consumer driver itself is an unfortunate place to define the
> provider data. This could potentially be moved to gpiolib-of.c quirks.
>
> > While this is true on Raspberry Pi based systems (2835/36/37, 2711,
> > 2712), this is not true on 7712/77122 Broadcom STB systems which use the
> > SPI driver, but not the GPIO driver.
> >
> > There used to be an early check:
> >
> >         chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
> >         if (!chip)
> >                 return 0;
> >
> > which would accomplish that nicely, bring something similar back by
> > checking for the compatible strings matched by the pinctrl-bcm2835.c
> > driver, if there is no Device Tree node matching those compatible
> > strings, then we won't find any GPIO provider registered by the
> > "pinctrl-bcm2835" driver.
> >
> > Fixes: 21f252cd29f0 ("spi: bcm2835: reduce the abuse of the GPIO API")
> > Signed-off-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
> > ---
> >   drivers/spi/spi-bcm2835.c | 15 ++++++++++++++-
> >   1 file changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
> > index a5d621b94d5e..5926e004d9a6 100644
> > --- a/drivers/spi/spi-bcm2835.c
> > +++ b/drivers/spi/spi-bcm2835.c
> > @@ -1226,7 +1226,12 @@ static int bcm2835_spi_setup(struct spi_device *spi)
> >          struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
> >          struct bcm2835_spidev *target = spi_get_ctldata(spi);
> >          struct gpiod_lookup_table *lookup __free(kfree) = NULL;
> > -       int ret;
> > +       const char *pinctrl_compats[] = {
> > +               "brcm,bcm2835-gpio",
> > +               "brcm,bcm2711-gpio",
> > +               "brcm,bcm7211-gpio",
> > +       };
> > +       int ret, i;
> >          u32 cs;
> >
> >          if (!target) {
> > @@ -1291,6 +1296,14 @@ static int bcm2835_spi_setup(struct spi_device *spi)
> >                  goto err_cleanup;
> >          }
> >
> > +       for (i = 0; i < ARRAY_SIZE(pinctrl_compats); i++) {
> > +               if (of_find_compatible_node(NULL, NULL, pinctrl_compats[i]))
> > +                       break;
> > +       }
> > +
> > +       if (i == ARRAY_SIZE(pinctrl_compats))
> > +               return 0;
> > +
> >          /*
> >           * TODO: The code below is a slightly better alternative to the utter
> >           * abuse of the GPIO API that I found here before. It creates a
> > --
> > 2.34.1
>
> The fix is good for now but I'd still try to move this out of the
> driver at some point.
>
> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

Thanks, I will see what I can do on that front, but if you don't hear 
from me in the next few weeks, don't hesitate to ask again :)
--
Florian