Re: [PATCH] gpio: max732x: Use irqchip template

[Sam Protsenko <semen.protsenko@xxxxxxxxxx>]

Hi Linus,

On Tue, 21 Jul 2020 at 12:54, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>
> On Sun, Jul 19, 2020 at 6:34 PM Sam Protsenko
> <semen.protsenko@xxxxxxxxxx> wrote:
> > On Fri, 17 Jul 2020 at 17:19, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> > >
> > > This makes the driver use the irqchip template to assign
> > > properties to the gpio_irq_chip instead of using the
> > > explicit calls to gpiochip_irqchip_add_nested() and
> > > gpiochip_set_nested_irqchip(). The irqchip is instead
> > > added while adding the gpiochip.
> > >
> > > Cc: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> > > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
>
> > I can test it on my MAX7325 board with BeagleBone Black in a day or
> > two.
>
> Thanks! No hurry.
>
> > Do you want me to verify your patch on top of linux-mainline or
> > linux-next?
>
> Either should work.
>
> > Also, is there any specific stuff you want me to look at,
> > or making sure there are no regressions w.r.t. IRQ from the chip is
> > enough?
>
> Just that really, that the IRQs happen as before.
>

Just tested it on my MAX7325 board [1], by adding gpio-keys and
gpio-leds to BBB dts [2]. Alas, the patch seems to be breaking IRQs.
Before the patch, I can see gpio-buttons appear in /proc/interrupts
and dmesg is clear of errors. After applying the patch, no gpio-keys
appear in /proc/interrupts and dmesg is reporting errors like this:

    irq: no irq domain found for max7325@68 !

This is probably because the patch is setting gpio_chip structure
fields after devm_gpiochip_add_data() was executed. Next hacky change
fixes it:

<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>
@@ -695,11 +695,11 @@ static int max732x_probe(struct i2c_client *client,
                        return ret;
        }

-       ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip);
+       ret = max732x_irq_setup(chip, id);
        if (ret)
                return ret;

-       ret = max732x_irq_setup(chip, id);
+       ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip);
        if (ret)
                return ret;
 <<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>

I didn't check if it's a correct fix, so the diff above is only to
check the idea. Anyway, if you send v2 I can retest it, as my setup is
ready.

Thanks!

[1] https://github.com/joe-skb7/max7325-pcb
[2] https://github.com/joe-skb7/linux-mainline-bbb-max732x/commits/max732_bbb_test

> Yours,
> Linus Walleij