linux-kernel - Re: [PATCH] pinctrl: qcom: spmi-gpio: make the irqchip immutable

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Message-ID: <CAOX2RU4MpyEQ0RtcrZ07VXRbB+SWWU=1zWfYUXhQFtvh=MCiDw@mail.gmail.com>
Date:   Wed, 13 Jul 2022 14:33:32 +0200
From:   Robert Marko <robimarko@...il.com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        linux-gpio@...r.kernel.org,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: qcom: spmi-gpio: make the irqchip immutable

On Wed, 13 Jul 2022 at 13:47, Marc Zyngier <maz@...nel.org> wrote:
>
> On 2022-07-13 12:08, Robert Marko wrote:
> > On Tue, 12 Jul 2022 at 17:12, Marc Zyngier <maz@...nel.org> wrote:
> >>
> >> On Tue, 12 Jul 2022 13:44:45 +0100,
> >> Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org> wrote:
> >> >
> >> > On Tue, Jul 12, 2022 at 11:42:32AM +0100, Marc Zyngier wrote:
> >> > > On Fri, 24 Jun 2022 20:51:12 +0100,
> >> > > Robert Marko <robimarko@...il.com> wrote:
> >> > > >
> >> > > > Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as
> >> > > > immutable") added a warning to indicate if the gpiolib is altering the
> >> > > > internals of irqchips.
> >> > > >
> >> > > > Following this change the following warning is now observed for the SPMI
> >> > > > PMIC pinctrl driver:
> >> > > > gpio gpiochip1: (200f000.spmi:pmic@0:gpio@...0): not an immutable chip, please consider fixing it!
> >> > > >
> >> > > > Fix this by making the irqchip in the SPMI PMIC pinctrl driver immutable.
> >> > > >
> >> > > > Signed-off-by: Robert Marko <robimarko@...il.com>
> >> > > > ---
> >> > > >  drivers/pinctrl/qcom/pinctrl-spmi-gpio.c | 22 ++++++++++++----------
> >> > > >  1 file changed, 12 insertions(+), 10 deletions(-)
> >> > > >
> >> > > > diff --git a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> >> > > > index c3255b0bece4..406ee0933d0b 100644
> >> > > > --- a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> >> > > > +++ b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
> >> > > > @@ -171,7 +171,6 @@ struct pmic_gpio_state {
> >> > > >   struct regmap   *map;
> >> > > >   struct pinctrl_dev *ctrl;
> >> > > >   struct gpio_chip chip;
> >> > > > - struct irq_chip irq;
> >> > > >   u8 usid;
> >> > > >   u8 pid_base;
> >> > > >  };
> >> > > > @@ -988,6 +987,17 @@ static void *pmic_gpio_populate_parent_fwspec(struct gpio_chip *chip,
> >> > > >   return fwspec;
> >> > > >  }
> >> > > >
> >> > > > +static const struct irq_chip spmi_gpio_irq_chip = {
> >> > > > + .name           = "spmi-gpio",
> >> > > > + .irq_ack        = irq_chip_ack_parent,
> >> > > > + .irq_mask       = irq_chip_mask_parent,
> >> > > > + .irq_unmask     = irq_chip_unmask_parent,
> >> > >
> >> > > No, this is wrong. Please look at the documentation to see how you
> >> > > must now directly call into the gpiolib helpers for these two
> >> > > callbacks.
> >> > >
> >> >
> >> > IIUC, you are referring to gpiochip_disable_irq() and
> >> > gpiochip_enable_irq() APIs.
> >>
> >> I am indeed.
> >>
> >> > These APIs are supposed to let the gpiolib know about that the IRQ
> >> > usage of these GPIOs. But for the case of hierarchial IRQ domain,
> >> > isn't the parent is going to do that?
> >>
> >> Why would it? The parent has no clue about what sits above it. In a
> >> hierarchical configuration, each level is responsible for its own
> >> level, and the GPIO layer should be responsible for its own
> >> management.
> >>
> >> > Please correct me if I'm wrong.
> >>
> >> I'm afraid you are, and this patch is a fairly obvious change in
> >> behaviour, as the callbacks you mention above are not called anymore,
> >> while they were before.
> >>
> >> If they are not necessary (for reasons I can't fathom), then this
> >> should be clearly explained.
> >
> > Hi Marc,
> > I will look at IRQ GPIO docs, but in this case, then we have more
> > conversions that
> > are not correct.
>
> Then please point them out.

Oh, now I get the issue, I was misunderstanding it completely.
gpiochip_enable_irq and gpiochip_disable_irq are not being called
at all.

However, I dont see them being called before the conversion as well.
I am not really familiar with the PMIC IRQ-s, looked like an easy conversion
to get rid of the warning.

Manivannan can you shed some light on this?

Regards,
Robert





>
>          M.
> --
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