Re: [RFCv3 PATCH 3/4] gpiolib: override irq_enable/disable

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, Aug 31, 2018 at 4:37 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote:

> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> When using the gpiolib irqchip helpers install irq_enable/disable
> hooks for the irqchip to ensure that gpiolib knows when the irq
> is enabled or disabled, allowing drivers to disable the irq and then
> use it as an output pin, and later switch the direction to input and
> re-enable the irq.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>

Overall I'm a big fan of this as you already know!

> +       /*
> +        * It is possible for a driver to override this, but only if the
> +        * alternative functions are both implemented.
> +        */
> +       if (!irqchip->irq_request_resources &&
> +           !irqchip->irq_release_resources) {
> +               irqchip->irq_request_resources = gpiochip_irq_reqres;
> +               irqchip->irq_release_resources = gpiochip_irq_relres;
> +       }
> +
> +       gpiochip->irq.irq_enable = irqchip->irq_enable;
> +       gpiochip->irq.irq_disable = irqchip->irq_disable;
> +
> +       irqchip->irq_enable = gpiochip_irq_enable;
> +       irqchip->irq_disable = gpiochip_irq_disable;

Actully the latter method, to use local copies of the enable/disable
function pointers in gpiochip->irq is what we should use also
for the request/release_resources callbacks.

The chips that actually use local irq_request_resources and
irq_release resources AND GPIOLIB_IRQCHIP are limited to:

drivers/gpio/gpio-dwapb.c
drivers/pinctrl/intel/pinctrl-intel.c
drivers/pinctrl/pinctrl-st.c
drivers/pinctrl/qcom/pinctrl-msm.c

As far as I can tell.

They probably all have some boilerplate related to reimplementing
part of the core functions.

But we can fix that in a separate patch after this.

Yours,
Linus Walleij