Re: [PATCH] pinctrl: qcom: support gpio_chip .set_config call

[Shawn Guo <shawn.guo@linaro.org>]

On Mon, Mar 01, 2021 at 07:07:03PM +0200, Andy Shevchenko wrote:
> On Sun, Feb 28, 2021 at 4:55 AM Shawn Guo <shawn.guo@linaro.org> wrote:
> >
> > In case of ACPI boot, GPIO core does the right thing to parse GPIO pin
> > configs from ACPI table, and call into gpio_chip's .set_config hook for
> > setting them up.  It enables such support on qcom platform by using
> > generic config function, which in turn calls into .pin_config_set of
> > pinconf for setting up hardware.  For qcom platform, it's possible to
> > reuse pin group config functions for pin config hooks, because every pin
> > is maintained as a single group.
> >
> > This change fixes the problem that Touchpad of Lenovo Flex 5G laptop
> > doesn't work with ACPI boot, because PullUp config of Touchpad GpioInt
> > pin is not set up by kernel driver.
> 
> by the kernel
> 
> ...
> 
> >         .pin_config_group_get   = msm_config_group_get,
> >         .pin_config_group_set   = msm_config_group_set,
> > +       .pin_config_get         = msm_config_group_get,
> > +       .pin_config_set         = msm_config_group_set,
> 
> This can't be right. They have different semantics.

As mentioned in the commit log, this works considering every pin is
maintained as a single group on Qualcomm platform.  So configuring one
pin is essentially to configure the group containing the pin.  I can do
something like below, if you think that's easier to understand.

static int msm_config_pin_get(struct pinctrl_dev *pctldev, unsigned int pin,
                              unsigned long *config)
{
        return msm_config_group_get(pctldev, pin, config);
}

static int msm_config_pin_set(struct pinctrl_dev *pctldev, unsigned pin,
                              unsigned long *configs, unsigned num_configs)
{
        return msm_config_group_set(pctldev, pin, configs, num_configs);
}

static const struct pinconf_ops msm_pinconf_ops = {
	...
        .pin_config_get         = msm_config_pin_get,
        .pin_config_set         = msm_config_pin_set,
};

Shawn