Re: [PATCH v1] pinctrl: intel: Actually disable Tx and Rx buffers on GPIO request

[Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>]

> On Dec 8, 2020, at 01:59, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> 
> Mistakenly the buffers (input and output) become together enabled for a little
> period of time during GPIO request. This is problematic, because instead of
> initial motive to disable them in the commit af7e3eeb84e2
> ("pinctrl: intel: Disable input and output buffer when switching to GPIO"),
> the driven value on the pin, which might be used as an IRQ line, brings
> firmware of some touch pads in an awkward state that needs a full power off
> to recover. Fix this by, as stated in a culprit commit, disabling the buffers.
> 
> Fixes: af7e3eeb84e2 ("pinctrl: intel: Disable input and output buffer when switching to GPIO")
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=210497
> Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

Tested-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>

> ---
> drivers/pinctrl/intel/pinctrl-intel.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
> index e77145e3b31b..5cd720f5b0e1 100644
> --- a/drivers/pinctrl/intel/pinctrl-intel.c
> +++ b/drivers/pinctrl/intel/pinctrl-intel.c
> @@ -452,8 +452,8 @@ static void intel_gpio_set_gpio_mode(void __iomem *padcfg0)
> 	value |= PADCFG0_PMODE_GPIO;
> 
> 	/* Disable input and output buffers */
> -	value &= ~PADCFG0_GPIORXDIS;
> -	value &= ~PADCFG0_GPIOTXDIS;
> +	value |= PADCFG0_GPIORXDIS;
> +	value |= PADCFG0_GPIOTXDIS;
> 
> 	/* Disable SCI/SMI/NMI generation */
> 	value &= ~(PADCFG0_GPIROUTIOXAPIC | PADCFG0_GPIROUTSCI);
> -- 
> 2.29.2
> 
>