Re: Suspicious debounce handling code in pintctrl-baytrail

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Jan 26, 2017 at 02:20:20PM +0100, Jean Delvare wrote:
> Hi Cristina,
> 
> In this commit:
> 
> commit 658b476c742fe379e7020309fd590a27b457a4c1
> Date:   Fri Apr 1 14:00:07 2016 +0300
> 
>     pinctrl: baytrail: Add debounce configuration
> 
> you added support for getting and setting debounce configuration for
> the Baytrail pins. Now gcc complains about the following:
> 
>   CC [M]  drivers/pinctrl/intel/pinctrl-baytrail.o
> drivers/pinctrl/intel/pinctrl-baytrail.c: In function ‘byt_pin_config_set’:
> drivers/pinctrl/intel/pinctrl-baytrail.c:1181:17: warning: variable ‘debounce’ set but not used [-Wunused-but-set-variable]
>   u32 conf, val, debounce;
>                  ^
> 
> I looked at the code, and it indeed looks wrong. You are reading the
> BYT_DEBOUNCE_REG register, clearing the debounce time bits from it, and
> then writing the debounce time bits to the *BYT_CONF0_REG* register.
> This is certainly corrupting the chip configuration, as the
> configuration register bits 2-0 have a completely different meaning
> (mux configuration.)

Yes, you are right.

This is fixed by following commit from Andy:

https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=fixes&id=04ff5a095d662e0879f0eb04b9247e092210aeff