On Fri, Feb 14, 2020 at 10:59:42AM -0500, Sasha Levin wrote:
> From: Kevin Hao <haokexin@gmail.com>
> 
> [ Upstream commit 9c6722d85e92233082da2b3623685bba54d6093e ]
> 
> In commit 242587616710 ("gpiolib: Add support for the irqdomain which
> doesn't use irq_fwspec as arg") we have changed the return type of
> gpiochip_populate_parent_fwspec_twocell/fourcell() from void to void *,
> but forgot to add a return statement for these two dummy functions.
> Add "return NULL" to fix the build warnings.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Kevin Hao <haokexin@gmail.com>
> Link: https://lore.kernel.org/r/20200116095003.30324-1-haokexin@gmail.com
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  include/linux/gpio/driver.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
> index 5dd9c982e2cbe..d7dc2b425532e 100644
> --- a/include/linux/gpio/driver.h
> +++ b/include/linux/gpio/driver.h
> @@ -545,6 +545,7 @@ static inline void gpiochip_populate_parent_fwspec_twocell(struct gpio_chip *chi
>  						    unsigned int parent_hwirq,
>  						    unsigned int parent_type)
>  {
> +	return NULL;

Hi Sasha,

This commit shouldn't go to the v5.4.x kernel. This is a fix for the 
commit 242587616710, but that commit doesn't exist in the v5.4.x kernel,
then it will trigger a build warning due to the wrong returning type.                                                                                                                         

Thanks,
Kevin
>  }
>  
>  static inline void gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *chip,
> @@ -552,6 +553,7 @@ static inline void gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *ch
>  						     unsigned int parent_hwirq,
>  						     unsigned int parent_type)
>  {
> +	return NULL;
>  }
>  
>  #endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
> -- 
> 2.20.1
>