Re: [PATCH RFT] powerpc/8xx: implement get_direction() in cpm1

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Le 03/06/2026 à 10:26, Bartosz Golaszewski a écrit :
> The lack of get_direction() callbacks in this driver causes GPIOLIB to
> emit a warning. Implement them for 16- and 32-bit variants.
> 
> Reported-by: Christophe Leroy <chleroy@kernel.org>
> Closes: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F63487206f6e5a93eaf9f41784317fe99d394312f.1780399750.git.chleroy%40kernel.org%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7C67d2207e02454f2ecf0008dec149d67c%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639160720043016747%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=k6%2FENNl94WS7QvRdhhmx8VvDyZKMNW8sAlKEq3AtQe4%3D&reserved=0
> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Tested-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>

> ---
> Hi Christophe, please test if this works for you to silence the warning
> from GPIO core.

Hi Bartosz, yes it does, many thanks for the fix.

By the way, wouldn't it also make sense to update the following comment 
in include/linux/gpio/driver.h to change from 'recommended' to 'mandatory' ?

  * @get_direction: returns direction for signal "offset", 0=out, 1=in,
  *	(same as GPIO_LINE_DIRECTION_OUT / GPIO_LINE_DIRECTION_IN),
  *	or negative error. It is recommended to always implement this
  *	function, even on input-only or output-only gpio chips.


> ---
>   arch/powerpc/platforms/8xx/cpm1.c | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/8xx/cpm1.c b/arch/powerpc/platforms/8xx/cpm1.c
> index f00734f0590cf7c7382f808dce27373d9ff3d8bc..b31376bf6778802a7f6b6b499066846b6b1f61e9 100644
> --- a/arch/powerpc/platforms/8xx/cpm1.c
> +++ b/arch/powerpc/platforms/8xx/cpm1.c
> @@ -472,6 +472,18 @@ static int cpm1_gpio16_dir_in(struct gpio_chip *gc, unsigned int gpio)
>   	return 0;
>   }
>   
> +static int cpm1_gpio16_get_direction(struct gpio_chip *gc, unsigned int gpio)
> +{
> +	struct cpm1_gpio16_chip *cpm1_gc = gpiochip_get_data(gc);
> +	struct cpm_ioport16 __iomem *iop = cpm1_gc->regs;
> +	u16 pin_mask = 1 << (15 - gpio);
> +
> +	if (in_be16(&iop->dir) & pin_mask)
> +		return GPIO_LINE_DIRECTION_OUT;
> +
> +	return GPIO_LINE_DIRECTION_IN;
> +}
> +
>   int cpm1_gpiochip_add16(struct device *dev)
>   {
>   	struct device_node *np = dev->of_node;
> @@ -498,6 +510,7 @@ int cpm1_gpiochip_add16(struct device *dev)
>   	gc->ngpio = 16;
>   	gc->direction_input = cpm1_gpio16_dir_in;
>   	gc->direction_output = cpm1_gpio16_dir_out;
> +	gc->get_direction = cpm1_gpio16_get_direction;
>   	gc->get = cpm1_gpio16_get;
>   	gc->set = cpm1_gpio16_set;
>   	gc->to_irq = cpm1_gpio16_to_irq;
> @@ -604,6 +617,18 @@ static int cpm1_gpio32_dir_in(struct gpio_chip *gc, unsigned int gpio)
>   	return 0;
>   }
>   
> +static int cpm1_gpio32_get_direction(struct gpio_chip *gc, unsigned int gpio)
> +{
> +	struct cpm1_gpio32_chip *cpm1_gc = gpiochip_get_data(gc);
> +	struct cpm_ioport32b __iomem *iop = cpm1_gc->regs;
> +	u32 pin_mask = 1 << (31 - gpio);
> +
> +	if (in_be32(&iop->dir) & pin_mask)
> +		return GPIO_LINE_DIRECTION_OUT;
> +
> +	return GPIO_LINE_DIRECTION_IN;
> +}
> +
>   int cpm1_gpiochip_add32(struct device *dev)
>   {
>   	struct device_node *np = dev->of_node;
> @@ -621,6 +646,7 @@ int cpm1_gpiochip_add32(struct device *dev)
>   	gc->ngpio = 32;
>   	gc->direction_input = cpm1_gpio32_dir_in;
>   	gc->direction_output = cpm1_gpio32_dir_out;
> +	gc->get_direction = cpm1_gpio32_get_direction;
>   	gc->get = cpm1_gpio32_get;
>   	gc->set = cpm1_gpio32_set;
>   	gc->parent = dev;
> 
> ---
> base-commit: b7bee4ca5688e30ca50fbc87b1b8f7eed7006c17
> change-id: 20260603-powerpc-8xx-cpm1-get-dir-698cefe92647
> 
> Best regards,