Re: [PATCH 1/2] gpio: i.MX: make _get_value() able to read output pin state

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 10/15/25 8:03 PM, Maud Spierings via B4 Relay wrote:
> From: Maud Spierings <maud_spierings@hotmail.com>
> 
> Make _get_value() read back the dr register instead of the psr register
> when the direction is set to output. Now _get_value() can actually read
> the state of an output gpio instead of being always low.
> 
> Signed-off-by: Maud Spierings <maud_spierings@hotmail.com>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> 
> ---
> inspired by similar logic being used in u-boot and Linux

That's useful info that should go into the commit message IMO, because
it explains why we think regression should be limited.

> ---
>  drivers/gpio/gpio-imx.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-imx.c b/drivers/gpio/gpio-imx.c
> index d9499c66cd..bb14c56399 100644
> --- a/drivers/gpio/gpio-imx.c
> +++ b/drivers/gpio/gpio-imx.c
> @@ -89,24 +89,27 @@ static int imx_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int
>  	return 0;
>  }
>  
> -static int imx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
> +static int imx_get_direction(struct gpio_chip *chip, unsigned offset)
>  {
>  	struct imx_gpio_chip *imxgpio = container_of(chip, struct imx_gpio_chip, chip);
>  	void __iomem *base = imxgpio->base;
> -	u32 val;
> -
> -	val = readl(base + imxgpio->regs->psr);
> +	u32 val = readl(base + imxgpio->regs->gdir);
>  
> -	return val & (1 << gpio) ? 1 : 0;
> +	return (val & (1 << offset)) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
>  }
>  
> -static int imx_get_direction(struct gpio_chip *chip, unsigned offset)
> +static int imx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
>  {
>  	struct imx_gpio_chip *imxgpio = container_of(chip, struct imx_gpio_chip, chip);
>  	void __iomem *base = imxgpio->base;
> -	u32 val = readl(base + imxgpio->regs->gdir);
> +	u32 val;
>  
> -	return (val & (1 << offset)) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
> +	if (imx_get_direction(chip, gpio) == GPIOF_DIR_IN)
> +		val = readl(base + imxgpio->regs->psr);
> +	else
> +		val = readl(base + imxgpio->regs->dr);
> +
> +	return val & (1 << gpio) ? 1 : 0;
>  }
>  
>  static struct gpio_ops imx_gpio_ops = {
> 

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