[PATCH v2] gpio: mxc_gpio: fix reading state of GPIO pins in output mode

[Fabio Estevam]

Adding more folks on Cc to help review it.


On Tue, Aug 27, 2024 at 11:13 PM Tomas Paukrt <tomaspaukrt at email.cz> wrote:
>
> The PSR register works correctly for GPIO pins in input mode,
> but always returns 0 for GPIO pins in output mode unless the SION
> bit is set. The DR register works correctly in both modes without
> the need to set the SION bit.
>
> Please note that the Linux gpio-mxc driver already uses
> the DR register for all GPIO pins in output mode:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=442b2494b17d1a4f0a14721580271eb23ebffd42
>
> Signed-off-by: Tomas Paukrt <tomaspaukrt at email.cz>
> ---
>  drivers/gpio/mxc_gpio.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/mxc_gpio.c b/drivers/gpio/mxc_gpio.c
> index cac6b32..5cd7681 100644
> --- a/drivers/gpio/mxc_gpio.c
> +++ b/drivers/gpio/mxc_gpio.c
> @@ -133,7 +133,7 @@ int gpio_get_value(unsigned gpio)
>
>         regs = (struct gpio_regs *)gpio_ports[port];
>
> -       val = (readl(&regs->gpio_psr) >> gpio) & 0x01;
> +       val = (readl(&regs->gpio_dr) >> gpio) & 0x01;
>
>         return val;
>  }
> @@ -210,7 +210,7 @@ static void mxc_gpio_bank_set_value(struct gpio_regs *regs, int offset,
>
>  static int mxc_gpio_bank_get_value(struct gpio_regs *regs, int offset)
>  {
> -       return (readl(&regs->gpio_psr) >> offset) & 0x01;
> +       return (readl(&regs->gpio_dr) >> offset) & 0x01;
>  }
>
>  /* set GPIO pin 'gpio' as an input */
> --
> 2.7.4
>