[PATCH] Ask a question about why can't use GPIOAO: GPIO_TEST_N
Neil Armstrong
narmstrong at baylibre.com
Mon Jul 18 01:20:36 PDT 2022
Hi,
On 14/07/2022 04:07, Zhang Ning wrote:
> first this is not a code review, just ask a question.
>
> I started to enable MagicBox M16S, and sent patches for review.
>
> but leds are not enabled.
>
> I have tried, and found gpioao: GPIO_TEST_N can control led on off.
>
> thus I add it to dts:
>
> leds {
> compatible = "gpio-leds";
>
> led-white {
> color = <LED_COLOR_ID_WHITE>;
> function = LED_FUNCTION_POWER;
> gpios = <&gpio_ao GPIO_TEST_N GPIO_ACTIVE_HIGH>;
> default-state = "keep";
> };
> };
>
> but failed with error -22.
>
> and simply change GPIO_TEST_N to GPIOAO_2, no error.
>
> thus find pinctrl driver doesn't allow to use this gpio.
>
> why?
The TEST_N pinctrl needs a SMC call to set the pin GPIO direction, so it needs
more code to control the pin.
I did an experimental support a few years ago:
https://github.com/superna9999/linux/commits/amlogic/v4.19/gpio-test-n
I would need to be refreshed to work on 5.20.
Neil
>
> Signed-off-by: Zhang Ning <zhangn1985 at qq.com>
> ---
> drivers/pinctrl/meson/pinctrl-meson-gxl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pinctrl/meson/pinctrl-meson-gxl.c b/drivers/pinctrl/meson/pinctrl-meson-gxl.c
> index 51408996255b..fb5fa88b30c7 100644
> --- a/drivers/pinctrl/meson/pinctrl-meson-gxl.c
> +++ b/drivers/pinctrl/meson/pinctrl-meson-gxl.c
> @@ -820,7 +820,7 @@ static struct meson_bank meson_gxl_periphs_banks[] = {
>
> static struct meson_bank meson_gxl_aobus_banks[] = {
> /* name first last irq pullen pull dir out in */
> - BANK("AO", GPIOAO_0, GPIOAO_9, 0, 9, 0, 16, 0, 0, 0, 0, 0, 16, 1, 0),
> + BANK("AO", GPIOAO_0, GPIO_TEST_N, 0, 9, 0, 16, 0, 0, 0, 0, 0, 16, 1, 0),
> };
>
> static struct meson_pinctrl_data meson_gxl_periphs_pinctrl_data = {
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