[PATCH 1/2] gpio: gpio-uclass: add OPEN_DRAIN flag parsing

[Neil Armstrong]

Hi,

This has already been pushed on u-boot master:
https://patchwork.ozlabs.org/project/uboot/patch/20200505084318.15307-2-narmstrong@baylibre.com/

Commit: 47bd533e9dd0f967ff7b62f3edfd6c97131e1501
Author: Neil Armstrong <narmstrong at baylibre.com>
Date:   Tue May 5 10:43:17 2020 +0200

    gpio: emulate open drain & open source in dm_gpio_set_value()

    Handle the GPIOD_OPEN_DRAIN & GPIOD_OPEN_SOURCE flags to emulate open drain
    and open source by setting the GPIO line as input depending on the
    requested value.

    The behaviour is taken from the Linux gpiolib.

    Signed-off-by: Neil Armstrong <narmstrong at baylibre.com>
    Reviewed-by: Simon Glass <sjg at chromium.org>

Neil

On 15/01/2021 06:15, Artem Lapkin wrote:
> add GPIOD_OPEN_DRAIN flag which cant parsed properly
> 
> Problem: for example cant power video system for sm1 g12a socs
> because OPEN_DRAIN flag cant parsed
> 
> DTS examples:
> 
> ```
> $ grep GPIO_OPEN_DRAIN\>  arch/arm/dts/meson-*.dt*
> arch/arm/dts/meson-g12a-sei510.dts:		gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
> arch/arm/dts/meson-g12a-u200.dts:		gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
> arch/arm/dts/meson-gx-libretech-pc.dtsi:	gpio = <&gpio GPIOH_3 GPIO_OPEN_DRAIN>;
> arch/arm/dts/meson-khadas-vim3.dtsi:		gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
> arch/arm/dts/meson-sm1-sei610.dts:		gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
> ```
> 
> Signed-off-by: Artem Lapkin <art at khadas.com>
> ---
>  drivers/gpio/gpio-uclass.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
> index bad6b71e0c..6225f32457 100644
> --- a/drivers/gpio/gpio-uclass.c
> +++ b/drivers/gpio/gpio-uclass.c
> @@ -574,6 +574,15 @@ int dm_gpio_set_value(const struct gpio_desc *desc, int value)
>  	if (ret)
>  		return ret;
>  
> +	if (desc->flags & GPIOD_OPEN_DRAIN) {
> +		if (value)
> +			gpio_get_ops(desc->dev)->direction_input(desc->dev, desc->offset);
> +		else
> +			gpio_get_ops(desc->dev)->direction_output(desc->dev, desc->offset, 0);
> +
> +		return 0;
> +	}
> +
>  	if (desc->flags & GPIOD_ACTIVE_LOW)
>  		value = !value;
>  
>