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

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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@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Neil Armstrong 2020-05-05 10:43:17 +02:00
parent 375d79cdbb
commit 47bd533e9d
1 changed files with 15 additions and 0 deletions
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15
drivers/gpio/gpio-uclass.c
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@ -526,6 +526,21 @@ int dm_gpio_set_value(const struct gpio_desc *desc, int value)
if (desc->flags & GPIOD_ACTIVE_LOW)
value = !value;
/*
* Emulate open drain by not actively driving the line high or
* Emulate open source by not actively driving the line low
*/
if ((desc->flags & GPIOD_OPEN_DRAIN && value) ||
(desc->flags & GPIOD_OPEN_SOURCE && !value))
return gpio_get_ops(desc->dev)->direction_input(desc->dev,
desc->offset);
else if (desc->flags & GPIOD_OPEN_DRAIN ||
desc->flags & GPIOD_OPEN_SOURCE)
return gpio_get_ops(desc->dev)->direction_output(desc->dev,
desc->offset,
value);
gpio_get_ops(desc->dev)->set_value(desc->dev, desc->offset, value);
return 0;
}