From: David Daney <david.daney@xxxxxxxxxx>
When we have a GPIO pin connected to an open-drain network, we want a
standard way of specifying this in the device tree. So we choose bit
1 of the flag field to indicate open drain.
A typical use case would be something like:
enum of_gpio_flags f;
.
.
.
reset_gpio = of_get_named_gpio_flags(node, "reset", 0, &f);
.
.
.
ret = gpio_request_one(reset_gpio,
(f & OF_GPIO_OPEN_DRAIN) ? GPIOF_OPEN_DRAIN : 0,
"reset");
.
.
.
gpio_direction_output(reset_gpio, 1);
gpio_set_value(reset_gpio, 0);
msleep(20);
gpio_set_value(reset_gpio, 1);
.
.
.
Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
---
include/linux/of_gpio.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index f14123a..0e374774 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -30,6 +30,7 @@ struct device_node;
*/
enum of_gpio_flags {
OF_GPIO_ACTIVE_LOW = 0x1,
+ OF_GPIO_OPEN_DRAIN = 0x2,
};
#ifdef CONFIG_OF_GPIO
--
1.7.11.7
--
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