On Tue, Feb 11, 2014 at 7:05 AM, David Daney <ddaney.c...@gmail.com> wrote: > From: David Daney <david.da...@cavium.com> > > 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);
This is also useful for gpiod_get(). However, while you are at it, could you also add a flag for the OF_GPIO_OPEN_SOURCE property? My joy would be complete if you could also take the time to update of_find_gpio() to pass these new flags back to the caller as it already does for OF_GPIO_ACTIVE_LOW. Then you could even switch your use-case to the gpiod interface and not bother with passing these flags by yourself anymore. Just sayin'. ;) Thanks, Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
