Messages in this thread | | | From | Alexandre Courbot <> | Date | Tue, 11 Feb 2014 13:31:44 +0900 | Subject | Re: [PATCH] of/gpio: Define OF_GPIO_OPEN_DRAIN flag for Open Drain outputs. |
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On Tue, Feb 11, 2014 at 7:05 AM, David Daney <ddaney.cavm@gmail.com> wrote: > From: David Daney <david.daney@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.
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