From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Sun, 28 Sep 2014 21:25:26 +0000 Subject: Re: [periperi] How to set default GPIO pin ? Message-Id: <2033766.6tR9OHe7ZC@avalon> List-Id: References: <8738cc0vx9.wl%kuninori.morimoto.gx@gmail.com> <2862746.g5u9pdpKDi@avalon> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org Hi Linus and Morimoto-san, On Tuesday 23 September 2014 17:06:28 Linus Walleij wrote: > On Wed, Sep 10, 2014 at 10:55 AM, Laurent Pinchart wrote: > > On Sunday 31 August 2014 22:08:52 Kuninori Morimoto wrote: > >> I know we can use "defalt" PFC settings on DT. > >> But, how to use "defalt" GPIO pin settings on DT ? > >> > >> We would like to use GPIO 7-17 as Low output, > >> and do nothing after boot. > > > > From a DT point of view I believe this is supposed to be done by > > specifying the output-low or output-high properties in the pinctrl > > configuration node. However, these properties are not supported by the PFC > > driver, and there's no easy way for the PFC driver to configure GPIOs > > handled by a different driver such as the gpio-rcar driver for instance. > > > > Linus, do you have any hindsight on how this should be implemented ? > > I have suggested adding GPIO hogs, so that a GPIO node can specify > that some GPIO's specified on the local ship be hogged high or > low at probe. Generic DT bindings and generic code in gpiolib.c. > > gpios-hog-high = <....>; > gpios-hog-low = <....>; How about just a gpios-hog property, with a list of gpio specifiers + flags ? That's bikeshedding I suppose. Morimoto-san, would you like to implement that ? :-) -- Regards, Laurent Pinchart