From mboxrd@z Thu Jan 1 00:00:00 1970 From: baruch@tkos.co.il (Baruch Siach) Date: Thu, 4 Jan 2018 21:35:35 +0200 Subject: [PATCH 2/4] dt-bindings: gpio: add raspberry pi GPIO expander binding In-Reply-To: <860502005.181510.1514917560724@email.1und1.de> References: <4ca1795c6e09eb89f481cdec55180b4f1165bbfd.1514898134.git.baruch@tkos.co.il> <860502005.181510.1514917560724@email.1und1.de> Message-ID: <20180104193535.63jmkxjvo3mynzpc@tarshish> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Stefan, On Tue, Jan 02, 2018 at 07:26:00PM +0100, Stefan Wahren wrote: > > Baruch Siach hat am 2. Januar 2018 um 14:19 geschrieben: > > > > > > The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware over > > I2C. The firmware mailbox interface allows the ARM core to control the > > GPIO lines. > > > > Signed-off-by: Baruch Siach > > --- > > .../bindings/gpio/brcm,bcm2835-expgpio.txt | 24 ++++++++++++++++++++++ > > 1 file changed, 24 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/gpio/brcm,bcm2835-expgpio.txt > > > > diff --git a/Documentation/devicetree/bindings/gpio/brcm,bcm2835-expgpio.txt b/Documentation/devicetree/bindings/gpio/brcm,bcm2835-expgpio.txt > > new file mode 100644 > > index 000000000000..55257f31a9be > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/gpio/brcm,bcm2835-expgpio.txt > > @@ -0,0 +1,24 @@ > > +Raspberry Pi GPIO expander > > + > > +The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware. The > > +firmware exposes a mailbox interface that allows the ARM core to control the > > +GPIO lines on the expander. > > + > > +Required properties: > > + > > +- compatible : Should be "brcm,bcm2835-expgpio" > > from my understand this driver is specific to the Raspberry Pi and it's > vendor is the Raspberry Pi Foundation. So i prefer Eric's suggestion of > "raspberrypi,firmware-gpio", which also applies to the filename. That was my inclination as well. But I thought that keeping DT compatibility with downstream is desirable. I'll change compatible/file/driver names to raspberry something. baruch > > +- gpio-controller : Marks the device node as a gpio controller > > +- #gpio-cells : Should be two. The first cell is the pin number, and > > + the second cell is used to specify the gpio polarity: > > + 0 = active high > > + 1 = active low > > +- firmware : Reference to the RPi firmware device node > > + > > +Example: > > + > > +expgpio: expgpio { > > + compatible = "brcm,bcm2835-expgpio"; > > + gpio-controller; > > + #gpio-cells = <2>; > > + firmware = <&firmware>; > > +}; -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -