Messages in this thread | | | Date | Sun, 27 Jan 2013 15:29:25 +0100 | From | Roland Stigge <> | Subject | Re: [PATCH 5/6 v14] gpio: Add device tree support to block GPIO API |
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On 27/01/13 14:07, Stijn Devriendt wrote: >> +Example: >> + >> + blockgpio { >> + compatible = "linux,gpio-block"; >> + >> + block0 { >> + gpios = <&gpio 3 0 0>, >> + <&gpio 3 1 0>; >> + }; >> + block1 { >> + gpios = <&gpio 4 1 0>, >> + <&gpio 4 3 0>, >> + <&gpio 4 2 0>, >> + <&gpio 4 4 0>, >> + <&gpio 4 5 0>, >> + <&gpio 4 6 0>, >> + <&gpio 4 7 0>, >> + <&gpio 4 8 0>, >> + <&gpio 4 9 0>, >> + <&gpio 4 10 0>, >> + <&gpio 4 19 0>; >> + }; >> + }; > > How do you see bindings for other kinds of drivers? > > In my patchset, it's possible for other drivers to use gpio-blocks. > One example we have is a power sequencer with 2 pins attached > to GPIO pins. These 2 pins form a 2bit word to select power margining. > These 2 pins need to be set synchronously (as otherwise when going > from profile 0 to profile 3 you pass either profile 1 or profile 2 which > could be bad for hardware) > > In the device-tree this is specified as: > > powr@0x20 { > // other properties > > gpios = <&gpio 4 0 > &gpio 5 0>; > }; > > Is this kind of integration also possible?
You can reference the gpio block via a phandle, e.g.:
blockgpio { compatible = "linux,gpio-block";
selector1 { gpios = <&gpio 4 0>, <&gpio 5 0>; }; };
powr@0x20 { // ...
gpios = <&selector1>; };
In the driver, you can get the gpio block like this:
block = gpio_block_find_by_name(of_parse_phandle(powr, "gpios", 0)->name);
(Simplified by removed error/NULL handling!)
If this turns out to be a common pattern, I can add a convenience "get" function for this.
Roland
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