Re: Configure standalone GPIO in device tree?

[Subodh Nijsure <snijsure-4jo+YWezP1RWk0Htik3J/w@public.gmane.org>]

On 06/11/2012 07:21 AM, Rob Herring wrote:
> On 06/11/2012 08:56 AM, Subodh Nijsure wrote:
>> Hello,
>>
>> I am working with a hardware that has couple of GPIOs that are not tied
>> to any specific device one to indicate board status, other to indicate
>> presence of this hardware to some other 'independent' hardware.
>>
>> I have been going through some of the device tree files and I haven't
>> come across way to represent a GPIO independent of a specific device, is
>> it possible to do so using DT? How would I specify such a GPIO?
>>
>> I am working on MX28 (MXS for linux) based platform but if there are
>> some other platforms already doing that would appreciate pointer to that
>> dt file.
> How do you program that gpio line? It has to be controlled from somewhere.
In non-dt version, .init_machine code used to configure GPIO using 
gpio_request_one() interface and set the values.

Currently as a hack on my board, I am doing the following, but that 
status led has nothing do with the ethernet driver.

                 mac0: ethernet@800f0000 {
                         phy-mode = "rmii";
                         pinctrl-names = "default";
                         pinctrl-0 = <&mac0_pins_a>;
                         status-led = <&gpio3 5 0>;
                         mac-address = [ 00 11 22 33 44 56 ];
                 };

                 int status_led;
                 struct device_node *np = pdev->dev.of_node;

                 status_led = of_get_named_gpio(np, "status-led", 0);
                 gpio_request_one(status_led, GPIOF_OUT_INIT_LOW, 
"status-led");

So in DT world I would like to  lookup  LED named status-led, only 
version I know of of_get_named_gpio() requires device_node pointer,so I 
guess I am looking for way to lookup gpio in .init_machine function, 
without having a pointer to a device_node, is that possible?

-Subodh