[U-Boot] [PATCH 06/10] mx23_olinuxino: Add support for status LED

Otavio Salvador
2013-01-30T16:08:39Z

On Wed, Jan 30, 2013 at 2:05 PM, Marek Vasut <marex@denx.de> wrote:
> Dear Otavio Salvador,
>
>> On Wed, Jan 30, 2013 at 1:39 PM, Marek Vasut <marex@denx.de> wrote:
>> > Dear Otavio Salvador,
>> >
>> >> On Wed, Jan 30, 2013 at 12:13 PM, Marek Vasut <marex@denx.de> wrote:
>> >> > Dear Otavio Salvador,
>> >> >
>> >> >> This allow user to know if the bootloader is running, even without a
>> >> >> serial console.
>> >> >>
>> >> >> Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
>> >> >
>> >> > Uh oh, how does this know which GPIO to toggle to drive the led this
>> >> > time ?
>> >>
>> >> The problem wasn't the code but me. I wasn't able to find the right
>> >> GPIO number at that time.
>> >
>> > This is not my question. My question is how does this toggle the GPIO for
>> > the LED?
>>
>> gpio_led driver (drivers/misc/gpio_led.c) does it.
>>
>> ...
>> void __led_init(led_id_t mask, int state)
>> {
>> gpio_request(mask, "gpio_led");
>> gpio_direction_output(mask, state == STATUS_LED_ON);
>> }
>>
>> void __led_set(led_id_t mask, int state)
>> {
>> gpio_set_value(mask, state == STATUS_LED_ON);
>> }
>> ...
>
> Ok, this didn't explain much to me.
>
>> > Moreover, you never set the LED GPIO as output.
>>
>> The driver handles it by itself.
>
> Oh ok.
>
> Now that I did read through the code, I have few more questions:
>
> Why can't STATUS_LED_BIT be the MX23_PAD_SSP1_DETECT__GPIO_2_1 now?

It can but than we need to include the iomux-mx23.h header. It in the
end is the same thing.

> Did you test
> CMD_LED, does it work when toggling the LED?

It does. Of course I tested it :)

--
Otavio Salvador O.S. Systems
E-mail: otavio at ossystems.com.br http://www.ossystems.com.br
Mobile: +55 53 9981-7854 http://projetos.ossystems.com.br