[U-Boot] [PATCH 1/2] add generic stubs for GPIO LEDs

[Bernhard Nortmann <bernhard.nortmann@web.de>]

Hello Simon!

Am 23.08.2015 23:21, schrieb Simon Glass:
> Hi Bernard,
>
> [...]
> If this is a new option it should be added to Kconfig. Otherwise:
>
> Reviewed-by: Simon Glass <sjg@chromium.org>
Right. Kconfig wasn't on my agenda, but I agree that it should go in there.
Unfortunately this points out further problems. The existing CONFIG_GPIO_LED
is not part of Kconfig, but gets set via board-specific (.h) includes. 
Kconfig
has/supports CONFIG_LED_GPIO, but that is related to the driver model
variant, and doesn't affect inclusion of drivers/misc/gpio_led.c ...
admittedly it's a bit of a mess.

> I am not a huge fan of the existing API. I would suggest that if you
> have the energy you could replace it with something like:
>
> enum led_colour_t {
>     led_red,
>     red_green,
>     ...
> };
>
> int led_set_on(enum led_colour_t colour, bool on)
Yes, I've been code-dancing a bit back and forth to get this stuff to fit in
with the existing API. One reason I have selected these "stub" functions
is that they are meant to match (and replace) the existing weak definitions
in arch/arm/lib/board.c. Also, my impression is that they exist as separate
functions to allow common/cmd_led.c to use them as function pointers,
namely for the construction of the led_commands[] array.

The API may not be pretty, but I have in fact tried to keep it as close to
the original as possible, with the goal of allowing to simply substitute
GPIO numbers for the "LED bits".

> BTW there is a device-tree-enabled LED driver node (see drivers/led).
> It might be worth considering using this on some sunxi boards.
Thanks! I'll definitely have a look into it.
(That one is related to the CONFIG_LED_GPIO mentioned above.)

Regards, B. Nortmann