Re: [PATCH v3] leds: implement OpenFirmare GPIO LED driver

From: Grant Likely
Date: Thu Jul 17 2008 - 00:15:49 EST


On Wed, Jul 16, 2008 at 04:18:52PM -0700, Trent Piepho wrote:
> On Tue, 15 Jul 2008, Anton Vorontsov wrote:
> > Despite leds-gpio and leds-openfirmware-gpio similar purposes, there
> > is not much code can be shared between the two drivers (both are mostly
> > driver bindings anyway).
>
> Why can't this driver use the existing gpio-led driver? Basically, do
> something like this:
>
> of_gpio_leds_probe(...)
> {
> gpio = of_get_gpio(np, 0);
> label = of_get_property(np, "label", NULL);
>
> struct gpio_led led = {
> .name = label,
> .gpio = gpio,
> };
>
> pdev = platform_device_register_simple("leds-gpio", 0, NULL, 0);
> platform_device_add_data(pdev, &led, sizeof(led));
> }

Ugh; that means registering *2* 'struct device' with the kernel instead of
one. One as a platform device and one as an of_platform device.
It's bad enough that the LED scheme we're using for OF bindings has a
separate registration for every single LED.

Now that it comes to it, I worry that this driver takes the wrong
approach. The number of resources dedicated per LED in this driver
seems pretty loony to me (one of_platform device per LED). The fact
that the binding specifies one node per LED makes of_platform not a very
efficient solution.

I think it would be better to have a module that scans the device tree
for LED nodes and registers a single leds-gpio platform device for the
whole lot.

Thoughts?

g.
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