linux-kernel - Re: "advanced" LED controllers

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Date:	Tue, 3 Mar 2015 17:15:29 +0900
From:	Alexandre Courbot <gnurou@...il.com>
To:	Pavel Machek <pavel@....cz>
Cc:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Felipe Balbi <balbi@...com>, Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	"linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: "advanced" LED controllers

On Mon, Mar 2, 2015 at 6:21 PM, Pavel Machek <pavel@....cz> wrote:
> On Wed 2015-02-25 18:06:07, Alexandre Courbot wrote:
>> On Wed, Feb 25, 2015 at 5:25 PM, Geert Uytterhoeven
>> <geert@...ux-m68k.org> wrote:
>> > CC linux-gpio, as this looks like the LED equivalent of bulk gpio?
>>
>> Indeed. The LED core could implement something similar to
>> gpiod_set_array() to allow several LEDs to be set in one call. If the
>> controller supports it, it would then set all the LEDs at once,
>> otherwise the core would apply the values serially.
>>
>> In leds-gpio.c, this multiple LED setting could be implemented by a
>> single call to gpiod_set_array() and the right thing would happen.
>
> Actually, there are two issues: some controlles can set all LEDs at
> once, and some can program pwm level smoothly using given program (and
> handle multiple leds in the process).

In any case, that would be handled at the controller level and should
work with a function similar to gpiod_set_array(), wouldn't it?
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