From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Date: Wed, 24 Jul 2019 21:16:39 +0000 Subject: Re: [PATCH] Enable backlight when trigger is activated Message-Id: List-Id: References: <20190718190849.GA11409@amd> <22d7eca4ad8aa2e73933c4f83c92221ce6e0945a.camel@collabora.com> <20190722075032.GA27524@amd> <6fc6af89-1455-7665-47e7-0568ecd87c9c@gmail.com> <20190724083355.GA27716@amd> In-Reply-To: <20190724083355.GA27716@amd> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Pavel Machek Cc: Ezequiel Garcia , kernel list , linux-arm-kernel , linux-omap@vger.kernel.org, tony@atomide.com, sre@kernel.org, nekit1000@gmail.com, mpartap@gmx.net, merlijn@wizzup.org, linux-leds@vger.kernel.org, b.zolnierkie@samsung.com, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org On 7/24/19 10:33 AM, Pavel Machek wrote: > Hi! > >>>>> +++ b/drivers/leds/trigger/ledtrig-backlight.c >>>>> @@ -114,6 +114,8 @@ static int bl_trig_activate(struct led_classdev *led) >>>>> n->old_status = UNBLANK; >>>>> n->notifier.notifier_call = fb_notifier_callback; >>>>> >>>>> + led_set_brightness(led, LED_ON); >>>>> + >>>> >>>> This looks fishy. >>>> >>>> Maybe you should use a default-state = "keep" instead? (and you'll have >>>> to support it in the LED driver). >>>> >>>> That'll give you proper "don't touch the LED if it was turned on" behavior, >>>> which is what you seem to want. >>> >>> Actually no, that's not what I want. LED should go on if the display >>> is active, as soon as trigger is activated. >>> >>> Unfortunately, I have see no good way to tell if the display is >>> active (and display is usually active when trigger is activated). >> >> default-state DT property can be also set to "on" >> (see Documentation/devicetree/bindings/leds/common.txt). > > Yes, except that it does not work with all drivers :-(. In particular, > it does not work with lm3532. > > We should really move more of the device tree parsing into core, so > that there's one place to fix... Right. We could have something similar to led_get_default_pattern(). led_get_default_state() ? -- Best regards, Jacek Anaszewski