From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v3 1/2] dt: bindings: lm3692x: Add bindings for lm3692x LED driver Date: Fri, 17 Nov 2017 12:20:32 +0100 Message-ID: <20171117112032.GA13855@amd> References: <20171115194203.13572-1-dmurphy@ti.com> <0a78c883-f074-cc19-3c0c-fc05607400e9@ti.com> <20171115222323.GA18290@amd> <82336eb7-2b89-d37b-d688-4e4302766346@gmail.com> <16189eab-5541-9550-c027-1c9d2b5fa6d7@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="dDRMvlgZJXvWKvBx" Return-path: Content-Disposition: inline In-Reply-To: <16189eab-5541-9550-c027-1c9d2b5fa6d7@ti.com> Sender: linux-leds-owner@vger.kernel.org To: Dan Murphy Cc: Jacek Anaszewski , robh+dt@kernel.org, mark.rutland@arm.com, rpurdie@rpsys.net, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, Lee Jones , Daniel Thompson , Jingoo Han List-Id: devicetree@vger.kernel.org --dDRMvlgZJXvWKvBx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >> If that does not yet exist... you want to create glue layer to be able > >> to use LED as a display backlight. (It may already exist, no idea). > >> > >> ... > >> > >> Actually or maybe a LED trigger. Just set LED's trigger to "this is > >> display backlight". > >=20 > > There is one already: > >=20 > > drivers/leds/trigger/ledtrig-backlight.c > >=20 > > It adds a LED class device to the fb_notifier_list > > (drivers/video/fbdev/core/fb_notify.c) > >=20 > > using fb_register_client(). The same is used in > > backlight_device_register (drivers/video/backlight/backlight.c). > >=20 > > Actually why do you want to have this driver in the LED subsystem, > > if it is advertised as "designed for LCD display backlighting"? >=20 > Well this is also advertised as a driver for Smart phone and tablet devic= es. And having worked with the Android lighting > solutions this is the preferred subsystem for Android. The Android OS ma= nages the led brightness based on ALS values and in > turn calls into the driver to control the brightness register through the= vendor provided lighting HAL. >=20 Well.. if it can control other LEDs than just backlight, I believe it can stay in the LED subsystem. > I am going to look at the backlight source to figure out how to get the s= ame functionality using the backlight subsystem. > Otherwise I will plug in this driver to the backlight subsystem through t= he notifier. >=20 The backlight trigger should be ok. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --dDRMvlgZJXvWKvBx Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAloOxgAACgkQMOfwapXb+vJlKACcD0C1bIT8JLHXg1TqcV77BreI iWgAn0gVkrfNTT81auusAT9qwA45QxUx =G/Vt -----END PGP SIGNATURE----- --dDRMvlgZJXvWKvBx--