From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v12 1/2] leds: core: Introduce LED pattern trigger Date: Fri, 21 Sep 2018 23:12:21 +0200 Message-ID: <20180921211221.GB18062@amd> References: <67ebebf02edd6d8ee42a13b139733e9cc680ea86.1536631975.git.baolin.wang@linaro.org> <324778a9-a32c-ae6e-337a-39845f214bfc@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1UWUbFP1cBYEclgG" Return-path: Content-Disposition: inline In-Reply-To: <324778a9-a32c-ae6e-337a-39845f214bfc@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Jacek Anaszewski Cc: Baolin Wang , rteysseyre@gmail.com, Bjorn Andersson , Mark Brown , Linus Walleij , Linux LED Subsystem , LKML List-Id: linux-leds@vger.kernel.org --1UWUbFP1cBYEclgG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri 2018-09-21 22:59:40, Jacek Anaszewski wrote: > Hi Baolin, >=20 > On 09/21/2018 05:31 AM, Baolin Wang wrote: > > Hi Jacek and Pavel, > >=20 > > On 11 September 2018 at 10:47, Baolin Wang wro= te: > >> This patch adds one new led trigger that LED device can configure > >> the software or hardware pattern and trigger it. > >> > >> Consumers can write 'pattern' file to enable the software pattern > >> which alters the brightness for the specified duration with one > >> software timer. > >> > >> Moreover consumers can write 'hw_pattern' file to enable the hardware > >> pattern for some LED controllers which can autonomously control > >> brightness over time, according to some preprogrammed hardware > >> patterns. > >> > >> Signed-off-by: Raphael Teysseyre > >> Signed-off-by: Baolin Wang > > Do you have any comments for the v12 patch set? Thanks. >=20 > We will probably have to remove hw_pattern from ledtrig-pattern > since we are unable to come up with generic interface for it. > Unless thread [0] will end up with some brilliant ideas. So far > we're waiting for Pavel's reply. >=20 > [0] https://lkml.org/lkml/2018/9/13/1216 Patch 1/2 is not controversial; I believe we can apply it now. 2/2: Non-linear or not, can we just ignore that for now? We don't have well-defined meaning of what brightness 128 means, so... I believe we can do that reasonably safely. I don't exactly understand what you are saying with the four tuples. Yes, sc27xx currently has a limit where it can do single rise, hold, lower, hold at zero. That is described by pattern: "0 rise_duration brightness high_duration brightness fall_duration 0 low_= duration" We should add this to sc27xx handler: > I'd actually like to see this at begining of function: > if (pattern[0].brightness !=3D 0) > return -EINVAL; > if (pattern[2].brightness !=3D 0) > return -EINVAL; > if (pattern[3].brightness !=3D 0) > return -EINVAL; > if (pattern[1].brightness !=3D pattern[2].brightness) > return -EINVAL; >=20 > ..so if user writes something unexpected, he gets the error back. Then it is compatible -- or should be. Pattern trigger should do the same -- rise, hold, lower, hold at zero. I don't really see the problem. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --1UWUbFP1cBYEclgG Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlulXrUACgkQMOfwapXb+vJjxwCfShrrN7WuiyD03m4OCK62wOJr tawAoMTx6qvVG0GNl5/Ei3a78aTJTMuE =3PAe -----END PGP SIGNATURE----- --1UWUbFP1cBYEclgG--