From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org> To: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Cc: Denis Carikli <denis-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, Eric B??nard <eric-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org>, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>, Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>, Richard Purdie <rpurdie-Fm38FmjxZ/leoWH0uzbU5w@public.gmane.org>, Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>, Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Lothar Wa??mann <LW-bxm8fMRDkQLDiMYJYoSAnRvVK+yQ3ZXh@public.gmane.org> Subject: Re: [PATCHv4] video: backlight: gpio-backlight: Add DT support. Date: Wed, 23 Oct 2013 15:42:36 +0200 [thread overview] Message-ID: <20131023134236.GE17512@ns203013.ovh.net> (raw) In-Reply-To: <20131022200141.GA8037@mithrandir> On 22:01 Tue 22 Oct , Thierry Reding wrote: > On Tue, Oct 22, 2013 at 05:34:45PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > > On 09:23 Tue 22 Oct , Thierry Reding wrote: > > > On Tue, Oct 22, 2013 at 06:58:33AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > > > > On 11:13 Mon 21 Oct , Denis Carikli wrote: > > > > > Cc: Richard Purdie <rpurdie-Fm38FmjxZ/leoWH0uzbU5w@public.gmane.org> > > > > > Cc: Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> > > > > > Cc: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> > > > > > Cc: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org> > > > > > Cc: Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org> > > > > > Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org> > > > > > Cc: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> > > > > > Cc: Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org> > > > > > Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > > > > > Cc: Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> > > > > > Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org > > > > > Cc: Lothar Waßmann <LW-bxm8fMRDkQLDiMYJYoSAnRvVK+yQ3ZXh@public.gmane.org> > > > > > Cc: Jean-Christophe Plagniol-Villard <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org> > > > > > Cc: Eric Bénard <eric-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org> > > > > > Signed-off-by: Denis Carikli <denis-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org> > > > > > --- > > > > > ChangeLog v3->v4: > > > > > - The default-brightness property is now optional, it defaults to 1 if not set. > > > > by default we set OFF not ON > > > > > > > > do not actiate driver or properti by default you can not known to consequence > > > > on the hw > > > > > > Turning on a backlight by default is what pretty much every backlight > > > driver does. I personally think that's the wrong default, I even tried > > > to get some discussion started recently about how we could change this. > > > However, given that this has been the case for possibly as long as the > > > subsystem has existed, suddenly changing it might cause quite a few of > > > our users to boot the new kernel and not see their display come up. As > > > with any other ABI, this isn't something we can just change without a > > > very good migration path. > > > > I'm sorry but the blacklight descibe in DT have nothing to do with the common > > pratice that the current driver have today > > That's not at all what I said. What I said was that the majority of > backlight drivers currently default to turning the backlight on when > probed. Therefore I think it would be consistent if this driver did the > same. This is a matter of C code not DT > > I also said that I don't think it's a very good default, but at the same > time we can't just go and change the default behaviour at will because > people may rely on it. so handle it in C not in DT For me the only value a default-brightness would be with a pwn or a ragned value but not on 0-1 for on vs off > > > put on by default if wrong specially without the property define. Even put it > > on by default it wrong as the bootloader may have set it already for splash > > screen and to avoid glitch the drivers need to detect this. > > I agree that would be preferable, but I don't know of any way to detect > what value the bootloader set a GPIO to. The GPIO API requires that you > call gpio_direction_output(), and that requires a value parameter which > will be used as the output level of the GPIO. For me gpio_get_value can return the value of a an output gpio but this need to be checked with LinusW > > > For me this should not even be a property but handled by the driver them > > selves in C. > > Agreed. There has been some discussion recently about whether devicetree > should be extended (or supplemented) to allow defining behaviour as well > (in addition to just hardware). But that's not immediately relevant here > at this time. yes to conclued NACK on the default-brightness here Best Regards, J. > > Thierry -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
WARNING: multiple messages have this Message-ID (diff)
From: plagnioj@jcrosoft.com (Jean-Christophe PLAGNIOL-VILLARD) To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv4] video: backlight: gpio-backlight: Add DT support. Date: Wed, 23 Oct 2013 15:42:36 +0200 [thread overview] Message-ID: <20131023134236.GE17512@ns203013.ovh.net> (raw) In-Reply-To: <20131022200141.GA8037@mithrandir> On 22:01 Tue 22 Oct , Thierry Reding wrote: > On Tue, Oct 22, 2013 at 05:34:45PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > > On 09:23 Tue 22 Oct , Thierry Reding wrote: > > > On Tue, Oct 22, 2013 at 06:58:33AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > > > > On 11:13 Mon 21 Oct , Denis Carikli wrote: > > > > > Cc: Richard Purdie <rpurdie@rpsys.net> > > > > > Cc: Jingoo Han <jg1.han@samsung.com> > > > > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > > > > Cc: Rob Herring <rob.herring@calxeda.com> > > > > > Cc: Pawel Moll <pawel.moll@arm.com> > > > > > Cc: Mark Rutland <mark.rutland@arm.com> > > > > > Cc: Stephen Warren <swarren@wwwdotorg.org> > > > > > Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> > > > > > Cc: devicetree at vger.kernel.org > > > > > Cc: Sascha Hauer <kernel@pengutronix.de> > > > > > Cc: linux-arm-kernel at lists.infradead.org > > > > > Cc: Lothar Wa?mann <LW@KARO-electronics.de> > > > > > Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> > > > > > Cc: Eric B?nard <eric@eukrea.com> > > > > > Signed-off-by: Denis Carikli <denis@eukrea.com> > > > > > --- > > > > > ChangeLog v3->v4: > > > > > - The default-brightness property is now optional, it defaults to 1 if not set. > > > > by default we set OFF not ON > > > > > > > > do not actiate driver or properti by default you can not known to consequence > > > > on the hw > > > > > > Turning on a backlight by default is what pretty much every backlight > > > driver does. I personally think that's the wrong default, I even tried > > > to get some discussion started recently about how we could change this. > > > However, given that this has been the case for possibly as long as the > > > subsystem has existed, suddenly changing it might cause quite a few of > > > our users to boot the new kernel and not see their display come up. As > > > with any other ABI, this isn't something we can just change without a > > > very good migration path. > > > > I'm sorry but the blacklight descibe in DT have nothing to do with the common > > pratice that the current driver have today > > That's not at all what I said. What I said was that the majority of > backlight drivers currently default to turning the backlight on when > probed. Therefore I think it would be consistent if this driver did the > same. This is a matter of C code not DT > > I also said that I don't think it's a very good default, but at the same > time we can't just go and change the default behaviour at will because > people may rely on it. so handle it in C not in DT For me the only value a default-brightness would be with a pwn or a ragned value but not on 0-1 for on vs off > > > put on by default if wrong specially without the property define. Even put it > > on by default it wrong as the bootloader may have set it already for splash > > screen and to avoid glitch the drivers need to detect this. > > I agree that would be preferable, but I don't know of any way to detect > what value the bootloader set a GPIO to. The GPIO API requires that you > call gpio_direction_output(), and that requires a value parameter which > will be used as the output level of the GPIO. For me gpio_get_value can return the value of a an output gpio but this need to be checked with LinusW > > > For me this should not even be a property but handled by the driver them > > selves in C. > > Agreed. There has been some discussion recently about whether devicetree > should be extended (or supplemented) to allow defining behaviour as well > (in addition to just hardware). But that's not immediately relevant here > at this time. yes to conclued NACK on the default-brightness here Best Regards, J. > > Thierry
next prev parent reply other threads:[~2013-10-23 13:42 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-10-18 15:04 [PATCH 01/11] of: add vendor prefix for Eukréa Electromatique Denis Carikli 2013-10-18 15:04 ` Denis Carikli 2013-10-18 15:04 ` [PATCH 02/11] video: imxfb: Introduce regulator support Denis Carikli 2013-10-18 15:04 ` Denis Carikli 2013-10-19 10:45 ` Jean-Christophe PLAGNIOL-VILLARD 2013-10-19 10:45 ` Jean-Christophe PLAGNIOL-VILLARD [not found] ` <20131019104555.GI18477-HVbc7XotTAhnXn40ka+A6Q@public.gmane.org> 2013-10-21 9:13 ` [PATCHv4] video: backlight: gpio-backlight: Add DT support Denis Carikli 2013-10-21 9:13 ` Denis Carikli [not found] ` <1382346813-8449-1-git-send-email-denis-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org> 2013-10-21 22:48 ` Laurent Pinchart 2013-10-21 22:48 ` Laurent Pinchart 2013-10-22 5:11 ` Jean-Christophe PLAGNIOL-VILLARD 2013-10-22 5:11 ` Jean-Christophe PLAGNIOL-VILLARD 2013-10-22 4:58 ` Jean-Christophe PLAGNIOL-VILLARD 2013-10-22 4:58 ` Jean-Christophe PLAGNIOL-VILLARD [not found] ` <20131022045833.GB17512-HVbc7XotTAhnXn40ka+A6Q@public.gmane.org> 2013-10-22 7:23 ` Thierry Reding 2013-10-22 7:23 ` Thierry Reding 2013-10-22 15:34 ` Jean-Christophe PLAGNIOL-VILLARD 2013-10-22 15:34 ` Jean-Christophe PLAGNIOL-VILLARD [not found] ` <20131022153445.GD17512-HVbc7XotTAhnXn40ka+A6Q@public.gmane.org> 2013-10-22 20:01 ` Thierry Reding 2013-10-22 20:01 ` Thierry Reding 2013-10-23 13:42 ` Jean-Christophe PLAGNIOL-VILLARD [this message] 2013-10-23 13:42 ` Jean-Christophe PLAGNIOL-VILLARD [not found] ` <20131023134236.GE17512-HVbc7XotTAhnXn40ka+A6Q@public.gmane.org> 2013-10-23 16:49 ` Stephen Warren 2013-10-23 16:49 ` Stephen Warren [not found] ` <5267FE02.6000001-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-10-23 20:08 ` Thierry Reding 2013-10-23 20:08 ` Thierry Reding 2013-10-23 16:51 ` Stephen Warren 2013-10-23 16:51 ` Stephen Warren [not found] ` <5267FE81.3070201-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-10-23 20:20 ` Thierry Reding 2013-10-23 20:20 ` Thierry Reding 2013-10-23 22:38 ` Laurent Pinchart 2013-10-23 22:38 ` Laurent Pinchart 2013-10-24 11:05 ` Thierry Reding 2013-10-24 11:05 ` Thierry Reding [not found] ` <20131024110524.GB11296-AwZRO8vwLAwmlAP/+Wk3EA@public.gmane.org> 2013-10-25 13:57 ` Laurent Pinchart 2013-10-25 13:57 ` Laurent Pinchart 2013-10-31 23:44 ` Jingoo Han 2013-10-31 23:44 ` Jingoo Han [not found] ` <003701ced693$2f856150$8e9023f0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> 2013-11-01 9:57 ` Thierry Reding 2013-11-01 9:57 ` Thierry Reding [not found] ` <20131101095754.GJ27864-AwZRO8vwLAwmlAP/+Wk3EA@public.gmane.org> 2013-11-04 0:20 ` Jingoo Han 2013-11-04 0:20 ` Jingoo Han 2013-10-31 23:37 ` Jingoo Han 2013-10-31 23:37 ` Jingoo Han [not found] ` <001e01ced692$267a6d90$736f48b0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> 2013-11-01 10:13 ` Thierry Reding 2013-11-01 10:13 ` Thierry Reding [not found] ` <20131101101346.GK27864-AwZRO8vwLAwmlAP/+Wk3EA@public.gmane.org> 2013-11-06 0:08 ` Laurent Pinchart 2013-11-06 0:08 ` Laurent Pinchart 2013-10-25 20:10 ` Grant Likely 2013-10-25 20:10 ` Grant Likely
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20131023134236.GE17512@ns203013.ovh.net \ --to=plagnioj-sclmfoaustbwk0htik3j/w@public.gmane.org \ --cc=LW-bxm8fMRDkQLDiMYJYoSAnRvVK+yQ3ZXh@public.gmane.org \ --cc=denis-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org \ --cc=devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=eric-fO0SIAKYzcbQT0dZR+AlfA@public.gmane.org \ --cc=ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org \ --cc=jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org \ --cc=kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org \ --cc=laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org \ --cc=linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org \ --cc=mark.rutland-5wv7dgnIgG8@public.gmane.org \ --cc=pawel.moll-5wv7dgnIgG8@public.gmane.org \ --cc=rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org \ --cc=rpurdie-Fm38FmjxZ/leoWH0uzbU5w@public.gmane.org \ --cc=swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org \ --cc=thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.