* Re: devicetree bindings for a generic led-based backlight driver [not found] ` <e7c5a500-4107-8895-d0fc-377c71cd3b34@gmail.com> @ 2019-07-06 15:19 ` Pavel Machek 2019-07-10 9:26 ` Jean-Jacques Hiblot 0 siblings, 1 reply; 2+ messages in thread From: Pavel Machek @ 2019-07-06 15:19 UTC (permalink / raw) To: Jacek Anaszewski Cc: Jean-Jacques Hiblot, devicetree, linux-leds, robh, Valkeinen, Tomi [-- Attachment #1: Type: text/plain, Size: 2255 bytes --] Hi! > >>> A few years ago (2015), Tomi Valkeinen posted a series implementing a > >>> backlight driver on top of a LED device. > >>> > >>> https://patchwork.kernel.org/patch/7293991/ > >>> https://patchwork.kernel.org/patch/7294001/ > >>> https://patchwork.kernel.org/patch/7293981/ > >>> > >>> The discussion stopped because he lacked the time to work on it. > >>> > >>> I will be taking over the task and, before heading in the wrong > >>> direction, wanted a confirmation that the binding Tomi last proposed in > >>> hist last email was indeed the preferred option. > >>> > >>> It will probably require some modifications in the LED core to create > >>> the right kind of led-device (normal, flash or backlight) based on the > >>> compatible option. > >> I recall that discussion. I gave my ack for the LED changes but > >> now we have more LED people that might want to look into that. > > > > Regarding the LED bindings as discussed by Tom and Rob in > > https://patchwork.kernel.org/patch/7293991/, what do you think of using > > a 'compatible' string to make a LED device also a backlight or a flash LED ? > > After going through the referenced discussion and refreshing my memory > it looks to me the most reasonable way to go for backlight case. > > Nevertheless I'd not tamper at LED flash support - if it's not broken, > don't fix it. > > Best regards, > Jacek Anaszewski > > > Here is the example from Tomi at the end of the discussion: > > > > /* tlc59108 is an i2c device */ > > tlc59116@40 { > > #address-cells = <1>; > > #size-cells = <0>; > > compatible = "ti,tlc59108"; > > reg = <0x40>; > > > > wan@0 { > > label = "wrt1900ac:amber:wan"; > > reg = <0x0>; > > }; > > > > bl@2 { > > label = "backlight"; > > reg = <0x2>; > > > > compatible = "led-backlight"; > > brightness-levels = <0 243 245 247 248 249 251 252 255>; > > default-brightness-level = <8>; > > > > enable-gpios = <&pcf_lcd 13 GPIO_ACTIVE_LOW>; So... this needs some kind of reference to display it belongs to, right? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 181 bytes --] ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: devicetree bindings for a generic led-based backlight driver 2019-07-06 15:19 ` devicetree bindings for a generic led-based backlight driver Pavel Machek @ 2019-07-10 9:26 ` Jean-Jacques Hiblot 0 siblings, 0 replies; 2+ messages in thread From: Jean-Jacques Hiblot @ 2019-07-10 9:26 UTC (permalink / raw) To: Pavel Machek, Jacek Anaszewski Cc: devicetree, linux-leds, robh, Valkeinen, Tomi Hi Pavel On 06/07/2019 17:19, Pavel Machek wrote: > Hi! > >>>>> A few years ago (2015), Tomi Valkeinen posted a series implementing a >>>>> backlight driver on top of a LED device. >>>>> >>>>> https://patchwork.kernel.org/patch/7293991/ >>>>> https://patchwork.kernel.org/patch/7294001/ >>>>> https://patchwork.kernel.org/patch/7293981/ >>>>> >>>>> The discussion stopped because he lacked the time to work on it. >>>>> >>>>> I will be taking over the task and, before heading in the wrong >>>>> direction, wanted a confirmation that the binding Tomi last proposed in >>>>> hist last email was indeed the preferred option. >>>>> >>>>> It will probably require some modifications in the LED core to create >>>>> the right kind of led-device (normal, flash or backlight) based on the >>>>> compatible option. >>>> I recall that discussion. I gave my ack for the LED changes but >>>> now we have more LED people that might want to look into that. >>> Regarding the LED bindings as discussed by Tom and Rob in >>> https://patchwork.kernel.org/patch/7293991/, what do you think of using >>> a 'compatible' string to make a LED device also a backlight or a flash LED ? >> After going through the referenced discussion and refreshing my memory >> it looks to me the most reasonable way to go for backlight case. >> >> Nevertheless I'd not tamper at LED flash support - if it's not broken, >> don't fix it. >> >> Best regards, >> Jacek Anaszewski >> >>> Here is the example from Tomi at the end of the discussion: >>> >>> /* tlc59108 is an i2c device */ >>> tlc59116@40 { >>> #address-cells = <1>; >>> #size-cells = <0>; >>> compatible = "ti,tlc59108"; >>> reg = <0x40>; >>> >>> wan@0 { >>> label = "wrt1900ac:amber:wan"; >>> reg = <0x0>; >>> }; >>> >>> bl@2 { >>> label = "backlight"; >>> reg = <0x2>; >>> >>> compatible = "led-backlight"; >>> brightness-levels = <0 243 245 247 248 249 251 252 255>; >>> default-brightness-level = <8>; >>> >>> enable-gpios = <&pcf_lcd 13 GPIO_ACTIVE_LOW>; > So... this needs some kind of reference to display it belongs to, > right? This is the reverse. The display uses a reference the backlight. JJ > > Pavel > ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-07-10 9:26 UTC | newest] Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <69f3a300-9e37-448d-e6fa-49c1c9ca0dd6@ti.com> [not found] ` <400ac00b-d3c7-b58f-52fa-8b18b6c7e4a2@gmail.com> [not found] ` <283a3b7c-c3ed-719e-14e3-fc73e08af880@ti.com> [not found] ` <e7c5a500-4107-8895-d0fc-377c71cd3b34@gmail.com> 2019-07-06 15:19 ` devicetree bindings for a generic led-based backlight driver Pavel Machek 2019-07-10 9:26 ` Jean-Jacques Hiblot
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