lkml.org 
[lkml]   [2019]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v3 1/5] leds: lm3532: Fix brightness control for i2c mode
On Mon 2019-08-26 15:44:37, Tony Lindgren wrote:
> * Pavel Machek <pavel@ucw.cz> [190826 22:14]:
> > On Mon 2019-08-26 14:58:22, Tony Lindgren wrote:
> > > Hi,
> > >
> > > * Dan Murphy <dmurphy@ti.com> [190820 19:53]:
> > > > Fix the brightness control for I2C mode. Instead of
> > > > changing the full scale current register update the ALS target
> > > > register for the appropriate banks.
> > > >
> > > > In addition clean up some code errors and random misspellings found
> > > > during coding.
> > > >
> > > > Tested on Droid4 as well as LM3532 EVM connected to a BeagleBoneBlack
> > > >
> > > > Fixes: e37a7f8d77e1 ("leds: lm3532: Introduce the lm3532 LED driver")
> > > > Reported-by: Pavel Machek <pavel@ucw.cz>
> > > > Signed-off-by: Dan Murphy <dmurphy@ti.com>
> > > > ---
> > > >
> > > > v3 - Removed register define updates - https://lore.kernel.org/patchwork/patch/1114542/
> > >
> > > Looks like starting with this patch in Linux next the LCD on droid4
> > > is so dim it's unreadable even with brightness set to 255. Setting
> > > brightness to 0 does blank it completely though.
> > >
> > > Did something maybe break with the various patch revisions or are
> > > we now missing some dts patch?
> >
> > Maybe missing dts patch. We should provide maximum current the LED can
> > handle...
>
> Or i2c control is somehow broken and only als control now works?

Well, max current led is obviously missing. Plus code does not check
the return from reading led-max-microamp.

ret = fwnode_property_read_u32(child, "led-max-microamp",
&led->full_scale_current);

Untested, but something like this is neccessary according to code
review.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Pavel

diff --git a/arch/arm/boot/dts/omap4-droid4-xt894.dts b/arch/arm/boot/dts/omap4-droid4-xt894.dts
index 4454449..b883b84 100644
--- a/arch/arm/boot/dts/omap4-droid4-xt894.dts
+++ b/arch/arm/boot/dts/omap4-droid4-xt894.dts
@@ -395,6 +395,7 @@
ti,led-mode = <0>;
label = ":backlight";
linux,default-trigger = "backlight";
+ led-max-microamp = 29800;
};

led@1 {
@@ -402,6 +403,7 @@
led-sources = <1>;
ti,led-mode = <0>;
label = ":kbd_backlight";
+ led-max-microamp = 29800;
};
};
};

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2019-08-27 14:18    [W:0.058 / U:4.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site