linux-kernel - Re: [PATCH v3 1/5] leds: lm3532: Fix brightness control for i2c mode

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Date:   Tue, 27 Aug 2019 08:01:41 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Pavel Machek <pavel@....cz>, Tony Lindgren <tony@...mide.com>
CC:     <jacek.anaszewski@...il.com>, <sre@...nel.org>,
        <nekit1000@...il.com>, <mpartap@....net>, <merlijn@...zup.org>,
        <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/5] leds: lm3532: Fix brightness control for i2c mode

Hello

On 8/27/19 7:44 AM, Dan Murphy wrote:
> Tony
>
> On 8/27/19 7:18 AM, Pavel Machek wrote:
>> On Mon 2019-08-26 15:44:37, Tony Lindgren wrote:
>>> * Pavel Machek <pavel@....cz> [190826 22:14]:
>>>> On Mon 2019-08-26 14:58:22, Tony Lindgren wrote:
>>>>> Hi,
>>>>>
>>>>> * Dan Murphy <dmurphy@...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@....cz>
>>>>>> Signed-off-by: Dan Murphy <dmurphy@...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?
>
> With only setting CONFIG_LEDS_LM3532=m to the next branch I get full 
> brightness with 255.
>
> I also see half brightness at 128 with the ramp down working.
>
> I am not able to reproduce this issue on my device.
>
Just to make sure my data was right I did a clean rebuild on commit 
1dbb9fb4082ce2a2f1cf9596881ddece062d15d0

from the led-next branch.

Just adding the above config flag.  I still cannot reproduce the issue

See attached pic

Dan

<snip>

Download attachment "droid4.jpg" of type "image/jpeg" (83115 bytes)