From mboxrd@z Thu Jan  1 00:00:00 1970
From: pali.rohar@gmail.com (Pali =?utf-8?B?Um9ow6Fy?=)
Date: Fri, 15 Jul 2016 09:40:52 +0200
Subject: outdated documentation for lp5523 LED driver?
In-Reply-To: <20160715073214.GC13429@amd>
References: <20160715073214.GC13429@amd>
Message-ID: <20160715074052.GE29844@pali>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Friday 15 July 2016 09:32:14 Pavel Machek wrote:
> Hi!
> 
> Documentation says that load/leds are only visible in the load mode,
> but that does not seem to be true (kernel 4.4.0 on N900).
> 
> # 1) Legacy interface - enginex_mode, enginex_load and enginex_leds
> #  Control interface for the engines:
> #    x is 1 .. 3
> #      enginex_mode : disabled, load, run
> #      enginex_load : microcode load (visible only in load mode)
> #      enginex_leds : led mux control (visible only in load mode)
> 
> pavel at n900:/sys/class/leds/lp5523:r/device$ ls -al engine*
> -rw-r--r-- 1 root root 4096 Jul  6 22:47 engine1_leds
> --w------- 1 root root 4096 Jul  6 22:47 engine1_load
> -rw-r--r-- 1 root root 4096 Jul  6 23:41 engine1_mode
> -rw-r--r-- 1 root root 4096 Jul  6 22:47 engine2_leds
> --w------- 1 root root 4096 Jul  6 22:47 engine2_load
> -rw-r--r-- 1 root root 4096 Jul  6 23:41 engine2_mode
> -rw-r--r-- 1 root root 4096 Jul  6 22:47 engine3_leds
> --w------- 1 root root 4096 Jul  6 22:47 engine3_load
> -rw-r--r-- 1 root root 4096 Jul  6 22:47 engine3_mode
> pavel at n900:/sys/class/leds/lp5523:r/device$ grep . engine*mode
> engine1_mode:run
> engine2_mode:load
> engine3_mode:run
> pavel at n900:/sys/class/leds/lp5523:r/device$

On 2.6.28 kernel is present only legacy interface and for this version
is above documentation correct. When engine is in "run" or "disabled",
then sysfs nodes _load and _leds are invisible.

So I suspect that bug is in current kernel code and documentation is
correct... So I would propose to fix kernel code to reflect
documentation...

> I got both the legacy and the firmware interface to work... but the
> firmware interface only seems to work once for me.
> 
> How new and old interface are expected to interact with each other is
> not clear to me.

In my opinion both interfaces could be used. They provide same states
load/run but via different sysfs files.

> What should be done there?
> 
> Best regards,
> 									Pavel
> 

-- 
Pali Roh?r
pali.rohar at gmail.com