linux-kernel - Re: [PATCH v13 RESEND 3/4] docs: ABI: Document LP5812 LED sysfs interfaces

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Message-ID: <1075a908-23d0-4a9e-97d2-cb68d1d6b675@infradead.org>
Date: Sun, 17 Aug 2025 19:07:21 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Nam Tran <trannamatk@...il.com>, lee@...nel.org,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: pavel@...nel.org, christophe.jaillet@...adoo.fr, krzk+dt@...nel.org,
 robh@...nel.org, conor+dt@...nel.org, corbet@....net,
 linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v13 RESEND 3/4] docs: ABI: Document LP5812 LED sysfs
 interfaces

Hi--

On 8/17/25 6:26 PM, Nam Tran wrote:
> The LP5812 is a 4x3 matrix RGB LED driver with autonomous animation
> engine control.
> 
> This patch documents the basic sysfs interfaces provided by the driver,
> including LED activation, current control, fault status, and simple
> chip-level operations such as software reset and fault clearing.
> 
> Signed-off-by: Nam Tran <trannamatk@...il.com>
> ---
>  .../ABI/testing/sysfs-bus-i2c-devices-lp5812  | 32 +++++++++++++++++++
>  .../ABI/testing/sysfs-class-led-lp5812        | 32 +++++++++++++++++++
>  MAINTAINERS                                   |  2 ++
>  3 files changed, 66 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-lp5812
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-lp5812
> 


> diff --git a/Documentation/ABI/testing/sysfs-class-led-lp5812 b/Documentation/ABI/testing/sysfs-class-led-lp5812
> new file mode 100644
> index 000000000000..93eeecc60864
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-lp5812
> @@ -0,0 +1,32 @@
> +What:		/sys/class/leds/led_<id>/activate
> +Date:		July 2025
> +KernelVersion:	6.17
> +Contact:	Nam Tran <trannamatk@...il.com>
> +Description:
> +		Activate or deactivate the specified LED channel. (WO)
> +		1 - Activate
> +		0 - Deactivate
> +
> +What:		/sys/class/leds/led_<id>/led_current
> +Date:		July 2025
> +KernelVersion:	6.17
> +Contact:	Nam Tran <trannamatk@...il.com>
> +Description:
> +		DC current level. (WO)
> +		Valid values: 0 - 255
> +
> +What:		/sys/class/leds/led_<id>/max_current
> +Date:		July 2025
> +KernelVersion:	6.17
> +Contact:	Nam Tran <trannamatk@...il.com>
> +Description:
> +		Shows maximum DC current bit setting. (RO)
> +		0 (default) means the LED maximum current is set to 25.5 mA.
> +		1 means the LED maximum current is set to 51 mA.
> +
> +What:		/sys/class/leds/led_<id>/lod_lsd
> +Date:		July 2025
> +KernelVersion:	6.17
> +Contact:	Nam Tran <trannamatk@...il.com>
> +Description:
> +		0 0 mean no lod and lsd fault detected, 1 1 mean lod and lsd fault detected (RO)

At first the "0 0" and "1 1" confused me (thought it was a typo),
but I think what you are showing here is a sysfs file with 2 values, right?
That used to be discouraged (or even nacked), although I don't know the
current policy on that.

@Greg, any comment?


-- 
~Randy