Re: [PATCH v2 0/4] leds: flash: LM3643 dual LED flash driver

[Ruslan Koreev]

Hi Rillian,

On Mon, Sep 28, 2026 at 10:42:33AM +0100, Rillian Grant wrote:
> This series adds a flash LED driver for the Texas Instruments
> LM3643. I wrote it to support the Windows Hello NIR illuminator on my
> ThinkPad X9-15 Gen 1, which has a single LED connected to both current
> sources. The driver has also been tested by Ruslan Koreev on a ThinkPad
> X1 Carbon Gen 14.

Thanks for folding my patches in. I retested v2 on the X1 Carbon Gen 14
(7.2.5): the DMI description is picked up, max_brightness is 71 and
writes above it are clamped, max_flash_brightness is 600000, torch off
puts the chip back in standby (ENABLE reads 0x00), and a flash strobe
times out and reports flash-timeout-exceeded as expected.

About the Sashiko comment on 2/4: led_classdev_register_ext() reads
max-brightness from the fwnode before it creates the class device, so
the window only exists when the firmware node has a max-brightness
larger than what led-max-microamp allows. The DMI nodes don't set it.
If you want to close it anyway, clamping the code in
lm3643_torch_set_brightness() against the limit derived from
led-max-microamp would make it independent of max_brightness.

For 3/4, dev_dbg() is fine with me.

Ruslan