[PATCH 0/2] leds: flash: lm3643: standby fix and ACPI LED description

[Ruslan Koreev]

These apply on top of Rillian Grant's "[RFC PATCH 0/2] leds: flash:
LM3643 dual LED flash driver" and answer two things from that thread.

Patch 1 addresses the two state-machine problems flagged by the Sashiko
review of the RFC, which Lee Jones asked to have addressed: switching
the last active output off left the chip in torch or flash mode instead
of standby.

Patch 2 addresses the question in the RFC cover letter about supplying
a default configuration on ACPI machines, where the chip is enumerated
as TXNW3643 without LED child nodes: it adds a DMI table describing the
LED as a software node, starting with the Lenovo ThinkPad X1 Carbon
Gen 14, where the LM3643 drives the Windows Hello IR flood illuminator
with both current sources feeding one LED. The limits are 100 mA torch
and 300 mA flash per output, well below the chip's maximums.

Tested on that laptop with Fedora 44 (kernel 7.2.5): the LED appears as
ir:flash, torch mode lights the ST VD55G1 IR camera's field of view and
the chip returns to standby when the torch is switched off, and face
authentication with howdy works on those frames.

Rillian, if you prefer to fold these into a v2 of your series, please
do; a DMI entry for the X9-15 Gen 1 only needs its product version
string.

Ruslan Koreev (2):
  leds: flash: lm3643: Return to standby when the last output is
    switched off
  leds: flash: lm3643: Describe the LED of ACPI boards without LED nodes

 drivers/leds/flash/leds-lm3643.c | 115 +++++++++++++++++++++++++++++--
 1 file changed, 109 insertions(+), 6 deletions(-)

-- 
2.55.0