dt-bindings: leds: qcom-lpg: Explain standalone PWM usage

LPG channels can be used for only outputting PWM signals by routing to
PMIC GPIOs without enabling TRILED. Explain this usage in the description
for better clarity.

Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://patch.msgid.link/20251119-lpg_triled_fix-v3-1-84b6dbdc774a@oss.qualcomm.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: fenglinw-qcom

Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml

@@ -13,6 +13,11 @@ description: >
   The Qualcomm Light Pulse Generator consists of three different hardware blocks;
   a ramp generator with lookup table (LUT), the light pulse generator and a three
   channel current sink. These blocks are found in a wide range of Qualcomm PMICs.
+  The light pulse generator (LPG) can also be used independently to output PWM
+  signal for standard PWM applications. In this scenario, the LPG output should
+  be routed to a specific PMIC GPIO by setting the GPIO pin mux to the special
+  functions indicated in the datasheet, the TRILED driver for the channel will
+  not be enabled in this configuration.
 
 properties:
   compatible: