I started here: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/888220.

Yes, sorry I added the wrong person to this bug.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/ec/+/d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db

commit d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db
Author: Aseda Aboagye <aaboagye@google.com>
Date: Tue Feb 06 07:05:39 2018

common: Add support for PWM LEDs.

This commit adds support for a common framework for PWM controlled LEDs.
If there are multiple LEDs, they will all follow the same pattern.  The
pattern is such that it follows the Chrome OS LED behaviour
specification, essentially a similar version of led_policy_std.c but for
PWM controlled LEDs.

To use this framework, a board must do the following:

- First, define the number of logical PWM LEDs which will be controlled
  by this common policy, CONFIG_LED_PWM_COUNT.

- Then declare those logical LEDs and define the PWM channels that
 comprise those LEDs. (struct pwm_led pwm_leds[]).

- Next, define what each color should look like (struct pwm_led
  led_color_map[]).

By default, the colors follow the recommended colors in the LED
behaviour spec, which assume an LED with a red and green channel.  If a
board differs or wishes to change the colors in general, they can
redefine the colors (CONFIG_LED_PWM_*_COLOR) as they see fit.  The
colors must be one in enum ec_led_colors.  These colors are the ones
that can represent the charging state, SoC state, etc.

BUG=b:69138917, chromium:752553 
BRANCH=None
TEST=make -j buildall
TEST=Enable led_pwm for meowth, and verify that LEDs behave as expected.

Change-Id: I945b86a7f8ed30df58d7da835d83577192548bea
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/888220
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Edward Hill <ecgh@chromium.org>

[add] https://crrev.com/d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db/include/led_pwm.h
[modify] https://crrev.com/d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db/include/config.h
[add] https://crrev.com/d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db/common/led_pwm.c
[modify] https://crrev.com/d940d2a991b33b5b1ad9d6a2698ebfcdaa0f59db/common/build.mk

I think a decent start is now merged. I could see us expanding on it if we wanted to add new features (i.e. - selective charge port indication (not that I'm a fan)).