The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/ec/+/d1beddc463f488e527a90bf5adea92e4e9199a8f

commit d1beddc463f488e527a90bf5adea92e4e9199a8f
Author: Shawn Nematbakhsh <shawnn@chromium.org>
Date: Thu May 26 21:38:38 2016

pwm: Modify new PWM host commands to take 16-bit duty cycle

EC_CMD_PWM_SET_DUTY / EC_CMD_PWM_GET_DUTY were recently added and are
not yet in use. Future-proof these commands by taking a 16-bit duty
cycle parameter and converting it between the [0-100] percent used by
internal EC functions.

BUG= chromium:615109 
BRANCH=None
TEST=Manual on chell.
`ectool pwmsetduty kb 65535` - Verify KB backlight goes to 100%
`ectool pwmgetduty kb` - Prints 65535
`ectool pwmgetduty 0` - Prints 65535
`ectool pwmsetduty 0 0` - Verify KB backlight goes to 0%
`ectool pwmgetduty kb` - Prints 0
`ectool pwmgetduty disp` - Error res 3 (unsupported PWM type)
`ectool pwmsetduty 1` - Error res 3 (non-existent PWM index)
`ectool pwmsetduty kb 6550` +
`ectool pwmgetduty kb` - Prints 6553 (round up)
`ectool pwmsetduty kb 6560` +
`ectool pwmgetduty kb` - Prints 6553 (round down)

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: Ic6996fc6e1e69359274b2f9a1120ee7002db991c
Reviewed-on: https://chromium-review.googlesource.com/347608
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>

[modify] https://crrev.com/d1beddc463f488e527a90bf5adea92e4e9199a8f/include/ec_commands.h
[modify] https://crrev.com/d1beddc463f488e527a90bf5adea92e4e9199a8f/common/pwm.c
[modify] https://crrev.com/d1beddc463f488e527a90bf5adea92e4e9199a8f/util/ectool.c

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/ec/+/26c5a22125916a53b62ac8226eb10af4c7a77c58

commit 26c5a22125916a53b62ac8226eb10af4c7a77c58
Author: Sam Hurst <shurst@google.com>
Date: Tue Aug 23 18:43:23 2016

pwm: Increse PWM duty resolution to 16bits

The current PWM interface allows for a pwm duty setting ranging from
0 to 100, resulting in a very coarse adjustment. To alleviate the
problem, the interface now allows for a pwm duty setting in the range
of 0 to 65535.

BUG= chromium:615109 
BRANCH=None
TEST=Manual on chell.
`ectool pwmsetduty 1 65535` - Verify LCD backlight goes to 100%
`ectool pwmgetduty 1` - Prints 65535
`ectool pwmsetduty 1 0` - Verify LCD backlight goes to 0%
`ectool pwmgetduty 1` - Prints 0

terminal pwmduty tests:
>pwmduty
PWM channels:
  0: 100%
  1: 62%
  2: 100%
  3: 80%
> pwmduty 1 50
Setting channel 1 to 50%
  1: 50%
> pwmduty 1 0
Setting channel 1 to 0%
  1: disabled
> pwmduty 1 100
Setting channel 1 to 100%
  1: 100%
> pwmduty 1 raw 0
Setting channel 1 to raw 0%
  1: disabled
> pwmduty 1 raw 65535
Setting channel 1 to raw 65535%
  1: 65535
> pwmduty
PWM channels:
  0: 100%
  1: 100%
  2: 100%
  3: 80%
> pwmduty 1 raw 30000
Setting channel 1 to raw 30000%
  1: 30000
> pwmduty
PWM channels:
  0: 100%
  1: 46%
  2: 100%
  3: 80%

Change-Id: I299b77585f3988e72d9ac918bdde7dc5fa3df6de
Reviewed-on: https://chromium-review.googlesource.com/374481
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Sam Hurst <shurst@google.com>
Reviewed-by: Shawn N <shawnn@chromium.org>

[modify] https://crrev.com/26c5a22125916a53b62ac8226eb10af4c7a77c58/board/kevin/board.c
[modify] https://crrev.com/26c5a22125916a53b62ac8226eb10af4c7a77c58/include/pwm.h
[modify] https://crrev.com/26c5a22125916a53b62ac8226eb10af4c7a77c58/common/pwm.c
[modify] https://crrev.com/26c5a22125916a53b62ac8226eb10af4c7a77c58/chip/npcx/pwm.c

Fixed?

Yup, fixed in above CL. Thanks Sam!

Well, I'm actually testing now and seeing a problem at max duty (65535). Kevin backlight goes off when I do this. Should I file a new bug or reopen?

Thanks for testing, we'll check that case.

I have confirmed the issue and I have a fix. File a new bug.

Filed: https://code.google.com/p/chrome-os-partner/issues/detail?id=57052

Let's close this one then :)