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| author | Brian Norris <briannorris@chromium.org> | 2016-07-16 01:28:44 +0200 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2016-07-25 10:40:41 +0200 |
| commit | 1f0d3bb02785f698dc273b9006a473194c32f874 (patch) | |
| tree | c4557cae6930d36e9e834d1cc39770672d7c0062 /Documentation | |
| parent | dt-bindings: pwm: Add binding for ChromeOS EC PWM (diff) | |
| download | linux-1f0d3bb02785f698dc273b9006a473194c32f874.tar.xz linux-1f0d3bb02785f698dc273b9006a473194c32f874.zip | |
pwm: Add ChromeOS EC PWM driver
Use the new ChromeOS EC EC_CMD_PWM_{GET,SET}_DUTY commands to control
one or more PWMs attached to the Embedded Controller. Because the EC
allows us to modify the duty cycle (as a percentage, where U16_MAX is
100%) but not the period, we assign the period a fixed value of
EC_PWM_MAX_DUTY and reject all attempts to change it.
This driver supports only device tree at the moment, because that
provides a very flexible way of describing the relationship between PWMs
and their consumer devices (e.g., backlight). On a non-DT system, we'll
probably want to use the non-GENERIC addressing (i.e., we'll need to
make special device instances that will use EC_PWM_TYPE_KB_LIGHT or
EC_PWM_TYPE_DISPLAY_LIGHT), as well as the relatively inflexible
pwm_lookup infrastructure for matching devices. Defer that work for now.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions