diff options
| author | Alper Nebi Yasak <alpernebiyasak@gmail.com> | 2020-10-22 23:49:26 +0300 |
|---|---|---|
| committer | Anatolij Gustschin <agust@denx.de> | 2021-04-10 16:07:12 +0200 |
| commit | fefa713b1843cf13d3132bfe0cf27710938c5d92 (patch) | |
| tree | 4ae09212a60da99436d30eb24b3f9d041553cdbe /drivers/pwm | |
| parent | 9749d2ea29e1a535c9ea8f850db8b6abe6df7b15 (diff) | |
video: backlight: Support PWMs without a known period_ns
The PWM device provided by Chrome OS EC doesn't really support anything
other than setting a relative duty cycle. To support it as a backlight,
this patch makes the PWM period optional in the device tree and pretends
the valid brightness range is its period_ns.
Also adds a sandbox test for a PWM channel that has a fixed period,
checking that the resulting duty_cycle matches on a set_config() even if
the requested period_ns can't be set.
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/sandbox_pwm.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/pwm/sandbox_pwm.c b/drivers/pwm/sandbox_pwm.c index 318dce7c14..4df15f0a2e 100644 --- a/drivers/pwm/sandbox_pwm.c +++ b/drivers/pwm/sandbox_pwm.c @@ -59,8 +59,15 @@ static int sandbox_pwm_set_config(struct udevice *dev, uint channel, if (channel >= NUM_CHANNELS) return -ENOSPC; chan = &priv->chan[channel]; - chan->period_ns = period_ns; - chan->duty_ns = duty_ns; + + if (channel == 2) { + /* Pretend to have some fixed period */ + chan->period_ns = 4096; + chan->duty_ns = duty_ns * 4096 / period_ns; + } else { + chan->period_ns = period_ns; + chan->duty_ns = duty_ns; + } return 0; } |