When the function pwm_backlight_update_status() was called with
brightness > 0, pwm_get_state() was called twice (once directly and once
in compute_duty_cycle). Also pwm_apply_state() was called twice (once in
pwm_backlight_power_on() and once directly).
Optimize this to do both calls only once.
Note that with this affects the order of regulator and PWM setup. It's
not expected to have a relevant effect on hardware. The rationale for
this is that the regulator (and the GPIO) are reasonable to switch in
pwm_backlight_power_on()/pwm_backlight_power_off() but the PWM has
nothing to do with power. (The post_pwm_on_delay and pwm_off_delay are
still there though.)
Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/video/backlight/pwm_bl.c | 28 ++++++++++------------------
1 file changed, 10 insertions(+), 18 deletions(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d0b22158cd70..0509fecd5715 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -40,10 +40,8 @@ struct pwm_bl_data {
static void pwm_backlight_power_on(struct pwm_bl_data *pb)
{
- struct pwm_state state;
int err;
- pwm_get_state(pb->pwm, &state);
if (pb->enabled)
return;
@@ -51,9 +49,6 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
if (err < 0)
dev_err(pb->dev, "failed to enable power supply\n");
- state.enabled = true;
- pwm_apply_state(pb->pwm, &state);
-
if (pb->post_pwm_on_delay)
msleep(pb->post_pwm_on_delay);
@@ -65,9 +60,6 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
static void pwm_backlight_power_off(struct pwm_bl_data *pb)
{
- struct pwm_state state;
-
- pwm_get_state(pb->pwm, &state);
if (!pb->enabled)
return;
@@ -77,28 +69,21 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
if (pb->pwm_off_delay)
msleep(pb->pwm_off_delay);
- state.enabled = false;
- state.duty_cycle = 0;
- pwm_apply_state(pb->pwm, &state);
-
regulator_disable(pb->power_supply);
pb->enabled = false;
}
-static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)
+static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness, struct pwm_state *state)
{
unsigned int lth = pb->lth_brightness;
- struct pwm_state state;
u64 duty_cycle;
- pwm_get_state(pb->pwm, &state);
-
if (pb->levels)
duty_cycle = pb->levels[brightness];
else
duty_cycle = brightness;
- duty_cycle *= state.period - lth;
+ duty_cycle *= state->period - lth;
do_div(duty_cycle, pb->scale);
return duty_cycle + lth;
@@ -115,11 +100,18 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
if (brightness > 0) {
pwm_get_state(pb->pwm, &state);
- state.duty_cycle = compute_duty_cycle(pb, brightness);
+ state.duty_cycle = compute_duty_cycle(pb, brightness, &state);
+ state.enabled = true;
pwm_apply_state(pb->pwm, &state);
+
pwm_backlight_power_on(pb);
} else {
pwm_backlight_power_off(pb);
+
+ pwm_get_state(pb->pwm, &state);
+ state.enabled = false;
+ state.duty_cycle = 0;
+ pwm_apply_state(pb->pwm, &state);
}
if (pb->notify_after)
--
2.39.0
