The "atomic" API allows us to configure PWM period and duty_cycle and
enable it in one call.
The patch also moves the pwm_init_state just before any use of the
pwm_state struct, this fixes a potential bug where pwm_get_state
can be called before pwm_init_state.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---
drivers/video/backlight/pwm_bl.c | 48 ++++++++++++++++++++------------
1 file changed, 30 insertions(+), 18 deletions(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index bdfcc0a71db1..2c734d55d607 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -46,7 +46,8 @@ struct pwm_bl_data {
void (*exit)(struct device *);
};
-static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
+static void pwm_backlight_power_on(struct pwm_bl_data *pb,
+ struct pwm_state *state)
{
int err;
@@ -57,7 +58,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
if (err < 0)
dev_err(pb->dev, "failed to enable power supply\n");
- pwm_enable(pb->pwm);
+ state->enabled = true;
+ pwm_apply_state(pb->pwm, state);
if (pb->post_pwm_on_delay)
msleep(pb->post_pwm_on_delay);
@@ -70,6 +72,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
static void pwm_backlight_power_off(struct pwm_bl_data *pb)
{
+ struct pwm_state state;
+
if (!pb->enabled)
return;
@@ -79,8 +83,11 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
if (pb->pwm_off_delay)
msleep(pb->pwm_off_delay);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_get_state(pb->pwm, &state);
+ state.enabled = false;
+ state.period = pb->period;
+ state.duty_cycle = 0;
+ pwm_apply_state(pb->pwm, &state);
regulator_disable(pb->power_supply);
pb->enabled = false;
@@ -106,6 +113,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
{
struct pwm_bl_data *pb = bl_get_data(bl);
int brightness = bl->props.brightness;
+ struct pwm_state state;
int duty_cycle;
if (bl->props.power != FB_BLANK_UNBLANK ||
@@ -118,8 +126,13 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
if (brightness > 0) {
duty_cycle = compute_duty_cycle(pb, brightness);
- pwm_config(pb->pwm, duty_cycle, pb->period);
- pwm_backlight_power_on(pb, brightness);
+ pwm_get_state(pb->pwm, &state);
+ state.duty_cycle = duty_cycle;
+ state.period = pb->period;
+ if (!state.enabled)
+ pwm_backlight_power_on(pb, &state);
+ else
+ pwm_apply_state(pb->pwm, &state);
} else
pwm_backlight_power_off(pb);
@@ -447,7 +460,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
struct device_node *node = pdev->dev.of_node;
struct pwm_bl_data *pb;
struct pwm_state state;
- struct pwm_args pargs;
unsigned int i;
int ret;
@@ -539,10 +551,17 @@ static int pwm_backlight_probe(struct platform_device *pdev)
dev_dbg(&pdev->dev, "got pwm for backlight\n");
- if (!data->levels) {
- /* Get the PWM period (in nanoseconds) */
- pwm_get_state(pb->pwm, &state);
+ /* Sync up PWM state and ensure it is off. */
+ pwm_init_state(pb->pwm, &state);
+ state.enabled = false;
+ ret = pwm_apply_state(pb->pwm, &state);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",
+ ret);
+ goto err_alloc;
+ }
+ if (!data->levels) {
ret = pwm_backlight_brightness_default(&pdev->dev, data,
state.period);
if (ret < 0) {
@@ -559,20 +578,13 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->levels = data->levels;
}
- /*
- * FIXME: pwm_apply_args() should be removed when switching to
- * the atomic PWM API.
- */
- pwm_apply_args(pb->pwm);
-
/*
* The DT case will set the pwm_period_ns field to 0 and store the
* period, parsed from the DT, in the PWM device. For the non-DT case,
* set the period from platform data if it has not already been set
* via the PWM lookup table.
*/
- pwm_get_args(pb->pwm, &pargs);
- pb->period = pargs.period;
+ pb->period = state.period;
if (!pb->period && (data->pwm_period_ns > 0))
pb->period = data->pwm_period_ns;
--
2.18.0
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