[PATCH v4 06/16] pwm: lpss: Correct get_state result for base_unit == 0

Hans de Goede
2020-07-08T21:15:10Z

The datasheet specifies that programming the base_unit part of the
ctrl register to 0 results in a contineous low signal.

Adjust the get_state method to reflect this by setting pwm_state.period
to 1 and duty_cycle to 0.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4:
- This is a new patch in v4 of this patchset
---
drivers/pwm/pwm-lpss.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 4f3d60ce9929..4d4de45cf99b 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -192,14 +192,16 @@ static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm,

freq = base_unit * lpwm->info->clk_rate;
do_div(freq, base_unit_range);
- if (freq == 0)
- state->period = NSEC_PER_SEC;
- else
+ if (freq == 0) {
+ /* In this case the PWM outputs a continous low signal */
+ state->period = 1;
+ state->duty_cycle = 0;
+ } else {
state->period = NSEC_PER_SEC / (unsigned long)freq;
-
- on_time_div *= state->period;
- do_div(on_time_div, 255);
- state->duty_cycle = on_time_div;
+ on_time_div *= state->period;
+ do_div(on_time_div, 255);
+ state->duty_cycle = on_time_div;
+ }

state->polarity = PWM_POLARITY_NORMAL;
state->enabled = !!(ctrl & PWM_ENABLE);
--
2.26.2