commit e73b0101ae5124bf7cd3fb5d250302ad2f16a416 upstream.
The period is the sum of on and off values. That is, calculate period as
($on + $off) / clkrate
instead of
$off / clkrate - $on / clkrate
that makes no sense.
Reported-by: Russell King <linux@xxxxxxxxxxxxxxx>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Fixes: 757642f9a584e ("gpio: mvebu: Add limited PWM support")
Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
This backported patch applies to all kernels between 4.14 and 5.10
(inclusive).
---
drivers/gpio/gpio-mvebu.c | 25 ++++++++++---------------
1 file changed, 10 insertions(+), 15 deletions(-)
diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index 2f245594a90a..ed7c5fc47f52 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -660,9 +660,8 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
spin_lock_irqsave(&mvpwm->lock, flags);
- val = (unsigned long long)
- readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
- val *= NSEC_PER_SEC;
+ u = readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
+ val = (unsigned long long) u * NSEC_PER_SEC;
do_div(val, mvpwm->clk_rate);
if (val > UINT_MAX)
state->duty_cycle = UINT_MAX;
@@ -671,21 +670,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
else
state->duty_cycle = 1;
- val = (unsigned long long)
- readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm));
+ val = (unsigned long long) u; /* on duration */
+ /* period = on + off duration */
+ val += readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm));
val *= NSEC_PER_SEC;
do_div(val, mvpwm->clk_rate);
- if (val < state->duty_cycle) {
+ if (val > UINT_MAX)
+ state->period = UINT_MAX;
+ else if (val)
+ state->period = val;
+ else
state->period = 1;
- } else {
- val -= state->duty_cycle;
- if (val > UINT_MAX)
- state->period = UINT_MAX;
- else if (val)
- state->period = val;
- else
- state->period = 1;
- }
regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
if (u)
--
2.29.2
