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@armlinux.org.uk Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Fixes: 757642f9a584e ("gpio: mvebu: Add limited PWM support") Signed-off-by: Baruch Siach baruch@tkos.co.il Signed-off-by: Bartosz Golaszewski bgolaszewski@baylibre.com [baruch: backport to kernels <= v5.10] Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Signed-off-by: Baruch Siach baruch@tkos.co.il ---
This backported patch applies to all kernels between 4.14 and 5.10 (inclusive).
v2:
* Add a note on backport with another SoB
* Add Uwe's Reviewed-by tag --- 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)