From 4afd772371d98e7569e26286c217db34479bb82b Mon Sep 17 00:00:00 2001 From: Baruch Siach Date: Sun, 17 Jan 2021 15:17:02 +0200 Subject: [PATCH] gpio: mvebu: fix pwm .get_state period calculation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Uwe Kleine-König Fixes: 757642f9a584e ("gpio: mvebu: Add limited PWM support") Signed-off-by: Baruch Siach Signed-off-by: Bartosz Golaszewski [baruch: backport to kernels <= v5.10] Reviewed-by: Uwe Kleine-König Signed-off-by: Baruch Siach Signed-off-by: Greg Kroah-Hartman --- 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 3985d6e1c17d..89a053b1d279 100644 --- a/drivers/gpio/gpio-mvebu.c +++ b/drivers/gpio/gpio-mvebu.c @@ -657,9 +657,8 @@ 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; @@ -668,21 +667,17 @@ 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)