gpio: mvebu: fix pwm .get_state period calculation

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>

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index 672681a..a912a8f 100644 (file)
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -676,20 +676,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
        else
                state->duty_cycle = 1;
 
+       val = (unsigned long long) u; /* on duration */
        regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
-       val = (unsigned long long) u * NSEC_PER_SEC;
+       val += (unsigned long long) u; /* period = on + off duration */
+       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)