@@ -667,22 +667,21 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
spin_lock_irqsave(&mvpwm->lock, flags);
regmap_read(mvpwm->regs, mvebu_pwmreg_blink_on_duration(mvpwm), &u);
- val = (unsigned long long) u * NSEC_PER_SEC;
- val = DIV_ROUND_UP_ULL(val, mvpwm->clk_rate);
- if (val)
- state->duty_cycle = val;
+ /* Hardware treats zero as 2^32. See mvebu_pwm_apply(). */
+ if (u > 0)
+ val = u;
else
- state->duty_cycle = 1;
+ val = UINT_MAX + 1ULL;
+ state->duty_cycle = DIV_ROUND_UP_ULL(val * NSEC_PER_SEC,
+ mvpwm->clk_rate);
- val = (unsigned long long) u; /* on duration */
regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
- val += (unsigned long long) u; /* period = on + off duration */
- val *= NSEC_PER_SEC;
- val = DIV_ROUND_UP_ULL(val, mvpwm->clk_rate);
- if (val)
- state->period = val;
+ /* period = on + off duration */
+ if (u > 0)
+ val += u;
else
- state->period = 1;
+ val += UINT_MAX + 1ULL;
+ state->period = DIV_ROUND_UP_ULL(val * NSEC_PER_SEC, mvpwm->clk_rate);
regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
if (u)
@@ -704,9 +703,15 @@ static int mvebu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
val = (unsigned long long) mvpwm->clk_rate * state->duty_cycle;
do_div(val, NSEC_PER_SEC);
- if (val > UINT_MAX)
+ if (val > UINT_MAX + 1ULL)
return -EINVAL;
- if (val)
+ /*
+ * Zero on/off values don't work as expected. Experimentation shows
+ * that zero value is treated as 2^32. This behavior is not documented.
+ */
+ if (val == UINT_MAX + 1ULL)
+ on = 0;
+ else if (val)
on = val;
else
on = 1;
@@ -714,9 +719,11 @@ static int mvebu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
val = (unsigned long long) mvpwm->clk_rate * state->period;
do_div(val, NSEC_PER_SEC);
val -= on;
- if (val > UINT_MAX)
+ if (val > UINT_MAX + 1ULL)
return -EINVAL;
- if (val)
+ if (val == UINT_MAX + 1ULL)
+ off = 0;
+ else if (val)
off = val;
else
off = 1;
Hardware appears to treat zero value as 2^32. Take advantage of this fact to support on/off values of up to UINT_MAX+1 == 2^32. Adjust both .apply and .get_state to handle zero as a special case. Rounded up division result in .get_state can't be zero, since the dividend is now larger than 0. Remove check for this case. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Analyzed-by: Russell King <linux@armlinux.org.uk> Signed-off-by: Baruch Siach <baruch@tkos.co.il> --- drivers/gpio/gpio-mvebu.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-)