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Commit 4e5ee86d authored by Baruch Siach's avatar Baruch Siach Committed by Greg Kroah-Hartman
Browse files

gpio: mvebu: fix pwm .get_state period calculation 



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: default avatarRussell King <linux@armlinux.org.uk>
Reviewed-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 757642f9 ("gpio: mvebu: Add limited PWM support")
Signed-off-by: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
[baruch: backport to kernels <= v5.10]
Reviewed-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c4ff839d

drivers/gpio/gpio-mvebu.c

+10 −15
Original line number Diff line number Diff line
@@ -650,9 +650,8 @@ 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;
@@ -661,21 +660,17 @@ 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) {

		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)