From f4a8e31ed84ec646c158824f423cb22d1f362bbf Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 1 Jul 2021 10:27:55 +0200 Subject: pwm: ep93xx: Ensure configuring period and duty_cycle isn't wrongly skipped MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As the last call to ep93xx_pwm_apply() might have exited early if state->enabled was false, the values for period and duty_cycle stored in pwm->state might not have been written to hardware and it must be ensured that they are configured before enabling the PWM. Fixes: 6d45374af539 ("pwm: ep93xx: Implement .apply callback") Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding --- drivers/pwm/pwm-ep93xx.c | 85 +++++++++++++++++++++++------------------------- 1 file changed, 40 insertions(+), 45 deletions(-) (limited to 'drivers/pwm') diff --git a/drivers/pwm/pwm-ep93xx.c b/drivers/pwm/pwm-ep93xx.c index 8a3d781e6514..fc3cb7d669c6 100644 --- a/drivers/pwm/pwm-ep93xx.c +++ b/drivers/pwm/pwm-ep93xx.c @@ -64,6 +64,11 @@ static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, int ret; struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); bool enabled = state->enabled; + void __iomem *base = ep93xx_pwm->base; + unsigned long long c; + unsigned long period_cycles; + unsigned long duty_cycles; + unsigned long term; if (state->polarity != pwm->state.polarity) { if (enabled) { @@ -97,57 +102,47 @@ static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return 0; } - if (state->period != pwm->state.period || - state->duty_cycle != pwm->state.duty_cycle) { - struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); - void __iomem *base = ep93xx_pwm->base; - unsigned long long c; - unsigned long period_cycles; - unsigned long duty_cycles; - unsigned long term; + /* + * The clock needs to be enabled to access the PWM registers. + * Configuration can be changed at any time. + */ + if (!pwm_is_enabled(pwm)) { + ret = clk_prepare_enable(ep93xx_pwm->clk); + if (ret) + return ret; + } - /* - * The clock needs to be enabled to access the PWM registers. - * Configuration can be changed at any time. - */ - if (!pwm_is_enabled(pwm)) { - ret = clk_prepare_enable(ep93xx_pwm->clk); - if (ret) - return ret; - } + c = clk_get_rate(ep93xx_pwm->clk); + c *= state->period; + do_div(c, 1000000000); + period_cycles = c; + + c = period_cycles; + c *= state->duty_cycle; + do_div(c, state->period); + duty_cycles = c; - c = clk_get_rate(ep93xx_pwm->clk); - c *= state->period; - do_div(c, 1000000000); - period_cycles = c; - - c = period_cycles; - c *= state->duty_cycle; - do_div(c, state->period); - duty_cycles = c; - - if (period_cycles < 0x10000 && duty_cycles < 0x10000) { - term = readw(base + EP93XX_PWMx_TERM_COUNT); - - /* Order is important if PWM is running */ - if (period_cycles > term) { - writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); - writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); - } else { - writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); - writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); - } - ret = 0; + if (period_cycles < 0x10000 && duty_cycles < 0x10000) { + term = readw(base + EP93XX_PWMx_TERM_COUNT); + + /* Order is important if PWM is running */ + if (period_cycles > term) { + writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); + writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); } else { - ret = -EINVAL; + writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); + writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); } + ret = 0; + } else { + ret = -EINVAL; + } - if (!pwm_is_enabled(pwm)) - clk_disable_unprepare(ep93xx_pwm->clk); + if (!pwm_is_enabled(pwm)) + clk_disable_unprepare(ep93xx_pwm->clk); - if (ret) - return ret; - } + if (ret) + return ret; if (!enabled) { ret = clk_prepare_enable(ep93xx_pwm->clk); -- cgit v1.2.3-59-g8ed1b