From 2f81b51d0d02074502ad27424c228ca760823668 Mon Sep 17 00:00:00 2001 From: Lino Sanfilippo Date: Wed, 9 Dec 2020 21:48:25 +0100 Subject: [PATCH] pwm: bcm2835: Support apply function for atomic configuration MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Use the newer .apply function of pwm_ops instead of .config, .enable, .disable and .set_polarity. This guarantees atomic changes of the pwm controller configuration. It also reduces the size of the driver. Since now period is a 64 bit value, add an extra check to reject periods that exceed the possible max value for the 32 bit register. This has been tested on a Raspberry PI 4. Signed-off-by: Lino Sanfilippo Reviewed-by: Uwe Kleine-König Signed-off-by: Thierry Reding --- drivers/pwm/pwm-bcm2835.c | 69 ++++++++++++++------------------------- 1 file changed, 24 insertions(+), 45 deletions(-) diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c index bc018daf1488..6ff5f04b3e07 100644 --- a/drivers/pwm/pwm-bcm2835.c +++ b/drivers/pwm/pwm-bcm2835.c @@ -58,13 +58,15 @@ static void bcm2835_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) writel(value, pc->base + PWM_CONTROL); } -static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, - int duty_ns, int period_ns) +static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) { + struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); unsigned long rate = clk_get_rate(pc->clk); + unsigned long long period; unsigned long scaler; - u32 period; + u32 val; if (!rate) { dev_err(pc->dev, "failed to get clock rate\n"); @@ -72,54 +74,34 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, } scaler = DIV_ROUND_CLOSEST(NSEC_PER_SEC, rate); - period = DIV_ROUND_CLOSEST(period_ns, scaler); + /* set period */ + period = DIV_ROUND_CLOSEST_ULL(state->period, scaler); - if (period < PERIOD_MIN) + /* dont accept a period that is too small or has been truncated */ + if ((period < PERIOD_MIN) || (period > U32_MAX)) return -EINVAL; - writel(DIV_ROUND_CLOSEST(duty_ns, scaler), - pc->base + DUTY(pwm->hwpwm)); writel(period, pc->base + PERIOD(pwm->hwpwm)); - return 0; -} - -static int bcm2835_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); - u32 value; - - value = readl(pc->base + PWM_CONTROL); - value |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm); - writel(value, pc->base + PWM_CONTROL); + /* set duty cycle */ + val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, scaler); + writel(val, pc->base + DUTY(pwm->hwpwm)); - return 0; -} + /* set polarity */ + val = readl(pc->base + PWM_CONTROL); -static void bcm2835_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); - u32 value; - - value = readl(pc->base + PWM_CONTROL); - value &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm)); - writel(value, pc->base + PWM_CONTROL); -} - -static int bcm2835_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, - enum pwm_polarity polarity) -{ - struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); - u32 value; - - value = readl(pc->base + PWM_CONTROL); + if (state->polarity == PWM_POLARITY_NORMAL) + val &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm)); + else + val |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm); - if (polarity == PWM_POLARITY_NORMAL) - value &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm)); + /* enable/disable */ + if (state->enabled) + val |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm); else - value |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm); + val &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm)); - writel(value, pc->base + PWM_CONTROL); + writel(val, pc->base + PWM_CONTROL); return 0; } @@ -127,10 +109,7 @@ static int bcm2835_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, static const struct pwm_ops bcm2835_pwm_ops = { .request = bcm2835_pwm_request, .free = bcm2835_pwm_free, - .config = bcm2835_pwm_config, - .enable = bcm2835_pwm_enable, - .disable = bcm2835_pwm_disable, - .set_polarity = bcm2835_set_polarity, + .apply = bcm2835_pwm_apply, .owner = THIS_MODULE, }; -- 2.20.1