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authorLino Sanfilippo <LinoSanfilippo@gmx.de>2020-12-09 21:48:25 +0100
committerThierry Reding <thierry.reding@gmail.com>2020-12-17 14:19:01 +0100
commit2f81b51d0d02074502ad27424c228ca760823668 (patch)
tree5639cebb9ceb430ff61425211ca88f61d6ab62cc /drivers/pwm
parentbb72e1dbae0e759252fcdb4a97917200e165bf91 (diff)
pwm: bcm2835: Support apply function for atomic configuration
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 <LinoSanfilippo@gmx.de> Reviewed-by: Uwe Kleine-K├Ânig <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-bcm2835.c69
1 files 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,
};