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 <[email protected]>
---
v4: Remove a superfluous blank line
Remove an unneeded cast (both requested by Uwe Kleine-König)
v3: Check against period truncation (also based on a review by Uwe)
v2: Fix compiler error for 64 bit builds
drivers/pwm/pwm-bcm2835.c | 69 +++++++++++++++++------------------------------
1 file changed, 24 insertions(+), 45 deletions(-) j
diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index d78f86f..4b1ee44 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,
};
--
2.7.4
On Wed, Dec 09, 2020 at 09:48:25PM +0100, Lino Sanfilippo wrote:
> 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 <[email protected]>
> ---
>
> v4: Remove a superfluous blank line
> Remove an unneeded cast (both requested by Uwe Kleine-König)
> v3: Check against period truncation (also based on a review by Uwe)
> v2: Fix compiler error for 64 bit builds
>
> drivers/pwm/pwm-bcm2835.c | 69 +++++++++++++++++------------------------------
> 1 file changed, 24 insertions(+), 45 deletions(-) j
Applied, thanks.
Thierry
On Wed, Dec 09, 2020 at 09:48:25PM +0100, Lino Sanfilippo wrote:
> 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 <[email protected]>
I replied to v3 earlier, this was supposed to go to this v4 of course.
Still had v3 open for comparing the two. So to ensure it is picked up:
Reviewed-by: Uwe Kleine-K?nig <[email protected]>
Best regards
Uwe
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