[PATCH 1/3] pwm: bcm2835: calculate scaler in pwm_config
Stefan Wahren
stefan.wahren at i2se.com
Tue Dec 1 14:55:39 PST 2015
Currently pwm-bcm2835 assumes a fixed clock rate and stores the
resulting scaler in the driver structure. But with the upcoming
PWM clock support for clk-bcm2835 the rate could change.
So calculate the scaler in pwm_config.
Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
---
drivers/pwm/pwm-bcm2835.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index b4c7f95..174cca9 100644
--- a/drivers/pwm/pwm-bcm2835.c
+++ b/drivers/pwm/pwm-bcm2835.c
@@ -29,7 +29,6 @@
struct bcm2835_pwm {
struct pwm_chip chip;
struct device *dev;
- unsigned long scaler;
void __iomem *base;
struct clk *clk;
};
@@ -66,6 +65,7 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
+ unsigned long scaler = NSEC_PER_SEC / clk_get_rate(pc->clk);
if (period_ns <= MIN_PERIOD) {
dev_err(pc->dev, "period %d not supported, minimum %d\n",
@@ -73,8 +73,8 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
return -EINVAL;
}
- writel(duty_ns / pc->scaler, pc->base + DUTY(pwm->hwpwm));
- writel(period_ns / pc->scaler, pc->base + PERIOD(pwm->hwpwm));
+ writel(duty_ns / scaler, pc->base + DUTY(pwm->hwpwm));
+ writel(period_ns / scaler, pc->base + PERIOD(pwm->hwpwm));
return 0;
}
@@ -156,8 +156,6 @@ static int bcm2835_pwm_probe(struct platform_device *pdev)
if (ret)
return ret;
- pc->scaler = NSEC_PER_SEC / clk_get_rate(pc->clk);
-
pc->chip.dev = &pdev->dev;
pc->chip.ops = &bcm2835_pwm_ops;
pc->chip.npwm = 2;
--
1.7.9.5
More information about the linux-arm-kernel
mailing list