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pwm: bcm2835: Fix period_ns range check 

The range check for period_ns was written under assumption of a fixed
PWM clock. With clk-bcm2835 driver the PWM clock is a dynamic one.
So fix this by doing the range check on the period register value.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Stefan Wahren 2019-08-24 16:09:47 +02:00 committed by Thierry Reding
parent 4537e52a52
commit 7e9713af31
1 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/pwm/pwm-bcm2835.c
View File

@ -21,7 +21,7 @@
#define PERIOD(x) (((x) * 0x10) + 0x10)
#define DUTY(x) (((x) * 0x10) + 0x14)
#define MIN_PERIOD 108 /* 9.2 MHz max. PWM clock */
#define PERIOD_MIN 0x2
struct bcm2835_pwm {
struct pwm_chip chip;
@ -64,6 +64,7 @@ static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
unsigned long rate = clk_get_rate(pc->clk);
unsigned long scaler;
u32 period;
if (!rate) {
dev_err(pc->dev, "failed to get clock rate\n");
@ -71,14 +72,14 @@ 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);
if (period_ns <= MIN_PERIOD)
if (period < PERIOD_MIN)
return -EINVAL;
writel(DIV_ROUND_CLOSEST(duty_ns, scaler),
pc->base + DUTY(pwm->hwpwm));
writel(DIV_ROUND_CLOSEST(period_ns, scaler),
pc->base + PERIOD(pwm->hwpwm));
writel(period, pc->base + PERIOD(pwm->hwpwm));
return 0;
}