pwm: bcm2835: Prevent division by zero

It's possible that the PWM clock becomes an orphan. So better check the
result of clk_get_rate() in order to prevent a division by zero.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index 174cca92f690..31a6992a445c 100644
--- a/drivers/pwm/pwm-bcm2835.c
+++ b/drivers/pwm/pwm-bcm2835.c
@@ -65,7 +65,15 @@ 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);
+        unsigned long rate = clk_get_rate(pc->clk);
+        unsigned long scaler;
+
+        if (!rate) {
+                dev_err(pc->dev, "failed to get clock rate\n");
+                return -EINVAL;
+        }
+
+        scaler = NSEC_PER_SEC / rate;
 
         if (period_ns <= MIN_PERIOD) {
                 dev_err(pc->dev, "period %d not supported, minimum %d\n",