[PATCH 2/3] pwm: bcm2835: prevent division by zero

Eric Anholt eric at anholt.net
Wed Dec 2 11:41:57 PST 2015


Mathieu Poirier <mathieu.poirier at linaro.org> writes:

> On 1 December 2015 at 15:55, Stefan Wahren <stefan.wahren at i2se.com> wrote:
>> It's possible that the pwm clock become 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 at i2se.com>
>> ---
>>  drivers/pwm/pwm-bcm2835.c |   10 +++++++++-
>>  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
>> index 174cca9..31a6992 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;
>
> Stefan,
>
> Please merge this code into patch 1/3.  That way it is done the right
> way the first time around.

They're separate changes and are good as separate patches.
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