Re: [PATCH] pwm: bcm-iproc: handle clk_get_rate() return

[Scott Branden]

On 2020-07-17 10:22 a.m., Ray Jui wrote:
> On 7/17/2020 10:07 AM, Scott Branden wrote:
> > From: Rayagonda Kokatanur <rayagonda.kokatanur@xxxxxxxxxxxx>
> >
> > Handle clk_get_rate() returning <= 0 condition to avoid
> > possible division by zero.
> >
> > Fixes: daa5abc41c80 ("pwm: Add support for Broadcom iProc PWM controller")
> > Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@xxxxxxxxxxxx>
> > Signed-off-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
> > ---
> >   drivers/pwm/pwm-bcm-iproc.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
> > index 1f829edd8ee7..72a8607b6c8d 100644
> > --- a/drivers/pwm/pwm-bcm-iproc.c
> > +++ b/drivers/pwm/pwm-bcm-iproc.c
> > @@ -86,6 +86,11 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> >   	u32 value, prescale;
> >   
> >   	rate = clk_get_rate(ip->clk);
> > +	if (rate == 0) {
> > +		state->period = 0;
> > +		state->duty_cycle = 0;
> > +		return;
> > +	}
I'll move the logic after the polarity and enabled fields are populated.
> Based on the pwm core code, 'get_state' expects the following fields to
> be populated: 'polarity', 'enabled', 'period', and 'duty cycle'.
>
> The above logic will leave 'polarity' and 'enabled' completely
> unpopulated when clock rate is zero.
>
> >   
> >   	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
> >