| Message ID | 20200717170743.25466-1-scott.branden@broadcom.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | pwm: bcm-iproc: handle clk_get_rate() return | expand |
On 7/17/2020 10:07 AM, Scott Branden wrote: > From: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> > > 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@broadcom.com> > Signed-off-by: Scott Branden <scott.branden@broadcom.com> > --- > 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; > + } 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); > >
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@broadcom.com> >> >> 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@broadcom.com> >> Signed-off-by: Scott Branden <scott.branden@broadcom.com> >> --- >> 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); >> >>
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; + } value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);