From: Rayagonda Kokatanur <[email protected]>
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 <[email protected]>
Signed-off-by: Scott Branden <[email protected]>
---
Changes from v1: ensure 'polarity' and 'enabled' are populated
when clk_get_rate is 0.
---
drivers/pwm/pwm-bcm-iproc.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
index 1f829edd8ee7..d392a828fc49 100644
--- a/drivers/pwm/pwm-bcm-iproc.c
+++ b/drivers/pwm/pwm-bcm-iproc.c
@@ -85,8 +85,6 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
u64 tmp, multi, rate;
u32 value, prescale;
- rate = clk_get_rate(ip->clk);
-
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
@@ -99,6 +97,13 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
else
state->polarity = PWM_POLARITY_INVERSED;
+ rate = clk_get_rate(ip->clk);
+ if (rate == 0) {
+ state->period = 0;
+ state->duty_cycle = 0;
+ return;
+ }
+
value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
prescale &= IPROC_PWM_PRESCALE_MAX;
--
2.17.1
On 7/17/2020 11:25 AM, Scott Branden wrote:
> From: Rayagonda Kokatanur <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Scott Branden <[email protected]>
>
> ---
> Changes from v1: ensure 'polarity' and 'enabled' are populated
> when clk_get_rate is 0.
> ---
> drivers/pwm/pwm-bcm-iproc.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
> index 1f829edd8ee7..d392a828fc49 100644
> --- a/drivers/pwm/pwm-bcm-iproc.c
> +++ b/drivers/pwm/pwm-bcm-iproc.c
> @@ -85,8 +85,6 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> u64 tmp, multi, rate;
> u32 value, prescale;
>
> - rate = clk_get_rate(ip->clk);
> -
> value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
>
> if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
> @@ -99,6 +97,13 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> else
> state->polarity = PWM_POLARITY_INVERSED;
>
> + rate = clk_get_rate(ip->clk);
> + if (rate == 0) {
> + state->period = 0;
> + state->duty_cycle = 0;
> + return;
> + }
> +
> value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
> prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
> prescale &= IPROC_PWM_PRESCALE_MAX;
>
This patch looks good to me. Thanks!
Reviewed-by: Ray Jui <[email protected]>
On Fri, Jul 17, 2020 at 11:25:12AM -0700, Scott Branden wrote:
> From: Rayagonda Kokatanur <[email protected]>
>
> Handle clk_get_rate() returning <= 0 condition to avoid
> possible division by zero.
You advertise handling <= 0, but in the code only == 0 is checked. One
of the two is wrong ...
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |
On 2020-07-17 4:04 p.m., Uwe Kleine-K?nig wrote:
> On Fri, Jul 17, 2020 at 11:25:12AM -0700, Scott Branden wrote:
>> From: Rayagonda Kokatanur <[email protected]>
>>
>> Handle clk_get_rate() returning <= 0 condition to avoid
>> possible division by zero.
> You advertise handling <= 0, but in the code only == 0 is checked. One
> of the two is wrong ...
I checked - clk_get_rate can't return negative values.
I'll update the commit message from <= to ==.
>
> Best regards
> Uwe
>
Thanks,
?Scott