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Fri, 17 Jul 2020 15:27:23 -0700 (PDT) Subject: Re: [PATCH v2] pwm: bcm-iproc: handle clk_get_rate() return To: Scott Branden , Thierry Reding , Lee Jones Cc: =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , BCM Kernel Feedback , linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, Rayagonda Kokatanur References: <20200717182512.26001-1-scott.branden@broadcom.com> From: Ray Jui Message-ID: Date: Fri, 17 Jul 2020 15:27:19 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200717182512.26001-1-scott.branden@broadcom.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/17/2020 11:25 AM, Scott Branden wrote: > From: Rayagonda Kokatanur > > 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 > Signed-off-by: Scott Branden > > --- > 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