From: Ray Jui <ray.jui@broadcom.com>
To: Scott Branden <scott.branden@broadcom.com>,
Thierry Reding <thierry.reding@gmail.com>,
Lee Jones <lee.jones@linaro.org>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"BCM Kernel Feedback" <bcm-kernel-feedback-list@broadcom.com>,
linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Rayagonda Kokatanur" <rayagonda.kokatanur@broadcom.com>
Subject: Re: [PATCH] pwm: bcm-iproc: handle clk_get_rate() return
Date: Fri, 17 Jul 2020 10:22:13 -0700 [thread overview]
Message-ID: <94f2aed1-d88d-3ee0-6e57-917f665951f2@broadcom.com> (raw)
In-Reply-To: <20200717170743.25466-1-scott.branden@broadcom.com>
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);
>
>
next prev parent reply other threads:[~2020-07-17 17:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 17:07 [PATCH] pwm: bcm-iproc: handle clk_get_rate() return Scott Branden
2020-07-17 17:22 ` Ray Jui [this message]
2020-07-17 18:24 ` Scott Branden
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