linux-kernel - Re: [PATCH] pwm: Check for negative duty-cycle and period

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Date:	Thu, 04 Oct 2012 10:15:52 +0900
From:	Jingoo Han <jg1.han@...sung.com>
To:	'Thierry Reding' <thierry.reding@...onic-design.de>,
	linux-kernel@...r.kernel.org
Cc:	'Shawn Guo' <shawn.guo@...aro.org>,
	'Mark Brown' <broonie@...nsource.wolfsonmicro.com>,
	'Arnd Bergmann' <arnd@...db.de>,
	'Sachin Kamat' <sachin.kamat@...aro.org>,
	'Axel Lin' <axel.lin@...il.com>,
	'Kukjin Kim' <kgene.kim@...sung.com>,
	'Jonghwan Choi' <jhbird.choi@...sung.com>,
	'Sascha Hauer' <s.hauer@...gutronix.de>,
	"'Philip, Avinash'" <avinashphilip@...com>,
	'Vaibhav Bedia' <vaibhav.bedia@...com>,
	'Jingoo Han' <jg1.han@...sung.com>
Subject: Re: [PATCH] pwm: Check for negative duty-cycle and period

On Monday, October 01, 2012 3:35 PM Thierry Reding wrote
> 
> Make sure the duty-cycle and period passed in are not negative. This
> should eventually be made implicit by making them unsigned. While at
> it, the drivers' .config() implementations can have the equivalent
> checks removed.
> 
> Signed-off-by: Thierry Reding <thierry.reding@...onic-design.de>
> Cc: Shawn Guo <shawn.guo@...aro.org>
> Cc: Mark Brown <broonie@...nsource.wolfsonmicro.com>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Sachin Kamat <sachin.kamat@...aro.org>
> Cc: Axel Lin <axel.lin@...il.com>
> Cc: Kukjin Kim <kgene.kim@...sung.com>
> Cc: Jingoo Han <jg1.han@...sung.com>

Acked-by: Jingoo Han <jg1.han@...sung.com>

> Cc: Jonghwan Choi <jhbird.choi@...sung.com>
> Cc: Sascha Hauer <s.hauer@...gutronix.de>
> Cc: "Philip, Avinash" <avinashphilip@...com>
> Cc: Vaibhav Bedia <vaibhav.bedia@...com>
> ---
>  drivers/pwm/core.c         | 2 +-
>  drivers/pwm/pwm-bfin.c     | 3 ---
>  drivers/pwm/pwm-pxa.c      | 3 ---
>  drivers/pwm/pwm-samsung.c  | 3 ---
>  drivers/pwm/pwm-tiecap.c   | 2 +-
>  drivers/pwm/pwm-tiehrpwm.c | 2 +-
>  6 files changed, 3 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 92b1782..f5acdaa 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -371,7 +371,7 @@ EXPORT_SYMBOL_GPL(pwm_free);
>   */
>  int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
>  {
> -	if (!pwm || period_ns == 0 || duty_ns > period_ns)
> +	if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
>  		return -EINVAL;
> 
>  	return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
> diff --git a/drivers/pwm/pwm-bfin.c b/drivers/pwm/pwm-bfin.c
> index d53c4e7..5da8e18 100644
> --- a/drivers/pwm/pwm-bfin.c
> +++ b/drivers/pwm/pwm-bfin.c
> @@ -69,9 +69,6 @@ static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	unsigned long period, duty;
>  	unsigned long long val;
> 
> -	if (duty_ns < 0 || duty_ns > period_ns)
> -		return -EINVAL;
> -
>  	val = (unsigned long long)get_sclk() * period_ns;
>  	do_div(val, NSEC_PER_SEC);
>  	period = val;
> diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
> index bd5867a..260c3a8 100644
> --- a/drivers/pwm/pwm-pxa.c
> +++ b/drivers/pwm/pwm-pxa.c
> @@ -70,9 +70,6 @@ static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	unsigned long offset;
>  	int rc;
> 
> -	if (period_ns == 0 || duty_ns > period_ns)
> -		return -EINVAL;
> -
>  	offset = pwm->hwpwm ? 0x10 : 0;
> 
>  	c = clk_get_rate(pc->clk);
> diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
> index e5187c0..023a3be 100644
> --- a/drivers/pwm/pwm-samsung.c
> +++ b/drivers/pwm/pwm-samsung.c
> @@ -126,9 +126,6 @@ static int s3c_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
>  		return -ERANGE;
> 
> -	if (duty_ns > period_ns)
> -		return -EINVAL;
> -
>  	if (period_ns == s3c->period_ns &&
>  	    duty_ns == s3c->duty_ns)
>  		return 0;
> diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
> index 081471f..d6d4cf0 100644
> --- a/drivers/pwm/pwm-tiecap.c
> +++ b/drivers/pwm/pwm-tiecap.c
> @@ -60,7 +60,7 @@ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	unsigned long period_cycles, duty_cycles;
>  	unsigned int reg_val;
> 
> -	if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
> +	if (period_ns > NSEC_PER_SEC)
>  		return -ERANGE;
> 
>  	c = pc->clk_rate;
> diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
> index caf00fe..d3c1dff 100644
> --- a/drivers/pwm/pwm-tiehrpwm.c
> +++ b/drivers/pwm/pwm-tiehrpwm.c
> @@ -221,7 +221,7 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	unsigned short ps_divval, tb_divval;
>  	int i, cmp_reg;
> 
> -	if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
> +	if (period_ns > NSEC_PER_SEC)
>  		return -ERANGE;
> 
>  	c = pc->clk_rate;
> --
> 1.7.12.2

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