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

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Date:	Mon,  1 Oct 2012 08:34:54 +0200
From:	Thierry Reding <thierry.reding@...onic-design.de>
To:	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>,
	Jingoo Han <jg1.han@...sung.com>,
	Jonghwan Choi <jhbird.choi@...sung.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	"Philip, Avinash" <avinashphilip@...com>,
	Vaibhav Bedia <vaibhav.bedia@...com>
Subject: [PATCH] pwm: Check for negative duty-cycle and period

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>
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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