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[v10,04/12] pwm: clps711x: Cast period to u32 before use as divisor

Message ID 8822fc43463039744581398be844f4417f62abcd.1584650604.git.gurus@codeaurora.org
State Changes Requested
Headers show
Series [v10,01/12] drm/i915: Use 64-bit division macro | expand

Commit Message

Guru Das Srinagesh March 19, 2020, 8:50 p.m. UTC
Since the PWM framework is switching struct pwm_args.period's datatype
to u64, prepare for this transition by typecasting it to u32.

Also, since the dividend is still a 32-bit number, any divisor greater
than UINT_MAX will cause the quotient to be zero, so return 0 in that
case to efficiently skip the division.

Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Arnd Bergmann <arnd@arndb.de>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-clps711x.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 924d39a..f34f1f3 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -43,7 +43,10 @@  static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
 static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
 {
 	/* Duty cycle 0..15 max */
-	return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
+	if (pwm->args.period > UINT_MAX)
+		return 0;
+
+	return DIV_ROUND_CLOSEST(v * 0xf, (u32)pwm->args.period);
 }
 
 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)