New subject: [U-Boot] [PATCH] bugfix i.mx6 pwm: prevent overflow of period_c * duty_ns

6 May 2015

Prevent overflow by casting duty_ns to ull first. This bug came up when trying to create a 200 Hz PWM
Signed-off-by: Brecht Neyrinck bnrn@psicontrol.com
---
 drivers/pwm/pwm-imx-util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-imx-util.c b/drivers/pwm/pwm-imx-util.c
index f1d0b35..79d86028 100644
--- a/drivers/pwm/pwm-imx-util.c
+++ b/drivers/pwm/pwm-imx-util.c
@@ -56,7 +56,7 @@ int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
    *prescale = *period_c / 0x10000 + 1;
*period_c /= *prescale;
-	c = (unsigned long long)(*period_c * duty_ns);
+	c = *period_c * (unsigned long long)duty_ns;
    do_div(c, period_ns);
    *duty_c = c;
-- 
1.8.2.3




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[U-Boot] [PATCH] bugfix i.mx6 pwm: prevent overflow of period_c * duty_ns

Brecht Neyrinck

Heiko Schocher

Signed-off-by: Brecht Neyrinck bnrn@psicontrol.com

Stefano Babic

Signed-off-by: Brecht Neyrinck bnrn@psicontrol.com

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