[U-Boot] [PATCH 05/11 v3] Exynos: Avoid a divide by zero by specifying a non-zero period for pwm 4

Akshay Saraswat akshay.s at samsung.com
Thu Mar 28 15:32:19 CET 2013


From: Gabe Black <gabeblack at google.com>

The pwm_config function in the exynos pwm driver divides by its period
period parameter. A function was calling pwm_config with a 0ns period and a
0ns duty cycle. That doesn't actually make any sense physically, and results
in a divide by zero in the driver. This change changes the parameters to be a
100000ns period and duty cycle.

Test with command "sf probe 1:0; time sf read 40008000 0 1000".
Try with different numbers of bytes and see that sane values are obtained
Build and boot U-boot with this patch, backlight works properly.

Signed-off-by: Gabe Black <gabeblack at google.com>
Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>
Acked-by: Simon Glass <sjg at chromium.org>
---
Changes since v2:
        - Fixed typo paremters in commit message.

Changes since v1:
        - Added "Acked-by: Simon Glass".

 arch/arm/cpu/armv7/s5p-common/timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/cpu/armv7/s5p-common/timer.c b/arch/arm/cpu/armv7/s5p-common/timer.c
index de61405..6a0fa58 100644
--- a/arch/arm/cpu/armv7/s5p-common/timer.c
+++ b/arch/arm/cpu/armv7/s5p-common/timer.c
@@ -58,7 +58,7 @@ int timer_init(void)
 {
 	/* PWM Timer 4 */
 	pwm_init(4, MUX_DIV_4, 0);
-	pwm_config(4, 0, 0);
+	pwm_config(4, 100000, 100000);
 	pwm_enable(4);
 
 	/* Use this as the current monotonic time in us */
-- 
1.8.0



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