Minkyu,

Thanks for comments. Please find my reply below the comment.

On 28/02/13 19:59, Akshay Saraswat wrote:

...

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 paremters to be a

typo. paremters -> parameter

...

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@google.com Signed-off-by: Akshay Saraswat akshay.s@samsung.com Acked-by: Simon Glass sjg@chromium.org

---

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);

0 is a numerator. I think.. it doesn't matter.

In file pwm.c line 98 we are doing: frequency = NS_IN_SEC / period_ns;

what we are passing in this call are the values of duty_ns and period_ns. So, there are places where divide by zero may occur. I think we should keep it to be on a safer side.

...

pwm_enable(4);

/* Use this as the current monotonic time in us */

Thanks, Minkyu Kang.

Regards, Akshay Saraswat