From: Minkyu Kang <mk7.kang@samsung.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 4/9 v2] Exynos: Avoid a divide by zero by specifying a non-zero period for pwm 4
Date: Thu, 28 Mar 2013 14:53:04 +0900 [thread overview]
Message-ID: <5153DAC0.8040606@samsung.com> (raw)
In-Reply-To: <1362049164-10297-5-git-send-email-akshay.s@samsung.com>
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.
> pwm_enable(4);
>
> /* Use this as the current monotonic time in us */
>
Thanks,
Minkyu Kang.
next prev parent reply other threads:[~2013-03-28 5:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-28 10:59 [U-Boot] [PATCH 0/9 v2] Fix and Re-organise PWM Timer Akshay Saraswat
2013-02-28 10:59 ` [U-Boot] [PATCH 1/9 v2] Exynos: Change get_timer() to work correctly Akshay Saraswat
2013-03-28 5:52 ` Minkyu Kang
2013-02-28 10:59 ` [U-Boot] [PATCH 2/9 v2] Exynos: Add timer_get_us function Akshay Saraswat
2013-02-28 10:59 ` [U-Boot] [PATCH 3/9 v2] Exynos: pwm: Fix two bugs in the exynos pwm configuration code Akshay Saraswat
2013-03-28 5:53 ` Minkyu Kang
2013-02-28 10:59 ` [U-Boot] [PATCH 4/9 v2] Exynos: Avoid a divide by zero by specifying a non-zero period for pwm 4 Akshay Saraswat
2013-03-28 5:53 ` Minkyu Kang [this message]
2013-02-28 10:59 ` [U-Boot] [PATCH 5/9 v2] Exynos: Tidy up the pwm_config function in the exynos pwm driver Akshay Saraswat
2013-02-28 10:59 ` [U-Boot] [PATCH 6/9 v2] Exynos: Add peripherial id for pwm Akshay Saraswat
2013-02-28 10:59 ` [U-Boot] [PATCH 7/9 v2] Exynos: clock: Add generic api to get the clk freq Akshay Saraswat
2013-02-28 13:37 ` Simon Glass
2013-03-28 5:52 ` Minkyu Kang
2013-02-28 10:59 ` [U-Boot] [PATCH 8/9 v2] Exynos: clock: Correct pwm source clk selection Akshay Saraswat
2013-02-28 10:59 ` [U-Boot] [PATCH 9/9 v2] Exynos: pwm: Use generic api to get pwm clk freq Akshay Saraswat
2013-02-28 13:40 ` Simon Glass
2013-03-28 5:52 ` Minkyu Kang
-- strict thread matches above, loose matches on Subject: below --
2013-03-28 14:29 [U-Boot] [PATCH 4/9 v2] Exynos: Avoid a divide by zero by specifying a non-zero period for pwm 4 Akshay Saraswat
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