Some small fixes in the exynos pwm driver:
1. NS_IN_HZ is non-sensical since these are not compatible units. This
constant actually describes the number of nanoseconds in a second. Renamed it
to NS_IN_SEC. Also dropped the unnecessary parenthesis.
2. The variable "period" is not used to hold a period, it's used to hold a
frequency. Renamed it to "frequency".
3. tcmp is an unsigned value, so (tcmp < 0) will never be true and the if
which checks that condition will never execute. Also, there should be no
problem if the pwm never switches, so there's no reason to subtract one from
tcmp and therefore no reason to compare it against zero. Removed both ifs. If
they weren't removed, tcmp should be a signed value.
4. Add a check for a 0 period.
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>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
First, the "div" value was being used incorrectly to compute the frequency of
the PWM timer. The value passed in is a constant which reflects the value
that would be found in a configuration register, 0 to 4. That should
correspond to a scaling factor of 1, 2, 4, 8, or 16, 1 << div, but div + 1 was
being used instead.
Second, the reset value of the timers were being calculated to give an overall
frequency, thrown out, and set to a maximum value. This was done so that PWM 4
could be used as the system clock by counting down from a high value, but it
was applied indiscriminantly. It should at most be applied only to PWM 4.
This change also takes the opportunity to tidy up the pwm_init function.
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>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
At present get_timer() does not return sane values. It should count up
smoothly in milliscond intervals.
We can change the PWM to count down at 1MHz, providing a resolution
of 1us and a range of about an hour between required get_timer() calls.
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
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
In general, The get_timer_masked function get the system time,
no the number of ticks. Such as the nand_wait_ready will use
get_timer_masked to delay the operations. And change the system
time to adopt to the CONFIG_SYS_HZ.
Signed-off-by: Hongbo Zhong <bocui107@gmail.com>
Tested-by: Jaehoon Chung<jh80.chung@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Fix:
pwm.c: In function 'pwm_config':
pwm.c:85:16: warning: variable 'timer_rate_hz' set but not used
[-Wunused-but-set-variable]
Signed-off-by: Anatolij Gustschin <agust@denx.de>
This is common pwm driver of S5P.
Signed-off-by: Donghwa Lee <dh09.lee@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Wolfgang Denk
Gabe Black
Simon Glass
Zhong Hongbo
Anatolij Gustschin
Donghwa Lee