Hi Minkyu,
Thanks for your comments.
>Dear Akshay,
>
>On 28/02/13 19:59, Akshay Saraswat wrote:
>> 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.
>>
>> @@ -167,20 +167,24 @@ int pwm_init(int pwm_id, int div, int invert)
>> val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
>> writel(val, &pwm->tcfg1);
>>
>> - timer_rate_hz = get_pwm_clk() / ((prescaler + 1) *
>> - (div + 1));
>> + if (pwm_id == 4) {
>> + /*
>> + * TODO(sjg): Use this as a countdown timer for now. We count
>> + * down from the maximum value to 0, then reset.
>> + */
>> + ticks_per_period = -1UL;
>> + } else {
>> + const unsigned long pwm_hz = 1000;
>> + unsigned long timer_rate_hz = get_pwm_clk() /
>> + ((prescaler + 1) * (1 << div));
>
>good catch. thanks.
>
>>
>> - timer_rate_hz = timer_rate_hz / CONFIG_SYS_HZ;
>> + ticks_per_period = timer_rate_hz / pwm_hz;
>
>why don't you use CONFIG_SYS_HZ?
>pwm_hz seems to constant.
CONFIG_SYS_HZ may change with boards and as per needs.
But requirement here is for a constant value 1000
for all calculations which should remain 1000 only.
That's why using pwm_hz and not CONFIG_SYS_HZ.
>
>> + }
>>
>> /* set count value */
>> offset = pwm_id * 3;
>>
>> - /*
>> - * TODO(sjg): Use this as a countdown timer for now. We count down
>> - * from the maximum value to 0, then reset.
>> - */
>> - timer_rate_hz = -1;
>> - writel(timer_rate_hz, &pwm->tcntb0 + offset);
>> + writel(ticks_per_period, &pwm->tcntb0 + offset);
>>
>> val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id));
>> if (invert && (pwm_id < 4))
>>
>
>Thanks,
>Minkyu Kang.
>
Regards,
Akshay Saraswat
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