[PATCH dev-5.0 v2 1/5] media: platform: Aspeed: Remove use of reset line

[Eddie James]

On 3/29/19 6:54 PM, Jae Hyun Yoo wrote:
>>   static void aspeed_video_off(struct aspeed_video *video)
>>   {
>> -    aspeed_video_reset(video);
>> +    /* Disable interrupts */
>> +    aspeed_video_write(video, VE_INTERRUPT_CTRL, 0);
>>         /* Turn off the relevant clocks */
>>       clk_disable_unprepare(video->vclk);
>> @@ -508,7 +497,13 @@ static void aspeed_video_on(struct aspeed_video 
>> *video)
>>       clk_prepare_enable(video->eclk);
>>       clk_prepare_enable(video->vclk);
>>   -    aspeed_video_reset(video);
>> +    /*
>> +     * Delay (and don't sleep in case in interrupt context) to let the
>> +     * clocks stabilize. Without this, mode detection sometimes fails.
>> +     * Possibly the registers don't update too soon after clocks are
>> +     * enabled.
>> +     */
>> +    udelay(100);
>>   }
>
> aspeed_video_off() will be called from interrupt context too. Are you
> sure that this 100us delay is needed at here? If it's actually needed,
> would it be batter to use devm_request_threaded_irq() instead of
> devm_request_irq() in aspeed_video_init() function?

Well this isn't new to this patchset, it delayed 100us before in 
aspeed_video_reset.

I am quite sure it's needed.

Since the ast2500 has only one logical processor, I'm not sure a 
threaded irq would function any differently.

>
> Cheers,
> Jae
>