Re: [PATCH 14/16] media: ti-vpe: cal: improve wait for CIO resetdone

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

On 16/03/2020 14:43, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Fri, Mar 13, 2020 at 01:41:19PM +0200, Tomi Valkeinen wrote:
>> Sometimes waiting for ComplexIO resetdone timeouts. Testing shows that
>> sometimes we need to wait more than what the current code does. It is
>> not clear how long this wait can be, but it is based on how quickly the
>> sensor provides a valid clock, and how quickly CAL syncs to it.
>>
>> Change the code to make it more obvious how long we'll wait, and set a
>> wider range for usleep_range. Increase the timeout to 750ms.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
>> ---
>>   drivers/media/platform/ti-vpe/cal.c | 13 +++++++------
>>   1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
>> index 319312770eea..929f9b3ca4f9 100644
>> --- a/drivers/media/platform/ti-vpe/cal.c
>> +++ b/drivers/media/platform/ti-vpe/cal.c
>> @@ -824,20 +824,21 @@ static void csi2_phy_init(struct cal_ctx *ctx)
>>   
>>   static void csi2_wait_complexio_reset(struct cal_ctx *ctx)
>>   {
>> -	int i;
>> +	unsigned long timeout;
>>   
>> -	for (i = 0; i < 250; i++) {
>> +	timeout = jiffies + msecs_to_jiffies(750);
>> +	while (time_before(jiffies, timeout)) {
>>   		if (reg_read_field(ctx->dev,
>>   				   CAL_CSI2_COMPLEXIO_CFG(ctx->csi2_port),
>>   				   CAL_CSI2_COMPLEXIO_CFG_RESET_DONE_MASK) ==
>>   		    CAL_CSI2_COMPLEXIO_CFG_RESET_DONE_RESETCOMPLETED)
>>   			break;
>> -		usleep_range(1000, 1100);
>> +		usleep_range(500, 5000);
>>   	}
> 
> How about using readx_poll_timeout() ?

There's no function that directly fits readx_poll_timeout's accessor function, so I think using 
readl_poll_timeout and calculating the address manually would be the way to use *_poll_timeout.

But it does skip the register access functions the driver uses (reg_read/write).

So... It would be nice to use *_poll_timeout, but I'm not sure if it worth breaking the register 
access model the driver uses.

  Tomi

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