[v13,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Peter Rosin <peda@axentia.se>]

On 2018-10-25 23:55, Ajay Gupta wrote:
> Hi Heikki and Andy
> [...]
>>>> Shouldn't you return -ETIMEDOUT if count == 0?
>>> Yes. Good catch. Does the below fix looks ok?
>>>
>>>         do {
>>>                 status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
>>>                 if (status < 0)
>>>                         return status;
>>>
>>>                 usleep_range(10000, 11000);
>>>
>>>                 status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
>>>                 if (status < 0)
>>>                         return status;
>>>
>>>                 if (!data)
>>>                         return 0;
>>>         } while (data && count--);
>>
>> Doesn't that condition break out of the loop immediately?
> How? I didn't get your point? We want to break out when data is
> zero (interrupt status cleared).

The statement

	if (!data)
		return 0;

ensures that 'data' is non-zero when the loop continues, so checking
that 'data' is non-zero in the while loop test is pointless.

>>> Ah, I see, but why you not reorganize it to put this into do-while loop?
> We actually need to check data after reading it so will reorganize accordingly.
> do {
> 	read
> 	check for data and break out if (!data)
> 	write
> 	sleep
> } while (--count);

Here, you have fixed the "issue" (but it doesn't match v14).

Cheers,
Peter