On Tuesday, February 03, 2015 8:13 AM, Ian Abbott wrote:
> On 03/02/15 12:38, Nicholas Mc Guire wrote:
>> The if and the else branch code are identical - so the condition has no
>> effect on the effective code - this patch removes the condition and the
>> duplicated code.
>>
>> Signed-off-by: Nicholas Mc Guire <[email protected]>
>> ---
>>
>> The if and else branch are identical code thus the condition has no effect
>>
>> if (cmd->scan_begin_src == TRIG_FOLLOW) {
>> /* internal trigger */
>> err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
>> } else {
>> /* external trigger */
>> /* should be level/edge, hi/lo specification here */
>> err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
>> }
>>
> I think what that comment means is that it should allow scan_begin_arg
> to have various combinations of the CR_EDGE and CR_INVERT bits set.
> I.e. it ought to allow whatever combination of CR_EDGE and CR_INVERT
> better describes the nature of the external trigger signal, in addition
> to allowing the lazy default value 0.
>
> I don't know what the nature of the external trigger signal is, as I
> haven't seen the manual. I think Hartley might have seen one.
According to the manual, the external trigger is not "programmable". It's
a Schmitt trigger input, enables on TTL logic low, with a 22K pullup.
Since the 'scan_begin_arg' is not actually used for the analog input async
command, I think removing the comments completely is fine. Just change
the check to:
err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
Regards,
Hartley
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