Re: [PATCH v3] iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs

[Jonathan Cameron <jic23@kernel.org>]

On 22/03/16 08:49, Linus Walleij wrote:
> On Mon, Mar 21, 2016 at 2:48 PM, Michael Hennerich
> <michael.hennerich@analog.com> wrote:
> 
>> The thing is that the device directly supports an OPEN DRAIN mode.
>>
>> If the consumer asks for open drain mode - everything works as expected.
>> However instead of utilizing the on-chip feature, GPIOLIB will emulate open
>> drain behaviour by configuring the chip for input when someone writes logic
>> high.
>>
>> So the comment above was really meant to say -
>> remove on-chip OPEN DRAIN mode, consumers should use the GPIOLIB
>> implementation if required.
> 
> This is very interesting.
> 
> So if a hardware has *real* open drain, i.e. a bit in hardware that says
> "set me in open drain mode" we should manage this in gpiolib
> and provide a special callback in the vtable for it, right? Because it
> is certainly better to do this with hardware, if we can.
H*** yeah.  Funny how open drain stuff is popping up left right and centre
all of a sudden.
> 
> I'll send a draft patch and we can see if this is what you want.
Cool.  I like fast solutions ;)
> 
> Yours,
> Linus Walleij
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