Re: [PATCH] misc: add driver for Renesas R-Car Gyro-ADC/speed-pulseinterfaces

[Sergei Shtylyov]

Hello.

On 07/14/2013 12:12 PM, Lars-Peter Clausen wrote:

> > > > > And are you sure you want to control this through sysfs?  There's no
> > > > > other better user/kernel apis for it?

> > > >       I found none, besides ioctl(), as the device driven is rather
> > > > unique. But I thought that sysfs is "ioctl() today", so I went with it...

> > > It does sound like it would fit better into IIO than just a misc driver,
> > > even if it's the only hardware of its kind.

> >     I got somewhat familiarized myself with drivers/iio/ infrastructure and I
> > have found a place only the for ADC device in which the customer currently
> > has no interest.
> >     The other trouble is that I'll have to backport this driver to 3.4 which
> > doesn't contain the IIO infrastructure at all. :-(

> It has, it's just still in staging in 3.4. But the API (except for minor
> modifications) and more importantly the ABI are the same.

   Thank you for the useful information. I wouldn't probably have 
figured it out to search there.

> There is a angular velocity channel type in IIO. maybe that could be used to
> report the Speed-Pulse-ADC values.

   You probably misunderstood from my terse description. Multichannel 
ADC interface is separate from the speed-pulse interface which has on 
its single input digital PWM signal of varying frequency. Speed pulse 
i/f measures pulse count and period. I've found no adequate channel type 
in IIO infrastructure so far. I'll mail the IIO maintainers with a 
request for help probably...

> - Lars

WBR, Sergei

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