[PATCH 0/3] RFC: Add a drm_aux-dev module.

[Daniel Vetter]

On Tue, Sep 15, 2015 at 10:03:09AM -0700, Rafael Antognolli wrote:
> On Tue, Sep 15, 2015 at 07:46:55PM +0300, Ville Syrjälä wrote:
> > On Tue, Sep 15, 2015 at 07:41:06PM +0300, Ville Syrjälä wrote:
> > > On Tue, Sep 15, 2015 at 09:34:15AM -0700, Rafael Antognolli wrote:
> > > > On Tue, Sep 15, 2015 at 10:35:19AM +0300, Ville Syrjälä wrote:
> > > > > On Mon, Sep 14, 2015 at 04:12:29PM -0700, Rafael Antognolli wrote:
> > > > > > This is a tentative implementation of a module that allows reading/writing
> > > > > > arbitrary dpcd registers, following the suggestion from Daniel Vetter. It
> > > > > > assumes the drm aux helpers were used by the driver.
> > > > > > 
> > > > > > I tried to follow the i2c-dev implementation as close as possible, but the only
> > > > > > operations that are provided on the dev node are two different ioctl's, one for
> > > > > > reading a register and another one for writing it.
> > > > > 
> > > > > Why would you use ioctls instead of normal read/write syscalls?
> > > > > 
> > > > 
> > > > For writing, that should work fine, I can easily change that if you
> > > > prefer.
> > > > 
> > > > For reading, one has to first tell which register address is going to be
> > > > read.
> > > 
> > > seek()
> > 
> > Sorry typo. Make that lseek(). 
> > 
> Oh, nice, I'll update the patch with this and remove the notifier stuff,
> thanks!

Well there's also other modes like i2c over aux, and that would be easier
to support with an ioctl in a uniform way. So not sure how much value
there is in reusing read/write for i2c ...

But I really don't have a strong opinion about this.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch