On Wed, 16 Sep 2015, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > On Wed, Sep 16, 2015 at 01:09:54PM -0700, Daniel Vetter wrote: >> 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 ... > > We already have i2c-dev for i2c. So not sure what you're after here. Yeah, definitely don't reinvent the wheel for this. BR, Jani. > > i2c is a bit of a mess on the protocol level. Lots of devices do > interesting things with it, so it can't really make do with just > read/write/lseek. Apart from i2c-over-aux, the rest is all about > DPCD access, and for that read/write/lseek is all you ever need. > > -- > Ville Syrjälä > Intel OTC > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
