Re: [RFC v2] Another approach to IR

From: Andy Walls
Date: Wed Dec 02 2009 - 20:04:02 EST


On Wed, 2009-12-02 at 14:55 -0500, Jarod Wilson wrote:
> On Dec 2, 2009, at 2:33 PM, Mauro Carvalho Chehab wrote:
>
> > Dmitry Torokhov wrote:
> >>
> ...
> >>>> (for each remote/substream that they can recognize).
> >>> I'm assuming that, by remote, you're referring to a remote receiver (and not to
> >>> the remote itself), right?
> >>
> >> If we could separate by remote transmitter that would be the best I
> >> think, but I understand that it is rarely possible?
> >
> > IMHO, the better is to use a separate interface for the IR transmitters,
> > on the devices that support this feature. There are only a few devices
> > I'm aware of that are able to transmit IR codes.
>
> If I'm thinking clearly, there are only three lirc kernel drivers that
> support transmit, lirc_mceusb, lirc_zilog and lirc_serial. The mceusb
> driver was posted, so I won't rehash what it is here. The zilog driver
> binds to a Zilog z80 microprocessor thingy (iirc) exposed via i2c,
> found on many Hauppauge v4l/dvb devices (PVR-150, HVR-1600, HD-PVR,
> etc). The serial driver is fairly self-explanatory as well.
>
> There are also a few userspace-driven devices that do transmit, but
> I'm assuming they're (currently) irrelevant to this discussion.


I've got the CX23888 integrated IR Rx done and Tx nearly done. I was
waiting to see how kfifo and lirc_dev panned out before making the
interface to userspace.

The CX23885, CX23418, and CX2584x integrated IR is essentially the same.
I hope to have CX23885 IR done by Christmas.

Both of those IR devices are/will be encapsulated in a v4l2_subdevice
object internally. I was going to write lirc_v4l glue between the
v4l2_device/v4l2_subdev_ir_ops and lirc_dev.

As for the the I2C chips, I was going to go back and encapsulate those
in the v4l2_subdevice object as well, so then my notional lirc_v4l could
pick those up too. The I2C subsystem only allows one binding to an I2C
client address/name on a bus. So without some new glue like a notional
lirc_v4l, it *may* be hard to share between ir-kbd-i2c and lirc_i2c and
lirc_zilog.

Regards,
Andy

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