Re: [Qemu-devel] [PATCH v3] chardev/char-i2c: Implement Linux I2C character device

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Thu, May 16, 2019 at 02:49:45PM +0100, Ernest Esene wrote:
> On Wed, May 15, 2019 at 03:17:12PM +0100, Stefan Hajnoczi wrote:
> > On Fri, May 10, 2019 at 07:04:10PM +0100, Ernest Esene wrote:
> > > Add support for Linux I2C character device for I2C device passthrough
> > > For example:
> > > -chardev i2c,address=0x46,path=/dev/i2c-N,id=i2c-chardev
> > > 
> > > QEMU supports emulation of I2C devices in software but currently can't
> > > passthrough to real I2C devices. This feature is needed by developers
> > > using QEMU for writing and testing software for I2C devices.
> > > 
> > > Signed-off-by: Ernest Esene <eroken1@gmail.com>
> > 
> > How is -chardev i2c meant to be used?  Do you have code to connect this
> > new chardev type to an emulated I2C bus?
> It is meant to be connected to emulated I2C bus as you've stated, but I
> don't have the code yet.

I'd like to see that code first, especially if it uses the chardev ioctl
to perform operations other than just read/write.  That could influence
the design of chardev-i2c.

Please keep this patch out-of-tree unless someone has an immediate use
for it.  If it gets merged too early (especially if a QEMU release is
made), then it's difficult to change the command-line interface if
changes are required to make it work with the I2C emulation.

Stefan

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