On Wed, Feb 2, 2022 at 9:31 AM Philippe Mathieu-Daudé <
f4bug@amsat.org> wrote:
On 2/2/22 17:40, Patrick Venture wrote:
> Philippe,
>
> I0202 08:29:45.380384 6641 stream.go:31] qemu: child buses at
> "pca9546": "channel[*]", "channel[*]", "channel[*]", "channel[*]"
>
> Ok, so that's interesting. In one system (using qom-list) it's
> correct, but then when using it to do path assignment
> (qdev-monitor), it fails...
>
> I'm not as fond of the name i2c-bus.%d, since they're referred to as
> channels in the datasheet. If I do the manual name creation, can I
> keep the name channel or should I pivot over?
>
> Thanks
>
>
> -- >8 --
> diff --git a/hw/i2c/i2c_mux_pca954x.c b/hw/i2c/i2c_mux_pca954x.c
> index f9ce633b3a..a9517b612a 100644
> --- a/hw/i2c/i2c_mux_pca954x.c
> +++ b/hw/i2c/i2c_mux_pca954x.c
> @@ -189,9 +189,11 @@ static void pca954x_init(Object *obj)
>
> /* SMBus modules. Cannot fail. */
> for (i = 0; i < c->nchans; i++) {
> + g_autofree gchar *bus_name =
> g_strdup_printf("i2c.%d", i);
> +
> /* start all channels as disabled. */
> s->enabled[i] = false;
> - s->bus[i] = i2c_init_bus(DEVICE(s), "channel[*]");
> + s->bus[i] = i2c_init_bus(DEVICE(s), bus_name);
> }
> }
>
> ---
>
> (look at HMP 'info qtree' output).
>
> > }
> > }
>
> With the change:
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org
> <mailto:f4bug@amsat.org>>
> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org
> <mailto:f4bug@amsat.org>>
>
>
> Just saw your reply, and found a bunch of other non-spam in my spam
> folder. I sent the message to the anti-spam team, hopefully that'll
> resolve this for myself and presumably others.
Thanks. I suppose the problem is the amsat.org domain.
Yours aren't the only ones I've missed, but who knows.
> I definitely see the same result with the qdev-monitor, but was really
> surprised that the qom-list worked. I'll explicitly set the name, and
> i2c.%d is fine. The detail that they're channels is not really
> important to the end user presumably.
I agree it is better to follow datasheets, thus I am fine if you
change and use channel. How would it look like? "channel.0"?
FYI qdev busses are described in docs/qdev-device-use.txt.
Thanks. I went with i2c.%d in v2, since I figured it wasn't super important.
We should be able to plug a device using some command line
such "-device i2c_test_dev,bus=channel.0,addr=0x55".
I wonder how to select the base PCA9548 ...
So I have been working on that, and I have been running into a different issue, but related.
/smbus[1]/i2c-bus/pca9546/i2c.0 works to add a device via command line.
However, if there are two pca9546s on that main bus. So if i do:
/smbus[1]/i2c-bus/child[0]/i2c.0 it'll respond that there is no child[0], but rather includes "pca9546, pca9546"
Maybe we need to pass the PCA ID to pca954x_init(), so we can
name "channel.2.0" for the 1st channel on the 2nd PCA?
It sounds like you're thinking about the same problem overall.
Regards,
Phil.