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Re: [PATCH v2 4/4] hw/i2c: add pca954x i2c-mux switch
From: |
Patrick Venture |
Subject: |
Re: [PATCH v2 4/4] hw/i2c: add pca954x i2c-mux switch |
Date: |
Fri, 9 Apr 2021 10:21:12 -0700 |
On Fri, Apr 9, 2021 at 9:51 AM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> Hi Patrick,
>
> On 4/9/21 6:25 PM, Patrick Venture wrote:
> > The pca954x is an i2c mux, and this adds support for two variants of
> > this device: the pca9546 and pca9548.
> >
> > This device is very common on BMCs to route a different channel to each
> > PCIe i2c bus downstream from the BMC.
> >
> > Signed-off-by: Patrick Venture <venture@google.com>
> > Reviewed-by: Hao Wu <wuhaotsh@google.com>
> > Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
> > ---
> > MAINTAINERS | 6 +
> > hw/i2c/Kconfig | 4 +
> > hw/i2c/i2c_mux_pca954x.c | 290 +++++++++++++++++++++++++++++++
> > hw/i2c/meson.build | 1 +
> > hw/i2c/trace-events | 5 +
> > include/hw/i2c/i2c_mux_pca954x.h | 19 ++
> > 6 files changed, 325 insertions(+)
> > create mode 100644 hw/i2c/i2c_mux_pca954x.c
> > create mode 100644 include/hw/i2c/i2c_mux_pca954x.h
>
> > diff --git a/hw/i2c/Kconfig b/hw/i2c/Kconfig
> > index 09642a6dcb..8d120a25d5 100644
> > --- a/hw/i2c/Kconfig
> > +++ b/hw/i2c/Kconfig
> > @@ -28,3 +28,7 @@ config IMX_I2C
> > config MPC_I2C
> > bool
> > select I2C
> > +
> > +config PCA954X
> > + bool
> > + select I2C
>
> Do you have a circular dependency when also using:
>
> depends on I2C
>
> ?
I'm somewhat new to qemu -- I don't know what you mean, since I2C
doesn't depend on pca954x, I don't imagine there could be a circular
dependency.
>
> > +static void pca954x_realize(DeviceState *dev, Error **errp)
> > +{
> > + Pca954xState *s = PCA954X(dev);
> > + Pca954xClass *c = PCA954X_GET_CLASS(s);
> > + int i;
> > +
> > + /* SMBus modules. Cannot fail. */
> > + for (i = 0; i < c->nchans; i++) {
> > + Object *obj = OBJECT(&s->channel[i]);
> > + sysbus_realize(SYS_BUS_DEVICE(obj), &error_abort);
>
> No need to cast to Object:
>
> sysbus_realize(SYS_BUS_DEVICE(&s->channel[i]), &error_abort);
>
Ack, will fix in v3.
> > + }
> > +}
Re: [PATCH v2 0/4] hw/i2c: Adds pca954x i2c mux switch device, Corey Minyard, 2021/04/09