Re: [PATCH 1/8] i2c: export i2c_client_type structure

Jean Delvare
2017-03-13T13:50:56Z

Hi Dmitry,

On Fri, 10 Mar 2017 00:12:46 +0100, Wolfram Sang wrote:
> On Thu, Mar 09, 2017 at 02:16:37PM -0800, Dmitry Torokhov wrote:
> > i2c bus has 2 different types of device belonging to the same bus and
> > bus notifiers use device type to distinguish between adapters and clients.

Out of curiosity, is this something unusual, or other bus types do the
same?

> > Previously we only had i2c_adapter_type exported, which made code wanting
> > to work with i2c_client devices test for type not equal to adapter type.
> > This unfortunately is not safe if we ever add another type to the bus,
> > so let's export i2c_client_type as well.
> >
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > ---
> >
> > Wolfram, this is the patch I was talking about in the other mail.
>
> I see. From a glimpse, I am fine with the patch. I'll add Jean Delvare
> to CC, though, in case I missed some detail he still knows. Furthermore,
> while I agree that testing for "not adapter" when one means "is client"
> is not nice, is there a bigger benefit than being correct in your queue?

No objection from me.

Reviewed-by: Jean Delvare <jdelvare@suse.de>

> >
> > drivers/i2c/i2c-core.c | 4 ++--
> > include/linux/i2c.h | 1 +
> > 2 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index 34a5115484dd..446e341e9508 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -74,7 +74,6 @@
> > static DEFINE_MUTEX(core_lock);
> > static DEFINE_IDR(i2c_adapter_idr);
> >
> > -static struct device_type i2c_client_type;
> > static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
> >
> > static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
> > @@ -1096,11 +1095,12 @@ struct bus_type i2c_bus_type = {
> > };
> > EXPORT_SYMBOL_GPL(i2c_bus_type);
> >
> > -static struct device_type i2c_client_type = {
> > +struct device_type i2c_client_type = {
> > .groups = i2c_dev_groups,
> > .uevent = i2c_device_uevent,
> > .release = i2c_client_dev_release,
> > };
> > +EXPORT_SYMBOL_GPL(i2c_client_type);
> >
> >
> > /**
> > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> > index 2cc3988d127b..89ca5e56b433 100644
> > --- a/include/linux/i2c.h
> > +++ b/include/linux/i2c.h
> > @@ -37,6 +37,7 @@
> >
> > extern struct bus_type i2c_bus_type;
> > extern struct device_type i2c_adapter_type;
> > +extern struct device_type i2c_client_type;
> >
> > /* --- General options ------------------------------------------------ */
> >
> > --
> > 2.12.0.246.ga2ecc84866-goog
> >

--
Jean Delvare
SUSE L3 Support