> > We have a problem. There are lots of I2C device ID tables scattered
> > around the kernel which are redundant in all Device Tree and/or ACPI
> > only supported device drivers. After recent discussions it has become
> > apparent that the only thing blocking the complete removal of these
> > tables is the continued support of 'register an I2C device via sysfs'
> > functionality. As the sysfs method doesn't know anything about Device
> > Tree or ACPI, we can not pass any nodes in. This patch searches all
> > known Device Tree nodes and attempts to acquire a match from the
> > device name provided via sysfs. It can not fail, but if found assigns
> > the matching of_node to i2c_board_info prior to registering.
>
> Ummm... blech! :-)
>
> It shouldn't actually be necessary to have a node when instantiating an
> i2c_device... in fact, there /shouldn't/ be a node if the device is
> getting instantiated by had via sysfs. If there was a node, then I would
> expect a device to have been created at the same time.
You're right. I realised that about 10 mins after I sent the patch!
> I think panto's overlays solve the problem where a node actually is
> required to instantiate the device by actually adding a node and letting
> the i2c subsystem create the associated device automatically.
This looks like it's exactly what I need. Pulling the code now.
> > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> > ---
> > drivers/i2c/i2c-core.c | 31 +++++++++++++++++++++++++++++++
> > 1 file changed, 31 insertions(+)
> >
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index 7c7f4b8..2e47641 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -64,6 +64,7 @@ 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 device_node *of_i2c_type_to_node(char *type);
> >
> > static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
> >
> > @@ -863,6 +864,8 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
> > return -EINVAL;
> > }
> >
> > + info.of_node = of_i2c_type_to_node(info.type);
> > +
> > client = i2c_new_device(adap, &info);
> > if (!client)
> > return -EINVAL;
> > @@ -1088,8 +1091,36 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
> > return i2c_verify_adapter(dev);
> > }
> > EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
> > +
> > +static struct device_node *of_i2c_type_to_node(char *type)
> > +{
> > + struct device_node *np;
> > + const char *compatible, *name;
> > + int len;
> > +
> > + if (!type)
> > + return NULL;
> > +
> > + for_each_of_allnodes(np) {
> > + compatible = of_get_property(np, "compatible", &len);
> > + if (!compatible)
> > + continue;
> > +
> > + name = strchr(compatible, ',');
> > + if (!name)
> > + name = compatible;
> > + else
> > + name++;
> > +
> > + if (!strncmp(name, type, len - (name - compatible)))
> > + return np;
> > + }
> > +
> > + return NULL;
> > +}
> > #else
> > static void of_i2c_register_devices(struct i2c_adapter *adap) { }
> > +static struct device_node *of_i2c_type_to_node(char *type) { return NULL; }
> > #endif /* CONFIG_OF */
> >
> > /* ACPI support code */
>
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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