On Fri, Sep 05, 2014 at 04:02:19PM +0200, Jean-Michel Hautbois wrote: > Some I2C devices have multiple addresses assigned, for example each address > corresponding to a different internal register map page of the device. > So far drivers which need support for this have handled this with a driver > specific and non-generic implementation, e.g. passing the additional address > via platform data. > > This patch provides a new helper function called i2c_new_secondary_device() > which is intended to provide a generic way to get the secondary address > as well as instantiate a struct i2c_client for the secondary address. > > The function expects a pointer to the primary i2c_client, a name > for the secondary address and an optional default address. The name is used > as a handle to specify which secondary address to get. > > The default address is used as a fallback in case no secondary address > was explicitly specified. In case no secondary address and no default > address were specified the function returns NULL. > > For now the function only supports look-up of the secondary address > from devicetree, but it can be extended in the future > to for example support board files and/or ACPI. > > Signed-off-by: Jean-Michel Hautbois <jean-michel.hautbois@xxxxxxxxxxx> Sorry, just noticed this one. Srinivas (CC'd) and I did similar patch series here: http://patchwork.ozlabs.org/patch/338342/ We should probably collaborate on this one to get both DT and ACPI supported. > --- > drivers/i2c/i2c-core.c | 40 ++++++++++++++++++++++++++++++++++++++++ > include/linux/i2c.h | 8 ++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 632057a..ef31d6f 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -798,6 +798,46 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) > } > EXPORT_SYMBOL_GPL(i2c_new_dummy); > > +/** > + * i2c_new_secondary_device - Helper to get the instantiated secondary address > + * @client: Handle to the primary client > + * @name: Handle to specify which secondary address to get > + * @default_addr: Used as a fallback if no secondary address was specified > + * Context: can sleep > + * > + * This returns an I2C client bound to the "dummy" driver based on DT parsing. > + * > + * This returns the new i2c client, which should be saved for later use with > + * i2c_unregister_device(); or NULL to indicate an error. > + */ > +struct i2c_client *i2c_new_secondary_device(struct i2c_client *client, > + const char *name, > + u16 default_addr) > +{ > + int i; > + u32 addr; > + struct device_node *np; > + > + np = client->dev.of_node; > + > + if (np) { > + i = of_property_match_string(np, "reg-names", name); > + if (i >= 0) > + of_property_read_u32_index(np, "reg", i, &addr); > + else if (default_addr != 0) > + addr = default_addr; > + else > + addr = NULL; > + } else { > + addr = default_addr; > + } > + > + dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); > + return i2c_new_dummy(client->adapter, addr); > +} > +EXPORT_SYMBOL_GPL(i2c_new_secondary_device); > + > + > /* ------------------------------------------------------------------------- */ > > /* I2C bus adapters -- one roots each I2C or SMBUS segment */ > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index a95efeb..0f190e6 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -322,6 +322,14 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); > extern struct i2c_client * > i2c_new_dummy(struct i2c_adapter *adap, u16 address); > > +/* Helper function providing a generic way to get the secondary address > + * as well as a client handle to this extra address. > + */ > +extern struct i2c_client * > +i2c_new_secondary_device(struct i2c_client *client, > + const char *name, > + u32 default_addr); > + > extern void i2c_unregister_device(struct i2c_client *); > #endif /* I2C */ > > -- > 2.0.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
