diff options
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c.txt | 7 | ||||
| -rw-r--r-- | drivers/i2c/i2c-core.c | 41 | ||||
| -rw-r--r-- | include/linux/i2c.h | 5 |
3 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt index c8d977ed847f..f31b2ad1552b 100644 --- a/Documentation/devicetree/bindings/i2c/i2c.txt +++ b/Documentation/devicetree/bindings/i2c/i2c.txt @@ -62,6 +62,13 @@ wants to support one of the below features, it should adapt the bindings below. - wakeup-source device can be used as a wakeup source. +- reg + I2C slave addresses + +- reg-names + Names of map programmable addresses. + It can contain any map needing another address than default one. + Binding may contain optional "interrupts" property, describing interrupts used by the device. I2C core will assign "irq" interrupt (or the very first interrupt if not using interrupt names) as primary interrupt for the slave. diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index af11b658984d..952d2f0c02c5 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1145,6 +1145,47 @@ 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 + * and create the associated device + * @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 + * + * I2C clients can be composed of multiple I2C slaves bound together in a single + * component. The I2C client driver then binds to the master I2C slave and needs + * to create I2C dummy clients to communicate with all the other slaves. + * + * This function creates and returns an I2C dummy client whose I2C address is + * retrieved from the platform firmware based on the given slave name. If no + * address is specified by the firmware default_addr is used. + * + * On DT-based platforms the address is retrieved from the "reg" property entry + * cell whose "reg-names" value matches the slave name. + * + * 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) +{ + struct device_node *np = client->dev.of_node; + u32 addr = default_addr; + int i; + + if (np) { + i = of_property_match_string(np, "reg-names", name); + if (i >= 0) + of_property_read_u32_index(np, "reg", i, &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 96a25ae14494..6df7bad8c26c 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -349,6 +349,11 @@ 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); +extern struct i2c_client * +i2c_new_secondary_device(struct i2c_client *client, + const char *name, + u16 default_addr); + extern void i2c_unregister_device(struct i2c_client *); #endif /* I2C */ |