diff options
Diffstat (limited to 'drivers/i2c/i2c-core.c')
| -rw-r--r-- | drivers/i2c/i2c-core.c | 41 |
1 files changed, 41 insertions, 0 deletions
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 */ |