This makes it possible to define i2c-devices at the kernel command line or as a module parameter for bus-drivers which want to offer such an functionality.
Drivers which are using it will have the a parameter named devices with format devname1@addr1,devname2@addr2,... e.g. devices=ds1307@0x68,pcf8563@0x51 The devices will be probed using the standard probe mechanism, the definition of up to 8 devices is allowed. Cc: Jean Delvare <[email protected]> Cc: Till Harbaum <[email protected]> Signed-off-by: Alexander Holler <[email protected]> --- Documentation/i2c/instantiating-devices | 37 ++++++++++++++++++++++++++++++ drivers/i2c/i2c-core.c | 40 +++++++++++++++++++++++++++++++++ include/linux/i2c.h | 14 ++++++++++++ 3 files changed, 91 insertions(+) diff --git a/Documentation/i2c/instantiating-devices b/Documentation/i2c/instantiating-devices index abf6361..1dbfdf3 100644 --- a/Documentation/i2c/instantiating-devices +++ b/Documentation/i2c/instantiating-devices @@ -209,3 +209,40 @@ device driver individually, it is much more efficient, and also has the advantage that you do not have to reload the driver to change a setting. You can also instantiate the device before the driver is loaded or even available, and you don't need to know what driver the device needs. + + +Method 5: By module parameter +----------------------------- + +If you want to add the possibility for user-defined optional devices to +your i2c-bus driver, do it like that in the source of the driver: + +(...) +MODULE_PARAM_I2C_OPTIONAL_DEVICES(opt_devices); +(...) + +static int i2c_my_bus_probe(...) +{ + (...) + i2c_add_adapter(&dev->adapter); + (...) + + i2c_add_optional_devices(&dev->adapter, opt_devices); + + return 0; +} +(...) + +The call to i2c_add_optional_devices() should only be done if and after +the driver is registered. opt_devices will be used as a name for a +static array of pointers to char (for usage with module_param_array_named() +in the macro MODULE_PARAM_I2C_OPTIONAL_DEVICES). + +This interfaces offers users the possibility to define devices by using a +module parameter. E.g. + +modprobe my_i2c_bus devices=ds1307@0x68,pcf8563@0x51 + +or even at the kernel command line with + +my_i2c_bus.devices=ds1307@0x68,pcf8563@0x51 diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index a7edf98..7d84bc40 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -2204,6 +2204,46 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, } EXPORT_SYMBOL(i2c_smbus_xfer); +void i2c_add_optional_devices(struct i2c_adapter *adapter, char **opt_devices) +{ + int i; + struct i2c_board_info i2c_info; + uint addr; + unsigned short i2c_addr[] = { 0, I2C_CLIENT_END }; + char *at; + + for (i = 0; opt_devices[i]; ++i) { + at = strchr(opt_devices[i], '@'); + if (at == NULL) { + dev_warn(&adapter->dev, + "address need in device definition '%s'\n", + opt_devices[i]); + continue; + } + *at++ = 0; + if (kstrtouint(at, 0, &addr) || addr >= I2C_CLIENT_END) { + *--at = '@'; + dev_warn(&adapter->dev, + "wrong address in slave definition '%s'\n", + opt_devices[i]); + continue; + } + memset(&i2c_info, 0, sizeof(struct i2c_board_info)); + strlcpy(i2c_info.type, opt_devices[i], I2C_NAME_SIZE); + *--at = '@'; /* if someone uses opt_devices afterwards */ + i2c_addr[0] = addr; + if (i2c_new_probed_device(adapter, &i2c_info, i2c_addr, NULL)) + dev_info(&adapter->dev, + "device %s at address 0x%02x registered\n", + i2c_info.type, addr); + else + dev_warn(&adapter->dev, + "device %s at address 0x%02x not found\n", + i2c_info.type, addr); + } +} +EXPORT_SYMBOL(i2c_add_optional_devices); + MODULE_AUTHOR("Simon G. Vogl <[email protected]>"); MODULE_DESCRIPTION("I2C-Bus main module"); MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 800de22..bd0cbb1 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -489,6 +489,20 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap) } /** + * Used for user-defined optional devices, see + * Documentation/i2c/instantiating-devices about how to use it. + */ + +extern void i2c_add_optional_devices(struct i2c_adapter *adapter, + char **opt_devices); + +#define MAX_OPTIONAL_I2C_DEVICES 8 +#define MODULE_PARAM_I2C_OPTIONAL_DEVICES(_opt_devices) \ + static char *_opt_devices[MAX_OPTIONAL_I2C_DEVICES]; \ + module_param_array_named(devices, _opt_devices, charp, NULL, 0); \ + MODULE_PARM_DESC(devices, "devname1@adr1,... (e.g. ds1307@0x68)") + +/** * module_i2c_driver() - Helper macro for registering a I2C driver * @__i2c_driver: i2c_driver struct * -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
