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Diffstat (limited to 'Documentation/i2c')
| -rw-r--r-- | Documentation/i2c/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/i2c/upgrading-clients.rst | 285 |
2 files changed, 0 insertions, 286 deletions
diff --git a/Documentation/i2c/index.rst b/Documentation/i2c/index.rst index fee4744475df..8a2ad3845191 100644 --- a/Documentation/i2c/index.rst +++ b/Documentation/i2c/index.rst @@ -62,7 +62,6 @@ Legacy documentation .. toctree:: :maxdepth: 1 - upgrading-clients old-module-parameters .. only:: subproject and html diff --git a/Documentation/i2c/upgrading-clients.rst b/Documentation/i2c/upgrading-clients.rst deleted file mode 100644 index 1708090d7b8f..000000000000 --- a/Documentation/i2c/upgrading-clients.rst +++ /dev/null @@ -1,285 +0,0 @@ -================================================= -Upgrading I2C Drivers to the new 2.6 Driver Model -================================================= - -Ben Dooks <ben-linux@fluff.org> - -Introduction ------------- - -This guide outlines how to alter existing Linux 2.6 client drivers from -the old to the new binding methods. - - -Example old-style driver ------------------------- - -:: - - struct example_state { - struct i2c_client client; - .... - }; - - static struct i2c_driver example_driver; - - static unsigned short ignore[] = { I2C_CLIENT_END }; - static unsigned short normal_addr[] = { OUR_ADDR, I2C_CLIENT_END }; - - I2C_CLIENT_INSMOD; - - static int example_attach(struct i2c_adapter *adap, int addr, int kind) - { - struct example_state *state; - struct device *dev = &adap->dev; /* to use for dev_ reports */ - int ret; - - state = kzalloc(sizeof(struct example_state), GFP_KERNEL); - if (state == NULL) { - dev_err(dev, "failed to create our state\n"); - return -ENOMEM; - } - - example->client.addr = addr; - example->client.flags = 0; - example->client.adapter = adap; - - i2c_set_clientdata(&state->i2c_client, state); - strscpy(client->i2c_client.name, "example", sizeof(client->i2c_client.name)); - - ret = i2c_attach_client(&state->i2c_client); - if (ret < 0) { - dev_err(dev, "failed to attach client\n"); - kfree(state); - return ret; - } - - dev = &state->i2c_client.dev; - - /* rest of the initialisation goes here. */ - - dev_info(dev, "example client created\n"); - - return 0; - } - - static int example_detach(struct i2c_client *client) - { - struct example_state *state = i2c_get_clientdata(client); - - i2c_detach_client(client); - kfree(state); - return 0; - } - - static int example_attach_adapter(struct i2c_adapter *adap) - { - return i2c_probe(adap, &addr_data, example_attach); - } - - static struct i2c_driver example_driver = { - .driver = { - .owner = THIS_MODULE, - .name = "example", - .pm = &example_pm_ops, - }, - .attach_adapter = example_attach_adapter, - .detach_client = example_detach, - }; - - -Updating the client -------------------- - -The new style binding model will check against a list of supported -devices and their associated address supplied by the code registering -the busses. This means that the driver .attach_adapter and -.detach_client methods can be removed, along with the addr_data, -as follows:: - - - static struct i2c_driver example_driver; - - - static unsigned short ignore[] = { I2C_CLIENT_END }; - - static unsigned short normal_addr[] = { OUR_ADDR, I2C_CLIENT_END }; - - - I2C_CLIENT_INSMOD; - - - static int example_attach_adapter(struct i2c_adapter *adap) - - { - - return i2c_probe(adap, &addr_data, example_attach); - - } - - static struct i2c_driver example_driver = { - - .attach_adapter = example_attach_adapter, - - .detach_client = example_detach, - } - -Add the probe and remove methods to the i2c_driver, as so:: - - static struct i2c_driver example_driver = { - + .probe = example_probe, - + .remove = example_remove, - } - -Change the example_attach method to accept the new parameters -which include the i2c_client that it will be working with:: - - - static int example_attach(struct i2c_adapter *adap, int addr, int kind) - + static int example_probe(struct i2c_client *client, - + const struct i2c_device_id *id) - -Change the name of example_attach to example_probe to align it with the -i2c_driver entry names. The rest of the probe routine will now need to be -changed as the i2c_client has already been setup for use. - -The necessary client fields have already been setup before -the probe function is called, so the following client setup -can be removed:: - - - example->client.addr = addr; - - example->client.flags = 0; - - example->client.adapter = adap; - - - - strscpy(client->i2c_client.name, "example", sizeof(client->i2c_client.name)); - -The i2c_set_clientdata is now:: - - - i2c_set_clientdata(&state->client, state); - + i2c_set_clientdata(client, state); - -The call to i2c_attach_client is no longer needed, if the probe -routine exits successfully, then the driver will be automatically -attached by the core. Change the probe routine as so:: - - - ret = i2c_attach_client(&state->i2c_client); - - if (ret < 0) { - - dev_err(dev, "failed to attach client\n"); - - kfree(state); - - return ret; - - } - - -Remove the storage of 'struct i2c_client' from the 'struct example_state' -as we are provided with the i2c_client in our example_probe. Instead we -store a pointer to it for when it is needed. - -:: - - struct example_state { - - struct i2c_client client; - + struct i2c_client *client; - -the new i2c client as so:: - - - struct device *dev = &adap->dev; /* to use for dev_ reports */ - + struct device *dev = &i2c_client->dev; /* to use for dev_ reports */ - -And remove the change after our client is attached, as the driver no -longer needs to register a new client structure with the core:: - - - dev = &state->i2c_client.dev; - -In the probe routine, ensure that the new state has the client stored -in it:: - - static int example_probe(struct i2c_client *i2c_client, - const struct i2c_device_id *id) - { - struct example_state *state; - struct device *dev = &i2c_client->dev; - int ret; - - state = kzalloc(sizeof(struct example_state), GFP_KERNEL); - if (state == NULL) { - dev_err(dev, "failed to create our state\n"); - return -ENOMEM; - } - - + state->client = i2c_client; - -Update the detach method, by changing the name to _remove and -to delete the i2c_detach_client call. It is possible that you -can also remove the ret variable as it is not needed for any -of the core functions. - -:: - - - static int example_detach(struct i2c_client *client) - + static int example_remove(struct i2c_client *client) - { - struct example_state *state = i2c_get_clientdata(client); - - - i2c_detach_client(client); - -And finally ensure that we have the correct ID table for the i2c-core -and other utilities:: - - + struct i2c_device_id example_idtable[] = { - + { "example", 0 }, - + { } - +}; - + - +MODULE_DEVICE_TABLE(i2c, example_idtable); - - static struct i2c_driver example_driver = { - .driver = { - .owner = THIS_MODULE, - .name = "example", - }, - + .id_table = example_ids, - - -Our driver should now look like this:: - - struct example_state { - struct i2c_client *client; - .... - }; - - static int example_probe(struct i2c_client *client, - const struct i2c_device_id *id) - { - struct example_state *state; - struct device *dev = &client->dev; - - state = kzalloc(sizeof(struct example_state), GFP_KERNEL); - if (state == NULL) { - dev_err(dev, "failed to create our state\n"); - return -ENOMEM; - } - - state->client = client; - i2c_set_clientdata(client, state); - - /* rest of the initialisation goes here. */ - - dev_info(dev, "example client created\n"); - - return 0; - } - - static int example_remove(struct i2c_client *client) - { - struct example_state *state = i2c_get_clientdata(client); - - kfree(state); - return 0; - } - - static struct i2c_device_id example_idtable[] = { - { "example", 0 }, - { } - }; - - MODULE_DEVICE_TABLE(i2c, example_idtable); - - static struct i2c_driver example_driver = { - .driver = { - .owner = THIS_MODULE, - .name = "example", - .pm = &example_pm_ops, - }, - .id_table = example_idtable, - .probe = example_probe, - .remove = example_remove, - }; |