From: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxxxxxxxx>
An adapter might need to know when a new device is about to be
added. This will soon bee needed to implement an "I2C address
translator" (ATR for short), a device that propagates I2C transactions
with a different slave address (an "alias" address). An ATR driver
needs to know when a slave is being added to find a suitable alias and
program the device translation map.
Add an attach/detach callback pair to allow adapter drivers to be
notified of clients being added and removed.
Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-core-base.c | 16 ++++++++++++++++
include/linux/i2c.h | 9 +++++++++
2 files changed, 25 insertions(+)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 28460f6a60cc..4f8776e065ce 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -778,6 +778,11 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
}
}
+ if (adap->attach_ops &&
+ adap->attach_ops->attach_client &&
+ adap->attach_ops->attach_client(adap, info, client) != 0)
+ goto err_attach_client;
+
status = device_register(&client->dev);
if (status)
goto out_free_props;
@@ -788,6 +793,9 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
return client;
out_free_props:
+ if (adap->attach_ops && adap->attach_ops->detach_client)
+ adap->attach_ops->detach_client(adap, client);
+err_attach_client:
if (info->properties)
device_remove_properties(&client->dev);
out_err_put_of_node:
@@ -810,9 +818,17 @@ EXPORT_SYMBOL_GPL(i2c_new_device);
*/
void i2c_unregister_device(struct i2c_client *client)
{
+ struct i2c_adapter *adap;
+
if (!client)
return;
+ adap = client->adapter;
+
+ if (adap->attach_ops &&
+ adap->attach_ops->detach_client)
+ adap->attach_ops->detach_client(adap, client);
+
if (client->dev.of_node) {
of_node_clear_flag(client->dev.of_node, OF_POPULATED);
of_node_put(client->dev.of_node);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 65b4eaed1d96..600d136b1056 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -551,6 +551,14 @@ struct i2c_lock_operations {
void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
};
+struct i2c_attach_operations {
+ int (*attach_client)(struct i2c_adapter *,
+ const struct i2c_board_info *,
+ struct i2c_client *);
+ void (*detach_client)(struct i2c_adapter *,
+ struct i2c_client *);
+};
+
/**
* struct i2c_timings - I2C timing information
* @bus_freq_hz: the bus frequency in Hz
@@ -674,6 +682,7 @@ struct i2c_adapter {
/* data fields that are valid for all devices */
const struct i2c_lock_operations *lock_ops;
+ const struct i2c_attach_operations *attach_ops;
struct rt_mutex bus_lock;
struct rt_mutex mux_lock;
--
2.17.1
