[PATCH v3 2/3] i2c: core: add device-managed version of i2c_new_dummy

Heiner Kallweit
2017-12-13T19:11:32Z

i2c_new_dummy is typically called from the probe function of the
driver for the primary i2c client. It requires calls to
i2c_unregister_device in the error path of the probe function and
in the remove function.
This can be simplified by introducing a device-managed version.

Note the changed error case return value type:
i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- use new function _i2c_new_dummy with detailed error codes
v3:
- no changes
---
Documentation/driver-model/devres.txt | 3 +++
drivers/i2c/i2c-core-base.c | 38 +++++++++++++++++++++++++++++++++++
include/linux/i2c.h | 3 +++
3 files changed, 44 insertions(+)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index c180045eb..6e2bccf85 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -259,6 +259,9 @@ GPIO
devm_gpio_request_one()
devm_gpio_free()

+I2C
+ devm_i2c_new_dummy
+
IIO
devm_iio_device_alloc()
devm_iio_device_free()
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 3faa9b1d3..7b3cd95be 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -840,6 +840,44 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
}
EXPORT_SYMBOL_GPL(i2c_new_dummy);

+static void devm_i2c_release_dummy(struct device *dev, void *res)
+{
+ i2c_unregister_device(*(struct i2c_client **)res);
+}
+
+/**
+ * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver
+ * @dev: device the managed resource is bound to
+ * @adapter: the adapter managing the device
+ * @address: seven bit address to be used
+ * Context: can sleep
+ *
+ * This is the device-managed version of i2c_new_dummy.
+ * Note the changed return value type: It returns the new i2c client
+ * or an ERR_PTR in case of an error.
+ */
+struct i2c_client *devm_i2c_new_dummy(struct device *dev,
+ struct i2c_adapter *adapter,
+ u16 address)
+{
+ struct i2c_client *ret, **dr;
+
+ dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
+ if (!dr)
+ return ERR_PTR(-ENOMEM);
+
+ ret = _i2c_new_dummy(adapter, address);
+ if (IS_ERR(ret)) {
+ devres_free(dr);
+ } else {
+ *dr = ret;
+ devres_add(dev, dr);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(devm_i2c_new_dummy);
+
/**
* i2c_new_secondary_device - Helper to get the instantiated secondary address
* and create the associated device
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 5d7f3c185..aca6ebbb8 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -441,6 +441,9 @@ 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 *
+devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address);
+
extern struct i2c_client *
i2c_new_secondary_device(struct i2c_client *client,
const char *name,
--
2.15.1