Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "Some I2C core API additions which are kind of simple but enhance error
  checking for users a lot, especially by returning errno now.

  There are wrappers to still support the old API but it will be removed
  once all users are converted"

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: core: add device-managed version of i2c_new_dummy
  i2c: core: improve return value handling of i2c_new_device and i2c_new_dummy

Documentation/driver-model/devres.txt

@@ -271,6 +271,9 @@ GPIO
   devm_gpio_request_one()
   devm_gpio_free()
 
+I2C
+  devm_i2c_new_dummy_device()
+
 IIO
   devm_iio_device_alloc()
   devm_iio_device_free()

drivers/i2c/i2c-core-base.c

@@ -714,7 +714,7 @@ static int i2c_dev_irq_from_resources(const struct resource *resources,
 }
 
 /**
- * i2c_new_device - instantiate an i2c device
+ * i2c_new_client_device - instantiate an i2c device
  * @adap: the adapter managing the device
  * @info: describes one I2C device; bus_num is ignored
  * Context: can sleep
@@ -727,17 +727,17 @@ static int i2c_dev_irq_from_resources(const struct resource *resources,
  * before any i2c_adapter could exist.
  *
  * This returns the new i2c client, which may be saved for later use with
- * i2c_unregister_device(); or NULL to indicate an error.
+ * i2c_unregister_device(); or an ERR_PTR to describe the error.
  */
-struct i2c_client *
-i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
+static struct i2c_client *
+i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 {
 	struct i2c_client	*client;
 	int			status;
 
 	client = kzalloc(sizeof *client, GFP_KERNEL);
 	if (!client)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	client->adapter = adap;
 
@@ -803,7 +803,31 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 		client->name, client->addr, status);
 out_err_silent:
 	kfree(client);
-	return NULL;
+	return ERR_PTR(status);
+}
+EXPORT_SYMBOL_GPL(i2c_new_client_device);
+
+/**
+ * i2c_new_device - instantiate an i2c device
+ * @adap: the adapter managing the device
+ * @info: describes one I2C device; bus_num is ignored
+ * Context: can sleep
+ *
+ * This deprecated function has the same functionality as
+ * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
+ * an error for compatibility with current I2C API. It will be removed once all
+ * users are converted.
+ *
+ * This returns the new i2c client, which may be saved for later use with
+ * i2c_unregister_device(); or NULL to indicate an error.
+ */
+struct i2c_client *
+i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
+{
+	struct i2c_client *ret;
+
+	ret = i2c_new_client_device(adap, info);
+	return IS_ERR(ret) ? NULL : ret;
 }
 EXPORT_SYMBOL_GPL(i2c_new_device);
 
@@ -854,7 +878,7 @@ static struct i2c_driver dummy_driver = {
 };
 
 /**
- * i2c_new_dummy - return a new i2c device bound to a dummy driver
+ * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
  * @adapter: the adapter managing the device
  * @address: seven bit address to be used
  * Context: can sleep
@@ -869,18 +893,86 @@ static struct i2c_driver dummy_driver = {
  * different driver.
  *
  * This returns the new i2c client, which should be saved for later use with
- * i2c_unregister_device(); or NULL to indicate an error.
+ * i2c_unregister_device(); or an ERR_PTR to describe the error.
  */
-struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
+static struct i2c_client *
+i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
 {
 	struct i2c_board_info info = {
 		I2C_BOARD_INFO("dummy", address),
 	};
 
-	return i2c_new_device(adapter, &info);
+	return i2c_new_client_device(adapter, &info);
+}
+EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
+
+/**
+ * i2c_new_dummy - return a new i2c device bound to a dummy driver
+ * @adapter: the adapter managing the device
+ * @address: seven bit address to be used
+ * Context: can sleep
+ *
+ * This deprecated function has the same functionality as @i2c_new_dummy_device,
+ * it just returns NULL instead of an ERR_PTR in case of an error for
+ * compatibility with current I2C API. It will be removed once all users are
+ * converted.
+ *
+ * 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_dummy(struct i2c_adapter *adapter, u16 address)
+{
+	struct i2c_client *ret;
+
+	ret = i2c_new_dummy_device(adapter, address);
+	return IS_ERR(ret) ? NULL : ret;
 }
 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 
+struct i2c_dummy_devres {
+	struct i2c_client *client;
+};
+
+static void devm_i2c_release_dummy(struct device *dev, void *res)
+{
+	struct i2c_dummy_devres *this = res;
+
+	i2c_unregister_device(this->client);
+}
+
+/**
+ * devm_i2c_new_dummy_device - 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_device. It returns the
+ * new i2c client or an ERR_PTR in case of an error.
+ */
+struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
+					     struct i2c_adapter *adapter,
+					     u16 address)
+{
+	struct i2c_dummy_devres *dr;
+	struct i2c_client *client;
+
+	dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return ERR_PTR(-ENOMEM);
+
+	client = i2c_new_dummy_device(adapter, address);
+	if (IS_ERR(client)) {
+		devres_free(dr);
+	} else {
+		dr->client = client;
+		devres_add(dev, dr);
+	}
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
+
 /**
  * i2c_new_secondary_device - Helper to get the instantiated secondary address
  * and create the associated device
@@ -1000,9 +1092,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 		info.flags |= I2C_CLIENT_SLAVE;
 	}
 
-	client = i2c_new_device(adap, &info);
-	if (!client)
-		return -EINVAL;
+	client = i2c_new_client_device(adap, &info);
+	if (IS_ERR(client))
+		return PTR_ERR(client);
 
 	/* Keep track of the added device */
 	mutex_lock(&adap->userspace_clients_lock);

include/linux/i2c.h

@@ -469,6 +469,9 @@ 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_device(struct device *dev, struct i2c_adapter *adap, u16 address);
+
 extern struct i2c_client *
 i2c_new_secondary_device(struct i2c_client *client,
 				const char *name,