[PATCH 1/3] i2c: core: add managed function for adding i2c adapters

[Yicong Yang <yangyicong@xxxxxxxxxxxxx>]

Some I2C controller drivers will only unregister the I2C
adapter in their .remove() callback, which can be done
by simply using a managed variant to add the I2C adapter.

So add the managed functions for adding the I2C adapter.

Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
---
 drivers/i2c/i2c-core-base.c | 39 +++++++++++++++++++++++++++++++++++++++
 include/linux/i2c.h         |  1 +
 2 files changed, 40 insertions(+)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 63ebf72..61486dc 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1550,6 +1550,38 @@ int i2c_add_adapter(struct i2c_adapter *adapter)
 }
 EXPORT_SYMBOL(i2c_add_adapter);
 
+static void devm_i2c_del_adapter(struct device *dev, void *ptr);
+
+/**
+ * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
+ * @dev: managing device for adding this I2C adapter
+ * @adapter: the adapter to add
+ * Context: can sleep
+ *
+ * Add adapter with dynamic bus number, same with i2c_add_adapter()
+ * but the adapter will be auto deleted on driver detach.
+ */
+int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
+{
+	struct i2c_adapter **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_i2c_del_adapter, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = i2c_add_adapter(adapter);
+	if (!ret) {
+		*ptr = adapter;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_i2c_add_adapter);
+
 /**
  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
  * @adap: the adapter to register (with adap->nr initialized)
@@ -1703,6 +1735,13 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 }
 EXPORT_SYMBOL(i2c_del_adapter);
 
+static void devm_i2c_del_adapter(struct device *dev, void *ptr)
+{
+	struct i2c_adapter *adapter = *((struct i2c_adapter **)ptr);
+
+	i2c_del_adapter(adapter);
+}
+
 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
 			    u32 def_val, bool use_def)
 {
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 5662265..10bd0b0 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -844,6 +844,7 @@ static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap)
  */
 #if IS_ENABLED(CONFIG_I2C)
 int i2c_add_adapter(struct i2c_adapter *adap);
+int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter);
 void i2c_del_adapter(struct i2c_adapter *adap);
 int i2c_add_numbered_adapter(struct i2c_adapter *adap);
 
-- 
2.8.1