I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI config

Clean up ACPI related code in the i2c core and add CONFIG_I2C_ACPI
to enable I2C ACPI code.

Current there is a race between removing I2C ACPI operation region
and ACPI AML code accessing. So make i2c core built-in if CONFIG_I2C_ACPI
is set.
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/Kconfig

@@ -2,7 +2,9 @@
 # I2C subsystem configuration
 #
 
-menuconfig I2C
+menu "I2C support"
+
+config I2C
 	tristate "I2C support"
 	select RT_MUTEXES
 	---help---
@@ -21,6 +23,18 @@ menuconfig I2C
 	  This I2C support can also be built as a module.  If so, the module
 	  will be called i2c-core.
 
+config I2C_ACPI
+	bool "I2C ACPI support"
+	select I2C
+	depends on ACPI
+	default y
+	help
+	  Say Y here if you want to enable ACPI I2C support. This includes support
+	  for automatic enumeration of I2C slave devices and support for ACPI I2C
+	  Operation Regions. Operation Regions allow firmware (BIOS) code to
+	  access I2C slave devices, such as smart batteries through an I2C host
+	  controller driver.
+
 if I2C
 
 config I2C_BOARDINFO
@@ -124,3 +138,5 @@ config I2C_DEBUG_BUS
 	  on.
 
 endif # I2C
+
+endmenu

drivers/i2c/Makefile

@@ -3,7 +3,7 @@
 #
 
 i2ccore-y := i2c-core.o
-i2ccore-$(CONFIG_ACPI)		+= i2c-acpi.o
+i2ccore-$(CONFIG_I2C_ACPI)	+= i2c-acpi.o
 
 obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)		+= i2ccore.o

drivers/i2c/i2c-acpi.c

@@ -37,6 +37,95 @@ struct gsb_buffer {
 	};
 } __packed;
 
+static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
+{
+	struct i2c_board_info *info = data;
+
+	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
+		struct acpi_resource_i2c_serialbus *sb;
+
+		sb = &ares->data.i2c_serial_bus;
+		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
+			info->addr = sb->slave_address;
+			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+				info->flags |= I2C_CLIENT_TEN;
+		}
+	} else if (info->irq < 0) {
+		struct resource r;
+
+		if (acpi_dev_resource_interrupt(ares, 0, &r))
+			info->irq = r.start;
+	}
+
+	/* Tell the ACPI core to skip this resource */
+	return 1;
+}
+
+static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct i2c_adapter *adapter = data;
+	struct list_head resource_list;
+	struct i2c_board_info info;
+	struct acpi_device *adev;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present)
+		return AE_OK;
+
+	memset(&info, 0, sizeof(info));
+	info.acpi_node.companion = adev;
+	info.irq = -1;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     acpi_i2c_add_resource, &info);
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (ret < 0 || !info.addr)
+		return AE_OK;
+
+	adev->power.flags.ignore_parent = true;
+	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
+	if (!i2c_new_device(adapter, &info)) {
+		adev->power.flags.ignore_parent = false;
+		dev_err(&adapter->dev,
+			"failed to add I2C device %s from ACPI\n",
+			dev_name(&adev->dev));
+	}
+
+	return AE_OK;
+}
+
+/**
+ * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
+ * @adap: pointer to adapter
+ *
+ * Enumerate all I2C slave devices behind this adapter by walking the ACPI
+ * namespace. When a device is found it will be added to the Linux device
+ * model and bound to the corresponding ACPI handle.
+ */
+void acpi_i2c_register_devices(struct i2c_adapter *adap)
+{
+	acpi_handle handle;
+	acpi_status status;
+
+	if (!adap->dev.parent)
+		return;
+
+	handle = ACPI_HANDLE(adap->dev.parent);
+	if (!handle)
+		return;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+				     acpi_i2c_add_device, NULL,
+				     adap, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
+}
+
 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 		u8 cmd, u8 *data, u8 data_len)
 {

drivers/i2c/i2c-core.c

@@ -1092,101 +1092,6 @@ EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
 #endif /* CONFIG_OF */
 
-/* ACPI support code */
-
-#if IS_ENABLED(CONFIG_ACPI)
-static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
-{
-	struct i2c_board_info *info = data;
-
-	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
-		struct acpi_resource_i2c_serialbus *sb;
-
-		sb = &ares->data.i2c_serial_bus;
-		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
-			info->addr = sb->slave_address;
-			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
-				info->flags |= I2C_CLIENT_TEN;
-		}
-	} else if (info->irq < 0) {
-		struct resource r;
-
-		if (acpi_dev_resource_interrupt(ares, 0, &r))
-			info->irq = r.start;
-	}
-
-	/* Tell the ACPI core to skip this resource */
-	return 1;
-}
-
-static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
-				       void *data, void **return_value)
-{
-	struct i2c_adapter *adapter = data;
-	struct list_head resource_list;
-	struct i2c_board_info info;
-	struct acpi_device *adev;
-	int ret;
-
-	if (acpi_bus_get_device(handle, &adev))
-		return AE_OK;
-	if (acpi_bus_get_status(adev) || !adev->status.present)
-		return AE_OK;
-
-	memset(&info, 0, sizeof(info));
-	info.acpi_node.companion = adev;
-	info.irq = -1;
-
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list,
-				     acpi_i2c_add_resource, &info);
-	acpi_dev_free_resource_list(&resource_list);
-
-	if (ret < 0 || !info.addr)
-		return AE_OK;
-
-	adev->power.flags.ignore_parent = true;
-	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
-	if (!i2c_new_device(adapter, &info)) {
-		adev->power.flags.ignore_parent = false;
-		dev_err(&adapter->dev,
-			"failed to add I2C device %s from ACPI\n",
-			dev_name(&adev->dev));
-	}
-
-	return AE_OK;
-}
-
-/**
- * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
- * @adap: pointer to adapter
- *
- * Enumerate all I2C slave devices behind this adapter by walking the ACPI
- * namespace. When a device is found it will be added to the Linux device
- * model and bound to the corresponding ACPI handle.
- */
-static void acpi_i2c_register_devices(struct i2c_adapter *adap)
-{
-	acpi_handle handle;
-	acpi_status status;
-
-	if (!adap->dev.parent)
-		return;
-
-	handle = ACPI_HANDLE(adap->dev.parent);
-	if (!handle)
-		return;
-
-	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-				     acpi_i2c_add_device, NULL,
-				     adap, NULL);
-	if (ACPI_FAILURE(status))
-		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
-}
-#else
-static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
-#endif /* CONFIG_ACPI */
-
 static int i2c_do_add_adapter(struct i2c_driver *driver,
 			      struct i2c_adapter *adap)
 {

include/linux/i2c.h

@@ -577,10 +577,12 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node
 }
 #endif /* CONFIG_OF */
 
-#ifdef CONFIG_ACPI
+#ifdef CONFIG_I2C_ACPI
 int acpi_i2c_install_space_handler(struct i2c_adapter *adapter);
 void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter);
+void acpi_i2c_register_devices(struct i2c_adapter *adap);
 #else
+static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
 static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
 { }
 static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)