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>

4 files changed, 107 insertions, 97 deletions

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 7b7ea320a258..3e3b680dc007 100644
--- a/drivers/i2c/Kconfig
+++ b/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
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 80db3073aa84..a1f590cbb435 100644
--- a/drivers/i2c/Makefile
+++ b/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
diff --git a/drivers/i2c/i2c-acpi.c b/drivers/i2c/i2c-acpi.c
index f7f4c89c09b3..e8b61967334b 100644
--- a/drivers/i2c/i2c-acpi.c
+++ b/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)
 {
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index e25cb84cb297..4ccff114b147 100644
--- a/drivers/i2c/i2c-core.c
+++ b/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)
 {