i2c: move ACPI helpers into the core

This follows what has already been done for the DeviceTree helpers. Move
the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update
documentation accordingly.

This also solves a problem reported by Jerry Snitselaar that we can't build
the ACPI I2C helpers as a module.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

7 files changed, 94 insertions, 129 deletions

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index 958266efcc20..d977778b5e67 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -228,18 +228,9 @@ ACPI handle like:
 I2C serial bus support
 ~~~~~~~~~~~~~~~~~~~~~~
 The slaves behind I2C bus controller only need to add the ACPI IDs like
-with the platform and SPI drivers. However the I2C bus controller driver
-needs to call acpi_i2c_register_devices() after it has added the adapter.
-
-An I2C bus (controller) driver does:
-
-        ...
-        ret = i2c_add_numbered_adapter(adapter);
-        if (ret)
-                /* handle error */
-
-        /* Enumerate the slave devices behind this bus via ACPI */
-        acpi_i2c_register_devices(adapter);
+with the platform and SPI drivers. The I2C core automatically enumerates
+any slave devices behind the controller device once the adapter is
+registered.
 
 Below is an example of how to add ACPI support to the existing mpu3050
 input driver:
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 100bd724f648..4e0162fa5d36 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -180,12 +180,6 @@ config ACPI_DOCK
           This driver supports ACPI-controlled docking stations and removable
           drive bays such as the IBM Ultrabay and the Dell Module Bay.
 
-config ACPI_I2C
-        def_tristate I2C
-        depends on I2C
-        help
-          ACPI I2C enumeration support.
-
 config ACPI_PROCESSOR
         tristate "Processor"
         select THERMAL
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 81dbeb83bb45..cdaf68b58b00 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -73,7 +73,6 @@ obj-$(CONFIG_ACPI_HED)		+= hed.o
 obj-$(CONFIG_ACPI_EC_DEBUGFS)   += ec_sys.o
 obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
 obj-$(CONFIG_ACPI_BGRT)         += bgrt.o
-obj-$(CONFIG_ACPI_I2C)          += acpi_i2c.o
 
 # processor has its own "processor." module_param namespace
 processor-y                     := processor_driver.o processor_throttling.o
diff --git a/drivers/acpi/acpi_i2c.c b/drivers/acpi/acpi_i2c.c
deleted file mode 100644
index a82c7626aa9b..000000000000
--- a/drivers/acpi/acpi_i2c.c
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
- * ACPI I2C enumeration support
- *
- * Copyright (C) 2012, Intel Corporation
- * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/acpi.h>
-#include <linux/device.h>
-#include <linux/export.h>
-#include <linux/i2c.h>
-#include <linux/ioport.h>
-
-ACPI_MODULE_NAME("i2c");
-
-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.handle = handle;
-        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;
-
-        strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
-        if (!i2c_new_device(adapter, &info)) {
-                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
- * @adapter: 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 *adapter)
-{
-        acpi_handle handle;
-        acpi_status status;
-
-        handle = ACPI_HANDLE(adapter->dev.parent);
-        if (!handle)
-                return;
-
-        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-                                     acpi_i2c_add_device, NULL,
-                                     adapter, NULL);
-        if (ACPI_FAILURE(status))
-                dev_warn(&adapter->dev, "failed to enumerate I2C slaves\n");
-}
-EXPORT_SYMBOL_GPL(acpi_i2c_register_devices);
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index ded77c3bd59c..6e99d9f56dee 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -171,7 +171,6 @@ static int dw_i2c_probe(struct platform_device *pdev)
                 dev_err(&pdev->dev, "failure adding adapter\n");
                 return r;
         }
-        acpi_i2c_register_devices(adap);
 
         pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
         pm_runtime_use_autosuspend(&pdev->dev);
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index e874b052b4f8..29d3f045a2bf 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1058,6 +1058,96 @@ 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.handle = handle;
+        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;
+
+        strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
+        if (!i2c_new_device(adapter, &info)) {
+                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;
+
+        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)
 {
@@ -1163,6 +1253,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 exit_recovery:
         /* create pre-declared device nodes */
         of_i2c_register_devices(adap);
+        acpi_i2c_register_devices(adap);
 
         if (adap->nr < __i2c_first_dynamic_bus_num)
                 i2c_scan_static_board_info(adap);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index ed53696e31a6..2ab11dc38077 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -564,10 +564,4 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node
 }
 #endif /* CONFIG_OF */
 
-#if IS_ENABLED(CONFIG_ACPI_I2C)
-extern void acpi_i2c_register_devices(struct i2c_adapter *adap);
-#else
-static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
-#endif
-
 #endif /* _LINUX_I2C_H */