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path: root/drivers/acpi/acpi_i2c.c
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Diffstat (limited to 'drivers/acpi/acpi_i2c.c')
-rw-r--r--drivers/acpi/acpi_i2c.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_i2c.c b/drivers/acpi/acpi_i2c.c
new file mode 100644
index 000000000000..82045e3f5cac
--- /dev/null
+++ b/drivers/acpi/acpi_i2c.c
@@ -0,0 +1,103 @@
+/*
+ * 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);
+ 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);