tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * ACPI I2C enumeration support
3 *
4 * Copyright (C) 2012, Intel Corporation
5 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/acpi.h>
13#include <linux/device.h>
14#include <linux/export.h>
15#include <linux/i2c.h>
16#include <linux/ioport.h>
17
18ACPI_MODULE_NAME("i2c");
19
20static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
21{
22 struct i2c_board_info *info = data;
23
24 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
25 struct acpi_resource_i2c_serialbus *sb;
26
27 sb = &ares->data.i2c_serial_bus;
28 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
29 info->addr = sb->slave_address;
30 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
31 info->flags |= I2C_CLIENT_TEN;
32 }
33 } else if (info->irq < 0) {
34 struct resource r;
35
36 if (acpi_dev_resource_interrupt(ares, 0, &r))
37 info->irq = r.start;
38 }
39
40 /* Tell the ACPI core to skip this resource */
41 return 1;
42}
43
44static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
45 void *data, void **return_value)
46{
47 struct i2c_adapter *adapter = data;
48 struct list_head resource_list;
49 struct i2c_board_info info;
50 struct acpi_device *adev;
51 int ret;
52
53 if (acpi_bus_get_device(handle, &adev))
54 return AE_OK;
55 if (acpi_bus_get_status(adev) || !adev->status.present)
56 return AE_OK;
57
58 memset(&info, 0, sizeof(info));
59 info.acpi_node.handle = handle;
60 info.irq = -1;
61
62 INIT_LIST_HEAD(&resource_list);
63 ret = acpi_dev_get_resources(adev, &resource_list,
64 acpi_i2c_add_resource, &info);
65 acpi_dev_free_resource_list(&resource_list);
66
67 if (ret < 0 || !info.addr)
68 return AE_OK;
69
70 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
71 if (!i2c_new_device(adapter, &info)) {
72 dev_err(&adapter->dev,
73 "failed to add I2C device %s from ACPI\n",
74 dev_name(&adev->dev));
75 }
76
77 return AE_OK;
78}
79
80/**
81 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
82 * @adapter: pointer to adapter
83 *
84 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
85 * namespace. When a device is found it will be added to the Linux device
86 * model and bound to the corresponding ACPI handle.
87 */
88void acpi_i2c_register_devices(struct i2c_adapter *adapter)
89{
90 acpi_handle handle;
91 acpi_status status;
92
93 handle = ACPI_HANDLE(adapter->dev.parent);
94 if (!handle)
95 return;
96
97 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
98 acpi_i2c_add_device, NULL,
99 adapter, NULL);
100 if (ACPI_FAILURE(status))
101 dev_warn(&adapter->dev, "failed to enumerate I2C slaves\n");
102}
103EXPORT_SYMBOL_GPL(acpi_i2c_register_devices);