Commit | Line | Data |
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2fa97feb LT |
1 | /* |
2 | * ACPI support for CMOS RTC Address Space access | |
3 | * | |
4 | * Copyright (C) 2013, Intel Corporation | |
5 | * Authors: Lan Tianyu <tianyu.lan@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/err.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <asm-generic/rtc.h> | |
18 | ||
19 | #include "internal.h" | |
20 | ||
21 | #define PREFIX "ACPI: " | |
22 | ||
23 | ACPI_MODULE_NAME("cmos rtc"); | |
24 | ||
25 | static const struct acpi_device_id acpi_cmos_rtc_ids[] = { | |
26 | { "PNP0B00" }, | |
27 | { "PNP0B01" }, | |
28 | { "PNP0B02" }, | |
29 | {} | |
30 | }; | |
31 | ||
32 | static acpi_status | |
33 | acpi_cmos_rtc_space_handler(u32 function, acpi_physical_address address, | |
34 | u32 bits, u64 *value64, | |
35 | void *handler_context, void *region_context) | |
36 | { | |
37 | int i; | |
38 | u8 *value = (u8 *)&value64; | |
39 | ||
40 | if (address > 0xff || !value64) | |
41 | return AE_BAD_PARAMETER; | |
42 | ||
43 | if (function != ACPI_WRITE && function != ACPI_READ) | |
44 | return AE_BAD_PARAMETER; | |
45 | ||
46 | spin_lock_irq(&rtc_lock); | |
47 | ||
48 | for (i = 0; i < DIV_ROUND_UP(bits, 8); ++i, ++address, ++value) | |
49 | if (function == ACPI_READ) | |
50 | *value = CMOS_READ(address); | |
51 | else | |
52 | CMOS_WRITE(*value, address); | |
53 | ||
54 | spin_unlock_irq(&rtc_lock); | |
55 | ||
56 | return AE_OK; | |
57 | } | |
58 | ||
59 | static int acpi_install_cmos_rtc_space_handler(struct acpi_device *adev, | |
60 | const struct acpi_device_id *id) | |
61 | { | |
62 | acpi_status status; | |
63 | ||
64 | status = acpi_install_address_space_handler(adev->handle, | |
65 | ACPI_ADR_SPACE_CMOS, | |
66 | &acpi_cmos_rtc_space_handler, | |
67 | NULL, NULL); | |
68 | if (ACPI_FAILURE(status)) { | |
69 | pr_err(PREFIX "Error installing CMOS-RTC region handler\n"); | |
70 | return -ENODEV; | |
71 | } | |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
76 | static void acpi_remove_cmos_rtc_space_handler(struct acpi_device *adev) | |
77 | { | |
78 | if (ACPI_FAILURE(acpi_remove_address_space_handler(adev->handle, | |
79 | ACPI_ADR_SPACE_CMOS, &acpi_cmos_rtc_space_handler))) | |
80 | pr_err(PREFIX "Error removing CMOS-RTC region handler\n"); | |
81 | } | |
82 | ||
83 | static struct acpi_scan_handler cmos_rtc_handler = { | |
84 | .ids = acpi_cmos_rtc_ids, | |
85 | .attach = acpi_install_cmos_rtc_space_handler, | |
86 | .detach = acpi_remove_cmos_rtc_space_handler, | |
87 | }; | |
88 | ||
89 | void __init acpi_cmos_rtc_init(void) | |
90 | { | |
91 | acpi_scan_add_handler(&cmos_rtc_handler); | |
92 | } |