tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
23ACPI_MODULE_NAME("cmos rtc");
24
25static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
26 { "PNP0B00" },
27 { "PNP0B01" },
28 { "PNP0B02" },
29 {}
30};
31
32static acpi_status
33acpi_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
59static 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
76static 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
83static 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
89void __init acpi_cmos_rtc_init(void)
90{
91 acpi_scan_add_handler(&cmos_rtc_handler);
92}