aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/acpi/acpi_cmos_rtc.c
blob: 84190ed89c04bb74f1a69d0c8d72fe23efbfacc2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
/*
 * ACPI support for CMOS RTC Address Space access
 *
 * Copyright (C) 2013, Intel Corporation
 * Authors: Lan Tianyu <tianyu.lan@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/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm-generic/rtc.h>

#include "internal.h"

#define PREFIX "ACPI: "

ACPI_MODULE_NAME("cmos rtc");

static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
	{ "PNP0B00" },
	{ "PNP0B01" },
	{ "PNP0B02" },
	{}
};

static acpi_status
acpi_cmos_rtc_space_handler(u32 function, acpi_physical_address address,
		      u32 bits, u64 *value64,
		      void *handler_context, void *region_context)
{
	int i;
	u8 *value = (u8 *)&value64;

	if (address > 0xff || !value64)
		return AE_BAD_PARAMETER;

	if (function != ACPI_WRITE && function != ACPI_READ)
		return AE_BAD_PARAMETER;

	spin_lock_irq(&rtc_lock);

	for (i = 0; i < DIV_ROUND_UP(bits, 8); ++i, ++address, ++value)
		if (function == ACPI_READ)
			*value = CMOS_READ(address);
		else
			CMOS_WRITE(*value, address);

	spin_unlock_irq(&rtc_lock);

	return AE_OK;
}

static int acpi_install_cmos_rtc_space_handler(struct acpi_device *adev,
		const struct acpi_device_id *id)
{
	acpi_status status;

	status = acpi_install_address_space_handler(adev->handle,
			ACPI_ADR_SPACE_CMOS,
			&acpi_cmos_rtc_space_handler,
			NULL, NULL);
	if (ACPI_FAILURE(status)) {
		pr_err(PREFIX "Error installing CMOS-RTC region handler\n");
		return -ENODEV;
	}

	return 0;
}

static void acpi_remove_cmos_rtc_space_handler(struct acpi_device *adev)
{
	if (ACPI_FAILURE(acpi_remove_address_space_handler(adev->handle,
			ACPI_ADR_SPACE_CMOS, &acpi_cmos_rtc_space_handler)))
		pr_err(PREFIX "Error removing CMOS-RTC region handler\n");
}

static struct acpi_scan_handler cmos_rtc_handler = {
	.ids = acpi_cmos_rtc_ids,
	.attach = acpi_install_cmos_rtc_space_handler,
	.detach = acpi_remove_cmos_rtc_space_handler,
};

void __init acpi_cmos_rtc_init(void)
{
	acpi_scan_add_handler(&cmos_rtc_handler);
}