1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/sh/boards/sh03/rtc.c -- CTP/PCI-SH03 on-chip RTC support
4 *
5 *  Copyright (C) 2004  Saito.K & Jeanne(ksaito@interface.co.jp)
6 *
7 */
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/sched.h>
12#include <linux/time.h>
13#include <linux/bcd.h>
14#include <linux/spinlock.h>
15#include <linux/io.h>
16#include <linux/rtc.h>
17#include <linux/platform_device.h>
18
19#define RTC_BASE	0xb0000000
20#define RTC_SEC1	(RTC_BASE + 0)
21#define RTC_SEC10	(RTC_BASE + 1)
22#define RTC_MIN1	(RTC_BASE + 2)
23#define RTC_MIN10	(RTC_BASE + 3)
24#define RTC_HOU1	(RTC_BASE + 4)
25#define RTC_HOU10	(RTC_BASE + 5)
26#define RTC_WEE1	(RTC_BASE + 6)
27#define RTC_DAY1	(RTC_BASE + 7)
28#define RTC_DAY10	(RTC_BASE + 8)
29#define RTC_MON1	(RTC_BASE + 9)
30#define RTC_MON10	(RTC_BASE + 10)
31#define RTC_YEA1	(RTC_BASE + 11)
32#define RTC_YEA10	(RTC_BASE + 12)
33#define RTC_YEA100	(RTC_BASE + 13)
34#define RTC_YEA1000	(RTC_BASE + 14)
35#define RTC_CTL		(RTC_BASE + 15)
36#define RTC_BUSY	1
37#define RTC_STOP	2
38
39static DEFINE_SPINLOCK(sh03_rtc_lock);
40
41static int sh03_rtc_gettimeofday(struct device *dev, struct rtc_time *tm)
42{
43	unsigned int year, mon, day, hour, min, sec;
44
45	spin_lock(&sh03_rtc_lock);
46 again:
47	do {
48		sec  = (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10;
49		min  = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
50		hour = (__raw_readb(RTC_HOU1) & 0xf) + (__raw_readb(RTC_HOU10) & 0xf) * 10;
51		day  = (__raw_readb(RTC_DAY1) & 0xf) + (__raw_readb(RTC_DAY10) & 0xf) * 10;
52		mon  = (__raw_readb(RTC_MON1) & 0xf) + (__raw_readb(RTC_MON10) & 0xf) * 10;
53		year = (__raw_readb(RTC_YEA1) & 0xf) + (__raw_readb(RTC_YEA10) & 0xf) * 10
54		     + (__raw_readb(RTC_YEA100 ) & 0xf) * 100
55		     + (__raw_readb(RTC_YEA1000) & 0xf) * 1000;
56	} while (sec != (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10);
57	if (year == 0 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
58	    hour > 23 || min > 59 || sec > 59) {
59		printk(KERN_ERR
60		       "SH-03 RTC: invalid value, resetting to 1 Jan 2000\n");
61		printk("year=%d, mon=%d, day=%d, hour=%d, min=%d, sec=%d\n",
62		       year, mon, day, hour, min, sec);
63
64		__raw_writeb(0, RTC_SEC1); __raw_writeb(0, RTC_SEC10);
65		__raw_writeb(0, RTC_MIN1); __raw_writeb(0, RTC_MIN10);
66		__raw_writeb(0, RTC_HOU1); __raw_writeb(0, RTC_HOU10);
67		__raw_writeb(6, RTC_WEE1);
68		__raw_writeb(1, RTC_DAY1); __raw_writeb(0, RTC_DAY10);
69		__raw_writeb(1, RTC_MON1); __raw_writeb(0, RTC_MON10);
70		__raw_writeb(0, RTC_YEA1); __raw_writeb(0, RTC_YEA10);
71		__raw_writeb(0, RTC_YEA100);
72		__raw_writeb(2, RTC_YEA1000);
73		__raw_writeb(0, RTC_CTL);
74		goto again;
75	}
76
77	spin_unlock(&sh03_rtc_lock);
78
79	tm->tm_sec  = sec;
80	tm->tm_min  = min;
81	tm->tm_hour = hour;
82	tm->tm_mday = day;
83	tm->tm_mon  = mon;
84	tm->tm_year = year - 1900;
85
86	return 0;
87}
88
89static int set_rtc_mmss(struct rtc_time *tm)
90{
91	int retval = 0;
92	int real_seconds, real_minutes, cmos_minutes;
93	int i;
94
95	/* gets recalled with irq locally disabled */
96	spin_lock(&sh03_rtc_lock);
97	for (i = 0 ; i < 1000000 ; i++)	/* may take up to 1 second... */
98		if (!(__raw_readb(RTC_CTL) & RTC_BUSY))
99			break;
100	cmos_minutes = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
101	real_seconds = tm->tm_sec;
102	real_minutes = tm->tm_min;
103	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
104		real_minutes += 30;		/* correct for half hour time zone */
105	real_minutes %= 60;
106
107	if (abs(real_minutes - cmos_minutes) < 30) {
108		__raw_writeb(real_seconds % 10, RTC_SEC1);
109		__raw_writeb(real_seconds / 10, RTC_SEC10);
110		__raw_writeb(real_minutes % 10, RTC_MIN1);
111		__raw_writeb(real_minutes / 10, RTC_MIN10);
112	} else {
113		printk_once(KERN_NOTICE
114		       "set_rtc_mmss: can't update from %d to %d\n",
115		       cmos_minutes, real_minutes);
116		retval = -EINVAL;
117	}
118	spin_unlock(&sh03_rtc_lock);
119
120	return retval;
121}
122
123int sh03_rtc_settimeofday(struct device *dev, struct rtc_time *tm)
124{
125	return set_rtc_mmss(tm);
126}
127
128static const struct rtc_class_ops rtc_generic_ops = {
129	.read_time = sh03_rtc_gettimeofday,
130	.set_time = sh03_rtc_settimeofday,
131};
132
133static int __init sh03_time_init(void)
134{
135	struct platform_device *pdev;
136
137	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
138					     &rtc_generic_ops,
139					     sizeof(rtc_generic_ops));
140
141	return PTR_ERR_OR_ZERO(pdev);
142}
143arch_initcall(sh03_time_init);
144