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
39 static DEFINE_SPINLOCK(sh03_rtc_lock);
40
41 static 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
89 static 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
123 static int sh03_rtc_settimeofday(struct device *dev, struct rtc_time *tm)
124 {
125 return set_rtc_mmss(tm);
126 }
127
128 static const struct rtc_class_ops rtc_generic_ops = {
129 .read_time = sh03_rtc_gettimeofday,
130 .set_time = sh03_rtc_settimeofday,
131 };
132
133 static 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 }
143 arch_initcall(sh03_time_init);
144
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