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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
d1dbd82e TB |
2 | /* |
3 | * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip | |
4 | * | |
5 | * Copyright (C) 2000 Silicon Graphics, Inc. | |
6 | * Written by Ulf Carlsson (ulfc@engr.sgi.com) | |
7 | * | |
8 | * Copyright (C) 2008 Thomas Bogendoerfer | |
9 | * | |
10 | * Based on code written by Paul Gortmaker. | |
d1dbd82e TB |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/rtc.h> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
d1dbd82e TB |
16 | #include <linux/platform_device.h> |
17 | #include <linux/bcd.h> | |
d7a6119f | 18 | #include <linux/io.h> |
8ff7b7d9 | 19 | #include <linux/err.h> |
d1dbd82e | 20 | |
d1dbd82e TB |
21 | struct m48t35_rtc { |
22 | u8 pad[0x7ff8]; /* starts at 0x7ff8 */ | |
10cf8300 TB |
23 | #ifdef CONFIG_SGI_IP27 |
24 | u8 hour; | |
25 | u8 min; | |
26 | u8 sec; | |
27 | u8 control; | |
28 | u8 year; | |
29 | u8 month; | |
30 | u8 date; | |
31 | u8 day; | |
32 | #else | |
d1dbd82e TB |
33 | u8 control; |
34 | u8 sec; | |
35 | u8 min; | |
36 | u8 hour; | |
37 | u8 day; | |
38 | u8 date; | |
39 | u8 month; | |
40 | u8 year; | |
10cf8300 | 41 | #endif |
d1dbd82e TB |
42 | }; |
43 | ||
44 | #define M48T35_RTC_SET 0x80 | |
45 | #define M48T35_RTC_READ 0x40 | |
46 | ||
47 | struct m48t35_priv { | |
48 | struct rtc_device *rtc; | |
49 | struct m48t35_rtc __iomem *reg; | |
50 | size_t size; | |
51 | unsigned long baseaddr; | |
52 | spinlock_t lock; | |
53 | }; | |
54 | ||
55 | static int m48t35_read_time(struct device *dev, struct rtc_time *tm) | |
56 | { | |
57 | struct m48t35_priv *priv = dev_get_drvdata(dev); | |
58 | u8 control; | |
59 | ||
60 | /* | |
61 | * Only the values that we read from the RTC are set. We leave | |
62 | * tm_wday, tm_yday and tm_isdst untouched. Even though the | |
63 | * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated | |
64 | * by the RTC when initially set to a non-zero value. | |
65 | */ | |
66 | spin_lock_irq(&priv->lock); | |
67 | control = readb(&priv->reg->control); | |
68 | writeb(control | M48T35_RTC_READ, &priv->reg->control); | |
69 | tm->tm_sec = readb(&priv->reg->sec); | |
70 | tm->tm_min = readb(&priv->reg->min); | |
71 | tm->tm_hour = readb(&priv->reg->hour); | |
72 | tm->tm_mday = readb(&priv->reg->date); | |
73 | tm->tm_mon = readb(&priv->reg->month); | |
74 | tm->tm_year = readb(&priv->reg->year); | |
75 | writeb(control, &priv->reg->control); | |
76 | spin_unlock_irq(&priv->lock); | |
77 | ||
78 | tm->tm_sec = bcd2bin(tm->tm_sec); | |
79 | tm->tm_min = bcd2bin(tm->tm_min); | |
80 | tm->tm_hour = bcd2bin(tm->tm_hour); | |
81 | tm->tm_mday = bcd2bin(tm->tm_mday); | |
82 | tm->tm_mon = bcd2bin(tm->tm_mon); | |
83 | tm->tm_year = bcd2bin(tm->tm_year); | |
84 | ||
85 | /* | |
86 | * Account for differences between how the RTC uses the values | |
87 | * and how they are defined in a struct rtc_time; | |
88 | */ | |
89 | tm->tm_year += 70; | |
90 | if (tm->tm_year <= 69) | |
91 | tm->tm_year += 100; | |
92 | ||
93 | tm->tm_mon--; | |
22652ba7 | 94 | return 0; |
d1dbd82e TB |
95 | } |
96 | ||
97 | static int m48t35_set_time(struct device *dev, struct rtc_time *tm) | |
98 | { | |
99 | struct m48t35_priv *priv = dev_get_drvdata(dev); | |
100 | unsigned char mon, day, hrs, min, sec; | |
101 | unsigned int yrs; | |
102 | u8 control; | |
103 | ||
104 | yrs = tm->tm_year + 1900; | |
105 | mon = tm->tm_mon + 1; /* tm_mon starts at zero */ | |
106 | day = tm->tm_mday; | |
107 | hrs = tm->tm_hour; | |
108 | min = tm->tm_min; | |
109 | sec = tm->tm_sec; | |
110 | ||
111 | if (yrs < 1970) | |
112 | return -EINVAL; | |
113 | ||
114 | yrs -= 1970; | |
115 | if (yrs > 255) /* They are unsigned */ | |
116 | return -EINVAL; | |
117 | ||
118 | if (yrs > 169) | |
119 | return -EINVAL; | |
120 | ||
121 | if (yrs >= 100) | |
122 | yrs -= 100; | |
123 | ||
124 | sec = bin2bcd(sec); | |
125 | min = bin2bcd(min); | |
126 | hrs = bin2bcd(hrs); | |
127 | day = bin2bcd(day); | |
128 | mon = bin2bcd(mon); | |
129 | yrs = bin2bcd(yrs); | |
130 | ||
131 | spin_lock_irq(&priv->lock); | |
132 | control = readb(&priv->reg->control); | |
133 | writeb(control | M48T35_RTC_SET, &priv->reg->control); | |
134 | writeb(yrs, &priv->reg->year); | |
135 | writeb(mon, &priv->reg->month); | |
136 | writeb(day, &priv->reg->date); | |
137 | writeb(hrs, &priv->reg->hour); | |
138 | writeb(min, &priv->reg->min); | |
139 | writeb(sec, &priv->reg->sec); | |
140 | writeb(control, &priv->reg->control); | |
141 | spin_unlock_irq(&priv->lock); | |
142 | return 0; | |
143 | } | |
144 | ||
145 | static const struct rtc_class_ops m48t35_ops = { | |
146 | .read_time = m48t35_read_time, | |
147 | .set_time = m48t35_set_time, | |
148 | }; | |
149 | ||
5a167f45 | 150 | static int m48t35_probe(struct platform_device *pdev) |
d1dbd82e | 151 | { |
d1dbd82e TB |
152 | struct resource *res; |
153 | struct m48t35_priv *priv; | |
d1dbd82e TB |
154 | |
155 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
156 | if (!res) | |
157 | return -ENODEV; | |
4f58cd9b | 158 | priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL); |
d1dbd82e TB |
159 | if (!priv) |
160 | return -ENOMEM; | |
161 | ||
28f65c11 | 162 | priv->size = resource_size(res); |
4f58cd9b SK |
163 | if (!devm_request_mem_region(&pdev->dev, res->start, priv->size, |
164 | pdev->name)) | |
165 | return -EBUSY; | |
eac1c3fc | 166 | |
d1dbd82e | 167 | priv->baseaddr = res->start; |
4f58cd9b SK |
168 | priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size); |
169 | if (!priv->reg) | |
170 | return -ENOMEM; | |
b74d2caa | 171 | |
d1dbd82e | 172 | spin_lock_init(&priv->lock); |
b74d2caa AZ |
173 | |
174 | platform_set_drvdata(pdev, priv); | |
175 | ||
4f58cd9b | 176 | priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35", |
d1dbd82e | 177 | &m48t35_ops, THIS_MODULE); |
dac30a98 | 178 | return PTR_ERR_OR_ZERO(priv->rtc); |
d1dbd82e TB |
179 | } |
180 | ||
d1dbd82e TB |
181 | static struct platform_driver m48t35_platform_driver = { |
182 | .driver = { | |
183 | .name = "rtc-m48t35", | |
d1dbd82e TB |
184 | }, |
185 | .probe = m48t35_probe, | |
d1dbd82e TB |
186 | }; |
187 | ||
0c4eae66 | 188 | module_platform_driver(m48t35_platform_driver); |
d1dbd82e TB |
189 | |
190 | MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); | |
191 | MODULE_DESCRIPTION("M48T35 RTC driver"); | |
192 | MODULE_LICENSE("GPL"); | |
d1dbd82e | 193 | MODULE_ALIAS("platform:rtc-m48t35"); |