clk: bcm: dvp: Add MODULE_DEVICE_TABLE()
[linux-2.6-microblaze.git] / drivers / rtc / rtc-m48t35.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
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.
11  */
12
13 #include <linux/module.h>
14 #include <linux/rtc.h>
15 #include <linux/slab.h>
16 #include <linux/platform_device.h>
17 #include <linux/bcd.h>
18 #include <linux/io.h>
19 #include <linux/err.h>
20
21 struct m48t35_rtc {
22         u8      pad[0x7ff8];    /* starts at 0x7ff8 */
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
33         u8      control;
34         u8      sec;
35         u8      min;
36         u8      hour;
37         u8      day;
38         u8      date;
39         u8      month;
40         u8      year;
41 #endif
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--;
94         return 0;
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
150 static int m48t35_probe(struct platform_device *pdev)
151 {
152         struct resource *res;
153         struct m48t35_priv *priv;
154
155         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
156         if (!res)
157                 return -ENODEV;
158         priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL);
159         if (!priv)
160                 return -ENOMEM;
161
162         priv->size = resource_size(res);
163         if (!devm_request_mem_region(&pdev->dev, res->start, priv->size,
164                                      pdev->name))
165                 return -EBUSY;
166
167         priv->baseaddr = res->start;
168         priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size);
169         if (!priv->reg)
170                 return -ENOMEM;
171
172         spin_lock_init(&priv->lock);
173
174         platform_set_drvdata(pdev, priv);
175
176         priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35",
177                                   &m48t35_ops, THIS_MODULE);
178         return PTR_ERR_OR_ZERO(priv->rtc);
179 }
180
181 static struct platform_driver m48t35_platform_driver = {
182         .driver         = {
183                 .name   = "rtc-m48t35",
184         },
185         .probe          = m48t35_probe,
186 };
187
188 module_platform_driver(m48t35_platform_driver);
189
190 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
191 MODULE_DESCRIPTION("M48T35 RTC driver");
192 MODULE_LICENSE("GPL");
193 MODULE_ALIAS("platform:rtc-m48t35");