1 // SPDX-License-Identifier: GPL-2.0-only
2 /* rtc-bq4802.c: TI BQ4802 RTC driver.
3 *
4 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/io.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
13 #include <linux/bcd.h>
14 #include <linux/slab.h>
15
16 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
17 MODULE_DESCRIPTION("TI BQ4802 RTC driver");
18 MODULE_LICENSE("GPL");
19
20 struct bq4802 {
21 void __iomem *regs;
22 unsigned long ioport;
23 struct rtc_device *rtc;
24 spinlock_t lock;
25 struct resource *r;
26 u8 (*read)(struct bq4802 *, int);
27 void (*write)(struct bq4802 *, int, u8);
28 };
29
bq4802_read_io(struct bq4802 * p,int off)30 static u8 bq4802_read_io(struct bq4802 *p, int off)
31 {
32 return inb(p->ioport + off);
33 }
34
bq4802_write_io(struct bq4802 * p,int off,u8 val)35 static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
36 {
37 outb(val, p->ioport + off);
38 }
39
bq4802_read_mem(struct bq4802 * p,int off)40 static u8 bq4802_read_mem(struct bq4802 *p, int off)
41 {
42 return readb(p->regs + off);
43 }
44
bq4802_write_mem(struct bq4802 * p,int off,u8 val)45 static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
46 {
47 writeb(val, p->regs + off);
48 }
49
bq4802_read_time(struct device * dev,struct rtc_time * tm)50 static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
51 {
52 struct bq4802 *p = dev_get_drvdata(dev);
53 unsigned long flags;
54 unsigned int century;
55 u8 val;
56
57 spin_lock_irqsave(&p->lock, flags);
58
59 val = p->read(p, 0x0e);
60 p->write(p, 0xe, val | 0x08);
61
62 tm->tm_sec = p->read(p, 0x00);
63 tm->tm_min = p->read(p, 0x02);
64 tm->tm_hour = p->read(p, 0x04);
65 tm->tm_mday = p->read(p, 0x06);
66 tm->tm_mon = p->read(p, 0x09);
67 tm->tm_year = p->read(p, 0x0a);
68 tm->tm_wday = p->read(p, 0x08);
69 century = p->read(p, 0x0f);
70
71 p->write(p, 0x0e, val);
72
73 spin_unlock_irqrestore(&p->lock, flags);
74
75 tm->tm_sec = bcd2bin(tm->tm_sec);
76 tm->tm_min = bcd2bin(tm->tm_min);
77 tm->tm_hour = bcd2bin(tm->tm_hour);
78 tm->tm_mday = bcd2bin(tm->tm_mday);
79 tm->tm_mon = bcd2bin(tm->tm_mon);
80 tm->tm_year = bcd2bin(tm->tm_year);
81 tm->tm_wday = bcd2bin(tm->tm_wday);
82 century = bcd2bin(century);
83
84 tm->tm_year += (century * 100);
85 tm->tm_year -= 1900;
86
87 tm->tm_mon--;
88
89 return 0;
90 }
91
bq4802_set_time(struct device * dev,struct rtc_time * tm)92 static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
93 {
94 struct bq4802 *p = dev_get_drvdata(dev);
95 u8 sec, min, hrs, day, mon, yrs, century, val;
96 unsigned long flags;
97 unsigned int year;
98
99 year = tm->tm_year + 1900;
100 century = year / 100;
101 yrs = year % 100;
102
103 mon = tm->tm_mon + 1; /* tm_mon starts at zero */
104 day = tm->tm_mday;
105 hrs = tm->tm_hour;
106 min = tm->tm_min;
107 sec = tm->tm_sec;
108
109 sec = bin2bcd(sec);
110 min = bin2bcd(min);
111 hrs = bin2bcd(hrs);
112 day = bin2bcd(day);
113 mon = bin2bcd(mon);
114 yrs = bin2bcd(yrs);
115 century = bin2bcd(century);
116
117 spin_lock_irqsave(&p->lock, flags);
118
119 val = p->read(p, 0x0e);
120 p->write(p, 0x0e, val | 0x08);
121
122 p->write(p, 0x00, sec);
123 p->write(p, 0x02, min);
124 p->write(p, 0x04, hrs);
125 p->write(p, 0x06, day);
126 p->write(p, 0x09, mon);
127 p->write(p, 0x0a, yrs);
128 p->write(p, 0x0f, century);
129
130 p->write(p, 0x0e, val);
131
132 spin_unlock_irqrestore(&p->lock, flags);
133
134 return 0;
135 }
136
137 static const struct rtc_class_ops bq4802_ops = {
138 .read_time = bq4802_read_time,
139 .set_time = bq4802_set_time,
140 };
141
bq4802_probe(struct platform_device * pdev)142 static int bq4802_probe(struct platform_device *pdev)
143 {
144 struct bq4802 *p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
145 int err = -ENOMEM;
146
147 if (!p)
148 goto out;
149
150 spin_lock_init(&p->lock);
151
152 p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
153 if (!p->r) {
154 p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
155 err = -EINVAL;
156 if (!p->r)
157 goto out;
158 }
159 if (p->r->flags & IORESOURCE_IO) {
160 p->ioport = p->r->start;
161 p->read = bq4802_read_io;
162 p->write = bq4802_write_io;
163 } else if (p->r->flags & IORESOURCE_MEM) {
164 p->regs = devm_ioremap(&pdev->dev, p->r->start,
165 resource_size(p->r));
166 if (!p->regs){
167 err = -ENOMEM;
168 goto out;
169 }
170 p->read = bq4802_read_mem;
171 p->write = bq4802_write_mem;
172 } else {
173 err = -EINVAL;
174 goto out;
175 }
176
177 platform_set_drvdata(pdev, p);
178
179 p->rtc = devm_rtc_device_register(&pdev->dev, "bq4802",
180 &bq4802_ops, THIS_MODULE);
181 if (IS_ERR(p->rtc)) {
182 err = PTR_ERR(p->rtc);
183 goto out;
184 }
185
186 err = 0;
187 out:
188 return err;
189
190 }
191
192 /* work with hotplug and coldplug */
193 MODULE_ALIAS("platform:rtc-bq4802");
194
195 static struct platform_driver bq4802_driver = {
196 .driver = {
197 .name = "rtc-bq4802",
198 },
199 .probe = bq4802_probe,
200 };
201
202 module_platform_driver(bq4802_driver);
203