xref: /openbmc/linux/drivers/rtc/rtc-bq4802.c (revision 2cf1c348)
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 
30 static u8 bq4802_read_io(struct bq4802 *p, int off)
31 {
32 	return inb(p->ioport + off);
33 }
34 
35 static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
36 {
37 	outb(val, p->ioport + off);
38 }
39 
40 static u8 bq4802_read_mem(struct bq4802 *p, int off)
41 {
42 	return readb(p->regs + off);
43 }
44 
45 static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
46 {
47 	writeb(val, p->regs + off);
48 }
49 
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 
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 
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