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
16MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
17MODULE_DESCRIPTION("TI BQ4802 RTC driver");
18MODULE_LICENSE("GPL");
19
20struct 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
30static u8 bq4802_read_io(struct bq4802 *p, int off)
31{
32	return inb(p->ioport + off);
33}
34
35static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
36{
37	outb(val, p->ioport + off);
38}
39
40static u8 bq4802_read_mem(struct bq4802 *p, int off)
41{
42	return readb(p->regs + off);
43}
44
45static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
46{
47	writeb(val, p->regs + off);
48}
49
50static 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
92static 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
137static const struct rtc_class_ops bq4802_ops = {
138	.read_time	= bq4802_read_time,
139	.set_time	= bq4802_set_time,
140};
141
142static 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;
187out:
188	return err;
189
190}
191
192/* work with hotplug and coldplug */
193MODULE_ALIAS("platform:rtc-bq4802");
194
195static struct platform_driver bq4802_driver = {
196	.driver		= {
197		.name	= "rtc-bq4802",
198	},
199	.probe		= bq4802_probe,
200};
201
202module_platform_driver(bq4802_driver);
203