tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * An rtc/i2c driver for the EM Microelectronic EM3027
3 * Copyright 2011 CompuLab, Ltd.
4 *
5 * Author: Mike Rapoport <mike@compulab.co.il>
6 *
7 * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include <linux/i2c.h>
15#include <linux/rtc.h>
16#include <linux/bcd.h>
17
18/* Registers */
19#define EM3027_REG_ON_OFF_CTRL 0x00
20#define EM3027_REG_IRQ_CTRL 0x01
21#define EM3027_REG_IRQ_FLAGS 0x02
22#define EM3027_REG_STATUS 0x03
23#define EM3027_REG_RST_CTRL 0x04
24
25#define EM3027_REG_WATCH_SEC 0x08
26#define EM3027_REG_WATCH_MIN 0x09
27#define EM3027_REG_WATCH_HOUR 0x0a
28#define EM3027_REG_WATCH_DATE 0x0b
29#define EM3027_REG_WATCH_DAY 0x0c
30#define EM3027_REG_WATCH_MON 0x0d
31#define EM3027_REG_WATCH_YEAR 0x0e
32
33#define EM3027_REG_ALARM_SEC 0x10
34#define EM3027_REG_ALARM_MIN 0x11
35#define EM3027_REG_ALARM_HOUR 0x12
36#define EM3027_REG_ALARM_DATE 0x13
37#define EM3027_REG_ALARM_DAY 0x14
38#define EM3027_REG_ALARM_MON 0x15
39#define EM3027_REG_ALARM_YEAR 0x16
40
41static struct i2c_driver em3027_driver;
42
43static int em3027_get_time(struct device *dev, struct rtc_time *tm)
44{
45 struct i2c_client *client = to_i2c_client(dev);
46
47 unsigned char addr = EM3027_REG_WATCH_SEC;
48 unsigned char buf[7];
49
50 struct i2c_msg msgs[] = {
51 {client->addr, 0, 1, &addr}, /* setup read addr */
52 {client->addr, I2C_M_RD, 7, buf}, /* read time/date */
53 };
54
55 /* read time/date registers */
56 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
57 dev_err(&client->dev, "%s: read error\n", __func__);
58 return -EIO;
59 }
60
61 tm->tm_sec = bcd2bin(buf[0]);
62 tm->tm_min = bcd2bin(buf[1]);
63 tm->tm_hour = bcd2bin(buf[2]);
64 tm->tm_mday = bcd2bin(buf[3]);
65 tm->tm_wday = bcd2bin(buf[4]);
66 tm->tm_mon = bcd2bin(buf[5]);
67 tm->tm_year = bcd2bin(buf[6]) + 100;
68
69 return 0;
70}
71
72static int em3027_set_time(struct device *dev, struct rtc_time *tm)
73{
74 struct i2c_client *client = to_i2c_client(dev);
75 unsigned char buf[8];
76
77 struct i2c_msg msg = {
78 client->addr, 0, 8, buf, /* write time/date */
79 };
80
81 buf[0] = EM3027_REG_WATCH_SEC;
82 buf[1] = bin2bcd(tm->tm_sec);
83 buf[2] = bin2bcd(tm->tm_min);
84 buf[3] = bin2bcd(tm->tm_hour);
85 buf[4] = bin2bcd(tm->tm_mday);
86 buf[5] = bin2bcd(tm->tm_wday);
87 buf[6] = bin2bcd(tm->tm_mon);
88 buf[7] = bin2bcd(tm->tm_year % 100);
89
90 /* write time/date registers */
91 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
92 dev_err(&client->dev, "%s: write error\n", __func__);
93 return -EIO;
94 }
95
96 return 0;
97}
98
99static const struct rtc_class_ops em3027_rtc_ops = {
100 .read_time = em3027_get_time,
101 .set_time = em3027_set_time,
102};
103
104static int em3027_probe(struct i2c_client *client,
105 const struct i2c_device_id *id)
106{
107 struct rtc_device *rtc;
108
109 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
110 return -ENODEV;
111
112 rtc = rtc_device_register(em3027_driver.driver.name, &client->dev,
113 &em3027_rtc_ops, THIS_MODULE);
114 if (IS_ERR(rtc))
115 return PTR_ERR(rtc);
116
117 i2c_set_clientdata(client, rtc);
118
119 return 0;
120}
121
122static int em3027_remove(struct i2c_client *client)
123{
124 struct rtc_device *rtc = i2c_get_clientdata(client);
125
126 if (rtc)
127 rtc_device_unregister(rtc);
128
129 return 0;
130}
131
132static struct i2c_device_id em3027_id[] = {
133 { "em3027", 0 },
134 { }
135};
136
137static struct i2c_driver em3027_driver = {
138 .driver = {
139 .name = "rtc-em3027",
140 },
141 .probe = &em3027_probe,
142 .remove = &em3027_remove,
143 .id_table = em3027_id,
144};
145
146static int __init em3027_init(void)
147{
148 return i2c_add_driver(&em3027_driver);
149}
150
151static void __exit em3027_exit(void)
152{
153 i2c_del_driver(&em3027_driver);
154}
155
156MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
157MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
158MODULE_LICENSE("GPL");
159
160module_init(em3027_init);
161module_exit(em3027_exit);