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Mike Rapoportae3551f2011-05-26 16:25:04 -07001/*
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>
Paul Gortmaker21138522011-05-27 09:57:25 -040017#include <linux/module.h>
Mike Rapoportae3551f2011-05-26 16:25:04 -070018
19/* Registers */
20#define EM3027_REG_ON_OFF_CTRL 0x00
21#define EM3027_REG_IRQ_CTRL 0x01
22#define EM3027_REG_IRQ_FLAGS 0x02
23#define EM3027_REG_STATUS 0x03
24#define EM3027_REG_RST_CTRL 0x04
25
26#define EM3027_REG_WATCH_SEC 0x08
27#define EM3027_REG_WATCH_MIN 0x09
28#define EM3027_REG_WATCH_HOUR 0x0a
29#define EM3027_REG_WATCH_DATE 0x0b
30#define EM3027_REG_WATCH_DAY 0x0c
31#define EM3027_REG_WATCH_MON 0x0d
32#define EM3027_REG_WATCH_YEAR 0x0e
33
34#define EM3027_REG_ALARM_SEC 0x10
35#define EM3027_REG_ALARM_MIN 0x11
36#define EM3027_REG_ALARM_HOUR 0x12
37#define EM3027_REG_ALARM_DATE 0x13
38#define EM3027_REG_ALARM_DAY 0x14
39#define EM3027_REG_ALARM_MON 0x15
40#define EM3027_REG_ALARM_YEAR 0x16
41
42static struct i2c_driver em3027_driver;
43
44static int em3027_get_time(struct device *dev, struct rtc_time *tm)
45{
46 struct i2c_client *client = to_i2c_client(dev);
47
48 unsigned char addr = EM3027_REG_WATCH_SEC;
49 unsigned char buf[7];
50
51 struct i2c_msg msgs[] = {
Shubhrajyoti D84cab862012-10-04 17:14:29 -070052 {/* setup read addr */
53 .addr = client->addr,
54 .len = 1,
55 .buf = &addr
56 },
57 {/* read time/date */
58 .addr = client->addr,
59 .flags = I2C_M_RD,
60 .len = 7,
61 .buf = buf
62 },
Mike Rapoportae3551f2011-05-26 16:25:04 -070063 };
64
65 /* read time/date registers */
66 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
67 dev_err(&client->dev, "%s: read error\n", __func__);
68 return -EIO;
69 }
70
71 tm->tm_sec = bcd2bin(buf[0]);
72 tm->tm_min = bcd2bin(buf[1]);
73 tm->tm_hour = bcd2bin(buf[2]);
74 tm->tm_mday = bcd2bin(buf[3]);
75 tm->tm_wday = bcd2bin(buf[4]);
76 tm->tm_mon = bcd2bin(buf[5]);
77 tm->tm_year = bcd2bin(buf[6]) + 100;
78
79 return 0;
80}
81
82static int em3027_set_time(struct device *dev, struct rtc_time *tm)
83{
84 struct i2c_client *client = to_i2c_client(dev);
85 unsigned char buf[8];
86
87 struct i2c_msg msg = {
Shubhrajyoti D84cab862012-10-04 17:14:29 -070088 .addr = client->addr,
89 .len = 8,
90 .buf = buf, /* write time/date */
Mike Rapoportae3551f2011-05-26 16:25:04 -070091 };
92
93 buf[0] = EM3027_REG_WATCH_SEC;
94 buf[1] = bin2bcd(tm->tm_sec);
95 buf[2] = bin2bcd(tm->tm_min);
96 buf[3] = bin2bcd(tm->tm_hour);
97 buf[4] = bin2bcd(tm->tm_mday);
98 buf[5] = bin2bcd(tm->tm_wday);
99 buf[6] = bin2bcd(tm->tm_mon);
100 buf[7] = bin2bcd(tm->tm_year % 100);
101
102 /* write time/date registers */
103 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
104 dev_err(&client->dev, "%s: write error\n", __func__);
105 return -EIO;
106 }
107
108 return 0;
109}
110
111static const struct rtc_class_ops em3027_rtc_ops = {
112 .read_time = em3027_get_time,
113 .set_time = em3027_set_time,
114};
115
116static int em3027_probe(struct i2c_client *client,
117 const struct i2c_device_id *id)
118{
119 struct rtc_device *rtc;
120
121 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
122 return -ENODEV;
123
124 rtc = rtc_device_register(em3027_driver.driver.name, &client->dev,
125 &em3027_rtc_ops, THIS_MODULE);
126 if (IS_ERR(rtc))
127 return PTR_ERR(rtc);
128
129 i2c_set_clientdata(client, rtc);
130
131 return 0;
132}
133
134static int em3027_remove(struct i2c_client *client)
135{
136 struct rtc_device *rtc = i2c_get_clientdata(client);
137
138 if (rtc)
139 rtc_device_unregister(rtc);
140
141 return 0;
142}
143
144static struct i2c_device_id em3027_id[] = {
145 { "em3027", 0 },
146 { }
147};
148
149static struct i2c_driver em3027_driver = {
150 .driver = {
151 .name = "rtc-em3027",
152 },
153 .probe = &em3027_probe,
154 .remove = &em3027_remove,
155 .id_table = em3027_id,
156};
157
Axel Lin0abc9202012-03-23 15:02:31 -0700158module_i2c_driver(em3027_driver);
Mike Rapoportae3551f2011-05-26 16:25:04 -0700159
160MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
161MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
162MODULE_LICENSE("GPL");