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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>
Peter Robinsone7069742015-04-16 12:45:07 -070018#include <linux/of.h>
Mike Rapoportae3551f2011-05-26 16:25:04 -070019
20/* Registers */
21#define EM3027_REG_ON_OFF_CTRL 0x00
22#define EM3027_REG_IRQ_CTRL 0x01
23#define EM3027_REG_IRQ_FLAGS 0x02
24#define EM3027_REG_STATUS 0x03
25#define EM3027_REG_RST_CTRL 0x04
26
27#define EM3027_REG_WATCH_SEC 0x08
28#define EM3027_REG_WATCH_MIN 0x09
29#define EM3027_REG_WATCH_HOUR 0x0a
30#define EM3027_REG_WATCH_DATE 0x0b
31#define EM3027_REG_WATCH_DAY 0x0c
32#define EM3027_REG_WATCH_MON 0x0d
33#define EM3027_REG_WATCH_YEAR 0x0e
34
35#define EM3027_REG_ALARM_SEC 0x10
36#define EM3027_REG_ALARM_MIN 0x11
37#define EM3027_REG_ALARM_HOUR 0x12
38#define EM3027_REG_ALARM_DATE 0x13
39#define EM3027_REG_ALARM_DAY 0x14
40#define EM3027_REG_ALARM_MON 0x15
41#define EM3027_REG_ALARM_YEAR 0x16
42
43static struct i2c_driver em3027_driver;
44
45static int em3027_get_time(struct device *dev, struct rtc_time *tm)
46{
47 struct i2c_client *client = to_i2c_client(dev);
48
49 unsigned char addr = EM3027_REG_WATCH_SEC;
50 unsigned char buf[7];
51
52 struct i2c_msg msgs[] = {
Shubhrajyoti D84cab862012-10-04 17:14:29 -070053 {/* setup read addr */
54 .addr = client->addr,
55 .len = 1,
56 .buf = &addr
57 },
58 {/* read time/date */
59 .addr = client->addr,
60 .flags = I2C_M_RD,
61 .len = 7,
62 .buf = buf
63 },
Mike Rapoportae3551f2011-05-26 16:25:04 -070064 };
65
66 /* read time/date registers */
67 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
68 dev_err(&client->dev, "%s: read error\n", __func__);
69 return -EIO;
70 }
71
72 tm->tm_sec = bcd2bin(buf[0]);
73 tm->tm_min = bcd2bin(buf[1]);
74 tm->tm_hour = bcd2bin(buf[2]);
75 tm->tm_mday = bcd2bin(buf[3]);
76 tm->tm_wday = bcd2bin(buf[4]);
77 tm->tm_mon = bcd2bin(buf[5]);
78 tm->tm_year = bcd2bin(buf[6]) + 100;
79
80 return 0;
81}
82
83static int em3027_set_time(struct device *dev, struct rtc_time *tm)
84{
85 struct i2c_client *client = to_i2c_client(dev);
86 unsigned char buf[8];
87
88 struct i2c_msg msg = {
Shubhrajyoti D84cab862012-10-04 17:14:29 -070089 .addr = client->addr,
90 .len = 8,
91 .buf = buf, /* write time/date */
Mike Rapoportae3551f2011-05-26 16:25:04 -070092 };
93
94 buf[0] = EM3027_REG_WATCH_SEC;
95 buf[1] = bin2bcd(tm->tm_sec);
96 buf[2] = bin2bcd(tm->tm_min);
97 buf[3] = bin2bcd(tm->tm_hour);
98 buf[4] = bin2bcd(tm->tm_mday);
99 buf[5] = bin2bcd(tm->tm_wday);
100 buf[6] = bin2bcd(tm->tm_mon);
101 buf[7] = bin2bcd(tm->tm_year % 100);
102
103 /* write time/date registers */
104 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
105 dev_err(&client->dev, "%s: write error\n", __func__);
106 return -EIO;
107 }
108
109 return 0;
110}
111
112static const struct rtc_class_ops em3027_rtc_ops = {
113 .read_time = em3027_get_time,
114 .set_time = em3027_set_time,
115};
116
117static int em3027_probe(struct i2c_client *client,
118 const struct i2c_device_id *id)
119{
120 struct rtc_device *rtc;
121
122 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
123 return -ENODEV;
124
Jingoo Han019b21d2013-04-29 16:19:37 -0700125 rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
Mike Rapoportae3551f2011-05-26 16:25:04 -0700126 &em3027_rtc_ops, THIS_MODULE);
127 if (IS_ERR(rtc))
128 return PTR_ERR(rtc);
129
130 i2c_set_clientdata(client, rtc);
131
132 return 0;
133}
134
Mike Rapoportae3551f2011-05-26 16:25:04 -0700135static struct i2c_device_id em3027_id[] = {
136 { "em3027", 0 },
137 { }
138};
Peter Robinsone7069742015-04-16 12:45:07 -0700139MODULE_DEVICE_TABLE(i2c, em3027_id);
140
141#ifdef CONFIG_OF
142static const struct of_device_id em3027_of_match[] = {
143 { .compatible = "emmicro,em3027", },
144 {}
145};
146MODULE_DEVICE_TABLE(of, em3027_of_match);
147#endif
Mike Rapoportae3551f2011-05-26 16:25:04 -0700148
149static struct i2c_driver em3027_driver = {
150 .driver = {
151 .name = "rtc-em3027",
Peter Robinsone7069742015-04-16 12:45:07 -0700152 .of_match_table = of_match_ptr(em3027_of_match),
Mike Rapoportae3551f2011-05-26 16:25:04 -0700153 },
154 .probe = &em3027_probe,
Mike Rapoportae3551f2011-05-26 16:25:04 -0700155 .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");