Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / rtc / rtc-ds1672.c
1 /*
2  * An rtc/i2c driver for the Dallas DS1672
3  * Copyright 2005-06 Tower Technologies
4  *
5  * Author: Alessandro Zummo <a.zummo@towertech.it>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #include <linux/i2c.h>
13 #include <linux/rtc.h>
14 #include <linux/module.h>
15
16 #define DRV_VERSION "0.4"
17
18 /* Registers */
19
20 #define DS1672_REG_CNT_BASE     0
21 #define DS1672_REG_CONTROL      4
22 #define DS1672_REG_TRICKLE      5
23
24 #define DS1672_REG_CONTROL_EOSC 0x80
25
26 static struct i2c_driver ds1672_driver;
27
28 /*
29  * In the routines that deal directly with the ds1672 hardware, we use
30  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
31  * Epoch is initialized as 2000. Time is set to UTC.
32  */
33 static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
34 {
35         unsigned long time;
36         unsigned char addr = DS1672_REG_CNT_BASE;
37         unsigned char buf[4];
38
39         struct i2c_msg msgs[] = {
40                 {/* setup read ptr */
41                         .addr = client->addr,
42                         .len = 1,
43                         .buf = &addr
44                 },
45                 {/* read date */
46                         .addr = client->addr,
47                         .flags = I2C_M_RD,
48                         .len = 4,
49                         .buf = buf
50                 },
51         };
52
53         /* read date registers */
54         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
55                 dev_err(&client->dev, "%s: read error\n", __func__);
56                 return -EIO;
57         }
58
59         dev_dbg(&client->dev,
60                 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
61                 __func__, buf[0], buf[1], buf[2], buf[3]);
62
63         time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
64
65         rtc_time_to_tm(time, tm);
66
67         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
68                 "mday=%d, mon=%d, year=%d, wday=%d\n",
69                 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
70                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
71
72         return 0;
73 }
74
75 static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
76 {
77         int xfer;
78         unsigned char buf[6];
79
80         buf[0] = DS1672_REG_CNT_BASE;
81         buf[1] = secs & 0x000000FF;
82         buf[2] = (secs & 0x0000FF00) >> 8;
83         buf[3] = (secs & 0x00FF0000) >> 16;
84         buf[4] = (secs & 0xFF000000) >> 24;
85         buf[5] = 0;             /* set control reg to enable counting */
86
87         xfer = i2c_master_send(client, buf, 6);
88         if (xfer != 6) {
89                 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
90                 return -EIO;
91         }
92
93         return 0;
94 }
95
96 static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
97 {
98         return ds1672_get_datetime(to_i2c_client(dev), tm);
99 }
100
101 static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
102 {
103         return ds1672_set_mmss(to_i2c_client(dev), secs);
104 }
105
106 static int ds1672_get_control(struct i2c_client *client, u8 *status)
107 {
108         unsigned char addr = DS1672_REG_CONTROL;
109
110         struct i2c_msg msgs[] = {
111                 {/* setup read ptr */
112                         .addr = client->addr,
113                         .len = 1,
114                         .buf = &addr
115                 },
116                 {/* read control */
117                         .addr = client->addr,
118                         .flags = I2C_M_RD,
119                         .len = 1,
120                         .buf = status
121                 },
122         };
123
124         /* read control register */
125         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
126                 dev_err(&client->dev, "%s: read error\n", __func__);
127                 return -EIO;
128         }
129
130         return 0;
131 }
132
133 /* following are the sysfs callback functions */
134 static ssize_t show_control(struct device *dev, struct device_attribute *attr,
135                             char *buf)
136 {
137         struct i2c_client *client = to_i2c_client(dev);
138         u8 control;
139         int err;
140
141         err = ds1672_get_control(client, &control);
142         if (err)
143                 return err;
144
145         return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
146                        ? "disabled" : "enabled");
147 }
148
149 static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
150
151 static const struct rtc_class_ops ds1672_rtc_ops = {
152         .read_time = ds1672_rtc_read_time,
153         .set_mmss = ds1672_rtc_set_mmss,
154 };
155
156 static int ds1672_probe(struct i2c_client *client,
157                         const struct i2c_device_id *id)
158 {
159         int err = 0;
160         u8 control;
161         struct rtc_device *rtc;
162
163         dev_dbg(&client->dev, "%s\n", __func__);
164
165         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
166                 return -ENODEV;
167
168         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
169
170         rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name,
171                                   &ds1672_rtc_ops, THIS_MODULE);
172
173         if (IS_ERR(rtc))
174                 return PTR_ERR(rtc);
175
176         i2c_set_clientdata(client, rtc);
177
178         /* read control register */
179         err = ds1672_get_control(client, &control);
180         if (err)
181                 goto exit_devreg;
182
183         if (control & DS1672_REG_CONTROL_EOSC)
184                 dev_warn(&client->dev, "Oscillator not enabled. "
185                          "Set time to enable.\n");
186
187         /* Register sysfs hooks */
188         err = device_create_file(&client->dev, &dev_attr_control);
189         if (err)
190                 goto exit_devreg;
191
192         return 0;
193
194  exit_devreg:
195         return err;
196 }
197
198 static struct i2c_device_id ds1672_id[] = {
199         { "ds1672", 0 },
200         { }
201 };
202
203 static struct i2c_driver ds1672_driver = {
204         .driver = {
205                    .name = "rtc-ds1672",
206                    },
207         .probe = &ds1672_probe,
208         .id_table = ds1672_id,
209 };
210
211 module_i2c_driver(ds1672_driver);
212
213 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
214 MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
215 MODULE_LICENSE("GPL");
216 MODULE_VERSION(DRV_VERSION);