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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
26static 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 */
33static 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 {client->addr, 0, 1, &addr}, /* setup read ptr */
41 {client->addr, I2C_M_RD, 4, buf}, /* read date */
42 };
43
44 /* read date registers */
45 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
46 dev_err(&client->dev, "%s: read error\n", __func__);
47 return -EIO;
48 }
49
50 dev_dbg(&client->dev,
51 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
52 __func__, buf[0], buf[1], buf[2], buf[3]);
53
54 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
55
56 rtc_time_to_tm(time, tm);
57
58 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
59 "mday=%d, mon=%d, year=%d, wday=%d\n",
60 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
61 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
62
63 return 0;
64}
65
66static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
67{
68 int xfer;
69 unsigned char buf[6];
70
71 buf[0] = DS1672_REG_CNT_BASE;
72 buf[1] = secs & 0x000000FF;
73 buf[2] = (secs & 0x0000FF00) >> 8;
74 buf[3] = (secs & 0x00FF0000) >> 16;
75 buf[4] = (secs & 0xFF000000) >> 24;
76 buf[5] = 0; /* set control reg to enable counting */
77
78 xfer = i2c_master_send(client, buf, 6);
79 if (xfer != 6) {
80 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
81 return -EIO;
82 }
83
84 return 0;
85}
86
87static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
88{
89 return ds1672_get_datetime(to_i2c_client(dev), tm);
90}
91
92static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
93{
94 return ds1672_set_mmss(to_i2c_client(dev), secs);
95}
96
97static int ds1672_get_control(struct i2c_client *client, u8 *status)
98{
99 unsigned char addr = DS1672_REG_CONTROL;
100
101 struct i2c_msg msgs[] = {
102 {client->addr, 0, 1, &addr}, /* setup read ptr */
103 {client->addr, I2C_M_RD, 1, status}, /* read control */
104 };
105
106 /* read control register */
107 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
108 dev_err(&client->dev, "%s: read error\n", __func__);
109 return -EIO;
110 }
111
112 return 0;
113}
114
115/* following are the sysfs callback functions */
116static ssize_t show_control(struct device *dev, struct device_attribute *attr,
117 char *buf)
118{
119 struct i2c_client *client = to_i2c_client(dev);
120 u8 control;
121 int err;
122
123 err = ds1672_get_control(client, &control);
124 if (err)
125 return err;
126
127 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
128 ? "disabled" : "enabled");
129}
130
131static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
132
133static const struct rtc_class_ops ds1672_rtc_ops = {
134 .read_time = ds1672_rtc_read_time,
135 .set_mmss = ds1672_rtc_set_mmss,
136};
137
138static int ds1672_remove(struct i2c_client *client)
139{
140 struct rtc_device *rtc = i2c_get_clientdata(client);
141
142 if (rtc)
143 rtc_device_unregister(rtc);
144
145 return 0;
146}
147
148static int ds1672_probe(struct i2c_client *client,
149 const struct i2c_device_id *id)
150{
151 int err = 0;
152 u8 control;
153 struct rtc_device *rtc;
154
155 dev_dbg(&client->dev, "%s\n", __func__);
156
157 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
158 return -ENODEV;
159
160 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
161
162 rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
163 &ds1672_rtc_ops, THIS_MODULE);
164
165 if (IS_ERR(rtc))
166 return PTR_ERR(rtc);
167
168 i2c_set_clientdata(client, rtc);
169
170 /* read control register */
171 err = ds1672_get_control(client, &control);
172 if (err)
173 goto exit_devreg;
174
175 if (control & DS1672_REG_CONTROL_EOSC)
176 dev_warn(&client->dev, "Oscillator not enabled. "
177 "Set time to enable.\n");
178
179 /* Register sysfs hooks */
180 err = device_create_file(&client->dev, &dev_attr_control);
181 if (err)
182 goto exit_devreg;
183
184 return 0;
185
186 exit_devreg:
187 rtc_device_unregister(rtc);
188 return err;
189}
190
191static struct i2c_device_id ds1672_id[] = {
192 { "ds1672", 0 },
193 { }
194};
195
196static struct i2c_driver ds1672_driver = {
197 .driver = {
198 .name = "rtc-ds1672",
199 },
200 .probe = &ds1672_probe,
201 .remove = &ds1672_remove,
202 .id_table = ds1672_id,
203};
204
205module_i2c_driver(ds1672_driver);
206
207MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
208MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
209MODULE_LICENSE("GPL");
210MODULE_VERSION(DRV_VERSION);
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/* Registers */
17
18#define DS1672_REG_CNT_BASE 0
19#define DS1672_REG_CONTROL 4
20#define DS1672_REG_TRICKLE 5
21
22#define DS1672_REG_CONTROL_EOSC 0x80
23
24static struct i2c_driver ds1672_driver;
25
26/*
27 * In the routines that deal directly with the ds1672 hardware, we use
28 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
29 * Epoch is initialized as 2000. Time is set to UTC.
30 */
31static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
32{
33 unsigned long time;
34 unsigned char addr = DS1672_REG_CNT_BASE;
35 unsigned char buf[4];
36
37 struct i2c_msg msgs[] = {
38 {/* setup read ptr */
39 .addr = client->addr,
40 .len = 1,
41 .buf = &addr
42 },
43 {/* read date */
44 .addr = client->addr,
45 .flags = I2C_M_RD,
46 .len = 4,
47 .buf = buf
48 },
49 };
50
51 /* read date registers */
52 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
53 dev_err(&client->dev, "%s: read error\n", __func__);
54 return -EIO;
55 }
56
57 dev_dbg(&client->dev,
58 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
59 __func__, buf[0], buf[1], buf[2], buf[3]);
60
61 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
62
63 rtc_time_to_tm(time, tm);
64
65 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
66 "mday=%d, mon=%d, year=%d, wday=%d\n",
67 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
68 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
69
70 return 0;
71}
72
73static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
74{
75 int xfer;
76 unsigned char buf[6];
77
78 buf[0] = DS1672_REG_CNT_BASE;
79 buf[1] = secs & 0x000000FF;
80 buf[2] = (secs & 0x0000FF00) >> 8;
81 buf[3] = (secs & 0x00FF0000) >> 16;
82 buf[4] = (secs & 0xFF000000) >> 24;
83 buf[5] = 0; /* set control reg to enable counting */
84
85 xfer = i2c_master_send(client, buf, 6);
86 if (xfer != 6) {
87 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
88 return -EIO;
89 }
90
91 return 0;
92}
93
94static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
95{
96 return ds1672_get_datetime(to_i2c_client(dev), tm);
97}
98
99static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
100{
101 return ds1672_set_mmss(to_i2c_client(dev), secs);
102}
103
104static int ds1672_get_control(struct i2c_client *client, u8 *status)
105{
106 unsigned char addr = DS1672_REG_CONTROL;
107
108 struct i2c_msg msgs[] = {
109 {/* setup read ptr */
110 .addr = client->addr,
111 .len = 1,
112 .buf = &addr
113 },
114 {/* read control */
115 .addr = client->addr,
116 .flags = I2C_M_RD,
117 .len = 1,
118 .buf = status
119 },
120 };
121
122 /* read control register */
123 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
124 dev_err(&client->dev, "%s: read error\n", __func__);
125 return -EIO;
126 }
127
128 return 0;
129}
130
131/* following are the sysfs callback functions */
132static ssize_t show_control(struct device *dev, struct device_attribute *attr,
133 char *buf)
134{
135 struct i2c_client *client = to_i2c_client(dev);
136 u8 control;
137 int err;
138
139 err = ds1672_get_control(client, &control);
140 if (err)
141 return err;
142
143 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
144 ? "disabled" : "enabled");
145}
146
147static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
148
149static const struct rtc_class_ops ds1672_rtc_ops = {
150 .read_time = ds1672_rtc_read_time,
151 .set_mmss = ds1672_rtc_set_mmss,
152};
153
154static int ds1672_probe(struct i2c_client *client,
155 const struct i2c_device_id *id)
156{
157 int err = 0;
158 u8 control;
159 struct rtc_device *rtc;
160
161 dev_dbg(&client->dev, "%s\n", __func__);
162
163 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
164 return -ENODEV;
165
166 rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name,
167 &ds1672_rtc_ops, THIS_MODULE);
168
169 if (IS_ERR(rtc))
170 return PTR_ERR(rtc);
171
172 i2c_set_clientdata(client, rtc);
173
174 /* read control register */
175 err = ds1672_get_control(client, &control);
176 if (err) {
177 dev_warn(&client->dev, "Unable to read the control register\n");
178 }
179
180 if (control & DS1672_REG_CONTROL_EOSC)
181 dev_warn(&client->dev, "Oscillator not enabled. "
182 "Set time to enable.\n");
183
184 /* Register sysfs hooks */
185 err = device_create_file(&client->dev, &dev_attr_control);
186 if (err)
187 dev_err(&client->dev, "Unable to create sysfs entry: %s\n",
188 dev_attr_control.attr.name);
189
190 return 0;
191}
192
193static const struct i2c_device_id ds1672_id[] = {
194 { "ds1672", 0 },
195 { }
196};
197MODULE_DEVICE_TABLE(i2c, ds1672_id);
198
199static const struct of_device_id ds1672_of_match[] = {
200 { .compatible = "dallas,ds1672" },
201 { }
202};
203MODULE_DEVICE_TABLE(of, ds1672_of_match);
204
205static struct i2c_driver ds1672_driver = {
206 .driver = {
207 .name = "rtc-ds1672",
208 .of_match_table = of_match_ptr(ds1672_of_match),
209 },
210 .probe = &ds1672_probe,
211 .id_table = ds1672_id,
212};
213
214module_i2c_driver(ds1672_driver);
215
216MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
217MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
218MODULE_LICENSE("GPL");