Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * An rtc/i2c driver for the Dallas DS1672
4 * Copyright 2005-06 Tower Technologies
5 *
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 */
8
9#include <linux/i2c.h>
10#include <linux/rtc.h>
11#include <linux/module.h>
12
13/* Registers */
14
15#define DS1672_REG_CNT_BASE 0
16#define DS1672_REG_CONTROL 4
17#define DS1672_REG_TRICKLE 5
18
19#define DS1672_REG_CONTROL_EOSC 0x80
20
21/*
22 * In the routines that deal directly with the ds1672 hardware, we use
23 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
24 * Time is set to UTC.
25 */
26static int ds1672_read_time(struct device *dev, struct rtc_time *tm)
27{
28 struct i2c_client *client = to_i2c_client(dev);
29 unsigned long time;
30 unsigned char addr = DS1672_REG_CONTROL;
31 unsigned char buf[4];
32
33 struct i2c_msg msgs[] = {
34 {/* setup read ptr */
35 .addr = client->addr,
36 .len = 1,
37 .buf = &addr
38 },
39 {/* read date */
40 .addr = client->addr,
41 .flags = I2C_M_RD,
42 .len = 1,
43 .buf = buf
44 },
45 };
46
47 /* read control register */
48 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
49 dev_warn(&client->dev, "Unable to read the control register\n");
50 return -EIO;
51 }
52
53 if (buf[0] & DS1672_REG_CONTROL_EOSC) {
54 dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n");
55 return -EINVAL;
56 }
57
58 addr = DS1672_REG_CNT_BASE;
59 msgs[1].len = 4;
60
61 /* read date registers */
62 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
63 dev_err(&client->dev, "%s: read error\n", __func__);
64 return -EIO;
65 }
66
67 dev_dbg(&client->dev,
68 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
69 __func__, buf[0], buf[1], buf[2], buf[3]);
70
71 time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
72 (buf[1] << 8) | buf[0];
73
74 rtc_time64_to_tm(time, tm);
75
76 dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm);
77
78 return 0;
79}
80
81static int ds1672_set_time(struct device *dev, struct rtc_time *tm)
82{
83 struct i2c_client *client = to_i2c_client(dev);
84 int xfer;
85 unsigned char buf[6];
86 unsigned long secs = rtc_tm_to_time64(tm);
87
88 buf[0] = DS1672_REG_CNT_BASE;
89 buf[1] = secs & 0x000000FF;
90 buf[2] = (secs & 0x0000FF00) >> 8;
91 buf[3] = (secs & 0x00FF0000) >> 16;
92 buf[4] = (secs & 0xFF000000) >> 24;
93 buf[5] = 0; /* set control reg to enable counting */
94
95 xfer = i2c_master_send(client, buf, 6);
96 if (xfer != 6) {
97 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
98 return -EIO;
99 }
100
101 return 0;
102}
103
104static const struct rtc_class_ops ds1672_rtc_ops = {
105 .read_time = ds1672_read_time,
106 .set_time = ds1672_set_time,
107};
108
109static int ds1672_probe(struct i2c_client *client,
110 const struct i2c_device_id *id)
111{
112 int err = 0;
113 struct rtc_device *rtc;
114
115 dev_dbg(&client->dev, "%s\n", __func__);
116
117 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
118 return -ENODEV;
119
120 rtc = devm_rtc_allocate_device(&client->dev);
121 if (IS_ERR(rtc))
122 return PTR_ERR(rtc);
123
124 rtc->ops = &ds1672_rtc_ops;
125 rtc->range_max = U32_MAX;
126
127 err = rtc_register_device(rtc);
128 if (err)
129 return err;
130
131 i2c_set_clientdata(client, rtc);
132
133 return 0;
134}
135
136static const struct i2c_device_id ds1672_id[] = {
137 { "ds1672", 0 },
138 { }
139};
140MODULE_DEVICE_TABLE(i2c, ds1672_id);
141
142static const struct of_device_id ds1672_of_match[] = {
143 { .compatible = "dallas,ds1672" },
144 { }
145};
146MODULE_DEVICE_TABLE(of, ds1672_of_match);
147
148static struct i2c_driver ds1672_driver = {
149 .driver = {
150 .name = "rtc-ds1672",
151 .of_match_table = of_match_ptr(ds1672_of_match),
152 },
153 .probe = &ds1672_probe,
154 .id_table = ds1672_id,
155};
156
157module_i2c_driver(ds1672_driver);
158
159MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
160MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
161MODULE_LICENSE("GPL");
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");