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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{
111 int err = 0;
112 struct rtc_device *rtc;
113
114 dev_dbg(&client->dev, "%s\n", __func__);
115
116 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
117 return -ENODEV;
118
119 rtc = devm_rtc_allocate_device(&client->dev);
120 if (IS_ERR(rtc))
121 return PTR_ERR(rtc);
122
123 rtc->ops = &ds1672_rtc_ops;
124 rtc->range_max = U32_MAX;
125
126 err = devm_rtc_register_device(rtc);
127 if (err)
128 return err;
129
130 i2c_set_clientdata(client, rtc);
131
132 return 0;
133}
134
135static const struct i2c_device_id ds1672_id[] = {
136 { "ds1672", 0 },
137 { }
138};
139MODULE_DEVICE_TABLE(i2c, ds1672_id);
140
141static const __maybe_unused struct of_device_id ds1672_of_match[] = {
142 { .compatible = "dallas,ds1672" },
143 { }
144};
145MODULE_DEVICE_TABLE(of, ds1672_of_match);
146
147static struct i2c_driver ds1672_driver = {
148 .driver = {
149 .name = "rtc-ds1672",
150 .of_match_table = of_match_ptr(ds1672_of_match),
151 },
152 .probe_new = ds1672_probe,
153 .id_table = ds1672_id,
154};
155
156module_i2c_driver(ds1672_driver);
157
158MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
159MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
160MODULE_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#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);