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69468320 | 1 | // SPDX-License-Identifier: GPL-2.0 |
edf1aaa3 AZ |
2 | /* |
3 | * An rtc/i2c driver for the Dallas DS1672 | |
3903586a AZ |
4 | * Copyright 2005-06 Tower Technologies |
5 | * | |
6 | * Author: Alessandro Zummo <a.zummo@towertech.it> | |
edf1aaa3 AZ |
7 | */ |
8 | ||
edf1aaa3 AZ |
9 | #include <linux/i2c.h> |
10 | #include <linux/rtc.h> | |
2113852b | 11 | #include <linux/module.h> |
edf1aaa3 | 12 | |
edf1aaa3 AZ |
13 | /* Registers */ |
14 | ||
15 | #define DS1672_REG_CNT_BASE 0 | |
16 | #define DS1672_REG_CONTROL 4 | |
17 | #define DS1672_REG_TRICKLE 5 | |
18 | ||
3903586a | 19 | #define DS1672_REG_CONTROL_EOSC 0x80 |
edf1aaa3 | 20 | |
edf1aaa3 AZ |
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 | |
d1fbe695 | 24 | * Time is set to UTC. |
edf1aaa3 | 25 | */ |
7a5670c7 | 26 | static int ds1672_read_time(struct device *dev, struct rtc_time *tm) |
edf1aaa3 | 27 | { |
7a5670c7 | 28 | struct i2c_client *client = to_i2c_client(dev); |
edf1aaa3 | 29 | unsigned long time; |
10e3efc1 | 30 | unsigned char addr = DS1672_REG_CONTROL; |
edf1aaa3 AZ |
31 | unsigned char buf[4]; |
32 | ||
33 | struct i2c_msg msgs[] = { | |
2bfc37df S |
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, | |
10e3efc1 | 42 | .len = 1, |
2bfc37df S |
43 | .buf = buf |
44 | }, | |
edf1aaa3 AZ |
45 | }; |
46 | ||
10e3efc1 AB |
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 | ||
edf1aaa3 AZ |
61 | /* read date registers */ |
62 | if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { | |
2a4e2b87 | 63 | dev_err(&client->dev, "%s: read error\n", __func__); |
edf1aaa3 AZ |
64 | return -EIO; |
65 | } | |
66 | ||
67 | dev_dbg(&client->dev, | |
11966adc | 68 | "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", |
2a4e2b87 | 69 | __func__, buf[0], buf[1], buf[2], buf[3]); |
edf1aaa3 | 70 | |
f0c04c27 CIK |
71 | time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | |
72 | (buf[1] << 8) | buf[0]; | |
edf1aaa3 | 73 | |
520d6516 | 74 | rtc_time64_to_tm(time, tm); |
edf1aaa3 | 75 | |
e3a76913 | 76 | dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm); |
edf1aaa3 AZ |
77 | |
78 | return 0; | |
79 | } | |
80 | ||
219219d9 | 81 | static int ds1672_set_time(struct device *dev, struct rtc_time *tm) |
edf1aaa3 | 82 | { |
7a5670c7 | 83 | struct i2c_client *client = to_i2c_client(dev); |
edf1aaa3 | 84 | int xfer; |
8a95b252 | 85 | unsigned char buf[6]; |
219219d9 | 86 | unsigned long secs = rtc_tm_to_time64(tm); |
edf1aaa3 AZ |
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; | |
1716b0fe | 93 | buf[5] = 0; /* set control reg to enable counting */ |
edf1aaa3 | 94 | |
8a95b252 KG |
95 | xfer = i2c_master_send(client, buf, 6); |
96 | if (xfer != 6) { | |
2a4e2b87 | 97 | dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); |
edf1aaa3 AZ |
98 | return -EIO; |
99 | } | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
ff8371ac | 104 | static const struct rtc_class_ops ds1672_rtc_ops = { |
7a5670c7 | 105 | .read_time = ds1672_read_time, |
219219d9 | 106 | .set_time = ds1672_set_time, |
edf1aaa3 AZ |
107 | }; |
108 | ||
1716b0fe AZ |
109 | static int ds1672_probe(struct i2c_client *client, |
110 | const struct i2c_device_id *id) | |
edf1aaa3 AZ |
111 | { |
112 | int err = 0; | |
edf1aaa3 AZ |
113 | struct rtc_device *rtc; |
114 | ||
1716b0fe | 115 | dev_dbg(&client->dev, "%s\n", __func__); |
edf1aaa3 | 116 | |
1716b0fe AZ |
117 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
118 | return -ENODEV; | |
edf1aaa3 | 119 | |
d1fbe695 AB |
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 | ||
fdcfd854 | 127 | err = devm_rtc_register_device(rtc); |
d1fbe695 AB |
128 | if (err) |
129 | return err; | |
edf1aaa3 | 130 | |
edf1aaa3 AZ |
131 | i2c_set_clientdata(client, rtc); |
132 | ||
133 | return 0; | |
edf1aaa3 AZ |
134 | } |
135 | ||
45a63518 | 136 | static const struct i2c_device_id ds1672_id[] = { |
fe102c71 AZ |
137 | { "ds1672", 0 }, |
138 | { } | |
139 | }; | |
8ad0f5b6 | 140 | MODULE_DEVICE_TABLE(i2c, ds1672_id); |
fe102c71 | 141 | |
23194ac0 JMC |
142 | static const struct of_device_id ds1672_of_match[] = { |
143 | { .compatible = "dallas,ds1672" }, | |
144 | { } | |
145 | }; | |
146 | MODULE_DEVICE_TABLE(of, ds1672_of_match); | |
147 | ||
1716b0fe AZ |
148 | static struct i2c_driver ds1672_driver = { |
149 | .driver = { | |
150 | .name = "rtc-ds1672", | |
23194ac0 JMC |
151 | .of_match_table = of_match_ptr(ds1672_of_match), |
152 | }, | |
1716b0fe | 153 | .probe = &ds1672_probe, |
fe102c71 | 154 | .id_table = ds1672_id, |
1716b0fe AZ |
155 | }; |
156 | ||
0abc9201 | 157 | module_i2c_driver(ds1672_driver); |
edf1aaa3 AZ |
158 | |
159 | MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); | |
160 | MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); | |
161 | MODULE_LICENSE("GPL"); |