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1 | /* |
2 | * An I2C driver for the PCF85063 RTC | |
3 | * Copyright 2014 Rose Technology | |
4 | * | |
5 | * Author: Søren Andersen <san@rosetechnology.dk> | |
6 | * Maintainers: http://www.nslu2-linux.org/ | |
7 | * | |
8 | * based on the other drivers in this same directory. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/bcd.h> | |
16 | #include <linux/rtc.h> | |
17 | #include <linux/module.h> | |
18 | ||
19 | #define DRV_VERSION "0.0.1" | |
20 | ||
21 | #define PCF85063_REG_CTRL1 0x00 /* status */ | |
22 | #define PCF85063_REG_CTRL2 0x01 | |
23 | ||
24 | #define PCF85063_REG_SC 0x04 /* datetime */ | |
25 | #define PCF85063_REG_MN 0x05 | |
26 | #define PCF85063_REG_HR 0x06 | |
27 | #define PCF85063_REG_DM 0x07 | |
28 | #define PCF85063_REG_DW 0x08 | |
29 | #define PCF85063_REG_MO 0x09 | |
30 | #define PCF85063_REG_YR 0x0A | |
31 | ||
32 | #define PCF85063_MO_C 0x80 /* century */ | |
33 | ||
34 | static struct i2c_driver pcf85063_driver; | |
35 | ||
36 | struct pcf85063 { | |
37 | struct rtc_device *rtc; | |
38 | int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ | |
39 | int voltage_low; /* indicates if a low_voltage was detected */ | |
40 | }; | |
41 | ||
42 | /* | |
43 | * In the routines that deal directly with the pcf85063 hardware, we use | |
44 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
45 | */ | |
46 | static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
47 | { | |
48 | struct pcf85063 *pcf85063 = i2c_get_clientdata(client); | |
49 | unsigned char buf[13] = { PCF85063_REG_CTRL1 }; | |
50 | struct i2c_msg msgs[] = { | |
51 | {/* setup read ptr */ | |
52 | .addr = client->addr, | |
53 | .len = 1, | |
54 | .buf = buf | |
55 | }, | |
56 | {/* read status + date */ | |
57 | .addr = client->addr, | |
58 | .flags = I2C_M_RD, | |
59 | .len = 13, | |
60 | .buf = buf | |
61 | }, | |
62 | }; | |
63 | ||
64 | /* read registers */ | |
65 | if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { | |
66 | dev_err(&client->dev, "%s: read error\n", __func__); | |
67 | return -EIO; | |
68 | } | |
69 | ||
70 | tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F); | |
71 | tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F); | |
72 | tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */ | |
73 | tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F); | |
74 | tm->tm_wday = buf[PCF85063_REG_DW] & 0x07; | |
75 | tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ | |
76 | tm->tm_year = bcd2bin(buf[PCF85063_REG_YR]); | |
77 | if (tm->tm_year < 70) | |
78 | tm->tm_year += 100; /* assume we are in 1970...2069 */ | |
79 | /* detect the polarity heuristically. see note above. */ | |
80 | pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ? | |
81 | (tm->tm_year >= 100) : (tm->tm_year < 100); | |
82 | ||
83 | /* the clock can give out invalid datetime, but we cannot return | |
84 | * -EINVAL otherwise hwclock will refuse to set the time on bootup. | |
85 | */ | |
86 | if (rtc_valid_tm(tm) < 0) | |
87 | dev_err(&client->dev, "retrieved date/time is not valid.\n"); | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
93 | { | |
94 | int i = 0, err = 0; | |
95 | unsigned char buf[11]; | |
96 | ||
97 | /* Control & status */ | |
98 | buf[PCF85063_REG_CTRL1] = 0; | |
99 | buf[PCF85063_REG_CTRL2] = 5; | |
100 | ||
101 | /* hours, minutes and seconds */ | |
102 | buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F; | |
103 | ||
104 | buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min); | |
105 | buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour); | |
106 | ||
107 | /* Day of month, 1 - 31 */ | |
108 | buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday); | |
109 | ||
110 | /* Day, 0 - 6 */ | |
111 | buf[PCF85063_REG_DW] = tm->tm_wday & 0x07; | |
112 | ||
113 | /* month, 1 - 12 */ | |
114 | buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1); | |
115 | ||
116 | /* year and century */ | |
117 | buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100); | |
118 | ||
119 | /* write register's data */ | |
120 | for (i = 0; i < sizeof(buf); i++) { | |
121 | unsigned char data[2] = { i, buf[i] }; | |
122 | ||
123 | err = i2c_master_send(client, data, sizeof(data)); | |
124 | if (err != sizeof(data)) { | |
125 | dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n", | |
126 | __func__, err, data[0], data[1]); | |
127 | return -EIO; | |
128 | } | |
129 | } | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
135 | { | |
136 | return pcf85063_get_datetime(to_i2c_client(dev), tm); | |
137 | } | |
138 | ||
139 | static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
140 | { | |
141 | return pcf85063_set_datetime(to_i2c_client(dev), tm); | |
142 | } | |
143 | ||
144 | static const struct rtc_class_ops pcf85063_rtc_ops = { | |
145 | .read_time = pcf85063_rtc_read_time, | |
146 | .set_time = pcf85063_rtc_set_time | |
147 | }; | |
148 | ||
149 | static int pcf85063_probe(struct i2c_client *client, | |
150 | const struct i2c_device_id *id) | |
151 | { | |
152 | struct pcf85063 *pcf85063; | |
153 | ||
154 | dev_dbg(&client->dev, "%s\n", __func__); | |
155 | ||
156 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
157 | return -ENODEV; | |
158 | ||
159 | pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063), | |
160 | GFP_KERNEL); | |
161 | if (!pcf85063) | |
162 | return -ENOMEM; | |
163 | ||
164 | dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); | |
165 | ||
166 | i2c_set_clientdata(client, pcf85063); | |
167 | ||
168 | pcf85063->rtc = devm_rtc_device_register(&client->dev, | |
169 | pcf85063_driver.driver.name, | |
170 | &pcf85063_rtc_ops, THIS_MODULE); | |
171 | ||
172 | return PTR_ERR_OR_ZERO(pcf85063->rtc); | |
173 | } | |
174 | ||
175 | static const struct i2c_device_id pcf85063_id[] = { | |
176 | { "pcf85063", 0 }, | |
177 | { } | |
178 | }; | |
179 | MODULE_DEVICE_TABLE(i2c, pcf85063_id); | |
180 | ||
181 | #ifdef CONFIG_OF | |
182 | static const struct of_device_id pcf85063_of_match[] = { | |
183 | { .compatible = "nxp,pcf85063" }, | |
184 | {} | |
185 | }; | |
186 | MODULE_DEVICE_TABLE(of, pcf85063_of_match); | |
187 | #endif | |
188 | ||
189 | static struct i2c_driver pcf85063_driver = { | |
190 | .driver = { | |
191 | .name = "rtc-pcf85063", | |
192 | .owner = THIS_MODULE, | |
193 | .of_match_table = of_match_ptr(pcf85063_of_match), | |
194 | }, | |
195 | .probe = pcf85063_probe, | |
196 | .id_table = pcf85063_id, | |
197 | }; | |
198 | ||
199 | module_i2c_driver(pcf85063_driver); | |
200 | ||
201 | MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>"); | |
202 | MODULE_DESCRIPTION("PCF85063 RTC driver"); | |
203 | MODULE_LICENSE("GPL"); | |
204 | MODULE_VERSION(DRV_VERSION); |