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d6c7428f RF |
1 | /* |
2 | * An I2C driver for the Intersil ISL 12022 | |
3 | * | |
4 | * Author: Roman Fietze <roman.fietze@telemotive.de> | |
5 | * | |
6 | * Based on the Philips PCF8563 RTC | |
7 | * by Alessandro Zummo <a.zummo@towertech.it>. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License version | |
11 | * 2 as published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/i2c.h> | |
15 | #include <linux/bcd.h> | |
16 | #include <linux/rtc.h> | |
17 | #include <linux/slab.h> | |
2113852b | 18 | #include <linux/module.h> |
17cc54b2 | 19 | #include <linux/err.h> |
d6c7428f RF |
20 | |
21 | #define DRV_VERSION "0.1" | |
22 | ||
23 | /* ISL register offsets */ | |
24 | #define ISL12022_REG_SC 0x00 | |
25 | #define ISL12022_REG_MN 0x01 | |
26 | #define ISL12022_REG_HR 0x02 | |
27 | #define ISL12022_REG_DT 0x03 | |
28 | #define ISL12022_REG_MO 0x04 | |
29 | #define ISL12022_REG_YR 0x05 | |
30 | #define ISL12022_REG_DW 0x06 | |
31 | ||
32 | #define ISL12022_REG_SR 0x07 | |
33 | #define ISL12022_REG_INT 0x08 | |
34 | ||
35 | /* ISL register bits */ | |
36 | #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ | |
37 | ||
38 | #define ISL12022_SR_LBAT85 (1 << 2) | |
39 | #define ISL12022_SR_LBAT75 (1 << 1) | |
40 | ||
41 | #define ISL12022_INT_WRTC (1 << 6) | |
42 | ||
43 | ||
44 | static struct i2c_driver isl12022_driver; | |
45 | ||
46 | struct isl12022 { | |
47 | struct rtc_device *rtc; | |
48 | ||
49 | bool write_enabled; /* true if write enable is set */ | |
50 | }; | |
51 | ||
52 | ||
53 | static int isl12022_read_regs(struct i2c_client *client, uint8_t reg, | |
54 | uint8_t *data, size_t n) | |
55 | { | |
56 | struct i2c_msg msgs[] = { | |
57 | { | |
58 | .addr = client->addr, | |
59 | .flags = 0, | |
60 | .len = 1, | |
61 | .buf = data | |
62 | }, /* setup read ptr */ | |
63 | { | |
64 | .addr = client->addr, | |
65 | .flags = I2C_M_RD, | |
66 | .len = n, | |
67 | .buf = data | |
68 | } | |
69 | }; | |
70 | ||
71 | int ret; | |
72 | ||
73 | data[0] = reg; | |
74 | ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
75 | if (ret != ARRAY_SIZE(msgs)) { | |
76 | dev_err(&client->dev, "%s: read error, ret=%d\n", | |
77 | __func__, ret); | |
78 | return -EIO; | |
79 | } | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | ||
85 | static int isl12022_write_reg(struct i2c_client *client, | |
86 | uint8_t reg, uint8_t val) | |
87 | { | |
88 | uint8_t data[2] = { reg, val }; | |
89 | int err; | |
90 | ||
91 | err = i2c_master_send(client, data, sizeof(data)); | |
92 | if (err != sizeof(data)) { | |
93 | dev_err(&client->dev, | |
94 | "%s: err=%d addr=%02x, data=%02x\n", | |
95 | __func__, err, data[0], data[1]); | |
96 | return -EIO; | |
97 | } | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | ||
103 | /* | |
104 | * In the routines that deal directly with the isl12022 hardware, we use | |
105 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
106 | */ | |
107 | static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
108 | { | |
109 | uint8_t buf[ISL12022_REG_INT + 1]; | |
110 | int ret; | |
111 | ||
112 | ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf)); | |
113 | if (ret) | |
114 | return ret; | |
115 | ||
116 | if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { | |
117 | dev_warn(&client->dev, | |
118 | "voltage dropped below %u%%, " | |
119 | "date and time is not reliable.\n", | |
120 | buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); | |
121 | } | |
122 | ||
123 | dev_dbg(&client->dev, | |
124 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " | |
125 | "mday=%02x, mon=%02x, year=%02x, wday=%02x, " | |
126 | "sr=%02x, int=%02x", | |
127 | __func__, | |
128 | buf[ISL12022_REG_SC], | |
129 | buf[ISL12022_REG_MN], | |
130 | buf[ISL12022_REG_HR], | |
131 | buf[ISL12022_REG_DT], | |
132 | buf[ISL12022_REG_MO], | |
133 | buf[ISL12022_REG_YR], | |
134 | buf[ISL12022_REG_DW], | |
135 | buf[ISL12022_REG_SR], | |
136 | buf[ISL12022_REG_INT]); | |
137 | ||
138 | tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); | |
139 | tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); | |
140 | tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); | |
141 | tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); | |
142 | tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; | |
143 | tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; | |
144 | tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; | |
145 | ||
146 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
147 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
148 | __func__, | |
149 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
150 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
151 | ||
152 | /* The clock can give out invalid datetime, but we cannot return | |
153 | * -EINVAL otherwise hwclock will refuse to set the time on bootup. */ | |
154 | if (rtc_valid_tm(tm) < 0) | |
155 | dev_err(&client->dev, "retrieved date and time is invalid.\n"); | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
160 | static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
161 | { | |
162 | struct isl12022 *isl12022 = i2c_get_clientdata(client); | |
163 | size_t i; | |
164 | int ret; | |
165 | uint8_t buf[ISL12022_REG_DW + 1]; | |
166 | ||
167 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
168 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
169 | __func__, | |
170 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
171 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
172 | ||
173 | if (!isl12022->write_enabled) { | |
174 | ||
175 | ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1); | |
176 | if (ret) | |
177 | return ret; | |
178 | ||
179 | /* Check if WRTC (write rtc enable) is set factory default is | |
180 | * 0 (not set) */ | |
181 | if (!(buf[0] & ISL12022_INT_WRTC)) { | |
182 | dev_info(&client->dev, | |
183 | "init write enable and 24 hour format\n"); | |
184 | ||
185 | /* Set the write enable bit. */ | |
186 | ret = isl12022_write_reg(client, | |
187 | ISL12022_REG_INT, | |
188 | buf[0] | ISL12022_INT_WRTC); | |
189 | if (ret) | |
190 | return ret; | |
191 | ||
192 | /* Write to any RTC register to start RTC, we use the | |
193 | * HR register, setting the MIL bit to use the 24 hour | |
194 | * format. */ | |
195 | ret = isl12022_read_regs(client, ISL12022_REG_HR, | |
196 | buf, 1); | |
197 | if (ret) | |
198 | return ret; | |
199 | ||
200 | ret = isl12022_write_reg(client, | |
201 | ISL12022_REG_HR, | |
202 | buf[0] | ISL12022_HR_MIL); | |
203 | if (ret) | |
204 | return ret; | |
205 | } | |
206 | ||
207 | isl12022->write_enabled = 1; | |
208 | } | |
209 | ||
210 | /* hours, minutes and seconds */ | |
211 | buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); | |
212 | buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); | |
6d23b258 | 213 | buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; |
d6c7428f RF |
214 | |
215 | buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); | |
216 | ||
217 | /* month, 1 - 12 */ | |
218 | buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); | |
219 | ||
220 | /* year and century */ | |
221 | buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); | |
222 | ||
223 | buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; | |
224 | ||
225 | /* write register's data */ | |
226 | for (i = 0; i < ARRAY_SIZE(buf); i++) { | |
227 | ret = isl12022_write_reg(client, ISL12022_REG_SC + i, | |
228 | buf[ISL12022_REG_SC + i]); | |
229 | if (ret) | |
230 | return -EIO; | |
0b7e0392 | 231 | } |
d6c7428f RF |
232 | |
233 | return 0; | |
234 | } | |
235 | ||
236 | static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
237 | { | |
238 | return isl12022_get_datetime(to_i2c_client(dev), tm); | |
239 | } | |
240 | ||
241 | static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
242 | { | |
243 | return isl12022_set_datetime(to_i2c_client(dev), tm); | |
244 | } | |
245 | ||
246 | static const struct rtc_class_ops isl12022_rtc_ops = { | |
247 | .read_time = isl12022_rtc_read_time, | |
248 | .set_time = isl12022_rtc_set_time, | |
249 | }; | |
250 | ||
251 | static int isl12022_probe(struct i2c_client *client, | |
252 | const struct i2c_device_id *id) | |
253 | { | |
254 | struct isl12022 *isl12022; | |
255 | ||
d6c7428f RF |
256 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
257 | return -ENODEV; | |
258 | ||
dc831f97 JH |
259 | isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022), |
260 | GFP_KERNEL); | |
d6c7428f RF |
261 | if (!isl12022) |
262 | return -ENOMEM; | |
263 | ||
264 | dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n"); | |
265 | ||
266 | i2c_set_clientdata(client, isl12022); | |
267 | ||
dc831f97 JH |
268 | isl12022->rtc = devm_rtc_device_register(&client->dev, |
269 | isl12022_driver.driver.name, | |
270 | &isl12022_rtc_ops, THIS_MODULE); | |
dac30a98 | 271 | return PTR_ERR_OR_ZERO(isl12022->rtc); |
d6c7428f RF |
272 | } |
273 | ||
d6c7428f RF |
274 | static const struct i2c_device_id isl12022_id[] = { |
275 | { "isl12022", 0 }, | |
d6c7428f RF |
276 | { } |
277 | }; | |
278 | MODULE_DEVICE_TABLE(i2c, isl12022_id); | |
279 | ||
280 | static struct i2c_driver isl12022_driver = { | |
281 | .driver = { | |
282 | .name = "rtc-isl12022", | |
283 | }, | |
284 | .probe = isl12022_probe, | |
d6c7428f RF |
285 | .id_table = isl12022_id, |
286 | }; | |
287 | ||
0abc9201 | 288 | module_i2c_driver(isl12022_driver); |
d6c7428f RF |
289 | |
290 | MODULE_AUTHOR("roman.fietze@telemotive.de"); | |
291 | MODULE_DESCRIPTION("ISL 12022 RTC driver"); | |
292 | MODULE_LICENSE("GPL"); | |
293 | MODULE_VERSION(DRV_VERSION); |