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9c0c5705 L |
1 | /* |
2 | * drivers/rtc/rtc-pcf8583.c | |
3 | * | |
4 | * Copyright (C) 2000 Russell King | |
02bb584f | 5 | * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix |
9c0c5705 L |
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 | * Driver for PCF8583 RTC & RAM chip | |
12 | * | |
13 | * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) | |
14 | */ | |
15 | #include <linux/module.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/slab.h> | |
77459b05 | 18 | #include <linux/rtc.h> |
9c0c5705 L |
19 | #include <linux/init.h> |
20 | #include <linux/errno.h> | |
21 | #include <linux/bcd.h> | |
22 | ||
23 | struct rtc_mem { | |
24 | unsigned int loc; | |
25 | unsigned int nr; | |
26 | unsigned char *data; | |
27 | }; | |
28 | ||
29 | struct pcf8583 { | |
9c0c5705 L |
30 | struct rtc_device *rtc; |
31 | unsigned char ctrl; | |
32 | }; | |
33 | ||
34 | #define CTRL_STOP 0x80 | |
35 | #define CTRL_HOLD 0x40 | |
36 | #define CTRL_32KHZ 0x00 | |
37 | #define CTRL_MASK 0x08 | |
38 | #define CTRL_ALARMEN 0x04 | |
39 | #define CTRL_ALARM 0x02 | |
40 | #define CTRL_TIMER 0x01 | |
41 | ||
9c0c5705 L |
42 | |
43 | static struct i2c_driver pcf8583_driver; | |
44 | ||
45 | #define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl | |
46 | #define set_ctrl(x, v) get_ctrl(x) = v | |
47 | ||
48 | #define CMOS_YEAR (64 + 128) | |
49 | #define CMOS_CHECKSUM (63) | |
50 | ||
51 | static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) | |
52 | { | |
53 | unsigned char buf[8], addr[1] = { 1 }; | |
54 | struct i2c_msg msgs[2] = { | |
55 | { | |
56 | .addr = client->addr, | |
57 | .flags = 0, | |
58 | .len = 1, | |
59 | .buf = addr, | |
60 | }, { | |
61 | .addr = client->addr, | |
62 | .flags = I2C_M_RD, | |
63 | .len = 6, | |
64 | .buf = buf, | |
65 | } | |
66 | }; | |
67 | int ret; | |
68 | ||
69 | memset(buf, 0, sizeof(buf)); | |
70 | ||
71 | ret = i2c_transfer(client->adapter, msgs, 2); | |
72 | if (ret == 2) { | |
73 | dt->tm_year = buf[4] >> 6; | |
74 | dt->tm_wday = buf[5] >> 5; | |
75 | ||
76 | buf[4] &= 0x3f; | |
77 | buf[5] &= 0x1f; | |
78 | ||
fe20ba70 AB |
79 | dt->tm_sec = bcd2bin(buf[1]); |
80 | dt->tm_min = bcd2bin(buf[2]); | |
81 | dt->tm_hour = bcd2bin(buf[3]); | |
82 | dt->tm_mday = bcd2bin(buf[4]); | |
83 | dt->tm_mon = bcd2bin(buf[5]) - 1; | |
9c0c5705 L |
84 | } |
85 | ||
86 | return ret == 2 ? 0 : -EIO; | |
87 | } | |
88 | ||
89 | static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) | |
90 | { | |
91 | unsigned char buf[8]; | |
92 | int ret, len = 6; | |
93 | ||
94 | buf[0] = 0; | |
95 | buf[1] = get_ctrl(client) | 0x80; | |
96 | buf[2] = 0; | |
fe20ba70 AB |
97 | buf[3] = bin2bcd(dt->tm_sec); |
98 | buf[4] = bin2bcd(dt->tm_min); | |
99 | buf[5] = bin2bcd(dt->tm_hour); | |
9c0c5705 L |
100 | |
101 | if (datetoo) { | |
102 | len = 8; | |
fe20ba70 AB |
103 | buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6); |
104 | buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5); | |
9c0c5705 L |
105 | } |
106 | ||
107 | ret = i2c_master_send(client, (char *)buf, len); | |
108 | if (ret != len) | |
109 | return -EIO; | |
110 | ||
111 | buf[1] = get_ctrl(client); | |
112 | ret = i2c_master_send(client, (char *)buf, 2); | |
113 | ||
114 | return ret == 2 ? 0 : -EIO; | |
115 | } | |
116 | ||
117 | static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
118 | { | |
119 | *ctrl = get_ctrl(client); | |
120 | return 0; | |
121 | } | |
122 | ||
123 | static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
124 | { | |
125 | unsigned char buf[2]; | |
126 | ||
127 | buf[0] = 0; | |
128 | buf[1] = *ctrl; | |
129 | set_ctrl(client, *ctrl); | |
130 | ||
131 | return i2c_master_send(client, (char *)buf, 2); | |
132 | } | |
133 | ||
134 | static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) | |
135 | { | |
136 | unsigned char addr[1]; | |
137 | struct i2c_msg msgs[2] = { | |
138 | { | |
139 | .addr = client->addr, | |
140 | .flags = 0, | |
141 | .len = 1, | |
142 | .buf = addr, | |
143 | }, { | |
144 | .addr = client->addr, | |
145 | .flags = I2C_M_RD, | |
146 | .len = mem->nr, | |
147 | .buf = mem->data, | |
148 | } | |
149 | }; | |
150 | ||
151 | if (mem->loc < 8) | |
152 | return -EINVAL; | |
153 | ||
154 | addr[0] = mem->loc; | |
155 | ||
156 | return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; | |
157 | } | |
158 | ||
159 | static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) | |
160 | { | |
037e291c JD |
161 | unsigned char buf[9]; |
162 | int ret; | |
9c0c5705 | 163 | |
037e291c | 164 | if (mem->loc < 8 || mem->nr > 8) |
9c0c5705 L |
165 | return -EINVAL; |
166 | ||
037e291c JD |
167 | buf[0] = mem->loc; |
168 | memcpy(buf + 1, mem->data, mem->nr); | |
9c0c5705 | 169 | |
037e291c JD |
170 | ret = i2c_master_send(client, buf, mem->nr + 1); |
171 | return ret == mem->nr + 1 ? 0 : -EIO; | |
9c0c5705 L |
172 | } |
173 | ||
174 | static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
175 | { | |
176 | struct i2c_client *client = to_i2c_client(dev); | |
177 | unsigned char ctrl, year[2]; | |
178 | struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year }; | |
179 | int real_year, year_offset, err; | |
180 | ||
181 | /* | |
182 | * Ensure that the RTC is running. | |
183 | */ | |
184 | pcf8583_get_ctrl(client, &ctrl); | |
185 | if (ctrl & (CTRL_STOP | CTRL_HOLD)) { | |
186 | unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); | |
187 | ||
79d13405 JH |
188 | dev_warn(dev, "resetting control %02x -> %02x\n", |
189 | ctrl, new_ctrl); | |
9c0c5705 | 190 | |
d1bda80a SK |
191 | err = pcf8583_set_ctrl(client, &new_ctrl); |
192 | if (err < 0) | |
9c0c5705 L |
193 | return err; |
194 | } | |
195 | ||
196 | if (pcf8583_get_datetime(client, tm) || | |
197 | pcf8583_read_mem(client, &mem)) | |
198 | return -EIO; | |
199 | ||
200 | real_year = year[0]; | |
201 | ||
202 | /* | |
203 | * The RTC year holds the LSB two bits of the current | |
204 | * year, which should reflect the LSB two bits of the | |
205 | * CMOS copy of the year. Any difference indicates | |
206 | * that we have to correct the CMOS version. | |
207 | */ | |
208 | year_offset = tm->tm_year - (real_year & 3); | |
209 | if (year_offset < 0) | |
210 | /* | |
211 | * RTC year wrapped. Adjust it appropriately. | |
212 | */ | |
213 | year_offset += 4; | |
214 | ||
0ed8f210 | 215 | tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; |
9c0c5705 L |
216 | |
217 | return 0; | |
218 | } | |
219 | ||
220 | static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
221 | { | |
222 | struct i2c_client *client = to_i2c_client(dev); | |
223 | unsigned char year[2], chk; | |
224 | struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year }; | |
225 | struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk }; | |
0ed8f210 | 226 | unsigned int proper_year = tm->tm_year + 1900; |
9c0c5705 L |
227 | int ret; |
228 | ||
229 | /* | |
230 | * The RTC's own 2-bit year must reflect the least | |
231 | * significant two bits of the CMOS year. | |
232 | */ | |
233 | ||
234 | ret = pcf8583_set_datetime(client, tm, 1); | |
235 | if (ret) | |
236 | return ret; | |
237 | ||
238 | ret = pcf8583_read_mem(client, &cmos_check); | |
239 | if (ret) | |
240 | return ret; | |
241 | ||
242 | ret = pcf8583_read_mem(client, &cmos_year); | |
243 | if (ret) | |
244 | return ret; | |
245 | ||
246 | chk -= year[1] + year[0]; | |
247 | ||
0ed8f210 RK |
248 | year[1] = proper_year / 100; |
249 | year[0] = proper_year % 100; | |
9c0c5705 L |
250 | |
251 | chk += year[1] + year[0]; | |
252 | ||
253 | ret = pcf8583_write_mem(client, &cmos_year); | |
254 | ||
255 | if (ret) | |
256 | return ret; | |
257 | ||
258 | ret = pcf8583_write_mem(client, &cmos_check); | |
259 | ||
260 | return ret; | |
261 | } | |
262 | ||
ff8371ac | 263 | static const struct rtc_class_ops pcf8583_rtc_ops = { |
9c0c5705 L |
264 | .read_time = pcf8583_rtc_read_time, |
265 | .set_time = pcf8583_rtc_set_time, | |
266 | }; | |
267 | ||
02bb584f WS |
268 | static int pcf8583_probe(struct i2c_client *client, |
269 | const struct i2c_device_id *id) | |
9c0c5705 | 270 | { |
02bb584f | 271 | struct pcf8583 *pcf8583; |
9c0c5705 | 272 | |
02bb584f WS |
273 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
274 | return -ENODEV; | |
c018664c | 275 | |
4ad21183 JH |
276 | pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583), |
277 | GFP_KERNEL); | |
02bb584f | 278 | if (!pcf8583) |
9c0c5705 L |
279 | return -ENOMEM; |
280 | ||
b74d2caa AZ |
281 | i2c_set_clientdata(client, pcf8583); |
282 | ||
4ad21183 JH |
283 | pcf8583->rtc = devm_rtc_device_register(&client->dev, |
284 | pcf8583_driver.driver.name, | |
285 | &pcf8583_rtc_ops, THIS_MODULE); | |
9c0c5705 | 286 | |
4ad21183 JH |
287 | if (IS_ERR(pcf8583->rtc)) |
288 | return PTR_ERR(pcf8583->rtc); | |
9c0c5705 | 289 | |
02bb584f | 290 | return 0; |
02bb584f | 291 | } |
9c0c5705 | 292 | |
02bb584f WS |
293 | static const struct i2c_device_id pcf8583_id[] = { |
294 | { "pcf8583", 0 }, | |
295 | { } | |
296 | }; | |
297 | MODULE_DEVICE_TABLE(i2c, pcf8583_id); | |
9c0c5705 | 298 | |
02bb584f WS |
299 | static struct i2c_driver pcf8583_driver = { |
300 | .driver = { | |
301 | .name = "pcf8583", | |
302 | .owner = THIS_MODULE, | |
303 | }, | |
304 | .probe = pcf8583_probe, | |
02bb584f WS |
305 | .id_table = pcf8583_id, |
306 | }; | |
9c0c5705 | 307 | |
0abc9201 | 308 | module_i2c_driver(pcf8583_driver); |
9c0c5705 L |
309 | |
310 | MODULE_AUTHOR("Russell King"); | |
311 | MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); | |
312 | MODULE_LICENSE("GPL"); |