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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9c0c5705 L |
2 | /* |
3 | * drivers/rtc/rtc-pcf8583.c | |
4 | * | |
5 | * Copyright (C) 2000 Russell King | |
02bb584f | 6 | * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix |
9c0c5705 | 7 | * |
9c0c5705 L |
8 | * Driver for PCF8583 RTC & RAM chip |
9 | * | |
10 | * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/i2c.h> | |
14 | #include <linux/slab.h> | |
77459b05 | 15 | #include <linux/rtc.h> |
9c0c5705 | 16 | #include <linux/init.h> |
ee605e0b | 17 | #include <linux/err.h> |
9c0c5705 L |
18 | #include <linux/errno.h> |
19 | #include <linux/bcd.h> | |
20 | ||
21 | struct rtc_mem { | |
22 | unsigned int loc; | |
23 | unsigned int nr; | |
24 | unsigned char *data; | |
25 | }; | |
26 | ||
27 | struct pcf8583 { | |
9c0c5705 L |
28 | struct rtc_device *rtc; |
29 | unsigned char ctrl; | |
30 | }; | |
31 | ||
32 | #define CTRL_STOP 0x80 | |
33 | #define CTRL_HOLD 0x40 | |
34 | #define CTRL_32KHZ 0x00 | |
35 | #define CTRL_MASK 0x08 | |
36 | #define CTRL_ALARMEN 0x04 | |
37 | #define CTRL_ALARM 0x02 | |
38 | #define CTRL_TIMER 0x01 | |
39 | ||
9c0c5705 L |
40 | |
41 | static struct i2c_driver pcf8583_driver; | |
42 | ||
43 | #define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl | |
44 | #define set_ctrl(x, v) get_ctrl(x) = v | |
45 | ||
46 | #define CMOS_YEAR (64 + 128) | |
47 | #define CMOS_CHECKSUM (63) | |
48 | ||
49 | static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) | |
50 | { | |
51 | unsigned char buf[8], addr[1] = { 1 }; | |
52 | struct i2c_msg msgs[2] = { | |
53 | { | |
54 | .addr = client->addr, | |
55 | .flags = 0, | |
56 | .len = 1, | |
57 | .buf = addr, | |
58 | }, { | |
59 | .addr = client->addr, | |
60 | .flags = I2C_M_RD, | |
61 | .len = 6, | |
62 | .buf = buf, | |
63 | } | |
64 | }; | |
65 | int ret; | |
66 | ||
67 | memset(buf, 0, sizeof(buf)); | |
68 | ||
69 | ret = i2c_transfer(client->adapter, msgs, 2); | |
70 | if (ret == 2) { | |
71 | dt->tm_year = buf[4] >> 6; | |
72 | dt->tm_wday = buf[5] >> 5; | |
73 | ||
74 | buf[4] &= 0x3f; | |
75 | buf[5] &= 0x1f; | |
76 | ||
fe20ba70 AB |
77 | dt->tm_sec = bcd2bin(buf[1]); |
78 | dt->tm_min = bcd2bin(buf[2]); | |
79 | dt->tm_hour = bcd2bin(buf[3]); | |
80 | dt->tm_mday = bcd2bin(buf[4]); | |
81 | dt->tm_mon = bcd2bin(buf[5]) - 1; | |
9c0c5705 L |
82 | } |
83 | ||
84 | return ret == 2 ? 0 : -EIO; | |
85 | } | |
86 | ||
87 | static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) | |
88 | { | |
89 | unsigned char buf[8]; | |
90 | int ret, len = 6; | |
91 | ||
92 | buf[0] = 0; | |
93 | buf[1] = get_ctrl(client) | 0x80; | |
94 | buf[2] = 0; | |
fe20ba70 AB |
95 | buf[3] = bin2bcd(dt->tm_sec); |
96 | buf[4] = bin2bcd(dt->tm_min); | |
97 | buf[5] = bin2bcd(dt->tm_hour); | |
9c0c5705 L |
98 | |
99 | if (datetoo) { | |
100 | len = 8; | |
fe20ba70 AB |
101 | buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6); |
102 | buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5); | |
9c0c5705 L |
103 | } |
104 | ||
105 | ret = i2c_master_send(client, (char *)buf, len); | |
106 | if (ret != len) | |
107 | return -EIO; | |
108 | ||
109 | buf[1] = get_ctrl(client); | |
110 | ret = i2c_master_send(client, (char *)buf, 2); | |
111 | ||
112 | return ret == 2 ? 0 : -EIO; | |
113 | } | |
114 | ||
115 | static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
116 | { | |
117 | *ctrl = get_ctrl(client); | |
118 | return 0; | |
119 | } | |
120 | ||
121 | static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
122 | { | |
123 | unsigned char buf[2]; | |
124 | ||
125 | buf[0] = 0; | |
126 | buf[1] = *ctrl; | |
127 | set_ctrl(client, *ctrl); | |
128 | ||
129 | return i2c_master_send(client, (char *)buf, 2); | |
130 | } | |
131 | ||
132 | static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) | |
133 | { | |
134 | unsigned char addr[1]; | |
135 | struct i2c_msg msgs[2] = { | |
136 | { | |
137 | .addr = client->addr, | |
138 | .flags = 0, | |
139 | .len = 1, | |
140 | .buf = addr, | |
141 | }, { | |
142 | .addr = client->addr, | |
143 | .flags = I2C_M_RD, | |
144 | .len = mem->nr, | |
145 | .buf = mem->data, | |
146 | } | |
147 | }; | |
148 | ||
149 | if (mem->loc < 8) | |
150 | return -EINVAL; | |
151 | ||
152 | addr[0] = mem->loc; | |
153 | ||
154 | return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; | |
155 | } | |
156 | ||
157 | static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) | |
158 | { | |
037e291c JD |
159 | unsigned char buf[9]; |
160 | int ret; | |
9c0c5705 | 161 | |
037e291c | 162 | if (mem->loc < 8 || mem->nr > 8) |
9c0c5705 L |
163 | return -EINVAL; |
164 | ||
037e291c JD |
165 | buf[0] = mem->loc; |
166 | memcpy(buf + 1, mem->data, mem->nr); | |
9c0c5705 | 167 | |
037e291c JD |
168 | ret = i2c_master_send(client, buf, mem->nr + 1); |
169 | return ret == mem->nr + 1 ? 0 : -EIO; | |
9c0c5705 L |
170 | } |
171 | ||
172 | static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
173 | { | |
174 | struct i2c_client *client = to_i2c_client(dev); | |
175 | unsigned char ctrl, year[2]; | |
473b8645 JL |
176 | struct rtc_mem mem = { |
177 | .loc = CMOS_YEAR, | |
178 | .nr = sizeof(year), | |
179 | .data = year | |
180 | }; | |
9c0c5705 L |
181 | int real_year, year_offset, err; |
182 | ||
183 | /* | |
184 | * Ensure that the RTC is running. | |
185 | */ | |
186 | pcf8583_get_ctrl(client, &ctrl); | |
187 | if (ctrl & (CTRL_STOP | CTRL_HOLD)) { | |
188 | unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); | |
189 | ||
79d13405 JH |
190 | dev_warn(dev, "resetting control %02x -> %02x\n", |
191 | ctrl, new_ctrl); | |
9c0c5705 | 192 | |
d1bda80a SK |
193 | err = pcf8583_set_ctrl(client, &new_ctrl); |
194 | if (err < 0) | |
9c0c5705 L |
195 | return err; |
196 | } | |
197 | ||
198 | if (pcf8583_get_datetime(client, tm) || | |
199 | pcf8583_read_mem(client, &mem)) | |
200 | return -EIO; | |
201 | ||
202 | real_year = year[0]; | |
203 | ||
204 | /* | |
205 | * The RTC year holds the LSB two bits of the current | |
206 | * year, which should reflect the LSB two bits of the | |
207 | * CMOS copy of the year. Any difference indicates | |
208 | * that we have to correct the CMOS version. | |
209 | */ | |
210 | year_offset = tm->tm_year - (real_year & 3); | |
211 | if (year_offset < 0) | |
212 | /* | |
213 | * RTC year wrapped. Adjust it appropriately. | |
214 | */ | |
215 | year_offset += 4; | |
216 | ||
0ed8f210 | 217 | tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; |
9c0c5705 L |
218 | |
219 | return 0; | |
220 | } | |
221 | ||
222 | static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
223 | { | |
224 | struct i2c_client *client = to_i2c_client(dev); | |
225 | unsigned char year[2], chk; | |
473b8645 JL |
226 | struct rtc_mem cmos_year = { |
227 | .loc = CMOS_YEAR, | |
228 | .nr = sizeof(year), | |
229 | .data = year | |
230 | }; | |
231 | struct rtc_mem cmos_check = { | |
232 | .loc = CMOS_CHECKSUM, | |
233 | .nr = 1, | |
234 | .data = &chk | |
235 | }; | |
0ed8f210 | 236 | unsigned int proper_year = tm->tm_year + 1900; |
9c0c5705 L |
237 | int ret; |
238 | ||
239 | /* | |
240 | * The RTC's own 2-bit year must reflect the least | |
241 | * significant two bits of the CMOS year. | |
242 | */ | |
243 | ||
244 | ret = pcf8583_set_datetime(client, tm, 1); | |
245 | if (ret) | |
246 | return ret; | |
247 | ||
248 | ret = pcf8583_read_mem(client, &cmos_check); | |
249 | if (ret) | |
250 | return ret; | |
251 | ||
252 | ret = pcf8583_read_mem(client, &cmos_year); | |
253 | if (ret) | |
254 | return ret; | |
255 | ||
256 | chk -= year[1] + year[0]; | |
257 | ||
0ed8f210 RK |
258 | year[1] = proper_year / 100; |
259 | year[0] = proper_year % 100; | |
9c0c5705 L |
260 | |
261 | chk += year[1] + year[0]; | |
262 | ||
263 | ret = pcf8583_write_mem(client, &cmos_year); | |
264 | ||
265 | if (ret) | |
266 | return ret; | |
267 | ||
268 | ret = pcf8583_write_mem(client, &cmos_check); | |
269 | ||
270 | return ret; | |
271 | } | |
272 | ||
ff8371ac | 273 | static const struct rtc_class_ops pcf8583_rtc_ops = { |
9c0c5705 L |
274 | .read_time = pcf8583_rtc_read_time, |
275 | .set_time = pcf8583_rtc_set_time, | |
276 | }; | |
277 | ||
02bb584f WS |
278 | static int pcf8583_probe(struct i2c_client *client, |
279 | const struct i2c_device_id *id) | |
9c0c5705 | 280 | { |
02bb584f | 281 | struct pcf8583 *pcf8583; |
9c0c5705 | 282 | |
02bb584f WS |
283 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
284 | return -ENODEV; | |
c018664c | 285 | |
4ad21183 JH |
286 | pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583), |
287 | GFP_KERNEL); | |
02bb584f | 288 | if (!pcf8583) |
9c0c5705 L |
289 | return -ENOMEM; |
290 | ||
b74d2caa AZ |
291 | i2c_set_clientdata(client, pcf8583); |
292 | ||
4ad21183 JH |
293 | pcf8583->rtc = devm_rtc_device_register(&client->dev, |
294 | pcf8583_driver.driver.name, | |
295 | &pcf8583_rtc_ops, THIS_MODULE); | |
9c0c5705 | 296 | |
dac30a98 | 297 | return PTR_ERR_OR_ZERO(pcf8583->rtc); |
02bb584f | 298 | } |
9c0c5705 | 299 | |
02bb584f WS |
300 | static const struct i2c_device_id pcf8583_id[] = { |
301 | { "pcf8583", 0 }, | |
302 | { } | |
303 | }; | |
304 | MODULE_DEVICE_TABLE(i2c, pcf8583_id); | |
9c0c5705 | 305 | |
02bb584f WS |
306 | static struct i2c_driver pcf8583_driver = { |
307 | .driver = { | |
308 | .name = "pcf8583", | |
02bb584f WS |
309 | }, |
310 | .probe = pcf8583_probe, | |
02bb584f WS |
311 | .id_table = pcf8583_id, |
312 | }; | |
9c0c5705 | 313 | |
0abc9201 | 314 | module_i2c_driver(pcf8583_driver); |
9c0c5705 L |
315 | |
316 | MODULE_AUTHOR("Russell King"); | |
317 | MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); | |
318 | MODULE_LICENSE("GPL"); |