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1/*
2 * drivers/rtc/rtc-pcf8583.c
3 *
4 * Copyright (C) 2000 Russell King
5 * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
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>
18#include <linux/rtc.h>
19#include <linux/init.h>
20#include <linux/err.h>
21#include <linux/errno.h>
22#include <linux/bcd.h>
23
24struct rtc_mem {
25 unsigned int loc;
26 unsigned int nr;
27 unsigned char *data;
28};
29
30struct pcf8583 {
31 struct rtc_device *rtc;
32 unsigned char ctrl;
33};
34
35#define CTRL_STOP 0x80
36#define CTRL_HOLD 0x40
37#define CTRL_32KHZ 0x00
38#define CTRL_MASK 0x08
39#define CTRL_ALARMEN 0x04
40#define CTRL_ALARM 0x02
41#define CTRL_TIMER 0x01
42
43
44static struct i2c_driver pcf8583_driver;
45
46#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
47#define set_ctrl(x, v) get_ctrl(x) = v
48
49#define CMOS_YEAR (64 + 128)
50#define CMOS_CHECKSUM (63)
51
52static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)
53{
54 unsigned char buf[8], addr[1] = { 1 };
55 struct i2c_msg msgs[2] = {
56 {
57 .addr = client->addr,
58 .flags = 0,
59 .len = 1,
60 .buf = addr,
61 }, {
62 .addr = client->addr,
63 .flags = I2C_M_RD,
64 .len = 6,
65 .buf = buf,
66 }
67 };
68 int ret;
69
70 memset(buf, 0, sizeof(buf));
71
72 ret = i2c_transfer(client->adapter, msgs, 2);
73 if (ret == 2) {
74 dt->tm_year = buf[4] >> 6;
75 dt->tm_wday = buf[5] >> 5;
76
77 buf[4] &= 0x3f;
78 buf[5] &= 0x1f;
79
80 dt->tm_sec = bcd2bin(buf[1]);
81 dt->tm_min = bcd2bin(buf[2]);
82 dt->tm_hour = bcd2bin(buf[3]);
83 dt->tm_mday = bcd2bin(buf[4]);
84 dt->tm_mon = bcd2bin(buf[5]) - 1;
85 }
86
87 return ret == 2 ? 0 : -EIO;
88}
89
90static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)
91{
92 unsigned char buf[8];
93 int ret, len = 6;
94
95 buf[0] = 0;
96 buf[1] = get_ctrl(client) | 0x80;
97 buf[2] = 0;
98 buf[3] = bin2bcd(dt->tm_sec);
99 buf[4] = bin2bcd(dt->tm_min);
100 buf[5] = bin2bcd(dt->tm_hour);
101
102 if (datetoo) {
103 len = 8;
104 buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6);
105 buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5);
106 }
107
108 ret = i2c_master_send(client, (char *)buf, len);
109 if (ret != len)
110 return -EIO;
111
112 buf[1] = get_ctrl(client);
113 ret = i2c_master_send(client, (char *)buf, 2);
114
115 return ret == 2 ? 0 : -EIO;
116}
117
118static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
119{
120 *ctrl = get_ctrl(client);
121 return 0;
122}
123
124static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
125{
126 unsigned char buf[2];
127
128 buf[0] = 0;
129 buf[1] = *ctrl;
130 set_ctrl(client, *ctrl);
131
132 return i2c_master_send(client, (char *)buf, 2);
133}
134
135static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)
136{
137 unsigned char addr[1];
138 struct i2c_msg msgs[2] = {
139 {
140 .addr = client->addr,
141 .flags = 0,
142 .len = 1,
143 .buf = addr,
144 }, {
145 .addr = client->addr,
146 .flags = I2C_M_RD,
147 .len = mem->nr,
148 .buf = mem->data,
149 }
150 };
151
152 if (mem->loc < 8)
153 return -EINVAL;
154
155 addr[0] = mem->loc;
156
157 return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
158}
159
160static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
161{
162 unsigned char buf[9];
163 int ret;
164
165 if (mem->loc < 8 || mem->nr > 8)
166 return -EINVAL;
167
168 buf[0] = mem->loc;
169 memcpy(buf + 1, mem->data, mem->nr);
170
171 ret = i2c_master_send(client, buf, mem->nr + 1);
172 return ret == mem->nr + 1 ? 0 : -EIO;
173}
174
175static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)
176{
177 struct i2c_client *client = to_i2c_client(dev);
178 unsigned char ctrl, year[2];
179 struct rtc_mem mem = {
180 .loc = CMOS_YEAR,
181 .nr = sizeof(year),
182 .data = year
183 };
184 int real_year, year_offset, err;
185
186 /*
187 * Ensure that the RTC is running.
188 */
189 pcf8583_get_ctrl(client, &ctrl);
190 if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
191 unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);
192
193 dev_warn(dev, "resetting control %02x -> %02x\n",
194 ctrl, new_ctrl);
195
196 err = pcf8583_set_ctrl(client, &new_ctrl);
197 if (err < 0)
198 return err;
199 }
200
201 if (pcf8583_get_datetime(client, tm) ||
202 pcf8583_read_mem(client, &mem))
203 return -EIO;
204
205 real_year = year[0];
206
207 /*
208 * The RTC year holds the LSB two bits of the current
209 * year, which should reflect the LSB two bits of the
210 * CMOS copy of the year. Any difference indicates
211 * that we have to correct the CMOS version.
212 */
213 year_offset = tm->tm_year - (real_year & 3);
214 if (year_offset < 0)
215 /*
216 * RTC year wrapped. Adjust it appropriately.
217 */
218 year_offset += 4;
219
220 tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
221
222 return 0;
223}
224
225static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
226{
227 struct i2c_client *client = to_i2c_client(dev);
228 unsigned char year[2], chk;
229 struct rtc_mem cmos_year = {
230 .loc = CMOS_YEAR,
231 .nr = sizeof(year),
232 .data = year
233 };
234 struct rtc_mem cmos_check = {
235 .loc = CMOS_CHECKSUM,
236 .nr = 1,
237 .data = &chk
238 };
239 unsigned int proper_year = tm->tm_year + 1900;
240 int ret;
241
242 /*
243 * The RTC's own 2-bit year must reflect the least
244 * significant two bits of the CMOS year.
245 */
246
247 ret = pcf8583_set_datetime(client, tm, 1);
248 if (ret)
249 return ret;
250
251 ret = pcf8583_read_mem(client, &cmos_check);
252 if (ret)
253 return ret;
254
255 ret = pcf8583_read_mem(client, &cmos_year);
256 if (ret)
257 return ret;
258
259 chk -= year[1] + year[0];
260
261 year[1] = proper_year / 100;
262 year[0] = proper_year % 100;
263
264 chk += year[1] + year[0];
265
266 ret = pcf8583_write_mem(client, &cmos_year);
267
268 if (ret)
269 return ret;
270
271 ret = pcf8583_write_mem(client, &cmos_check);
272
273 return ret;
274}
275
276static const struct rtc_class_ops pcf8583_rtc_ops = {
277 .read_time = pcf8583_rtc_read_time,
278 .set_time = pcf8583_rtc_set_time,
279};
280
281static int pcf8583_probe(struct i2c_client *client,
282 const struct i2c_device_id *id)
283{
284 struct pcf8583 *pcf8583;
285
286 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
287 return -ENODEV;
288
289 pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
290 GFP_KERNEL);
291 if (!pcf8583)
292 return -ENOMEM;
293
294 i2c_set_clientdata(client, pcf8583);
295
296 pcf8583->rtc = devm_rtc_device_register(&client->dev,
297 pcf8583_driver.driver.name,
298 &pcf8583_rtc_ops, THIS_MODULE);
299
300 return PTR_ERR_OR_ZERO(pcf8583->rtc);
301}
302
303static const struct i2c_device_id pcf8583_id[] = {
304 { "pcf8583", 0 },
305 { }
306};
307MODULE_DEVICE_TABLE(i2c, pcf8583_id);
308
309static struct i2c_driver pcf8583_driver = {
310 .driver = {
311 .name = "pcf8583",
312 },
313 .probe = pcf8583_probe,
314 .id_table = pcf8583_id,
315};
316
317module_i2c_driver(pcf8583_driver);
318
319MODULE_AUTHOR("Russell King");
320MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
321MODULE_LICENSE("GPL");
1/*
2 * drivers/rtc/rtc-pcf8583.c
3 *
4 * Copyright (C) 2000 Russell King
5 * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
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>
18#include <linux/rtc.h>
19#include <linux/init.h>
20#include <linux/errno.h>
21#include <linux/bcd.h>
22
23struct rtc_mem {
24 unsigned int loc;
25 unsigned int nr;
26 unsigned char *data;
27};
28
29struct pcf8583 {
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
42
43static 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
51static 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
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;
84 }
85
86 return ret == 2 ? 0 : -EIO;
87}
88
89static 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;
97 buf[3] = bin2bcd(dt->tm_sec);
98 buf[4] = bin2bcd(dt->tm_min);
99 buf[5] = bin2bcd(dt->tm_hour);
100
101 if (datetoo) {
102 len = 8;
103 buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6);
104 buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5);
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
117static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
118{
119 *ctrl = get_ctrl(client);
120 return 0;
121}
122
123static 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
134static 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
159static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
160{
161 unsigned char buf[9];
162 int ret;
163
164 if (mem->loc < 8 || mem->nr > 8)
165 return -EINVAL;
166
167 buf[0] = mem->loc;
168 memcpy(buf + 1, mem->data, mem->nr);
169
170 ret = i2c_master_send(client, buf, mem->nr + 1);
171 return ret == mem->nr + 1 ? 0 : -EIO;
172}
173
174static 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
188 printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",
189 ctrl, new_ctrl);
190
191 if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0)
192 return err;
193 }
194
195 if (pcf8583_get_datetime(client, tm) ||
196 pcf8583_read_mem(client, &mem))
197 return -EIO;
198
199 real_year = year[0];
200
201 /*
202 * The RTC year holds the LSB two bits of the current
203 * year, which should reflect the LSB two bits of the
204 * CMOS copy of the year. Any difference indicates
205 * that we have to correct the CMOS version.
206 */
207 year_offset = tm->tm_year - (real_year & 3);
208 if (year_offset < 0)
209 /*
210 * RTC year wrapped. Adjust it appropriately.
211 */
212 year_offset += 4;
213
214 tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
215
216 return 0;
217}
218
219static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
220{
221 struct i2c_client *client = to_i2c_client(dev);
222 unsigned char year[2], chk;
223 struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year };
224 struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
225 unsigned int proper_year = tm->tm_year + 1900;
226 int ret;
227
228 /*
229 * The RTC's own 2-bit year must reflect the least
230 * significant two bits of the CMOS year.
231 */
232
233 ret = pcf8583_set_datetime(client, tm, 1);
234 if (ret)
235 return ret;
236
237 ret = pcf8583_read_mem(client, &cmos_check);
238 if (ret)
239 return ret;
240
241 ret = pcf8583_read_mem(client, &cmos_year);
242 if (ret)
243 return ret;
244
245 chk -= year[1] + year[0];
246
247 year[1] = proper_year / 100;
248 year[0] = proper_year % 100;
249
250 chk += year[1] + year[0];
251
252 ret = pcf8583_write_mem(client, &cmos_year);
253
254 if (ret)
255 return ret;
256
257 ret = pcf8583_write_mem(client, &cmos_check);
258
259 return ret;
260}
261
262static const struct rtc_class_ops pcf8583_rtc_ops = {
263 .read_time = pcf8583_rtc_read_time,
264 .set_time = pcf8583_rtc_set_time,
265};
266
267static int pcf8583_probe(struct i2c_client *client,
268 const struct i2c_device_id *id)
269{
270 struct pcf8583 *pcf8583;
271 int err;
272
273 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
274 return -ENODEV;
275
276 pcf8583 = kzalloc(sizeof(struct pcf8583), GFP_KERNEL);
277 if (!pcf8583)
278 return -ENOMEM;
279
280 i2c_set_clientdata(client, pcf8583);
281
282 pcf8583->rtc = rtc_device_register(pcf8583_driver.driver.name,
283 &client->dev, &pcf8583_rtc_ops, THIS_MODULE);
284
285 if (IS_ERR(pcf8583->rtc)) {
286 err = PTR_ERR(pcf8583->rtc);
287 goto exit_kfree;
288 }
289
290 return 0;
291
292exit_kfree:
293 kfree(pcf8583);
294 return err;
295}
296
297static int __devexit pcf8583_remove(struct i2c_client *client)
298{
299 struct pcf8583 *pcf8583 = i2c_get_clientdata(client);
300
301 if (pcf8583->rtc)
302 rtc_device_unregister(pcf8583->rtc);
303 kfree(pcf8583);
304 return 0;
305}
306
307static const struct i2c_device_id pcf8583_id[] = {
308 { "pcf8583", 0 },
309 { }
310};
311MODULE_DEVICE_TABLE(i2c, pcf8583_id);
312
313static struct i2c_driver pcf8583_driver = {
314 .driver = {
315 .name = "pcf8583",
316 .owner = THIS_MODULE,
317 },
318 .probe = pcf8583_probe,
319 .remove = __devexit_p(pcf8583_remove),
320 .id_table = pcf8583_id,
321};
322
323static __init int pcf8583_init(void)
324{
325 return i2c_add_driver(&pcf8583_driver);
326}
327
328static __exit void pcf8583_exit(void)
329{
330 i2c_del_driver(&pcf8583_driver);
331}
332
333module_init(pcf8583_init);
334module_exit(pcf8583_exit);
335
336MODULE_AUTHOR("Russell King");
337MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
338MODULE_LICENSE("GPL");