ARM: tegra30: pm: flush L1 data before exit coherency on secondary CPU
[linux-2.6.git] / drivers / rtc / rtc-isl12022.c
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>
18
19 #define DRV_VERSION "0.1"
20
21 /* ISL register offsets */
22 #define ISL12022_REG_SC         0x00
23 #define ISL12022_REG_MN         0x01
24 #define ISL12022_REG_HR         0x02
25 #define ISL12022_REG_DT         0x03
26 #define ISL12022_REG_MO         0x04
27 #define ISL12022_REG_YR         0x05
28 #define ISL12022_REG_DW         0x06
29
30 #define ISL12022_REG_SR         0x07
31 #define ISL12022_REG_INT        0x08
32
33 /* ISL register bits */
34 #define ISL12022_HR_MIL         (1 << 7)        /* military or 24 hour time */
35
36 #define ISL12022_SR_LBAT85      (1 << 2)
37 #define ISL12022_SR_LBAT75      (1 << 1)
38
39 #define ISL12022_INT_WRTC       (1 << 6)
40
41
42 static struct i2c_driver isl12022_driver;
43
44 struct isl12022 {
45         struct rtc_device *rtc;
46
47         bool write_enabled;     /* true if write enable is set */
48 };
49
50
51 static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
52                               uint8_t *data, size_t n)
53 {
54         struct i2c_msg msgs[] = {
55                 {
56                         .addr   = client->addr,
57                         .flags  = 0,
58                         .len    = 1,
59                         .buf    = data
60                 },              /* setup read ptr */
61                 {
62                         .addr   = client->addr,
63                         .flags  = I2C_M_RD,
64                         .len    = n,
65                         .buf    = data
66                 }
67         };
68
69         int ret;
70
71         data[0] = reg;
72         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
73         if (ret != ARRAY_SIZE(msgs)) {
74                 dev_err(&client->dev, "%s: read error, ret=%d\n",
75                         __func__, ret);
76                 return -EIO;
77         }
78
79         return 0;
80 }
81
82
83 static int isl12022_write_reg(struct i2c_client *client,
84                               uint8_t reg, uint8_t val)
85 {
86         uint8_t data[2] = { reg, val };
87         int err;
88
89         err = i2c_master_send(client, data, sizeof(data));
90         if (err != sizeof(data)) {
91                 dev_err(&client->dev,
92                         "%s: err=%d addr=%02x, data=%02x\n",
93                         __func__, err, data[0], data[1]);
94                 return -EIO;
95         }
96
97         return 0;
98 }
99
100
101 /*
102  * In the routines that deal directly with the isl12022 hardware, we use
103  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
104  */
105 static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
106 {
107         uint8_t buf[ISL12022_REG_INT + 1];
108         int ret;
109
110         ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
111         if (ret)
112                 return ret;
113
114         if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
115                 dev_warn(&client->dev,
116                          "voltage dropped below %u%%, "
117                          "date and time is not reliable.\n",
118                          buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
119         }
120
121         dev_dbg(&client->dev,
122                 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
123                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
124                 "sr=%02x, int=%02x",
125                 __func__,
126                 buf[ISL12022_REG_SC],
127                 buf[ISL12022_REG_MN],
128                 buf[ISL12022_REG_HR],
129                 buf[ISL12022_REG_DT],
130                 buf[ISL12022_REG_MO],
131                 buf[ISL12022_REG_YR],
132                 buf[ISL12022_REG_DW],
133                 buf[ISL12022_REG_SR],
134                 buf[ISL12022_REG_INT]);
135
136         tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
137         tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
138         tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
139         tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
140         tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
141         tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
142         tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
143
144         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
145                 "mday=%d, mon=%d, year=%d, wday=%d\n",
146                 __func__,
147                 tm->tm_sec, tm->tm_min, tm->tm_hour,
148                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
149
150         /* The clock can give out invalid datetime, but we cannot return
151          * -EINVAL otherwise hwclock will refuse to set the time on bootup. */
152         if (rtc_valid_tm(tm) < 0)
153                 dev_err(&client->dev, "retrieved date and time is invalid.\n");
154
155         return 0;
156 }
157
158 static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
159 {
160         struct isl12022 *isl12022 = i2c_get_clientdata(client);
161         size_t i;
162         int ret;
163         uint8_t buf[ISL12022_REG_DW + 1];
164
165         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
166                 "mday=%d, mon=%d, year=%d, wday=%d\n",
167                 __func__,
168                 tm->tm_sec, tm->tm_min, tm->tm_hour,
169                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
170
171         if (!isl12022->write_enabled) {
172
173                 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
174                 if (ret)
175                         return ret;
176
177                 /* Check if WRTC (write rtc enable) is set factory default is
178                  * 0 (not set) */
179                 if (!(buf[0] & ISL12022_INT_WRTC)) {
180                         dev_info(&client->dev,
181                                  "init write enable and 24 hour format\n");
182
183                         /* Set the write enable bit. */
184                         ret = isl12022_write_reg(client,
185                                                  ISL12022_REG_INT,
186                                                  buf[0] | ISL12022_INT_WRTC);
187                         if (ret)
188                                 return ret;
189
190                         /* Write to any RTC register to start RTC, we use the
191                          * HR register, setting the MIL bit to use the 24 hour
192                          * format. */
193                         ret = isl12022_read_regs(client, ISL12022_REG_HR,
194                                                  buf, 1);
195                         if (ret)
196                                 return ret;
197
198                         ret = isl12022_write_reg(client,
199                                                  ISL12022_REG_HR,
200                                                  buf[0] | ISL12022_HR_MIL);
201                         if (ret)
202                                 return ret;
203                 }
204
205                 isl12022->write_enabled = 1;
206         }
207
208         /* hours, minutes and seconds */
209         buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
210         buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
211         buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
212
213         buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
214
215         /* month, 1 - 12 */
216         buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
217
218         /* year and century */
219         buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
220
221         buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
222
223         /* write register's data */
224         for (i = 0; i < ARRAY_SIZE(buf); i++) {
225                 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
226                                          buf[ISL12022_REG_SC + i]);
227                 if (ret)
228                         return -EIO;
229         };
230
231         return 0;
232 }
233
234 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
235 {
236         return isl12022_get_datetime(to_i2c_client(dev), tm);
237 }
238
239 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
240 {
241         return isl12022_set_datetime(to_i2c_client(dev), tm);
242 }
243
244 static const struct rtc_class_ops isl12022_rtc_ops = {
245         .read_time      = isl12022_rtc_read_time,
246         .set_time       = isl12022_rtc_set_time,
247 };
248
249 static int isl12022_probe(struct i2c_client *client,
250                           const struct i2c_device_id *id)
251 {
252         struct isl12022 *isl12022;
253
254         int ret = 0;
255
256         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
257                 return -ENODEV;
258
259         isl12022 = kzalloc(sizeof(struct isl12022), GFP_KERNEL);
260         if (!isl12022)
261                 return -ENOMEM;
262
263         dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n");
264
265         i2c_set_clientdata(client, isl12022);
266
267         isl12022->rtc = rtc_device_register(isl12022_driver.driver.name,
268                                             &client->dev,
269                                             &isl12022_rtc_ops,
270                                             THIS_MODULE);
271
272         if (IS_ERR(isl12022->rtc)) {
273                 ret = PTR_ERR(isl12022->rtc);
274                 goto exit_kfree;
275         }
276
277         return 0;
278
279 exit_kfree:
280         kfree(isl12022);
281
282         return ret;
283 }
284
285 static int isl12022_remove(struct i2c_client *client)
286 {
287         struct isl12022 *isl12022 = i2c_get_clientdata(client);
288
289         rtc_device_unregister(isl12022->rtc);
290         kfree(isl12022);
291
292         return 0;
293 }
294
295 static const struct i2c_device_id isl12022_id[] = {
296         { "isl12022", 0 },
297         { "rtc8564", 0 },
298         { }
299 };
300 MODULE_DEVICE_TABLE(i2c, isl12022_id);
301
302 static struct i2c_driver isl12022_driver = {
303         .driver         = {
304                 .name   = "rtc-isl12022",
305         },
306         .probe          = isl12022_probe,
307         .remove         = isl12022_remove,
308         .id_table       = isl12022_id,
309 };
310
311 static int __init isl12022_init(void)
312 {
313         return i2c_add_driver(&isl12022_driver);
314 }
315
316 static void __exit isl12022_exit(void)
317 {
318         i2c_del_driver(&isl12022_driver);
319 }
320
321 module_init(isl12022_init);
322 module_exit(isl12022_exit);
323
324 MODULE_AUTHOR("roman.fietze@telemotive.de");
325 MODULE_DESCRIPTION("ISL 12022 RTC driver");
326 MODULE_LICENSE("GPL");
327 MODULE_VERSION(DRV_VERSION);