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 #include <linux/module.h>
19
20 #define DRV_VERSION "0.1"
21
22 /* ISL register offsets */
23 #define ISL12022_REG_SC 0x00
24 #define ISL12022_REG_MN 0x01
25 #define ISL12022_REG_HR 0x02
26 #define ISL12022_REG_DT 0x03
27 #define ISL12022_REG_MO 0x04
28 #define ISL12022_REG_YR 0x05
29 #define ISL12022_REG_DW 0x06
30
31 #define ISL12022_REG_SR 0x07
32 #define ISL12022_REG_INT 0x08
33
34 /* ISL register bits */
35 #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
36
37 #define ISL12022_SR_LBAT85 (1 << 2)
38 #define ISL12022_SR_LBAT75 (1 << 1)
39
40 #define ISL12022_INT_WRTC (1 << 6)
41
42
43 static struct i2c_driver isl12022_driver;
44
45 struct isl12022 {
46 struct rtc_device *rtc;
47
48 bool write_enabled; /* true if write enable is set */
49 };
50
51
isl12022_read_regs(struct i2c_client * client,uint8_t reg,uint8_t * data,size_t n)52 static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
53 uint8_t *data, size_t n)
54 {
55 struct i2c_msg msgs[] = {
56 {
57 .addr = client->addr,
58 .flags = 0,
59 .len = 1,
60 .buf = data
61 }, /* setup read ptr */
62 {
63 .addr = client->addr,
64 .flags = I2C_M_RD,
65 .len = n,
66 .buf = data
67 }
68 };
69
70 int ret;
71
72 data[0] = reg;
73 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
74 if (ret != ARRAY_SIZE(msgs)) {
75 dev_err(&client->dev, "%s: read error, ret=%d\n",
76 __func__, ret);
77 return -EIO;
78 }
79
80 return 0;
81 }
82
83
isl12022_write_reg(struct i2c_client * client,uint8_t reg,uint8_t val)84 static int isl12022_write_reg(struct i2c_client *client,
85 uint8_t reg, uint8_t val)
86 {
87 uint8_t data[2] = { reg, val };
88 int err;
89
90 err = i2c_master_send(client, data, sizeof(data));
91 if (err != sizeof(data)) {
92 dev_err(&client->dev,
93 "%s: err=%d addr=%02x, data=%02x\n",
94 __func__, err, data[0], data[1]);
95 return -EIO;
96 }
97
98 return 0;
99 }
100
101
102 /*
103 * In the routines that deal directly with the isl12022 hardware, we use
104 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
105 */
isl12022_get_datetime(struct i2c_client * client,struct rtc_time * tm)106 static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
107 {
108 uint8_t buf[ISL12022_REG_INT + 1];
109 int ret;
110
111 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
112 if (ret)
113 return ret;
114
115 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
116 dev_warn(&client->dev,
117 "voltage dropped below %u%%, "
118 "date and time is not reliable.\n",
119 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
120 }
121
122 dev_dbg(&client->dev,
123 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
124 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
125 "sr=%02x, int=%02x",
126 __func__,
127 buf[ISL12022_REG_SC],
128 buf[ISL12022_REG_MN],
129 buf[ISL12022_REG_HR],
130 buf[ISL12022_REG_DT],
131 buf[ISL12022_REG_MO],
132 buf[ISL12022_REG_YR],
133 buf[ISL12022_REG_DW],
134 buf[ISL12022_REG_SR],
135 buf[ISL12022_REG_INT]);
136
137 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
138 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
139 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
140 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
141 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
142 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
143 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
144
145 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
146 "mday=%d, mon=%d, year=%d, wday=%d\n",
147 __func__,
148 tm->tm_sec, tm->tm_min, tm->tm_hour,
149 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
150
151 /* The clock can give out invalid datetime, but we cannot return
152 * -EINVAL otherwise hwclock will refuse to set the time on bootup. */
153 if (rtc_valid_tm(tm) < 0)
154 dev_err(&client->dev, "retrieved date and time is invalid.\n");
155
156 return 0;
157 }
158
isl12022_set_datetime(struct i2c_client * client,struct rtc_time * tm)159 static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
160 {
161 struct isl12022 *isl12022 = i2c_get_clientdata(client);
162 size_t i;
163 int ret;
164 uint8_t buf[ISL12022_REG_DW + 1];
165
166 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
167 "mday=%d, mon=%d, year=%d, wday=%d\n",
168 __func__,
169 tm->tm_sec, tm->tm_min, tm->tm_hour,
170 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
171
172 if (!isl12022->write_enabled) {
173
174 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
175 if (ret)
176 return ret;
177
178 /* Check if WRTC (write rtc enable) is set factory default is
179 * 0 (not set) */
180 if (!(buf[0] & ISL12022_INT_WRTC)) {
181 dev_info(&client->dev,
182 "init write enable and 24 hour format\n");
183
184 /* Set the write enable bit. */
185 ret = isl12022_write_reg(client,
186 ISL12022_REG_INT,
187 buf[0] | ISL12022_INT_WRTC);
188 if (ret)
189 return ret;
190
191 /* Write to any RTC register to start RTC, we use the
192 * HR register, setting the MIL bit to use the 24 hour
193 * format. */
194 ret = isl12022_read_regs(client, ISL12022_REG_HR,
195 buf, 1);
196 if (ret)
197 return ret;
198
199 ret = isl12022_write_reg(client,
200 ISL12022_REG_HR,
201 buf[0] | ISL12022_HR_MIL);
202 if (ret)
203 return ret;
204 }
205
206 isl12022->write_enabled = 1;
207 }
208
209 /* hours, minutes and seconds */
210 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
211 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
212 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
213
214 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
215
216 /* month, 1 - 12 */
217 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
218
219 /* year and century */
220 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
221
222 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
223
224 /* write register's data */
225 for (i = 0; i < ARRAY_SIZE(buf); i++) {
226 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
227 buf[ISL12022_REG_SC + i]);
228 if (ret)
229 return -EIO;
230 };
231
232 return 0;
233 }
234
isl12022_rtc_read_time(struct device * dev,struct rtc_time * tm)235 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
236 {
237 return isl12022_get_datetime(to_i2c_client(dev), tm);
238 }
239
isl12022_rtc_set_time(struct device * dev,struct rtc_time * tm)240 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
241 {
242 return isl12022_set_datetime(to_i2c_client(dev), tm);
243 }
244
245 static const struct rtc_class_ops isl12022_rtc_ops = {
246 .read_time = isl12022_rtc_read_time,
247 .set_time = isl12022_rtc_set_time,
248 };
249
isl12022_probe(struct i2c_client * client,const struct i2c_device_id * id)250 static int isl12022_probe(struct i2c_client *client,
251 const struct i2c_device_id *id)
252 {
253 struct isl12022 *isl12022;
254
255 int ret = 0;
256
257 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
258 return -ENODEV;
259
260 isl12022 = kzalloc(sizeof(struct isl12022), GFP_KERNEL);
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
268 isl12022->rtc = rtc_device_register(isl12022_driver.driver.name,
269 &client->dev,
270 &isl12022_rtc_ops,
271 THIS_MODULE);
272
273 if (IS_ERR(isl12022->rtc)) {
274 ret = PTR_ERR(isl12022->rtc);
275 goto exit_kfree;
276 }
277
278 return 0;
279
280 exit_kfree:
281 kfree(isl12022);
282
283 return ret;
284 }
285
isl12022_remove(struct i2c_client * client)286 static int isl12022_remove(struct i2c_client *client)
287 {
288 struct isl12022 *isl12022 = i2c_get_clientdata(client);
289
290 rtc_device_unregister(isl12022->rtc);
291 kfree(isl12022);
292
293 return 0;
294 }
295
296 static const struct i2c_device_id isl12022_id[] = {
297 { "isl12022", 0 },
298 { "rtc8564", 0 },
299 { }
300 };
301 MODULE_DEVICE_TABLE(i2c, isl12022_id);
302
303 static struct i2c_driver isl12022_driver = {
304 .driver = {
305 .name = "rtc-isl12022",
306 },
307 .probe = isl12022_probe,
308 .remove = isl12022_remove,
309 .id_table = isl12022_id,
310 };
311
312 module_i2c_driver(isl12022_driver);
313
314 MODULE_AUTHOR("roman.fietze@telemotive.de");
315 MODULE_DESCRIPTION("ISL 12022 RTC driver");
316 MODULE_LICENSE("GPL");
317 MODULE_VERSION(DRV_VERSION);
318