1 /*
2  * Micro Crystal RV-3029C2 rtc class driver
3  *
4  * Author: Gregory Hermant <gregory.hermant@calao-systems.com>
5  *
6  * based on previously existing rtc class drivers
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  * NOTE: Currently this driver only supports the bare minimum for read
13  * and write the RTC and alarms. The extra features provided by this chip
14  * (trickle charger, eeprom, T° compensation) are unavailable.
15  */
16 
17 #include <linux/module.h>
18 #include <linux/i2c.h>
19 #include <linux/bcd.h>
20 #include <linux/rtc.h>
21 
22 /* Register map */
23 /* control section */
24 #define RV3029C2_ONOFF_CTRL		0x00
25 #define RV3029C2_IRQ_CTRL		0x01
26 #define RV3029C2_IRQ_CTRL_AIE		(1 << 0)
27 #define RV3029C2_IRQ_FLAGS		0x02
28 #define RV3029C2_IRQ_FLAGS_AF		(1 << 0)
29 #define RV3029C2_STATUS			0x03
30 #define RV3029C2_STATUS_VLOW1		(1 << 2)
31 #define RV3029C2_STATUS_VLOW2		(1 << 3)
32 #define RV3029C2_STATUS_SR		(1 << 4)
33 #define RV3029C2_STATUS_PON		(1 << 5)
34 #define RV3029C2_STATUS_EEBUSY		(1 << 7)
35 #define RV3029C2_RST_CTRL		0x04
36 #define RV3029C2_CONTROL_SECTION_LEN	0x05
37 
38 /* watch section */
39 #define RV3029C2_W_SEC			0x08
40 #define RV3029C2_W_MINUTES		0x09
41 #define RV3029C2_W_HOURS		0x0A
42 #define RV3029C2_REG_HR_12_24		(1<<6)  /* 24h/12h mode */
43 #define RV3029C2_REG_HR_PM		(1<<5)  /* PM/AM bit in 12h mode */
44 #define RV3029C2_W_DATE			0x0B
45 #define RV3029C2_W_DAYS			0x0C
46 #define RV3029C2_W_MONTHS		0x0D
47 #define RV3029C2_W_YEARS		0x0E
48 #define RV3029C2_WATCH_SECTION_LEN	0x07
49 
50 /* alarm section */
51 #define RV3029C2_A_SC			0x10
52 #define RV3029C2_A_MN			0x11
53 #define RV3029C2_A_HR			0x12
54 #define RV3029C2_A_DT			0x13
55 #define RV3029C2_A_DW			0x14
56 #define RV3029C2_A_MO			0x15
57 #define RV3029C2_A_YR			0x16
58 #define RV3029C2_ALARM_SECTION_LEN	0x07
59 
60 /* timer section */
61 #define RV3029C2_TIMER_LOW		0x18
62 #define RV3029C2_TIMER_HIGH		0x19
63 
64 /* temperature section */
65 #define RV3029C2_TEMP_PAGE		0x20
66 
67 /* eeprom data section */
68 #define RV3029C2_E2P_EEDATA1		0x28
69 #define RV3029C2_E2P_EEDATA2		0x29
70 
71 /* eeprom control section */
72 #define RV3029C2_CONTROL_E2P_EECTRL	0x30
73 #define RV3029C2_TRICKLE_1K		(1<<0)  /*  1K resistance */
74 #define RV3029C2_TRICKLE_5K		(1<<1)  /*  5K resistance */
75 #define RV3029C2_TRICKLE_20K		(1<<2)  /* 20K resistance */
76 #define RV3029C2_TRICKLE_80K		(1<<3)  /* 80K resistance */
77 #define RV3029C2_CONTROL_E2P_XTALOFFSET	0x31
78 #define RV3029C2_CONTROL_E2P_QCOEF	0x32
79 #define RV3029C2_CONTROL_E2P_TURNOVER	0x33
80 
81 /* user ram section */
82 #define RV3029C2_USR1_RAM_PAGE		0x38
83 #define RV3029C2_USR1_SECTION_LEN	0x04
84 #define RV3029C2_USR2_RAM_PAGE		0x3C
85 #define RV3029C2_USR2_SECTION_LEN	0x04
86 
87 static int
rv3029c2_i2c_read_regs(struct i2c_client * client,u8 reg,u8 * buf,unsigned len)88 rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
89 	unsigned len)
90 {
91 	int ret;
92 
93 	if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
94 		(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
95 		return -EINVAL;
96 
97 	ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
98 	if (ret < 0)
99 		return ret;
100 	if (ret < len)
101 		return -EIO;
102 	return 0;
103 }
104 
105 static int
rv3029c2_i2c_write_regs(struct i2c_client * client,u8 reg,u8 const buf[],unsigned len)106 rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
107 			unsigned len)
108 {
109 	if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
110 		(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
111 		return -EINVAL;
112 
113 	return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
114 }
115 
116 static int
rv3029c2_i2c_get_sr(struct i2c_client * client,u8 * buf)117 rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
118 {
119 	int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
120 
121 	if (ret < 0)
122 		return -EIO;
123 	dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
124 	return 0;
125 }
126 
127 static int
rv3029c2_i2c_set_sr(struct i2c_client * client,u8 val)128 rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
129 {
130 	u8 buf[1];
131 	int sr;
132 
133 	buf[0] = val;
134 	sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
135 	dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
136 	if (sr < 0)
137 		return -EIO;
138 	return 0;
139 }
140 
141 static int
rv3029c2_i2c_read_time(struct i2c_client * client,struct rtc_time * tm)142 rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
143 {
144 	u8 buf[1];
145 	int ret;
146 	u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
147 
148 	ret = rv3029c2_i2c_get_sr(client, buf);
149 	if (ret < 0) {
150 		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
151 		return -EIO;
152 	}
153 
154 	ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
155 					RV3029C2_WATCH_SECTION_LEN);
156 	if (ret < 0) {
157 		dev_err(&client->dev, "%s: reading RTC section failed\n",
158 			__func__);
159 		return ret;
160 	}
161 
162 	tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
163 	tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
164 
165 	/* HR field has a more complex interpretation */
166 	{
167 		const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
168 		if (_hr & RV3029C2_REG_HR_12_24) {
169 			/* 12h format */
170 			tm->tm_hour = bcd2bin(_hr & 0x1f);
171 			if (_hr & RV3029C2_REG_HR_PM)	/* PM flag set */
172 				tm->tm_hour += 12;
173 		} else /* 24h format */
174 			tm->tm_hour = bcd2bin(_hr & 0x3f);
175 	}
176 
177 	tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
178 	tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
179 	tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
180 	tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
181 
182 	return 0;
183 }
184 
rv3029c2_rtc_read_time(struct device * dev,struct rtc_time * tm)185 static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
186 {
187 	return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
188 }
189 
190 static int
rv3029c2_i2c_read_alarm(struct i2c_client * client,struct rtc_wkalrm * alarm)191 rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
192 {
193 	struct rtc_time *const tm = &alarm->time;
194 	int ret;
195 	u8 regs[8];
196 
197 	ret = rv3029c2_i2c_get_sr(client, regs);
198 	if (ret < 0) {
199 		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
200 		return -EIO;
201 	}
202 
203 	ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
204 					RV3029C2_ALARM_SECTION_LEN);
205 
206 	if (ret < 0) {
207 		dev_err(&client->dev, "%s: reading alarm section failed\n",
208 			__func__);
209 		return ret;
210 	}
211 
212 	tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
213 	tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
214 	tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
215 	tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
216 	tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
217 	tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
218 	tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
219 
220 	return 0;
221 }
222 
223 static int
rv3029c2_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)224 rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
225 {
226 	return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
227 }
228 
rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client * client,int enable)229 static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
230 					int enable)
231 {
232 	int ret;
233 	u8 buf[1];
234 
235 	/* enable AIE irq */
236 	ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL,	buf, 1);
237 	if (ret < 0) {
238 		dev_err(&client->dev, "can't read INT reg\n");
239 		return ret;
240 	}
241 	if (enable)
242 		buf[0] |= RV3029C2_IRQ_CTRL_AIE;
243 	else
244 		buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
245 
246 	ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
247 	if (ret < 0) {
248 		dev_err(&client->dev, "can't set INT reg\n");
249 		return ret;
250 	}
251 
252 	return 0;
253 }
254 
rv3029c2_rtc_i2c_set_alarm(struct i2c_client * client,struct rtc_wkalrm * alarm)255 static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
256 					struct rtc_wkalrm *alarm)
257 {
258 	struct rtc_time *const tm = &alarm->time;
259 	int ret;
260 	u8 regs[8];
261 
262 	/*
263 	 * The clock has an 8 bit wide bcd-coded register (they never learn)
264 	 * for the year. tm_year is an offset from 1900 and we are interested
265 	 * in the 2000-2099 range, so any value less than 100 is invalid.
266 	*/
267 	if (tm->tm_year < 100)
268 		return -EINVAL;
269 
270 	ret = rv3029c2_i2c_get_sr(client, regs);
271 	if (ret < 0) {
272 		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
273 		return -EIO;
274 	}
275 	regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
276 	regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
277 	regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
278 	regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
279 	regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
280 	regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
281 	regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
282 
283 	ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
284 					RV3029C2_ALARM_SECTION_LEN);
285 	if (ret < 0)
286 		return ret;
287 
288 	if (alarm->enabled) {
289 		u8 buf[1];
290 
291 		/* clear AF flag */
292 		ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
293 						buf, 1);
294 		if (ret < 0) {
295 			dev_err(&client->dev, "can't read alarm flag\n");
296 			return ret;
297 		}
298 		buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
299 		ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
300 						buf, 1);
301 		if (ret < 0) {
302 			dev_err(&client->dev, "can't set alarm flag\n");
303 			return ret;
304 		}
305 		/* enable AIE irq */
306 		ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
307 		if (ret)
308 			return ret;
309 
310 		dev_dbg(&client->dev, "alarm IRQ armed\n");
311 	} else {
312 		/* disable AIE irq */
313 		ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 0);
314 		if (ret)
315 			return ret;
316 
317 		dev_dbg(&client->dev, "alarm IRQ disabled\n");
318 	}
319 
320 	return 0;
321 }
322 
rv3029c2_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)323 static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
324 {
325 	return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
326 }
327 
328 static int
rv3029c2_i2c_set_time(struct i2c_client * client,struct rtc_time const * tm)329 rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
330 {
331 	u8 regs[8];
332 	int ret;
333 
334 	/*
335 	 * The clock has an 8 bit wide bcd-coded register (they never learn)
336 	 * for the year. tm_year is an offset from 1900 and we are interested
337 	 * in the 2000-2099 range, so any value less than 100 is invalid.
338 	*/
339 	if (tm->tm_year < 100)
340 		return -EINVAL;
341 
342 	regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
343 	regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
344 	regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
345 	regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
346 	regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
347 	regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
348 	regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
349 
350 	ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
351 					RV3029C2_WATCH_SECTION_LEN);
352 	if (ret < 0)
353 		return ret;
354 
355 	ret = rv3029c2_i2c_get_sr(client, regs);
356 	if (ret < 0) {
357 		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
358 		return ret;
359 	}
360 	/* clear PON bit */
361 	ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
362 	if (ret < 0) {
363 		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
364 		return ret;
365 	}
366 
367 	return 0;
368 }
369 
rv3029c2_rtc_set_time(struct device * dev,struct rtc_time * tm)370 static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
371 {
372 	return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
373 }
374 
375 static const struct rtc_class_ops rv3029c2_rtc_ops = {
376 	.read_time	= rv3029c2_rtc_read_time,
377 	.set_time	= rv3029c2_rtc_set_time,
378 	.read_alarm	= rv3029c2_rtc_read_alarm,
379 	.set_alarm	= rv3029c2_rtc_set_alarm,
380 };
381 
382 static struct i2c_device_id rv3029c2_id[] = {
383 	{ "rv3029c2", 0 },
384 	{ }
385 };
386 MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
387 
388 static int __devinit
rv3029c2_probe(struct i2c_client * client,const struct i2c_device_id * id)389 rv3029c2_probe(struct i2c_client *client, const struct i2c_device_id *id)
390 {
391 	struct rtc_device *rtc;
392 	int rc = 0;
393 	u8 buf[1];
394 
395 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
396 		return -ENODEV;
397 
398 	rtc = rtc_device_register(client->name,
399 				&client->dev, &rv3029c2_rtc_ops,
400 				THIS_MODULE);
401 
402 	if (IS_ERR(rtc))
403 		return PTR_ERR(rtc);
404 
405 	i2c_set_clientdata(client, rtc);
406 
407 	rc = rv3029c2_i2c_get_sr(client, buf);
408 	if (rc < 0) {
409 		dev_err(&client->dev, "reading status failed\n");
410 		goto exit_unregister;
411 	}
412 
413 	return 0;
414 
415 exit_unregister:
416 	rtc_device_unregister(rtc);
417 
418 	return rc;
419 }
420 
rv3029c2_remove(struct i2c_client * client)421 static int __devexit rv3029c2_remove(struct i2c_client *client)
422 {
423 	struct rtc_device *rtc = i2c_get_clientdata(client);
424 
425 	rtc_device_unregister(rtc);
426 
427 	return 0;
428 }
429 
430 static struct i2c_driver rv3029c2_driver = {
431 	.driver = {
432 		.name = "rtc-rv3029c2",
433 	},
434 	.probe = rv3029c2_probe,
435 	.remove = __devexit_p(rv3029c2_remove),
436 	.id_table = rv3029c2_id,
437 };
438 
439 module_i2c_driver(rv3029c2_driver);
440 
441 MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
442 MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
443 MODULE_LICENSE("GPL");
444