1/*
2 * Intersil ISL1208 rtc class driver
3 *
4 * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
5 *
6 *  This program is free software; you can redistribute  it and/or modify it
7 *  under  the terms of  the GNU General  Public License as published by the
8 *  Free Software Foundation;  either version 2 of the  License, or (at your
9 *  option) any later version.
10 *
11 */
12
13#include <linux/module.h>
14#include <linux/i2c.h>
15#include <linux/bcd.h>
16#include <linux/rtc.h>
17
18#define DRV_NAME "isl1208"
19#define DRV_VERSION "0.2"
20
21/* Register map */
22/* rtc section */
23#define ISL1208_REG_SC  0x00
24#define ISL1208_REG_MN  0x01
25#define ISL1208_REG_HR  0x02
26#define ISL1208_REG_HR_MIL     (1<<7) /* 24h/12h mode */
27#define ISL1208_REG_HR_PM      (1<<5) /* PM/AM bit in 12h mode */
28#define ISL1208_REG_DT  0x03
29#define ISL1208_REG_MO  0x04
30#define ISL1208_REG_YR  0x05
31#define ISL1208_REG_DW  0x06
32#define ISL1208_RTC_SECTION_LEN 7
33
34/* control/status section */
35#define ISL1208_REG_SR  0x07
36#define ISL1208_REG_SR_ARST    (1<<7) /* auto reset */
37#define ISL1208_REG_SR_XTOSCB  (1<<6) /* crystal oscillator */
38#define ISL1208_REG_SR_WRTC    (1<<4) /* write rtc */
39#define ISL1208_REG_SR_ALM     (1<<2) /* alarm */
40#define ISL1208_REG_SR_BAT     (1<<1) /* battery */
41#define ISL1208_REG_SR_RTCF    (1<<0) /* rtc fail */
42#define ISL1208_REG_INT 0x08
43#define ISL1208_REG_09  0x09 /* reserved */
44#define ISL1208_REG_ATR 0x0a
45#define ISL1208_REG_DTR 0x0b
46
47/* alarm section */
48#define ISL1208_REG_SCA 0x0c
49#define ISL1208_REG_MNA 0x0d
50#define ISL1208_REG_HRA 0x0e
51#define ISL1208_REG_DTA 0x0f
52#define ISL1208_REG_MOA 0x10
53#define ISL1208_REG_DWA 0x11
54#define ISL1208_ALARM_SECTION_LEN 6
55
56/* user section */
57#define ISL1208_REG_USR1 0x12
58#define ISL1208_REG_USR2 0x13
59#define ISL1208_USR_SECTION_LEN 2
60
61/* i2c configuration */
62#define ISL1208_I2C_ADDR 0xde
63
64static unsigned short normal_i2c[] = {
65	ISL1208_I2C_ADDR>>1, I2C_CLIENT_END
66};
67I2C_CLIENT_INSMOD; /* defines addr_data */
68
69static int isl1208_attach_adapter(struct i2c_adapter *adapter);
70static int isl1208_detach_client(struct i2c_client *client);
71
72static struct i2c_driver isl1208_driver = {
73	.driver		= {
74		.name	= DRV_NAME,
75	},
76	.id		= I2C_DRIVERID_ISL1208,
77	.attach_adapter = &isl1208_attach_adapter,
78	.detach_client	= &isl1208_detach_client,
79};
80
81/* block read */
82static int
83isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
84		       unsigned len)
85{
86	u8 reg_addr[1] = { reg };
87	struct i2c_msg msgs[2] = {
88		{ client->addr, client->flags, sizeof(reg_addr), reg_addr },
89		{ client->addr, client->flags | I2C_M_RD, len, buf }
90	};
91	int ret;
92
93	BUG_ON(len == 0);
94	BUG_ON(reg > ISL1208_REG_USR2);
95	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
96
97	ret = i2c_transfer(client->adapter, msgs, 2);
98	if (ret > 0)
99		ret = 0;
100	return ret;
101}
102
103/* block write */
104static int
105isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
106		       unsigned len)
107{
108	u8 i2c_buf[ISL1208_REG_USR2 + 2];
109	struct i2c_msg msgs[1] = {
110		{ client->addr, client->flags, len + 1, i2c_buf }
111	};
112	int ret;
113
114	BUG_ON(len == 0);
115	BUG_ON(reg > ISL1208_REG_USR2);
116	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
117
118	i2c_buf[0] = reg;
119	memcpy(&i2c_buf[1], &buf[0], len);
120
121	ret = i2c_transfer(client->adapter, msgs, 1);
122	if (ret > 0)
123		ret = 0;
124	return ret;
125}
126
127/* simple check to see wether we have a isl1208 */
128static int isl1208_i2c_validate_client(struct i2c_client *client)
129{
130	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
131	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
132		0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
133	};
134	int i;
135	int ret;
136
137	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
138	if (ret < 0)
139		return ret;
140
141	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
142		if (regs[i] & zero_mask[i]) /* check if bits are cleared */
143			return -ENODEV;
144	}
145
146	return 0;
147}
148
149static int isl1208_i2c_get_sr(struct i2c_client *client)
150{
151	return i2c_smbus_read_byte_data(client, ISL1208_REG_SR) == -1 ? -EIO:0;
152}
153
154static int isl1208_i2c_get_atr(struct i2c_client *client)
155{
156	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
157
158	if (atr < 0)
159		return -EIO;
160
161	/* The 6bit value in the ATR register controls the load
162	 * capacitance C_load * in steps of 0.25pF
163	 *
164	 * bit (1<<5) of the ATR register is inverted
165	 *
166	 * C_load(ATR=0x20) =  4.50pF
167	 * C_load(ATR=0x00) = 12.50pF
168	 * C_load(ATR=0x1f) = 20.25pF
169	 *
170	 */
171
172	atr &= 0x3f; /* mask out lsb */
173	atr ^= 1<<5; /* invert 6th bit */
174	atr += 2*9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
175
176	return atr;
177}
178
179static int isl1208_i2c_get_dtr(struct i2c_client *client)
180{
181	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
182
183	if (dtr < 0)
184		return -EIO;
185
186	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
187	dtr = ((dtr & 0x3) * 20) * (dtr & (1<<2) ? -1 : 1);
188
189	return dtr;
190}
191
192static int isl1208_i2c_get_usr(struct i2c_client *client)
193{
194	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
195	int ret;
196
197	ret = isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
198				   ISL1208_USR_SECTION_LEN);
199	if (ret < 0)
200		return ret;
201
202	return (buf[1] << 8) | buf[0];
203}
204
205static int isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
206{
207	u8 buf[ISL1208_USR_SECTION_LEN];
208
209	buf[0] = usr & 0xff;
210	buf[1] = (usr >> 8) & 0xff;
211
212	return isl1208_i2c_set_regs (client, ISL1208_REG_USR1, buf,
213				     ISL1208_USR_SECTION_LEN);
214}
215
216static int isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
217{
218	struct i2c_client *const client = to_i2c_client(dev);
219	int sr, dtr, atr, usr;
220
221	sr = isl1208_i2c_get_sr(client);
222	if (sr < 0) {
223		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
224		return sr;
225	}
226
227	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
228		   (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
229		   (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
230		   (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
231		   (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
232		   (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
233		   (sr & ISL1208_REG_SR_ARST) ? " ARST" : "",
234		   sr);
235
236	seq_printf(seq, "batt_status\t: %s\n",
237		   (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
238
239	dtr = isl1208_i2c_get_dtr(client);
240	if (dtr >= 0 -1)
241		seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
242
243	atr = isl1208_i2c_get_atr(client);
244	if (atr >= 0)
245		seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
246			   atr>>2, (atr&0x3)*25);
247
248	usr = isl1208_i2c_get_usr(client);
249	if (usr >= 0)
250		seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
251
252	return 0;
253}
254
255
256static int isl1208_i2c_read_time(struct i2c_client *client,
257				 struct rtc_time *tm)
258{
259	int sr;
260	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
261
262	sr = isl1208_i2c_get_sr(client);
263	if (sr < 0) {
264		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
265		return -EIO;
266	}
267
268	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
269	if (sr < 0) {
270		dev_err(&client->dev, "%s: reading RTC section failed\n",
271			__func__);
272		return sr;
273	}
274
275	tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
276	tm->tm_min = BCD2BIN(regs[ISL1208_REG_MN]);
277	{ /* HR field has a more complex interpretation */
278		const u8 _hr = regs[ISL1208_REG_HR];
279		if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
280			tm->tm_hour = BCD2BIN(_hr & 0x3f);
281		else { // 12h format
282			tm->tm_hour = BCD2BIN(_hr & 0x1f);
283			if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
284				tm->tm_hour += 12;
285		}
286	}
287
288	tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DT]);
289	tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
290	tm->tm_year = BCD2BIN(regs[ISL1208_REG_YR]) + 100;
291	tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DW]);
292
293	return 0;
294}
295
296static int isl1208_i2c_read_alarm(struct i2c_client *client,
297				  struct rtc_wkalrm *alarm)
298{
299	struct rtc_time *const tm = &alarm->time;
300	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
301	int sr;
302
303	sr = isl1208_i2c_get_sr(client);
304	if (sr < 0) {
305		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
306		return sr;
307	}
308
309	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
310				  ISL1208_ALARM_SECTION_LEN);
311	if (sr < 0) {
312		dev_err(&client->dev, "%s: reading alarm section failed\n",
313			__func__);
314		return sr;
315	}
316
317	/* MSB of each alarm register is an enable bit */
318	tm->tm_sec  = BCD2BIN(regs[ISL1208_REG_SCA-ISL1208_REG_SCA] & 0x7f);
319	tm->tm_min  = BCD2BIN(regs[ISL1208_REG_MNA-ISL1208_REG_SCA] & 0x7f);
320	tm->tm_hour = BCD2BIN(regs[ISL1208_REG_HRA-ISL1208_REG_SCA] & 0x3f);
321	tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DTA-ISL1208_REG_SCA] & 0x3f);
322	tm->tm_mon  = BCD2BIN(regs[ISL1208_REG_MOA-ISL1208_REG_SCA] & 0x1f)-1;
323	tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DWA-ISL1208_REG_SCA] & 0x03);
324
325	return 0;
326}
327
328static int isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
329{
330	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
331}
332
333static int isl1208_i2c_set_time(struct i2c_client *client,
334				struct rtc_time const *tm)
335{
336	int sr;
337	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
338
339	regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
340	regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
341	regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
342
343	regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
344	regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
345	regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
346
347	regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
348
349	sr = isl1208_i2c_get_sr(client);
350	if (sr < 0) {
351		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
352		return sr;
353	}
354
355	/* set WRTC */
356	sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
357				       sr | ISL1208_REG_SR_WRTC);
358	if (sr < 0) {
359		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
360		return sr;
361	}
362
363	/* write RTC registers */
364	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
365	if (sr < 0) {
366		dev_err(&client->dev, "%s: writing RTC section failed\n",
367			__func__);
368		return sr;
369	}
370
371	/* clear WRTC again */
372	sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
373				       sr & ~ISL1208_REG_SR_WRTC);
374	if (sr < 0) {
375		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
376		return sr;
377	}
378
379	return 0;
380}
381
382
383static int isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
384{
385	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
386}
387
388static int isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
389{
390	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
391}
392
393static const struct rtc_class_ops isl1208_rtc_ops = {
394	.proc		= isl1208_rtc_proc,
395	.read_time	= isl1208_rtc_read_time,
396	.set_time	= isl1208_rtc_set_time,
397	.read_alarm	= isl1208_rtc_read_alarm,
398	//.set_alarm	= isl1208_rtc_set_alarm,
399};
400
401/* sysfs interface */
402
403static ssize_t isl1208_sysfs_show_atrim(struct device *dev,
404					struct device_attribute *attr,
405					char *buf)
406{
407	int atr;
408
409	atr = isl1208_i2c_get_atr(to_i2c_client(dev));
410	if (atr < 0)
411		return atr;
412
413	return sprintf(buf, "%d.%.2d pF\n", atr>>2, (atr&0x3)*25);
414}
415static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
416
417static ssize_t isl1208_sysfs_show_dtrim(struct device *dev,
418					struct device_attribute *attr,
419					char *buf)
420{
421	int dtr;
422
423	dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
424	if (dtr < 0)
425		return dtr;
426
427	return sprintf(buf, "%d ppm\n", dtr);
428}
429static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
430
431static ssize_t isl1208_sysfs_show_usr(struct device *dev,
432				       struct device_attribute *attr,
433				       char *buf)
434{
435	int usr;
436
437	usr = isl1208_i2c_get_usr(to_i2c_client(dev));
438	if (usr < 0)
439		return usr;
440
441	return sprintf(buf, "0x%.4x\n", usr);
442}
443
444static ssize_t isl1208_sysfs_store_usr(struct device *dev,
445				       struct device_attribute *attr,
446				       const char *buf, size_t count)
447{
448	int usr = -1;
449
450	if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
451		if (sscanf(buf, "%x", &usr) != 1)
452			return -EINVAL;
453	} else {
454		if (sscanf(buf, "%d", &usr) != 1)
455			return -EINVAL;
456	}
457
458	if (usr < 0 || usr > 0xffff)
459		return -EINVAL;
460
461	return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
462}
463static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
464		   isl1208_sysfs_store_usr);
465
466static int
467isl1208_probe(struct i2c_adapter *adapter, int addr, int kind)
468{
469	int rc = 0;
470	struct i2c_client *new_client = NULL;
471	struct rtc_device *rtc = NULL;
472
473	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
474		rc = -ENODEV;
475		goto failout;
476	}
477
478	new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
479	if (new_client == NULL) {
480		rc = -ENOMEM;
481		goto failout;
482	}
483
484	new_client->addr = addr;
485	new_client->adapter = adapter;
486	new_client->driver = &isl1208_driver;
487	new_client->flags = 0;
488	strcpy(new_client->name, DRV_NAME);
489
490	if (kind < 0) {
491		rc = isl1208_i2c_validate_client(new_client);
492		if (rc < 0)
493			goto failout;
494	}
495
496	rc = i2c_attach_client(new_client);
497	if (rc < 0)
498		goto failout;
499
500	dev_info(&new_client->dev,
501		 "chip found, driver version " DRV_VERSION "\n");
502
503	rtc = rtc_device_register(isl1208_driver.driver.name,
504				  &new_client->dev,
505				  &isl1208_rtc_ops, THIS_MODULE);
506
507	if (IS_ERR(rtc)) {
508		rc = PTR_ERR(rtc);
509		goto failout_detach;
510	}
511
512	i2c_set_clientdata(new_client, rtc);
513
514	rc = isl1208_i2c_get_sr(new_client);
515	if (rc < 0) {
516		dev_err(&new_client->dev, "reading status failed\n");
517		goto failout_unregister;
518	}
519
520	if (rc & ISL1208_REG_SR_RTCF)
521		dev_warn(&new_client->dev, "rtc power failure detected, "
522			 "please set clock.\n");
523
524	rc = device_create_file(&new_client->dev, &dev_attr_atrim);
525	if (rc < 0)
526		goto failout_unregister;
527	rc = device_create_file(&new_client->dev, &dev_attr_dtrim);
528	if (rc < 0)
529		goto failout_atrim;
530	rc = device_create_file(&new_client->dev, &dev_attr_usr);
531	if (rc < 0)
532		goto failout_dtrim;
533
534	return 0;
535
536 failout_dtrim:
537	device_remove_file(&new_client->dev, &dev_attr_dtrim);
538 failout_atrim:
539	device_remove_file(&new_client->dev, &dev_attr_atrim);
540 failout_unregister:
541	rtc_device_unregister(rtc);
542 failout_detach:
543	i2c_detach_client(new_client);
544 failout:
545	kfree(new_client);
546	return rc;
547}
548
549static int
550isl1208_attach_adapter (struct i2c_adapter *adapter)
551{
552	return i2c_probe(adapter, &addr_data, isl1208_probe);
553}
554
555static int
556isl1208_detach_client(struct i2c_client *client)
557{
558	int rc;
559	struct rtc_device *const rtc = i2c_get_clientdata(client);
560
561	if (rtc)
562		rtc_device_unregister(rtc); /* do we need to kfree? */
563
564	rc = i2c_detach_client(client);
565	if (rc)
566		return rc;
567
568	kfree(client);
569
570	return 0;
571}
572
573/* module management */
574
575static int __init isl1208_init(void)
576{
577	return i2c_add_driver(&isl1208_driver);
578}
579
580static void __exit isl1208_exit(void)
581{
582	i2c_del_driver(&isl1208_driver);
583}
584
585MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
586MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
587MODULE_LICENSE("GPL");
588MODULE_VERSION(DRV_VERSION);
589
590module_init(isl1208_init);
591module_exit(isl1208_exit);
592