1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Intersil ISL1208 rtc class driver
  4 *
  5 * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
  6 */
  7
  8#include <linux/bcd.h>
  9#include <linux/i2c.h>
 10#include <linux/module.h>
 11#include <linux/of_device.h>
 12#include <linux/of_irq.h>
 13#include <linux/rtc.h>
 14
 15/* Register map */
 16/* rtc section */
 17#define ISL1208_REG_SC  0x00
 18#define ISL1208_REG_MN  0x01
 19#define ISL1208_REG_HR  0x02
 20#define ISL1208_REG_HR_MIL     (1<<7)	/* 24h/12h mode */
 21#define ISL1208_REG_HR_PM      (1<<5)	/* PM/AM bit in 12h mode */
 22#define ISL1208_REG_DT  0x03
 23#define ISL1208_REG_MO  0x04
 24#define ISL1208_REG_YR  0x05
 25#define ISL1208_REG_DW  0x06
 26#define ISL1208_RTC_SECTION_LEN 7
 27
 28/* control/status section */
 29#define ISL1208_REG_SR  0x07
 30#define ISL1208_REG_SR_ARST    (1<<7)	/* auto reset */
 31#define ISL1208_REG_SR_XTOSCB  (1<<6)	/* crystal oscillator */
 32#define ISL1208_REG_SR_WRTC    (1<<4)	/* write rtc */
 33#define ISL1208_REG_SR_EVT     (1<<3)	/* event */
 34#define ISL1208_REG_SR_ALM     (1<<2)	/* alarm */
 35#define ISL1208_REG_SR_BAT     (1<<1)	/* battery */
 36#define ISL1208_REG_SR_RTCF    (1<<0)	/* rtc fail */
 37#define ISL1208_REG_INT 0x08
 38#define ISL1208_REG_INT_ALME   (1<<6)   /* alarm enable */
 39#define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
 40#define ISL1219_REG_EV  0x09
 41#define ISL1219_REG_EV_EVEN    (1<<4)   /* event detection enable */
 42#define ISL1219_REG_EV_EVIENB  (1<<7)   /* event in pull-up disable */
 43#define ISL1208_REG_ATR 0x0a
 44#define ISL1208_REG_DTR 0x0b
 45
 46/* alarm section */
 47#define ISL1208_REG_SCA 0x0c
 48#define ISL1208_REG_MNA 0x0d
 49#define ISL1208_REG_HRA 0x0e
 50#define ISL1208_REG_DTA 0x0f
 51#define ISL1208_REG_MOA 0x10
 52#define ISL1208_REG_DWA 0x11
 53#define ISL1208_ALARM_SECTION_LEN 6
 54
 55/* user section */
 56#define ISL1208_REG_USR1 0x12
 57#define ISL1208_REG_USR2 0x13
 58#define ISL1208_USR_SECTION_LEN 2
 59
 60/* event section */
 61#define ISL1219_REG_SCT 0x14
 62#define ISL1219_REG_MNT 0x15
 63#define ISL1219_REG_HRT 0x16
 64#define ISL1219_REG_DTT 0x17
 65#define ISL1219_REG_MOT 0x18
 66#define ISL1219_REG_YRT 0x19
 67#define ISL1219_EVT_SECTION_LEN 6
 68
 69static struct i2c_driver isl1208_driver;
 70
 71/* ISL1208 various variants */
 72enum isl1208_id {
 73	TYPE_ISL1208 = 0,
 74	TYPE_ISL1209,
 75	TYPE_ISL1218,
 76	TYPE_ISL1219,
 77	ISL_LAST_ID
 78};
 79
 80/* Chip capabilities table */
 81static const struct isl1208_config {
 82	const char	name[8];
 83	unsigned int	nvmem_length;
 84	unsigned	has_tamper:1;
 85	unsigned	has_timestamp:1;
 86} isl1208_configs[] = {
 87	[TYPE_ISL1208] = { "isl1208", 2, false, false },
 88	[TYPE_ISL1209] = { "isl1209", 2, true,  false },
 89	[TYPE_ISL1218] = { "isl1218", 8, false, false },
 90	[TYPE_ISL1219] = { "isl1219", 2, true,  true },
 91};
 92
 93static const struct i2c_device_id isl1208_id[] = {
 94	{ "isl1208", TYPE_ISL1208 },
 95	{ "isl1209", TYPE_ISL1209 },
 96	{ "isl1218", TYPE_ISL1218 },
 97	{ "isl1219", TYPE_ISL1219 },
 98	{ }
 99};
100MODULE_DEVICE_TABLE(i2c, isl1208_id);
101
102static const __maybe_unused struct of_device_id isl1208_of_match[] = {
103	{ .compatible = "isil,isl1208", .data = &isl1208_configs[TYPE_ISL1208] },
104	{ .compatible = "isil,isl1209", .data = &isl1208_configs[TYPE_ISL1209] },
105	{ .compatible = "isil,isl1218", .data = &isl1208_configs[TYPE_ISL1218] },
106	{ .compatible = "isil,isl1219", .data = &isl1208_configs[TYPE_ISL1219] },
107	{ }
108};
109MODULE_DEVICE_TABLE(of, isl1208_of_match);
110
111/* Device state */
112struct isl1208_state {
113	struct nvmem_config nvmem_config;
114	struct rtc_device *rtc;
115	const struct isl1208_config *config;
116};
117
118/* block read */
119static int
120isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
121		      unsigned len)
122{
123	int ret;
124
125	WARN_ON(reg > ISL1219_REG_YRT);
126	WARN_ON(reg + len > ISL1219_REG_YRT + 1);
127
128	ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
129	return (ret < 0) ? ret : 0;
130}
131
132/* block write */
133static int
134isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
135		     unsigned len)
136{
137	int ret;
138
139	WARN_ON(reg > ISL1219_REG_YRT);
140	WARN_ON(reg + len > ISL1219_REG_YRT + 1);
141
142	ret = i2c_smbus_write_i2c_block_data(client, reg, len, buf);
143	return (ret < 0) ? ret : 0;
144}
145
146/* simple check to see whether we have a isl1208 */
147static int
148isl1208_i2c_validate_client(struct i2c_client *client)
149{
150	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
151	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
152		0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
153	};
154	int i;
155	int ret;
156
157	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
158	if (ret < 0)
159		return ret;
160
161	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
162		if (regs[i] & zero_mask[i])	/* check if bits are cleared */
163			return -ENODEV;
164	}
165
166	return 0;
167}
168
169static int
170isl1208_i2c_get_sr(struct i2c_client *client)
171{
172	return i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
173}
174
175static int
176isl1208_i2c_get_atr(struct i2c_client *client)
177{
178	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
179	if (atr < 0)
180		return atr;
181
182	/* The 6bit value in the ATR register controls the load
183	 * capacitance C_load * in steps of 0.25pF
184	 *
185	 * bit (1<<5) of the ATR register is inverted
186	 *
187	 * C_load(ATR=0x20) =  4.50pF
188	 * C_load(ATR=0x00) = 12.50pF
189	 * C_load(ATR=0x1f) = 20.25pF
190	 *
191	 */
192
193	atr &= 0x3f;		/* mask out lsb */
194	atr ^= 1 << 5;		/* invert 6th bit */
195	atr += 2 * 9;		/* add offset of 4.5pF; unit[atr] = 0.25pF */
196
197	return atr;
198}
199
200/* returns adjustment value + 100 */
201static int
202isl1208_i2c_get_dtr(struct i2c_client *client)
203{
204	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
205	if (dtr < 0)
206		return -EIO;
207
208	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
209	dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
210
211	return dtr + 100;
212}
213
214static int
215isl1208_i2c_get_usr(struct i2c_client *client)
216{
217	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
218	int ret;
219
220	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
221				    ISL1208_USR_SECTION_LEN);
222	if (ret < 0)
223		return ret;
224
225	return (buf[1] << 8) | buf[0];
226}
227
228static int
229isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
230{
231	u8 buf[ISL1208_USR_SECTION_LEN];
232
233	buf[0] = usr & 0xff;
234	buf[1] = (usr >> 8) & 0xff;
235
236	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
237				    ISL1208_USR_SECTION_LEN);
238}
239
240static int
241isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
242{
243	int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
244
245	if (icr < 0) {
246		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
247		return icr;
248	}
249
250	if (enable)
251		icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
252	else
253		icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
254
255	icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
256	if (icr < 0) {
257		dev_err(&client->dev, "%s: writing INT failed\n", __func__);
258		return icr;
259	}
260
261	return 0;
262}
263
264static int
265isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
266{
267	struct i2c_client *const client = to_i2c_client(dev);
268	int sr, dtr, atr, usr;
269
270	sr = isl1208_i2c_get_sr(client);
271	if (sr < 0) {
272		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
273		return sr;
274	}
275
276	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
277		   (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
278		   (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
279		   (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
280		   (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
281		   (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
282		   (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
283
284	seq_printf(seq, "batt_status\t: %s\n",
285		   (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
286
287	dtr = isl1208_i2c_get_dtr(client);
288	if (dtr >= 0)
289		seq_printf(seq, "digital_trim\t: %d ppm\n", dtr - 100);
290
291	atr = isl1208_i2c_get_atr(client);
292	if (atr >= 0)
293		seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
294			   atr >> 2, (atr & 0x3) * 25);
295
296	usr = isl1208_i2c_get_usr(client);
297	if (usr >= 0)
298		seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
299
300	return 0;
301}
302
303static int
304isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
305{
306	int sr;
307	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
308
309	sr = isl1208_i2c_get_sr(client);
310	if (sr < 0) {
311		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
312		return -EIO;
313	}
314
315	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
316	if (sr < 0) {
317		dev_err(&client->dev, "%s: reading RTC section failed\n",
318			__func__);
319		return sr;
320	}
321
322	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
323	tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
324
325	/* HR field has a more complex interpretation */
326	{
327		const u8 _hr = regs[ISL1208_REG_HR];
328		if (_hr & ISL1208_REG_HR_MIL)	/* 24h format */
329			tm->tm_hour = bcd2bin(_hr & 0x3f);
330		else {
331			/* 12h format */
332			tm->tm_hour = bcd2bin(_hr & 0x1f);
333			if (_hr & ISL1208_REG_HR_PM)	/* PM flag set */
334				tm->tm_hour += 12;
335		}
336	}
337
338	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
339	tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1;	/* rtc starts at 1 */
340	tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
341	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
342
343	return 0;
344}
345
346static int
347isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
348{
349	struct rtc_time *const tm = &alarm->time;
350	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
351	int icr, yr, sr = isl1208_i2c_get_sr(client);
352
353	if (sr < 0) {
354		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
355		return sr;
356	}
357
358	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
359				   ISL1208_ALARM_SECTION_LEN);
360	if (sr < 0) {
361		dev_err(&client->dev, "%s: reading alarm section failed\n",
362			__func__);
363		return sr;
364	}
365
366	/* MSB of each alarm register is an enable bit */
367	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
368	tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
369	tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
370	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
371	tm->tm_mon =
372		bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
373	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
374
375	/* The alarm doesn't store the year so get it from the rtc section */
376	yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
377	if (yr < 0) {
378		dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
379		return yr;
380	}
381	tm->tm_year = bcd2bin(yr) + 100;
382
383	icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
384	if (icr < 0) {
385		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
386		return icr;
387	}
388	alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
389
390	return 0;
391}
392
393static int
394isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
395{
396	struct rtc_time *alarm_tm = &alarm->time;
397	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
398	const int offs = ISL1208_REG_SCA;
399	struct rtc_time rtc_tm;
400	int err, enable;
401
402	err = isl1208_i2c_read_time(client, &rtc_tm);
403	if (err)
404		return err;
405
406	/* If the alarm time is before the current time disable the alarm */
407	if (!alarm->enabled || rtc_tm_sub(alarm_tm, &rtc_tm) <= 0)
408		enable = 0x00;
409	else
410		enable = 0x80;
411
412	/* Program the alarm and enable it for each setting */
413	regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
414	regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
415	regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
416		ISL1208_REG_HR_MIL | enable;
417
418	regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
419	regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
420	regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
421
422	/* write ALARM registers */
423	err = isl1208_i2c_set_regs(client, offs, regs,
424				  ISL1208_ALARM_SECTION_LEN);
425	if (err < 0) {
426		dev_err(&client->dev, "%s: writing ALARM section failed\n",
427			__func__);
428		return err;
429	}
430
431	err = isl1208_rtc_toggle_alarm(client, enable);
432	if (err)
433		return err;
434
435	return 0;
436}
437
438static int
439isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
440{
441	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
442}
443
444static int
445isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
446{
447	int sr;
448	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
449
450	/* The clock has an 8 bit wide bcd-coded register (they never learn)
451	 * for the year. tm_year is an offset from 1900 and we are interested
452	 * in the 2000-2099 range, so any value less than 100 is invalid.
453	 */
454	if (tm->tm_year < 100)
455		return -EINVAL;
456
457	regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
458	regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
459	regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
460
461	regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
462	regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
463	regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
464
465	regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
466
467	sr = isl1208_i2c_get_sr(client);
468	if (sr < 0) {
469		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
470		return sr;
471	}
472
473	/* set WRTC */
474	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
475				       sr | ISL1208_REG_SR_WRTC);
476	if (sr < 0) {
477		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
478		return sr;
479	}
480
481	/* write RTC registers */
482	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
483	if (sr < 0) {
484		dev_err(&client->dev, "%s: writing RTC section failed\n",
485			__func__);
486		return sr;
487	}
488
489	/* clear WRTC again */
490	sr = isl1208_i2c_get_sr(client);
491	if (sr < 0) {
492		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
493		return sr;
494	}
495	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
496				       sr & ~ISL1208_REG_SR_WRTC);
497	if (sr < 0) {
498		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
499		return sr;
500	}
501
502	return 0;
503}
504
505
506static int
507isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
508{
509	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
510}
511
512static int
513isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
514{
515	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
516}
517
518static int
519isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
520{
521	return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
522}
523
524static ssize_t timestamp0_store(struct device *dev,
525				struct device_attribute *attr,
526				const char *buf, size_t count)
527{
528	struct i2c_client *client = to_i2c_client(dev->parent);
529	int sr;
530
531	sr = isl1208_i2c_get_sr(client);
532	if (sr < 0) {
533		dev_err(dev, "%s: reading SR failed\n", __func__);
534		return sr;
535	}
536
537	sr &= ~ISL1208_REG_SR_EVT;
538
539	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
540	if (sr < 0)
541		dev_err(dev, "%s: writing SR failed\n",
542			__func__);
543
544	return count;
545};
546
547static ssize_t timestamp0_show(struct device *dev,
548			       struct device_attribute *attr, char *buf)
549{
550	struct i2c_client *client = to_i2c_client(dev->parent);
551	u8 regs[ISL1219_EVT_SECTION_LEN] = { 0, };
552	struct rtc_time tm;
553	int sr;
554
555	sr = isl1208_i2c_get_sr(client);
556	if (sr < 0) {
557		dev_err(dev, "%s: reading SR failed\n", __func__);
558		return sr;
559	}
560
561	if (!(sr & ISL1208_REG_SR_EVT))
562		return 0;
563
564	sr = isl1208_i2c_read_regs(client, ISL1219_REG_SCT, regs,
565				   ISL1219_EVT_SECTION_LEN);
566	if (sr < 0) {
567		dev_err(dev, "%s: reading event section failed\n",
568			__func__);
569		return 0;
570	}
571
572	/* MSB of each alarm register is an enable bit */
573	tm.tm_sec = bcd2bin(regs[ISL1219_REG_SCT - ISL1219_REG_SCT] & 0x7f);
574	tm.tm_min = bcd2bin(regs[ISL1219_REG_MNT - ISL1219_REG_SCT] & 0x7f);
575	tm.tm_hour = bcd2bin(regs[ISL1219_REG_HRT - ISL1219_REG_SCT] & 0x3f);
576	tm.tm_mday = bcd2bin(regs[ISL1219_REG_DTT - ISL1219_REG_SCT] & 0x3f);
577	tm.tm_mon =
578		bcd2bin(regs[ISL1219_REG_MOT - ISL1219_REG_SCT] & 0x1f) - 1;
579	tm.tm_year = bcd2bin(regs[ISL1219_REG_YRT - ISL1219_REG_SCT]) + 100;
580
581	sr = rtc_valid_tm(&tm);
582	if (sr)
583		return sr;
584
585	return sprintf(buf, "%llu\n",
586				(unsigned long long)rtc_tm_to_time64(&tm));
587};
588
589static DEVICE_ATTR_RW(timestamp0);
590
591static irqreturn_t
592isl1208_rtc_interrupt(int irq, void *data)
593{
594	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
595	struct i2c_client *client = data;
596	struct isl1208_state *isl1208 = i2c_get_clientdata(client);
597	int handled = 0, sr, err;
598
599	/*
600	 * I2C reads get NAK'ed if we read straight away after an interrupt?
601	 * Using a mdelay/msleep didn't seem to help either, so we work around
602	 * this by continually trying to read the register for a short time.
603	 */
604	while (1) {
605		sr = isl1208_i2c_get_sr(client);
606		if (sr >= 0)
607			break;
608
609		if (time_after(jiffies, timeout)) {
610			dev_err(&client->dev, "%s: reading SR failed\n",
611				__func__);
612			return sr;
613		}
614	}
615
616	if (sr & ISL1208_REG_SR_ALM) {
617		dev_dbg(&client->dev, "alarm!\n");
618
619		rtc_update_irq(isl1208->rtc, 1, RTC_IRQF | RTC_AF);
620
621		/* Clear the alarm */
622		sr &= ~ISL1208_REG_SR_ALM;
623		sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
624		if (sr < 0)
625			dev_err(&client->dev, "%s: writing SR failed\n",
626				__func__);
627		else
628			handled = 1;
629
630		/* Disable the alarm */
631		err = isl1208_rtc_toggle_alarm(client, 0);
632		if (err)
633			return err;
634	}
635
636	if (isl1208->config->has_tamper && (sr & ISL1208_REG_SR_EVT)) {
637		dev_warn(&client->dev, "event detected");
638		handled = 1;
639		if (isl1208->config->has_timestamp)
640			sysfs_notify(&isl1208->rtc->dev.kobj, NULL,
641				     dev_attr_timestamp0.attr.name);
642	}
643
644	return handled ? IRQ_HANDLED : IRQ_NONE;
645}
646
647static const struct rtc_class_ops isl1208_rtc_ops = {
648	.proc = isl1208_rtc_proc,
649	.read_time = isl1208_rtc_read_time,
650	.set_time = isl1208_rtc_set_time,
651	.read_alarm = isl1208_rtc_read_alarm,
652	.set_alarm = isl1208_rtc_set_alarm,
653};
654
655/* sysfs interface */
656
657static ssize_t
658isl1208_sysfs_show_atrim(struct device *dev,
659			 struct device_attribute *attr, char *buf)
660{
661	int atr = isl1208_i2c_get_atr(to_i2c_client(dev->parent));
662	if (atr < 0)
663		return atr;
664
665	return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
666}
667
668static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
669
670static ssize_t
671isl1208_sysfs_show_dtrim(struct device *dev,
672			 struct device_attribute *attr, char *buf)
673{
674	int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev->parent));
675	if (dtr < 0)
676		return dtr;
677
678	return sprintf(buf, "%d ppm\n", dtr - 100);
679}
680
681static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
682
683static ssize_t
684isl1208_sysfs_show_usr(struct device *dev,
685		       struct device_attribute *attr, char *buf)
686{
687	int usr = isl1208_i2c_get_usr(to_i2c_client(dev->parent));
688	if (usr < 0)
689		return usr;
690
691	return sprintf(buf, "0x%.4x\n", usr);
692}
693
694static ssize_t
695isl1208_sysfs_store_usr(struct device *dev,
696			struct device_attribute *attr,
697			const char *buf, size_t count)
698{
699	int usr = -1;
700
701	if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
702		if (sscanf(buf, "%x", &usr) != 1)
703			return -EINVAL;
704	} else {
705		if (sscanf(buf, "%d", &usr) != 1)
706			return -EINVAL;
707	}
708
709	if (usr < 0 || usr > 0xffff)
710		return -EINVAL;
711
712	if (isl1208_i2c_set_usr(to_i2c_client(dev->parent), usr))
713		return -EIO;
714
715	return count;
716}
717
718static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
719		   isl1208_sysfs_store_usr);
720
721static struct attribute *isl1208_rtc_attrs[] = {
722	&dev_attr_atrim.attr,
723	&dev_attr_dtrim.attr,
724	&dev_attr_usr.attr,
725	NULL
726};
727
728static const struct attribute_group isl1208_rtc_sysfs_files = {
729	.attrs	= isl1208_rtc_attrs,
730};
731
732static struct attribute *isl1219_rtc_attrs[] = {
733	&dev_attr_timestamp0.attr,
734	NULL
735};
736
737static const struct attribute_group isl1219_rtc_sysfs_files = {
738	.attrs	= isl1219_rtc_attrs,
739};
740
741static int isl1208_nvmem_read(void *priv, unsigned int off, void *buf,
742			      size_t count)
743{
744	struct isl1208_state *isl1208 = priv;
745	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
746	int ret;
747
748	/* nvmem sanitizes offset/count for us, but count==0 is possible */
749	if (!count)
750		return count;
751	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
752				    count);
753	return ret == 0 ? count : ret;
754}
755
756static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
757			       size_t count)
758{
759	struct isl1208_state *isl1208 = priv;
760	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
761	int ret;
762
763	/* nvmem sanitizes off/count for us, but count==0 is possible */
764	if (!count)
765		return count;
766	ret = isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
767				   count);
768
769	return ret == 0 ? count : ret;
770}
771
772static const struct nvmem_config isl1208_nvmem_config = {
773	.name = "isl1208_nvram",
774	.word_size = 1,
775	.stride = 1,
776	/* .size from chip specific config */
777	.reg_read = isl1208_nvmem_read,
778	.reg_write = isl1208_nvmem_write,
779};
780
781static int isl1208_setup_irq(struct i2c_client *client, int irq)
782{
783	int rc = devm_request_threaded_irq(&client->dev, irq, NULL,
784					isl1208_rtc_interrupt,
785					IRQF_SHARED | IRQF_ONESHOT,
786					isl1208_driver.driver.name,
787					client);
788	if (!rc) {
789		device_init_wakeup(&client->dev, 1);
790		enable_irq_wake(irq);
791	} else {
792		dev_err(&client->dev,
793			"Unable to request irq %d, no alarm support\n",
794			irq);
795	}
796	return rc;
797}
798
799static int
800isl1208_probe(struct i2c_client *client)
801{
802	int rc = 0;
803	struct isl1208_state *isl1208;
804	int evdet_irq = -1;
805
806	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
807		return -ENODEV;
808
809	if (isl1208_i2c_validate_client(client) < 0)
810		return -ENODEV;
811
812	/* Allocate driver state, point i2c client data to it */
813	isl1208 = devm_kzalloc(&client->dev, sizeof(*isl1208), GFP_KERNEL);
814	if (!isl1208)
815		return -ENOMEM;
816	i2c_set_clientdata(client, isl1208);
817
818	/* Determine which chip we have */
819	if (client->dev.of_node) {
820		isl1208->config = of_device_get_match_data(&client->dev);
821		if (!isl1208->config)
822			return -ENODEV;
823	} else {
824		const struct i2c_device_id *id = i2c_match_id(isl1208_id, client);
825
826		if (id->driver_data >= ISL_LAST_ID)
827			return -ENODEV;
828		isl1208->config = &isl1208_configs[id->driver_data];
829	}
830
831	isl1208->rtc = devm_rtc_allocate_device(&client->dev);
832	if (IS_ERR(isl1208->rtc))
833		return PTR_ERR(isl1208->rtc);
834
835	isl1208->rtc->ops = &isl1208_rtc_ops;
836
837	/* Setup nvmem configuration in driver state struct */
838	isl1208->nvmem_config = isl1208_nvmem_config;
839	isl1208->nvmem_config.size = isl1208->config->nvmem_length;
840	isl1208->nvmem_config.priv = isl1208;
841
842	rc = isl1208_i2c_get_sr(client);
843	if (rc < 0) {
844		dev_err(&client->dev, "reading status failed\n");
845		return rc;
846	}
847
848	if (rc & ISL1208_REG_SR_RTCF)
849		dev_warn(&client->dev, "rtc power failure detected, "
850			 "please set clock.\n");
851
852	if (isl1208->config->has_tamper) {
853		struct device_node *np = client->dev.of_node;
854		u32 evienb;
855
856		rc = i2c_smbus_read_byte_data(client, ISL1219_REG_EV);
857		if (rc < 0) {
858			dev_err(&client->dev, "failed to read EV reg\n");
859			return rc;
860		}
861		rc |= ISL1219_REG_EV_EVEN;
862		if (!of_property_read_u32(np, "isil,ev-evienb", &evienb)) {
863			if (evienb)
864				rc |= ISL1219_REG_EV_EVIENB;
865			else
866				rc &= ~ISL1219_REG_EV_EVIENB;
867		}
868		rc = i2c_smbus_write_byte_data(client, ISL1219_REG_EV, rc);
869		if (rc < 0) {
870			dev_err(&client->dev, "could not enable tamper detection\n");
871			return rc;
872		}
873		evdet_irq = of_irq_get_byname(np, "evdet");
874	}
875	if (isl1208->config->has_timestamp) {
876		rc = rtc_add_group(isl1208->rtc, &isl1219_rtc_sysfs_files);
877		if (rc)
878			return rc;
879	}
880
881	rc = rtc_add_group(isl1208->rtc, &isl1208_rtc_sysfs_files);
882	if (rc)
883		return rc;
884
885	if (client->irq > 0) {
886		rc = isl1208_setup_irq(client, client->irq);
887		if (rc)
888			return rc;
889
890	} else {
891		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, isl1208->rtc->features);
892	}
893
894	if (evdet_irq > 0 && evdet_irq != client->irq)
895		rc = isl1208_setup_irq(client, evdet_irq);
896	if (rc)
897		return rc;
898
899	rc = devm_rtc_nvmem_register(isl1208->rtc, &isl1208->nvmem_config);
900	if (rc)
901		return rc;
902
903	return devm_rtc_register_device(isl1208->rtc);
904}
905
906static struct i2c_driver isl1208_driver = {
907	.driver = {
908		.name = "rtc-isl1208",
909		.of_match_table = of_match_ptr(isl1208_of_match),
910	},
911	.probe_new = isl1208_probe,
912	.id_table = isl1208_id,
913};
914
915module_i2c_driver(isl1208_driver);
916
917MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
918MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
919MODULE_LICENSE("GPL");