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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * An I2C driver for the Intersil ISL 12022
4 *
5 * Author: Roman Fietze <roman.fietze@telemotive.de>
6 *
7 * Based on the Philips PCF8563 RTC
8 * by Alessandro Zummo <a.zummo@towertech.it>.
9 */
10
11#include <linux/bcd.h>
12#include <linux/bitfield.h>
13#include <linux/clk-provider.h>
14#include <linux/err.h>
15#include <linux/hwmon.h>
16#include <linux/i2c.h>
17#include <linux/module.h>
18#include <linux/regmap.h>
19#include <linux/rtc.h>
20#include <linux/slab.h>
21
22#include <asm/byteorder.h>
23
24/* RTC - Real time clock registers */
25#define ISL12022_REG_SC 0x00
26#define ISL12022_REG_MN 0x01
27#define ISL12022_REG_HR 0x02
28#define ISL12022_REG_DT 0x03
29#define ISL12022_REG_MO 0x04
30#define ISL12022_REG_YR 0x05
31#define ISL12022_REG_DW 0x06
32
33/* CSR - Control and status registers */
34#define ISL12022_REG_SR 0x07
35#define ISL12022_REG_INT 0x08
36#define ISL12022_REG_PWR_VBAT 0x0a
37#define ISL12022_REG_BETA 0x0d
38
39/* ALARM - Alarm registers */
40#define ISL12022_REG_SCA0 0x10
41#define ISL12022_REG_MNA0 0x11
42#define ISL12022_REG_HRA0 0x12
43#define ISL12022_REG_DTA0 0x13
44#define ISL12022_REG_MOA0 0x14
45#define ISL12022_REG_DWA0 0x15
46#define ISL12022_ALARM ISL12022_REG_SCA0
47#define ISL12022_ALARM_LEN (ISL12022_REG_DWA0 - ISL12022_REG_SCA0 + 1)
48
49/* TEMP - Temperature sensor registers */
50#define ISL12022_REG_TEMP_L 0x28
51
52/* ISL register bits */
53#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
54
55#define ISL12022_SR_ALM (1 << 4)
56#define ISL12022_SR_LBAT85 (1 << 2)
57#define ISL12022_SR_LBAT75 (1 << 1)
58
59#define ISL12022_INT_ARST (1 << 7)
60#define ISL12022_INT_WRTC (1 << 6)
61#define ISL12022_INT_IM (1 << 5)
62#define ISL12022_INT_FOBATB (1 << 4)
63#define ISL12022_INT_FO_MASK GENMASK(3, 0)
64#define ISL12022_INT_FO_OFF 0x0
65#define ISL12022_INT_FO_32K 0x1
66
67#define ISL12022_REG_VB85_MASK GENMASK(5, 3)
68#define ISL12022_REG_VB75_MASK GENMASK(2, 0)
69
70#define ISL12022_ALARM_ENABLE (1 << 7) /* for all ALARM registers */
71
72#define ISL12022_BETA_TSE (1 << 7)
73
74static struct i2c_driver isl12022_driver;
75
76struct isl12022 {
77 struct rtc_device *rtc;
78 struct regmap *regmap;
79 int irq;
80 bool irq_enabled;
81};
82
83static umode_t isl12022_hwmon_is_visible(const void *data,
84 enum hwmon_sensor_types type,
85 u32 attr, int channel)
86{
87 if (type == hwmon_temp && attr == hwmon_temp_input)
88 return 0444;
89
90 return 0;
91}
92
93/*
94 * A user-initiated temperature conversion is not started by this function,
95 * so the temperature is updated once every ~60 seconds.
96 */
97static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
98{
99 struct regmap *regmap = dev_get_drvdata(dev);
100 int temp, ret;
101 __le16 buf;
102
103 ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L, &buf, sizeof(buf));
104 if (ret)
105 return ret;
106 /*
107 * Temperature is represented as a 10-bit number, unit half-Kelvins.
108 */
109 temp = le16_to_cpu(buf);
110 temp *= 500;
111 temp -= 273000;
112
113 *mC = temp;
114
115 return 0;
116}
117
118static int isl12022_hwmon_read(struct device *dev,
119 enum hwmon_sensor_types type,
120 u32 attr, int channel, long *val)
121{
122 if (type == hwmon_temp && attr == hwmon_temp_input)
123 return isl12022_hwmon_read_temp(dev, val);
124
125 return -EOPNOTSUPP;
126}
127
128static const struct hwmon_channel_info * const isl12022_hwmon_info[] = {
129 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
130 NULL
131};
132
133static const struct hwmon_ops isl12022_hwmon_ops = {
134 .is_visible = isl12022_hwmon_is_visible,
135 .read = isl12022_hwmon_read,
136};
137
138static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
139 .ops = &isl12022_hwmon_ops,
140 .info = isl12022_hwmon_info,
141};
142
143static void isl12022_hwmon_register(struct device *dev)
144{
145 struct isl12022 *isl12022 = dev_get_drvdata(dev);
146 struct regmap *regmap = isl12022->regmap;
147 struct device *hwmon;
148 int ret;
149
150 if (!IS_REACHABLE(CONFIG_HWMON))
151 return;
152
153 ret = regmap_update_bits(regmap, ISL12022_REG_BETA,
154 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
155 if (ret) {
156 dev_warn(dev, "unable to enable temperature sensor\n");
157 return;
158 }
159
160 hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", regmap,
161 &isl12022_hwmon_chip_info,
162 NULL);
163 if (IS_ERR(hwmon))
164 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
165}
166
167/*
168 * In the routines that deal directly with the isl12022 hardware, we use
169 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
170 */
171static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
172{
173 struct isl12022 *isl12022 = dev_get_drvdata(dev);
174 struct regmap *regmap = isl12022->regmap;
175 u8 buf[ISL12022_REG_INT + 1];
176 int ret;
177
178 ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf));
179 if (ret)
180 return ret;
181
182 dev_dbg(dev,
183 "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, sr=%02x, int=%02x",
184 buf[ISL12022_REG_SC],
185 buf[ISL12022_REG_MN],
186 buf[ISL12022_REG_HR],
187 buf[ISL12022_REG_DT],
188 buf[ISL12022_REG_MO],
189 buf[ISL12022_REG_YR],
190 buf[ISL12022_REG_DW],
191 buf[ISL12022_REG_SR],
192 buf[ISL12022_REG_INT]);
193
194 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
195 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
196 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
197 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
198 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
199 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
200 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
201
202 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
203
204 return 0;
205}
206
207static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
208{
209 struct isl12022 *isl12022 = dev_get_drvdata(dev);
210 struct regmap *regmap = isl12022->regmap;
211 int ret;
212 u8 buf[ISL12022_REG_DW + 1];
213
214 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
215
216 /* Ensure the write enable bit is set. */
217 ret = regmap_update_bits(regmap, ISL12022_REG_INT,
218 ISL12022_INT_WRTC, ISL12022_INT_WRTC);
219 if (ret)
220 return ret;
221
222 /* hours, minutes and seconds */
223 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
224 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
225 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
226
227 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
228
229 /* month, 1 - 12 */
230 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
231
232 /* year and century */
233 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
234
235 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
236
237 return regmap_bulk_write(regmap, ISL12022_REG_SC, buf, sizeof(buf));
238}
239
240static int isl12022_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
241{
242 struct rtc_time *tm = &alarm->time;
243 struct isl12022 *isl12022 = dev_get_drvdata(dev);
244 struct regmap *regmap = isl12022->regmap;
245 u8 buf[ISL12022_ALARM_LEN];
246 unsigned int i, yr;
247 int ret;
248
249 ret = regmap_bulk_read(regmap, ISL12022_ALARM, buf, sizeof(buf));
250 if (ret) {
251 dev_dbg(dev, "%s: reading ALARM registers failed\n",
252 __func__);
253 return ret;
254 }
255
256 /* The alarm doesn't store the year so get it from the rtc section */
257 ret = regmap_read(regmap, ISL12022_REG_YR, &yr);
258 if (ret) {
259 dev_dbg(dev, "%s: reading YR register failed\n", __func__);
260 return ret;
261 }
262
263 dev_dbg(dev,
264 "%s: sc=%02x, mn=%02x, hr=%02x, dt=%02x, mo=%02x, dw=%02x yr=%u\n",
265 __func__, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], yr);
266
267 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SCA0 - ISL12022_ALARM] & 0x7F);
268 tm->tm_min = bcd2bin(buf[ISL12022_REG_MNA0 - ISL12022_ALARM] & 0x7F);
269 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HRA0 - ISL12022_ALARM] & 0x3F);
270 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DTA0 - ISL12022_ALARM] & 0x3F);
271 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MOA0 - ISL12022_ALARM] & 0x1F) - 1;
272 tm->tm_wday = buf[ISL12022_REG_DWA0 - ISL12022_ALARM] & 0x07;
273 tm->tm_year = bcd2bin(yr) + 100;
274
275 for (i = 0; i < ISL12022_ALARM_LEN; i++) {
276 if (buf[i] & ISL12022_ALARM_ENABLE) {
277 alarm->enabled = 1;
278 break;
279 }
280 }
281
282 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
283
284 return 0;
285}
286
287static int isl12022_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
288{
289 struct rtc_time *alarm_tm = &alarm->time;
290 struct isl12022 *isl12022 = dev_get_drvdata(dev);
291 struct regmap *regmap = isl12022->regmap;
292 u8 regs[ISL12022_ALARM_LEN] = { 0, };
293 struct rtc_time rtc_tm;
294 int ret, enable, dw;
295
296 ret = isl12022_rtc_read_time(dev, &rtc_tm);
297 if (ret)
298 return ret;
299
300 /* If the alarm time is before the current time disable the alarm */
301 if (!alarm->enabled || rtc_tm_sub(alarm_tm, &rtc_tm) <= 0)
302 enable = 0;
303 else
304 enable = ISL12022_ALARM_ENABLE;
305
306 /*
307 * Set non-matching day of the week to safeguard against early false
308 * matching while setting all the alarm registers (this rtc lacks a
309 * general alarm/irq enable/disable bit).
310 */
311 ret = regmap_read(regmap, ISL12022_REG_DW, &dw);
312 if (ret) {
313 dev_dbg(dev, "%s: reading DW failed\n", __func__);
314 return ret;
315 }
316 /* ~4 days into the future should be enough to avoid match */
317 dw = ((dw + 4) % 7) | ISL12022_ALARM_ENABLE;
318 ret = regmap_write(regmap, ISL12022_REG_DWA0, dw);
319 if (ret) {
320 dev_dbg(dev, "%s: writing DWA0 failed\n", __func__);
321 return ret;
322 }
323
324 /* Program the alarm and enable it for each setting */
325 regs[ISL12022_REG_SCA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_sec) | enable;
326 regs[ISL12022_REG_MNA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_min) | enable;
327 regs[ISL12022_REG_HRA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_hour) | enable;
328 regs[ISL12022_REG_DTA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_mday) | enable;
329 regs[ISL12022_REG_MOA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
330 regs[ISL12022_REG_DWA0 - ISL12022_ALARM] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
331
332 /* write ALARM registers */
333 ret = regmap_bulk_write(regmap, ISL12022_ALARM, ®s, sizeof(regs));
334 if (ret) {
335 dev_dbg(dev, "%s: writing ALARM registers failed\n", __func__);
336 return ret;
337 }
338
339 return 0;
340}
341
342static irqreturn_t isl12022_rtc_interrupt(int irq, void *data)
343{
344 struct isl12022 *isl12022 = data;
345 struct rtc_device *rtc = isl12022->rtc;
346 struct device *dev = &rtc->dev;
347 struct regmap *regmap = isl12022->regmap;
348 u32 val = 0;
349 unsigned long events = 0;
350 int ret;
351
352 ret = regmap_read(regmap, ISL12022_REG_SR, &val);
353 if (ret) {
354 dev_dbg(dev, "%s: reading SR failed\n", __func__);
355 return IRQ_HANDLED;
356 }
357
358 if (val & ISL12022_SR_ALM)
359 events |= RTC_IRQF | RTC_AF;
360
361 if (events & RTC_AF)
362 dev_dbg(dev, "alarm!\n");
363
364 if (!events)
365 return IRQ_NONE;
366
367 rtc_update_irq(rtc, 1, events);
368 return IRQ_HANDLED;
369}
370
371static int isl12022_rtc_alarm_irq_enable(struct device *dev,
372 unsigned int enabled)
373{
374 struct isl12022 *isl12022 = dev_get_drvdata(dev);
375
376 /* Make sure enabled is 0 or 1 */
377 enabled = !!enabled;
378
379 if (isl12022->irq_enabled == enabled)
380 return 0;
381
382 if (enabled)
383 enable_irq(isl12022->irq);
384 else
385 disable_irq(isl12022->irq);
386
387 isl12022->irq_enabled = enabled;
388
389 return 0;
390}
391
392static int isl12022_setup_irq(struct device *dev, int irq)
393{
394 struct isl12022 *isl12022 = dev_get_drvdata(dev);
395 struct regmap *regmap = isl12022->regmap;
396 unsigned int reg_mask, reg_val;
397 u8 buf[ISL12022_ALARM_LEN] = { 0, };
398 int ret;
399
400 /* Clear and disable all alarm registers */
401 ret = regmap_bulk_write(regmap, ISL12022_ALARM, buf, sizeof(buf));
402 if (ret)
403 return ret;
404
405 /*
406 * Enable automatic reset of ALM bit and enable single event interrupt
407 * mode.
408 */
409 reg_mask = ISL12022_INT_ARST | ISL12022_INT_IM | ISL12022_INT_FO_MASK;
410 reg_val = ISL12022_INT_ARST | ISL12022_INT_FO_OFF;
411 ret = regmap_write_bits(regmap, ISL12022_REG_INT,
412 reg_mask, reg_val);
413 if (ret)
414 return ret;
415
416 ret = devm_request_threaded_irq(dev, irq, NULL,
417 isl12022_rtc_interrupt,
418 IRQF_SHARED | IRQF_ONESHOT,
419 isl12022_driver.driver.name,
420 isl12022);
421 if (ret)
422 return dev_err_probe(dev, ret, "Unable to request irq %d\n", irq);
423
424 isl12022->irq = irq;
425 return 0;
426}
427
428static int isl12022_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
429{
430 struct isl12022 *isl12022 = dev_get_drvdata(dev);
431 struct regmap *regmap = isl12022->regmap;
432 u32 user, val;
433 int ret;
434
435 switch (cmd) {
436 case RTC_VL_READ:
437 ret = regmap_read(regmap, ISL12022_REG_SR, &val);
438 if (ret)
439 return ret;
440
441 user = 0;
442 if (val & ISL12022_SR_LBAT85)
443 user |= RTC_VL_BACKUP_LOW;
444
445 if (val & ISL12022_SR_LBAT75)
446 user |= RTC_VL_BACKUP_EMPTY;
447
448 return put_user(user, (u32 __user *)arg);
449
450 default:
451 return -ENOIOCTLCMD;
452 }
453}
454
455static const struct rtc_class_ops isl12022_rtc_ops = {
456 .ioctl = isl12022_rtc_ioctl,
457 .read_time = isl12022_rtc_read_time,
458 .set_time = isl12022_rtc_set_time,
459 .read_alarm = isl12022_rtc_read_alarm,
460 .set_alarm = isl12022_rtc_set_alarm,
461 .alarm_irq_enable = isl12022_rtc_alarm_irq_enable,
462};
463
464static const struct regmap_config regmap_config = {
465 .reg_bits = 8,
466 .val_bits = 8,
467 .use_single_write = true,
468};
469
470static int isl12022_register_clock(struct device *dev)
471{
472 struct isl12022 *isl12022 = dev_get_drvdata(dev);
473 struct regmap *regmap = isl12022->regmap;
474 struct clk_hw *hw;
475 int ret;
476
477 if (!device_property_present(dev, "#clock-cells")) {
478 /*
479 * Disabling the F_OUT pin reduces the power
480 * consumption in battery mode by ~25%.
481 */
482 regmap_update_bits(regmap, ISL12022_REG_INT, ISL12022_INT_FO_MASK,
483 ISL12022_INT_FO_OFF);
484
485 return 0;
486 }
487
488 if (!IS_ENABLED(CONFIG_COMMON_CLK))
489 return 0;
490
491 /*
492 * For now, only support a fixed clock of 32768Hz (the reset default).
493 */
494 ret = regmap_update_bits(regmap, ISL12022_REG_INT,
495 ISL12022_INT_FO_MASK, ISL12022_INT_FO_32K);
496 if (ret)
497 return ret;
498
499 hw = devm_clk_hw_register_fixed_rate(dev, "isl12022", NULL, 0, 32768);
500 if (IS_ERR(hw))
501 return PTR_ERR(hw);
502
503 return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
504}
505
506static const u32 trip_levels[2][7] = {
507 { 2125000, 2295000, 2550000, 2805000, 3060000, 4250000, 4675000 },
508 { 1875000, 2025000, 2250000, 2475000, 2700000, 3750000, 4125000 },
509};
510
511static void isl12022_set_trip_levels(struct device *dev)
512{
513 struct isl12022 *isl12022 = dev_get_drvdata(dev);
514 struct regmap *regmap = isl12022->regmap;
515 u32 levels[2] = {0, 0};
516 int ret, i, j, x[2];
517 u8 val, mask;
518
519 device_property_read_u32_array(dev, "isil,battery-trip-levels-microvolt",
520 levels, 2);
521
522 for (i = 0; i < 2; i++) {
523 for (j = 0; j < ARRAY_SIZE(trip_levels[i]) - 1; j++) {
524 if (levels[i] <= trip_levels[i][j])
525 break;
526 }
527 x[i] = j;
528 }
529
530 val = FIELD_PREP(ISL12022_REG_VB85_MASK, x[0]) |
531 FIELD_PREP(ISL12022_REG_VB75_MASK, x[1]);
532 mask = ISL12022_REG_VB85_MASK | ISL12022_REG_VB75_MASK;
533
534 ret = regmap_update_bits(regmap, ISL12022_REG_PWR_VBAT, mask, val);
535 if (ret)
536 dev_warn(dev, "unable to set battery alarm levels: %d\n", ret);
537
538 /*
539 * Force a write of the TSE bit in the BETA register, in order
540 * to trigger an update of the LBAT75 and LBAT85 bits in the
541 * status register. In battery backup mode, those bits have
542 * another meaning, so without this, they may contain stale
543 * values for up to a minute after power-on.
544 */
545 regmap_write_bits(regmap, ISL12022_REG_BETA,
546 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
547}
548
549static int isl12022_probe(struct i2c_client *client)
550{
551 struct isl12022 *isl12022;
552 struct rtc_device *rtc;
553 struct regmap *regmap;
554 int ret;
555
556 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
557 return -ENODEV;
558
559 /* Allocate driver state */
560 isl12022 = devm_kzalloc(&client->dev, sizeof(*isl12022), GFP_KERNEL);
561 if (!isl12022)
562 return -ENOMEM;
563
564 regmap = devm_regmap_init_i2c(client, ®map_config);
565 if (IS_ERR(regmap))
566 return dev_err_probe(&client->dev, PTR_ERR(regmap), "regmap allocation failed\n");
567 isl12022->regmap = regmap;
568
569 dev_set_drvdata(&client->dev, isl12022);
570
571 ret = isl12022_register_clock(&client->dev);
572 if (ret)
573 return ret;
574
575 isl12022_set_trip_levels(&client->dev);
576 isl12022_hwmon_register(&client->dev);
577
578 rtc = devm_rtc_allocate_device(&client->dev);
579 if (IS_ERR(rtc))
580 return PTR_ERR(rtc);
581 isl12022->rtc = rtc;
582
583 rtc->ops = &isl12022_rtc_ops;
584 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
585 rtc->range_max = RTC_TIMESTAMP_END_2099;
586
587 if (client->irq > 0) {
588 ret = isl12022_setup_irq(&client->dev, client->irq);
589 if (ret)
590 return ret;
591 } else {
592 clear_bit(RTC_FEATURE_ALARM, rtc->features);
593 }
594
595 return devm_rtc_register_device(rtc);
596}
597
598static const struct of_device_id isl12022_dt_match[] = {
599 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
600 { .compatible = "isil,isl12022" },
601 { },
602};
603MODULE_DEVICE_TABLE(of, isl12022_dt_match);
604
605static const struct i2c_device_id isl12022_id[] = {
606 { "isl12022" },
607 { }
608};
609MODULE_DEVICE_TABLE(i2c, isl12022_id);
610
611static struct i2c_driver isl12022_driver = {
612 .driver = {
613 .name = "rtc-isl12022",
614 .of_match_table = isl12022_dt_match,
615 },
616 .probe = isl12022_probe,
617 .id_table = isl12022_id,
618};
619
620module_i2c_driver(isl12022_driver);
621
622MODULE_AUTHOR("roman.fietze@telemotive.de");
623MODULE_DESCRIPTION("ISL 12022 RTC driver");
624MODULE_LICENSE("GPL");
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#include <linux/err.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22
23/* ISL register offsets */
24#define ISL12022_REG_SC 0x00
25#define ISL12022_REG_MN 0x01
26#define ISL12022_REG_HR 0x02
27#define ISL12022_REG_DT 0x03
28#define ISL12022_REG_MO 0x04
29#define ISL12022_REG_YR 0x05
30#define ISL12022_REG_DW 0x06
31
32#define ISL12022_REG_SR 0x07
33#define ISL12022_REG_INT 0x08
34
35/* ISL register bits */
36#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
37
38#define ISL12022_SR_LBAT85 (1 << 2)
39#define ISL12022_SR_LBAT75 (1 << 1)
40
41#define ISL12022_INT_WRTC (1 << 6)
42
43
44static struct i2c_driver isl12022_driver;
45
46struct isl12022 {
47 struct rtc_device *rtc;
48
49 bool write_enabled; /* true if write enable is set */
50};
51
52
53static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
54 uint8_t *data, size_t n)
55{
56 struct i2c_msg msgs[] = {
57 {
58 .addr = client->addr,
59 .flags = 0,
60 .len = 1,
61 .buf = data
62 }, /* setup read ptr */
63 {
64 .addr = client->addr,
65 .flags = I2C_M_RD,
66 .len = n,
67 .buf = data
68 }
69 };
70
71 int ret;
72
73 data[0] = reg;
74 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
75 if (ret != ARRAY_SIZE(msgs)) {
76 dev_err(&client->dev, "%s: read error, ret=%d\n",
77 __func__, ret);
78 return -EIO;
79 }
80
81 return 0;
82}
83
84
85static int isl12022_write_reg(struct i2c_client *client,
86 uint8_t reg, uint8_t val)
87{
88 uint8_t data[2] = { reg, val };
89 int err;
90
91 err = i2c_master_send(client, data, sizeof(data));
92 if (err != sizeof(data)) {
93 dev_err(&client->dev,
94 "%s: err=%d addr=%02x, data=%02x\n",
95 __func__, err, data[0], data[1]);
96 return -EIO;
97 }
98
99 return 0;
100}
101
102
103/*
104 * In the routines that deal directly with the isl12022 hardware, we use
105 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
106 */
107static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
108{
109 struct i2c_client *client = to_i2c_client(dev);
110 uint8_t buf[ISL12022_REG_INT + 1];
111 int ret;
112
113 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
114 if (ret)
115 return ret;
116
117 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
118 dev_warn(&client->dev,
119 "voltage dropped below %u%%, "
120 "date and time is not reliable.\n",
121 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
122 }
123
124 dev_dbg(&client->dev,
125 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
126 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
127 "sr=%02x, int=%02x",
128 __func__,
129 buf[ISL12022_REG_SC],
130 buf[ISL12022_REG_MN],
131 buf[ISL12022_REG_HR],
132 buf[ISL12022_REG_DT],
133 buf[ISL12022_REG_MO],
134 buf[ISL12022_REG_YR],
135 buf[ISL12022_REG_DW],
136 buf[ISL12022_REG_SR],
137 buf[ISL12022_REG_INT]);
138
139 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
140 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
141 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
142 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
143 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
144 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
145 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
146
147 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
148 "mday=%d, mon=%d, year=%d, wday=%d\n",
149 __func__,
150 tm->tm_sec, tm->tm_min, tm->tm_hour,
151 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
152
153 return 0;
154}
155
156static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
157{
158 struct i2c_client *client = to_i2c_client(dev);
159 struct isl12022 *isl12022 = i2c_get_clientdata(client);
160 size_t i;
161 int ret;
162 uint8_t buf[ISL12022_REG_DW + 1];
163
164 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
165 "mday=%d, mon=%d, year=%d, wday=%d\n",
166 __func__,
167 tm->tm_sec, tm->tm_min, tm->tm_hour,
168 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
169
170 if (!isl12022->write_enabled) {
171
172 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
173 if (ret)
174 return ret;
175
176 /* Check if WRTC (write rtc enable) is set factory default is
177 * 0 (not set) */
178 if (!(buf[0] & ISL12022_INT_WRTC)) {
179 dev_info(&client->dev,
180 "init write enable and 24 hour format\n");
181
182 /* Set the write enable bit. */
183 ret = isl12022_write_reg(client,
184 ISL12022_REG_INT,
185 buf[0] | ISL12022_INT_WRTC);
186 if (ret)
187 return ret;
188
189 /* Write to any RTC register to start RTC, we use the
190 * HR register, setting the MIL bit to use the 24 hour
191 * format. */
192 ret = isl12022_read_regs(client, ISL12022_REG_HR,
193 buf, 1);
194 if (ret)
195 return ret;
196
197 ret = isl12022_write_reg(client,
198 ISL12022_REG_HR,
199 buf[0] | ISL12022_HR_MIL);
200 if (ret)
201 return ret;
202 }
203
204 isl12022->write_enabled = true;
205 }
206
207 /* hours, minutes and seconds */
208 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
209 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
210 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
211
212 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
213
214 /* month, 1 - 12 */
215 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
216
217 /* year and century */
218 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
219
220 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
221
222 /* write register's data */
223 for (i = 0; i < ARRAY_SIZE(buf); i++) {
224 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
225 buf[ISL12022_REG_SC + i]);
226 if (ret)
227 return -EIO;
228 }
229
230 return 0;
231}
232
233static const struct rtc_class_ops isl12022_rtc_ops = {
234 .read_time = isl12022_rtc_read_time,
235 .set_time = isl12022_rtc_set_time,
236};
237
238static int isl12022_probe(struct i2c_client *client,
239 const struct i2c_device_id *id)
240{
241 struct isl12022 *isl12022;
242
243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
244 return -ENODEV;
245
246 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
247 GFP_KERNEL);
248 if (!isl12022)
249 return -ENOMEM;
250
251 i2c_set_clientdata(client, isl12022);
252
253 isl12022->rtc = devm_rtc_device_register(&client->dev,
254 isl12022_driver.driver.name,
255 &isl12022_rtc_ops, THIS_MODULE);
256 return PTR_ERR_OR_ZERO(isl12022->rtc);
257}
258
259#ifdef CONFIG_OF
260static const struct of_device_id isl12022_dt_match[] = {
261 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
262 { .compatible = "isil,isl12022" },
263 { },
264};
265MODULE_DEVICE_TABLE(of, isl12022_dt_match);
266#endif
267
268static const struct i2c_device_id isl12022_id[] = {
269 { "isl12022", 0 },
270 { }
271};
272MODULE_DEVICE_TABLE(i2c, isl12022_id);
273
274static struct i2c_driver isl12022_driver = {
275 .driver = {
276 .name = "rtc-isl12022",
277#ifdef CONFIG_OF
278 .of_match_table = of_match_ptr(isl12022_dt_match),
279#endif
280 },
281 .probe = isl12022_probe,
282 .id_table = isl12022_id,
283};
284
285module_i2c_driver(isl12022_driver);
286
287MODULE_AUTHOR("roman.fietze@telemotive.de");
288MODULE_DESCRIPTION("ISL 12022 RTC driver");
289MODULE_LICENSE("GPL");