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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Avionic Design GmbH
4 */
5
6#include <linux/bcd.h>
7#include <linux/bitfield.h>
8#include <linux/i2c.h>
9#include <linux/module.h>
10#include <linux/regmap.h>
11#include <linux/rtc.h>
12#include <linux/of.h>
13#include <linux/pm_wakeirq.h>
14
15#define PCF8523_REG_CONTROL1 0x00
16#define PCF8523_CONTROL1_CAP_SEL BIT(7)
17#define PCF8523_CONTROL1_STOP BIT(5)
18#define PCF8523_CONTROL1_AIE BIT(1)
19
20#define PCF8523_REG_CONTROL2 0x01
21#define PCF8523_CONTROL2_AF BIT(3)
22
23#define PCF8523_REG_CONTROL3 0x02
24#define PCF8523_CONTROL3_PM GENMASK(7, 5)
25#define PCF8523_PM_STANDBY 0x7
26#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
27#define PCF8523_CONTROL3_BSF BIT(3)
28
29#define PCF8523_REG_SECONDS 0x03
30#define PCF8523_SECONDS_OS BIT(7)
31
32#define PCF8523_REG_MINUTES 0x04
33#define PCF8523_REG_HOURS 0x05
34#define PCF8523_REG_DAYS 0x06
35#define PCF8523_REG_WEEKDAYS 0x07
36#define PCF8523_REG_MONTHS 0x08
37#define PCF8523_REG_YEARS 0x09
38
39#define PCF8523_REG_MINUTE_ALARM 0x0a
40#define PCF8523_REG_HOUR_ALARM 0x0b
41#define PCF8523_REG_DAY_ALARM 0x0c
42#define PCF8523_REG_WEEKDAY_ALARM 0x0d
43#define ALARM_DIS BIT(7)
44
45#define PCF8523_REG_OFFSET 0x0e
46#define PCF8523_OFFSET_MODE BIT(7)
47
48#define PCF8523_TMR_CLKOUT_CTRL 0x0f
49
50struct pcf8523 {
51 struct rtc_device *rtc;
52 struct regmap *regmap;
53};
54
55static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
56{
57 u32 load, value = 0;
58
59 load = 12500;
60 of_property_read_u32(node, "quartz-load-femtofarads", &load);
61
62 switch (load) {
63 default:
64 dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
65 load);
66 fallthrough;
67 case 12500:
68 value = PCF8523_CONTROL1_CAP_SEL;
69 break;
70 case 7000:
71 break;
72 }
73
74 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
75 PCF8523_CONTROL1_CAP_SEL, value);
76}
77
78static irqreturn_t pcf8523_irq(int irq, void *dev_id)
79{
80 struct pcf8523 *pcf8523 = dev_id;
81 u32 value;
82 int err;
83
84 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
85 if (err < 0)
86 return IRQ_HANDLED;
87
88 if (value & PCF8523_CONTROL2_AF) {
89 value &= ~PCF8523_CONTROL2_AF;
90 regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
91 rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
92
93 return IRQ_HANDLED;
94 }
95
96 return IRQ_NONE;
97}
98
99static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
100{
101 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
102 u8 regs[10];
103 int err;
104
105 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
106 sizeof(regs));
107 if (err < 0)
108 return err;
109
110 if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
111 return -EINVAL;
112
113 tm->tm_sec = bcd2bin(regs[3] & 0x7f);
114 tm->tm_min = bcd2bin(regs[4] & 0x7f);
115 tm->tm_hour = bcd2bin(regs[5] & 0x3f);
116 tm->tm_mday = bcd2bin(regs[6] & 0x3f);
117 tm->tm_wday = regs[7] & 0x7;
118 tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
119 tm->tm_year = bcd2bin(regs[9]) + 100;
120
121 return 0;
122}
123
124static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
125{
126 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
127 u8 regs[7];
128 int err;
129
130 err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
131 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
132 if (err < 0)
133 return err;
134
135 /* This will purposely overwrite PCF8523_SECONDS_OS */
136 regs[0] = bin2bcd(tm->tm_sec);
137 regs[1] = bin2bcd(tm->tm_min);
138 regs[2] = bin2bcd(tm->tm_hour);
139 regs[3] = bin2bcd(tm->tm_mday);
140 regs[4] = tm->tm_wday;
141 regs[5] = bin2bcd(tm->tm_mon + 1);
142 regs[6] = bin2bcd(tm->tm_year - 100);
143
144 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
145 sizeof(regs));
146 if (err < 0) {
147 /*
148 * If the time cannot be set, restart the RTC anyway. Note
149 * that errors are ignored if the RTC cannot be started so
150 * that we have a chance to propagate the original error.
151 */
152 regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
153 PCF8523_CONTROL1_STOP, 0);
154 return err;
155 }
156
157 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
158 PCF8523_CONTROL1_STOP, 0);
159}
160
161static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
162{
163 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
164 u8 regs[4];
165 u32 value;
166 int err;
167
168 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
169 sizeof(regs));
170 if (err < 0)
171 return err;
172
173 tm->time.tm_sec = 0;
174 tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
175 tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
176 tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
177 tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
178
179 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
180 if (err < 0)
181 return err;
182 tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
183
184 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
185 if (err < 0)
186 return err;
187 tm->pending = !!(value & PCF8523_CONTROL2_AF);
188
189 return 0;
190}
191
192static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
193{
194 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
195
196 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
197 PCF8523_CONTROL1_AIE, enabled ?
198 PCF8523_CONTROL1_AIE : 0);
199}
200
201static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
202{
203 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
204 u8 regs[5];
205 int err;
206
207 err = pcf8523_irq_enable(dev, 0);
208 if (err)
209 return err;
210
211 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
212 if (err < 0)
213 return err;
214
215 regs[0] = bin2bcd(tm->time.tm_min);
216 regs[1] = bin2bcd(tm->time.tm_hour);
217 regs[2] = bin2bcd(tm->time.tm_mday);
218 regs[3] = ALARM_DIS;
219
220 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
221 sizeof(regs));
222 if (err < 0)
223 return err;
224
225 if (tm->enabled)
226 return pcf8523_irq_enable(dev, tm->enabled);
227
228 return 0;
229}
230
231static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
232{
233 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
234 int ret;
235 u32 value;
236
237 switch (param->param) {
238 case RTC_PARAM_BACKUP_SWITCH_MODE:
239 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
240 if (ret < 0)
241 return ret;
242
243 value = FIELD_GET(PCF8523_CONTROL3_PM, value);
244
245 switch (value) {
246 case 0x0:
247 case 0x4:
248 param->uvalue = RTC_BSM_LEVEL;
249 break;
250 case 0x1:
251 case 0x5:
252 param->uvalue = RTC_BSM_DIRECT;
253 break;
254 case PCF8523_PM_STANDBY:
255 param->uvalue = RTC_BSM_STANDBY;
256 break;
257 default:
258 param->uvalue = RTC_BSM_DISABLED;
259 }
260
261 break;
262
263 default:
264 return -EINVAL;
265 }
266
267 return 0;
268}
269
270static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
271{
272 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
273 u8 mode;
274
275 switch (param->param) {
276 case RTC_PARAM_BACKUP_SWITCH_MODE:
277 switch (param->uvalue) {
278 case RTC_BSM_DISABLED:
279 mode = 0x2;
280 break;
281 case RTC_BSM_DIRECT:
282 mode = 0x1;
283 break;
284 case RTC_BSM_LEVEL:
285 mode = 0x0;
286 break;
287 case RTC_BSM_STANDBY:
288 mode = PCF8523_PM_STANDBY;
289 break;
290 default:
291 return -EINVAL;
292 }
293
294 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
295 PCF8523_CONTROL3_PM,
296 FIELD_PREP(PCF8523_CONTROL3_PM, mode));
297
298 break;
299
300 default:
301 return -EINVAL;
302 }
303
304 return 0;
305}
306
307static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
308 unsigned long arg)
309{
310 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
311 unsigned int flags = 0;
312 u32 value;
313 int ret;
314
315 switch (cmd) {
316 case RTC_VL_READ:
317 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
318 if (ret < 0)
319 return ret;
320
321 if (value & PCF8523_CONTROL3_BLF)
322 flags |= RTC_VL_BACKUP_LOW;
323
324 ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
325 if (ret < 0)
326 return ret;
327
328 if (value & PCF8523_SECONDS_OS)
329 flags |= RTC_VL_DATA_INVALID;
330
331 return put_user(flags, (unsigned int __user *)arg);
332
333 default:
334 return -ENOIOCTLCMD;
335 }
336}
337
338static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
339{
340 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
341 int err;
342 u32 value;
343 s8 val;
344
345 err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
346 if (err < 0)
347 return err;
348
349 /* sign extend the 7-bit offset value */
350 val = value << 1;
351 *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
352
353 return 0;
354}
355
356static int pcf8523_rtc_set_offset(struct device *dev, long offset)
357{
358 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
359 long reg_m0, reg_m1;
360 u32 value;
361
362 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
363 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
364
365 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
366 value = reg_m0 & 0x7f;
367 else
368 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
369
370 return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
371}
372
373static const struct rtc_class_ops pcf8523_rtc_ops = {
374 .read_time = pcf8523_rtc_read_time,
375 .set_time = pcf8523_rtc_set_time,
376 .read_alarm = pcf8523_rtc_read_alarm,
377 .set_alarm = pcf8523_rtc_set_alarm,
378 .alarm_irq_enable = pcf8523_irq_enable,
379 .ioctl = pcf8523_rtc_ioctl,
380 .read_offset = pcf8523_rtc_read_offset,
381 .set_offset = pcf8523_rtc_set_offset,
382 .param_get = pcf8523_param_get,
383 .param_set = pcf8523_param_set,
384};
385
386static const struct regmap_config regmap_config = {
387 .reg_bits = 8,
388 .val_bits = 8,
389 .max_register = 0x13,
390};
391
392static int pcf8523_probe(struct i2c_client *client)
393{
394 struct pcf8523 *pcf8523;
395 struct rtc_device *rtc;
396 bool wakeup_source = false;
397 u32 value;
398 int err;
399
400 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
401 return -ENODEV;
402
403 pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
404 if (!pcf8523)
405 return -ENOMEM;
406
407 pcf8523->regmap = devm_regmap_init_i2c(client, ®map_config);
408 if (IS_ERR(pcf8523->regmap))
409 return PTR_ERR(pcf8523->regmap);
410
411 i2c_set_clientdata(client, pcf8523);
412
413 rtc = devm_rtc_allocate_device(&client->dev);
414 if (IS_ERR(rtc))
415 return PTR_ERR(rtc);
416 pcf8523->rtc = rtc;
417
418 err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
419 if (err < 0)
420 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
421 err);
422
423 err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
424 if (err < 0)
425 return err;
426
427 if (value & PCF8523_SECONDS_OS) {
428 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
429 if (err < 0)
430 return err;
431
432 if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
433 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
434 value & ~PCF8523_CONTROL3_PM);
435 if (err < 0)
436 return err;
437 }
438 }
439
440 rtc->ops = &pcf8523_rtc_ops;
441 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
442 rtc->range_max = RTC_TIMESTAMP_END_2099;
443 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
444 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
445
446 if (client->irq > 0) {
447 unsigned long irqflags = IRQF_TRIGGER_LOW;
448
449 if (dev_fwnode(&client->dev))
450 irqflags = 0;
451
452 err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
453 if (err < 0)
454 return err;
455
456 err = devm_request_threaded_irq(&client->dev, client->irq,
457 NULL, pcf8523_irq,
458 IRQF_SHARED | IRQF_ONESHOT | irqflags,
459 dev_name(&rtc->dev), pcf8523);
460 if (err)
461 return err;
462
463 dev_pm_set_wake_irq(&client->dev, client->irq);
464 }
465
466 wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
467 if (client->irq > 0 || wakeup_source)
468 device_init_wakeup(&client->dev, true);
469
470 return devm_rtc_register_device(rtc);
471}
472
473static const struct i2c_device_id pcf8523_id[] = {
474 { "pcf8523", 0 },
475 { }
476};
477MODULE_DEVICE_TABLE(i2c, pcf8523_id);
478
479static const struct of_device_id pcf8523_of_match[] = {
480 { .compatible = "nxp,pcf8523" },
481 { .compatible = "microcrystal,rv8523" },
482 { }
483};
484MODULE_DEVICE_TABLE(of, pcf8523_of_match);
485
486static struct i2c_driver pcf8523_driver = {
487 .driver = {
488 .name = "rtc-pcf8523",
489 .of_match_table = pcf8523_of_match,
490 },
491 .probe = pcf8523_probe,
492 .id_table = pcf8523_id,
493};
494module_i2c_driver(pcf8523_driver);
495
496MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
497MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
498MODULE_LICENSE("GPL v2");
1/*
2 * Copyright (C) 2012 Avionic Design GmbH
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/bcd.h>
10#include <linux/i2c.h>
11#include <linux/module.h>
12#include <linux/rtc.h>
13#include <linux/of.h>
14
15#define DRIVER_NAME "rtc-pcf8523"
16
17#define REG_CONTROL1 0x00
18#define REG_CONTROL1_CAP_SEL (1 << 7)
19#define REG_CONTROL1_STOP (1 << 5)
20
21#define REG_CONTROL3 0x02
22#define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */
23#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
24#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
25#define REG_CONTROL3_PM_MASK 0xe0
26#define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */
27
28#define REG_SECONDS 0x03
29#define REG_SECONDS_OS (1 << 7)
30
31#define REG_MINUTES 0x04
32#define REG_HOURS 0x05
33#define REG_DAYS 0x06
34#define REG_WEEKDAYS 0x07
35#define REG_MONTHS 0x08
36#define REG_YEARS 0x09
37
38#define REG_OFFSET 0x0e
39#define REG_OFFSET_MODE BIT(7)
40
41struct pcf8523 {
42 struct rtc_device *rtc;
43};
44
45static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
46{
47 struct i2c_msg msgs[2];
48 u8 value = 0;
49 int err;
50
51 msgs[0].addr = client->addr;
52 msgs[0].flags = 0;
53 msgs[0].len = sizeof(reg);
54 msgs[0].buf = ®
55
56 msgs[1].addr = client->addr;
57 msgs[1].flags = I2C_M_RD;
58 msgs[1].len = sizeof(value);
59 msgs[1].buf = &value;
60
61 err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
62 if (err < 0)
63 return err;
64
65 *valuep = value;
66
67 return 0;
68}
69
70static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
71{
72 u8 buffer[2] = { reg, value };
73 struct i2c_msg msg;
74 int err;
75
76 msg.addr = client->addr;
77 msg.flags = 0;
78 msg.len = sizeof(buffer);
79 msg.buf = buffer;
80
81 err = i2c_transfer(client->adapter, &msg, 1);
82 if (err < 0)
83 return err;
84
85 return 0;
86}
87
88static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
89{
90 u8 value;
91 int err;
92
93 err = pcf8523_read(client, REG_CONTROL1, &value);
94 if (err < 0)
95 return err;
96
97 if (!high)
98 value &= ~REG_CONTROL1_CAP_SEL;
99 else
100 value |= REG_CONTROL1_CAP_SEL;
101
102 err = pcf8523_write(client, REG_CONTROL1, value);
103 if (err < 0)
104 return err;
105
106 return err;
107}
108
109static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
110{
111 u8 value;
112 int err;
113
114 err = pcf8523_read(client, REG_CONTROL3, &value);
115 if (err < 0)
116 return err;
117
118 value = (value & ~REG_CONTROL3_PM_MASK) | pm;
119
120 err = pcf8523_write(client, REG_CONTROL3, value);
121 if (err < 0)
122 return err;
123
124 return 0;
125}
126
127static int pcf8523_stop_rtc(struct i2c_client *client)
128{
129 u8 value;
130 int err;
131
132 err = pcf8523_read(client, REG_CONTROL1, &value);
133 if (err < 0)
134 return err;
135
136 value |= REG_CONTROL1_STOP;
137
138 err = pcf8523_write(client, REG_CONTROL1, value);
139 if (err < 0)
140 return err;
141
142 return 0;
143}
144
145static int pcf8523_start_rtc(struct i2c_client *client)
146{
147 u8 value;
148 int err;
149
150 err = pcf8523_read(client, REG_CONTROL1, &value);
151 if (err < 0)
152 return err;
153
154 value &= ~REG_CONTROL1_STOP;
155
156 err = pcf8523_write(client, REG_CONTROL1, value);
157 if (err < 0)
158 return err;
159
160 return 0;
161}
162
163static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
164{
165 struct i2c_client *client = to_i2c_client(dev);
166 u8 start = REG_SECONDS, regs[7];
167 struct i2c_msg msgs[2];
168 int err;
169
170 msgs[0].addr = client->addr;
171 msgs[0].flags = 0;
172 msgs[0].len = 1;
173 msgs[0].buf = &start;
174
175 msgs[1].addr = client->addr;
176 msgs[1].flags = I2C_M_RD;
177 msgs[1].len = sizeof(regs);
178 msgs[1].buf = regs;
179
180 err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
181 if (err < 0)
182 return err;
183
184 if (regs[0] & REG_SECONDS_OS)
185 return -EINVAL;
186
187 tm->tm_sec = bcd2bin(regs[0] & 0x7f);
188 tm->tm_min = bcd2bin(regs[1] & 0x7f);
189 tm->tm_hour = bcd2bin(regs[2] & 0x3f);
190 tm->tm_mday = bcd2bin(regs[3] & 0x3f);
191 tm->tm_wday = regs[4] & 0x7;
192 tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
193 tm->tm_year = bcd2bin(regs[6]) + 100;
194
195 return 0;
196}
197
198static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
199{
200 struct i2c_client *client = to_i2c_client(dev);
201 struct i2c_msg msg;
202 u8 regs[8];
203 int err;
204
205 /*
206 * The hardware can only store values between 0 and 99 in it's YEAR
207 * register (with 99 overflowing to 0 on increment).
208 * After 2100-02-28 we could start interpreting the year to be in the
209 * interval [2100, 2199], but there is no path to switch in a smooth way
210 * because the chip handles YEAR=0x00 (and the out-of-spec
211 * YEAR=0xa0) as a leap year, but 2100 isn't.
212 */
213 if (tm->tm_year < 100 || tm->tm_year >= 200)
214 return -EINVAL;
215
216 err = pcf8523_stop_rtc(client);
217 if (err < 0)
218 return err;
219
220 regs[0] = REG_SECONDS;
221 /* This will purposely overwrite REG_SECONDS_OS */
222 regs[1] = bin2bcd(tm->tm_sec);
223 regs[2] = bin2bcd(tm->tm_min);
224 regs[3] = bin2bcd(tm->tm_hour);
225 regs[4] = bin2bcd(tm->tm_mday);
226 regs[5] = tm->tm_wday;
227 regs[6] = bin2bcd(tm->tm_mon + 1);
228 regs[7] = bin2bcd(tm->tm_year - 100);
229
230 msg.addr = client->addr;
231 msg.flags = 0;
232 msg.len = sizeof(regs);
233 msg.buf = regs;
234
235 err = i2c_transfer(client->adapter, &msg, 1);
236 if (err < 0) {
237 /*
238 * If the time cannot be set, restart the RTC anyway. Note
239 * that errors are ignored if the RTC cannot be started so
240 * that we have a chance to propagate the original error.
241 */
242 pcf8523_start_rtc(client);
243 return err;
244 }
245
246 return pcf8523_start_rtc(client);
247}
248
249#ifdef CONFIG_RTC_INTF_DEV
250static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
251 unsigned long arg)
252{
253 struct i2c_client *client = to_i2c_client(dev);
254 u8 value;
255 int ret = 0, err;
256
257 switch (cmd) {
258 case RTC_VL_READ:
259 err = pcf8523_read(client, REG_CONTROL3, &value);
260 if (err < 0)
261 return err;
262
263 if (value & REG_CONTROL3_BLF)
264 ret = 1;
265
266 if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
267 return -EFAULT;
268
269 return 0;
270 default:
271 return -ENOIOCTLCMD;
272 }
273}
274#else
275#define pcf8523_rtc_ioctl NULL
276#endif
277
278static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
279{
280 struct i2c_client *client = to_i2c_client(dev);
281 int err;
282 u8 value;
283 s8 val;
284
285 err = pcf8523_read(client, REG_OFFSET, &value);
286 if (err < 0)
287 return err;
288
289 /* sign extend the 7-bit offset value */
290 val = value << 1;
291 *offset = (value & REG_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
292
293 return 0;
294}
295
296static int pcf8523_rtc_set_offset(struct device *dev, long offset)
297{
298 struct i2c_client *client = to_i2c_client(dev);
299 long reg_m0, reg_m1;
300 u8 value;
301
302 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
303 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
304
305 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
306 value = reg_m0 & 0x7f;
307 else
308 value = (reg_m1 & 0x7f) | REG_OFFSET_MODE;
309
310 return pcf8523_write(client, REG_OFFSET, value);
311}
312
313static const struct rtc_class_ops pcf8523_rtc_ops = {
314 .read_time = pcf8523_rtc_read_time,
315 .set_time = pcf8523_rtc_set_time,
316 .ioctl = pcf8523_rtc_ioctl,
317 .read_offset = pcf8523_rtc_read_offset,
318 .set_offset = pcf8523_rtc_set_offset,
319};
320
321static int pcf8523_probe(struct i2c_client *client,
322 const struct i2c_device_id *id)
323{
324 struct pcf8523 *pcf;
325 int err;
326
327 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
328 return -ENODEV;
329
330 pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
331 if (!pcf)
332 return -ENOMEM;
333
334 err = pcf8523_select_capacitance(client, true);
335 if (err < 0)
336 return err;
337
338 err = pcf8523_set_pm(client, 0);
339 if (err < 0)
340 return err;
341
342 pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
343 &pcf8523_rtc_ops, THIS_MODULE);
344 if (IS_ERR(pcf->rtc))
345 return PTR_ERR(pcf->rtc);
346
347 i2c_set_clientdata(client, pcf);
348
349 return 0;
350}
351
352static const struct i2c_device_id pcf8523_id[] = {
353 { "pcf8523", 0 },
354 { }
355};
356MODULE_DEVICE_TABLE(i2c, pcf8523_id);
357
358#ifdef CONFIG_OF
359static const struct of_device_id pcf8523_of_match[] = {
360 { .compatible = "nxp,pcf8523" },
361 { }
362};
363MODULE_DEVICE_TABLE(of, pcf8523_of_match);
364#endif
365
366static struct i2c_driver pcf8523_driver = {
367 .driver = {
368 .name = DRIVER_NAME,
369 .of_match_table = of_match_ptr(pcf8523_of_match),
370 },
371 .probe = pcf8523_probe,
372 .id_table = pcf8523_id,
373};
374module_i2c_driver(pcf8523_driver);
375
376MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
377MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
378MODULE_LICENSE("GPL v2");