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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * EPSON TOYOCOM RTC-7301SF/DG Driver
4 *
5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
6 *
7 * Based on rtc-rp5c01.c
8 *
9 * Datasheet: http://www5.epsondevice.com/en/products/parallel/rtc7301sf.html
10 */
11
12#include <linux/io.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/mod_devicetable.h>
16#include <linux/delay.h>
17#include <linux/regmap.h>
18#include <linux/platform_device.h>
19#include <linux/rtc.h>
20
21#define DRV_NAME "rtc-r7301"
22
23#define RTC7301_1_SEC 0x0 /* Bank 0 and Band 1 */
24#define RTC7301_10_SEC 0x1 /* Bank 0 and Band 1 */
25#define RTC7301_AE BIT(3)
26#define RTC7301_1_MIN 0x2 /* Bank 0 and Band 1 */
27#define RTC7301_10_MIN 0x3 /* Bank 0 and Band 1 */
28#define RTC7301_1_HOUR 0x4 /* Bank 0 and Band 1 */
29#define RTC7301_10_HOUR 0x5 /* Bank 0 and Band 1 */
30#define RTC7301_DAY_OF_WEEK 0x6 /* Bank 0 and Band 1 */
31#define RTC7301_1_DAY 0x7 /* Bank 0 and Band 1 */
32#define RTC7301_10_DAY 0x8 /* Bank 0 and Band 1 */
33#define RTC7301_1_MONTH 0x9 /* Bank 0 */
34#define RTC7301_10_MONTH 0xa /* Bank 0 */
35#define RTC7301_1_YEAR 0xb /* Bank 0 */
36#define RTC7301_10_YEAR 0xc /* Bank 0 */
37#define RTC7301_100_YEAR 0xd /* Bank 0 */
38#define RTC7301_1000_YEAR 0xe /* Bank 0 */
39#define RTC7301_ALARM_CONTROL 0xe /* Bank 1 */
40#define RTC7301_ALARM_CONTROL_AIE BIT(0)
41#define RTC7301_ALARM_CONTROL_AF BIT(1)
42#define RTC7301_TIMER_CONTROL 0xe /* Bank 2 */
43#define RTC7301_TIMER_CONTROL_TIE BIT(0)
44#define RTC7301_TIMER_CONTROL_TF BIT(1)
45#define RTC7301_CONTROL 0xf /* All banks */
46#define RTC7301_CONTROL_BUSY BIT(0)
47#define RTC7301_CONTROL_STOP BIT(1)
48#define RTC7301_CONTROL_BANK_SEL_0 BIT(2)
49#define RTC7301_CONTROL_BANK_SEL_1 BIT(3)
50
51struct rtc7301_priv {
52 struct regmap *regmap;
53 int irq;
54 spinlock_t lock;
55 u8 bank;
56};
57
58static const struct regmap_config rtc7301_regmap_config = {
59 .reg_bits = 32,
60 .val_bits = 8,
61 .reg_stride = 4,
62};
63
64static u8 rtc7301_read(struct rtc7301_priv *priv, unsigned int reg)
65{
66 int reg_stride = regmap_get_reg_stride(priv->regmap);
67 unsigned int val;
68
69 regmap_read(priv->regmap, reg_stride * reg, &val);
70
71 return val & 0xf;
72}
73
74static void rtc7301_write(struct rtc7301_priv *priv, u8 val, unsigned int reg)
75{
76 int reg_stride = regmap_get_reg_stride(priv->regmap);
77
78 regmap_write(priv->regmap, reg_stride * reg, val);
79}
80
81static void rtc7301_update_bits(struct rtc7301_priv *priv, unsigned int reg,
82 u8 mask, u8 val)
83{
84 int reg_stride = regmap_get_reg_stride(priv->regmap);
85
86 regmap_update_bits(priv->regmap, reg_stride * reg, mask, val);
87}
88
89static int rtc7301_wait_while_busy(struct rtc7301_priv *priv)
90{
91 int retries = 100;
92
93 while (retries-- > 0) {
94 u8 val;
95
96 val = rtc7301_read(priv, RTC7301_CONTROL);
97 if (!(val & RTC7301_CONTROL_BUSY))
98 return 0;
99
100 udelay(300);
101 }
102
103 return -ETIMEDOUT;
104}
105
106static void rtc7301_stop(struct rtc7301_priv *priv)
107{
108 rtc7301_update_bits(priv, RTC7301_CONTROL, RTC7301_CONTROL_STOP,
109 RTC7301_CONTROL_STOP);
110}
111
112static void rtc7301_start(struct rtc7301_priv *priv)
113{
114 rtc7301_update_bits(priv, RTC7301_CONTROL, RTC7301_CONTROL_STOP, 0);
115}
116
117static void rtc7301_select_bank(struct rtc7301_priv *priv, u8 bank)
118{
119 u8 val = 0;
120
121 if (bank == priv->bank)
122 return;
123
124 if (bank & BIT(0))
125 val |= RTC7301_CONTROL_BANK_SEL_0;
126 if (bank & BIT(1))
127 val |= RTC7301_CONTROL_BANK_SEL_1;
128
129 rtc7301_update_bits(priv, RTC7301_CONTROL,
130 RTC7301_CONTROL_BANK_SEL_0 |
131 RTC7301_CONTROL_BANK_SEL_1, val);
132
133 priv->bank = bank;
134}
135
136static void rtc7301_get_time(struct rtc7301_priv *priv, struct rtc_time *tm,
137 bool alarm)
138{
139 int year;
140
141 tm->tm_sec = rtc7301_read(priv, RTC7301_1_SEC);
142 tm->tm_sec += (rtc7301_read(priv, RTC7301_10_SEC) & ~RTC7301_AE) * 10;
143 tm->tm_min = rtc7301_read(priv, RTC7301_1_MIN);
144 tm->tm_min += (rtc7301_read(priv, RTC7301_10_MIN) & ~RTC7301_AE) * 10;
145 tm->tm_hour = rtc7301_read(priv, RTC7301_1_HOUR);
146 tm->tm_hour += (rtc7301_read(priv, RTC7301_10_HOUR) & ~RTC7301_AE) * 10;
147 tm->tm_mday = rtc7301_read(priv, RTC7301_1_DAY);
148 tm->tm_mday += (rtc7301_read(priv, RTC7301_10_DAY) & ~RTC7301_AE) * 10;
149
150 if (alarm) {
151 tm->tm_wday = -1;
152 tm->tm_mon = -1;
153 tm->tm_year = -1;
154 tm->tm_yday = -1;
155 tm->tm_isdst = -1;
156 return;
157 }
158
159 tm->tm_wday = (rtc7301_read(priv, RTC7301_DAY_OF_WEEK) & ~RTC7301_AE);
160 tm->tm_mon = rtc7301_read(priv, RTC7301_10_MONTH) * 10 +
161 rtc7301_read(priv, RTC7301_1_MONTH) - 1;
162 year = rtc7301_read(priv, RTC7301_1000_YEAR) * 1000 +
163 rtc7301_read(priv, RTC7301_100_YEAR) * 100 +
164 rtc7301_read(priv, RTC7301_10_YEAR) * 10 +
165 rtc7301_read(priv, RTC7301_1_YEAR);
166
167 tm->tm_year = year - 1900;
168}
169
170static void rtc7301_write_time(struct rtc7301_priv *priv, struct rtc_time *tm,
171 bool alarm)
172{
173 int year;
174
175 rtc7301_write(priv, tm->tm_sec % 10, RTC7301_1_SEC);
176 rtc7301_write(priv, tm->tm_sec / 10, RTC7301_10_SEC);
177
178 rtc7301_write(priv, tm->tm_min % 10, RTC7301_1_MIN);
179 rtc7301_write(priv, tm->tm_min / 10, RTC7301_10_MIN);
180
181 rtc7301_write(priv, tm->tm_hour % 10, RTC7301_1_HOUR);
182 rtc7301_write(priv, tm->tm_hour / 10, RTC7301_10_HOUR);
183
184 rtc7301_write(priv, tm->tm_mday % 10, RTC7301_1_DAY);
185 rtc7301_write(priv, tm->tm_mday / 10, RTC7301_10_DAY);
186
187 /* Don't care for alarm register */
188 rtc7301_write(priv, alarm ? RTC7301_AE : tm->tm_wday,
189 RTC7301_DAY_OF_WEEK);
190
191 if (alarm)
192 return;
193
194 rtc7301_write(priv, (tm->tm_mon + 1) % 10, RTC7301_1_MONTH);
195 rtc7301_write(priv, (tm->tm_mon + 1) / 10, RTC7301_10_MONTH);
196
197 year = tm->tm_year + 1900;
198
199 rtc7301_write(priv, year % 10, RTC7301_1_YEAR);
200 rtc7301_write(priv, (year / 10) % 10, RTC7301_10_YEAR);
201 rtc7301_write(priv, (year / 100) % 10, RTC7301_100_YEAR);
202 rtc7301_write(priv, year / 1000, RTC7301_1000_YEAR);
203}
204
205static void rtc7301_alarm_irq(struct rtc7301_priv *priv, unsigned int enabled)
206{
207 rtc7301_update_bits(priv, RTC7301_ALARM_CONTROL,
208 RTC7301_ALARM_CONTROL_AF |
209 RTC7301_ALARM_CONTROL_AIE,
210 enabled ? RTC7301_ALARM_CONTROL_AIE : 0);
211}
212
213static int rtc7301_read_time(struct device *dev, struct rtc_time *tm)
214{
215 struct rtc7301_priv *priv = dev_get_drvdata(dev);
216 unsigned long flags;
217 int err;
218
219 spin_lock_irqsave(&priv->lock, flags);
220
221 rtc7301_select_bank(priv, 0);
222
223 err = rtc7301_wait_while_busy(priv);
224 if (!err)
225 rtc7301_get_time(priv, tm, false);
226
227 spin_unlock_irqrestore(&priv->lock, flags);
228
229 return err;
230}
231
232static int rtc7301_set_time(struct device *dev, struct rtc_time *tm)
233{
234 struct rtc7301_priv *priv = dev_get_drvdata(dev);
235 unsigned long flags;
236
237 spin_lock_irqsave(&priv->lock, flags);
238
239 rtc7301_stop(priv);
240 udelay(300);
241 rtc7301_select_bank(priv, 0);
242 rtc7301_write_time(priv, tm, false);
243 rtc7301_start(priv);
244
245 spin_unlock_irqrestore(&priv->lock, flags);
246
247 return 0;
248}
249
250static int rtc7301_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
251{
252 struct rtc7301_priv *priv = dev_get_drvdata(dev);
253 unsigned long flags;
254 u8 alrm_ctrl;
255
256 if (priv->irq <= 0)
257 return -EINVAL;
258
259 spin_lock_irqsave(&priv->lock, flags);
260
261 rtc7301_select_bank(priv, 1);
262 rtc7301_get_time(priv, &alarm->time, true);
263
264 alrm_ctrl = rtc7301_read(priv, RTC7301_ALARM_CONTROL);
265
266 alarm->enabled = !!(alrm_ctrl & RTC7301_ALARM_CONTROL_AIE);
267 alarm->pending = !!(alrm_ctrl & RTC7301_ALARM_CONTROL_AF);
268
269 spin_unlock_irqrestore(&priv->lock, flags);
270
271 return 0;
272}
273
274static int rtc7301_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
275{
276 struct rtc7301_priv *priv = dev_get_drvdata(dev);
277 unsigned long flags;
278
279 if (priv->irq <= 0)
280 return -EINVAL;
281
282 spin_lock_irqsave(&priv->lock, flags);
283
284 rtc7301_select_bank(priv, 1);
285 rtc7301_write_time(priv, &alarm->time, true);
286 rtc7301_alarm_irq(priv, alarm->enabled);
287
288 spin_unlock_irqrestore(&priv->lock, flags);
289
290 return 0;
291}
292
293static int rtc7301_alarm_irq_enable(struct device *dev, unsigned int enabled)
294{
295 struct rtc7301_priv *priv = dev_get_drvdata(dev);
296 unsigned long flags;
297
298 if (priv->irq <= 0)
299 return -EINVAL;
300
301 spin_lock_irqsave(&priv->lock, flags);
302
303 rtc7301_select_bank(priv, 1);
304 rtc7301_alarm_irq(priv, enabled);
305
306 spin_unlock_irqrestore(&priv->lock, flags);
307
308 return 0;
309}
310
311static const struct rtc_class_ops rtc7301_rtc_ops = {
312 .read_time = rtc7301_read_time,
313 .set_time = rtc7301_set_time,
314 .read_alarm = rtc7301_read_alarm,
315 .set_alarm = rtc7301_set_alarm,
316 .alarm_irq_enable = rtc7301_alarm_irq_enable,
317};
318
319static irqreturn_t rtc7301_irq_handler(int irq, void *dev_id)
320{
321 struct rtc_device *rtc = dev_id;
322 struct rtc7301_priv *priv = dev_get_drvdata(rtc->dev.parent);
323 unsigned long flags;
324 irqreturn_t ret = IRQ_NONE;
325 u8 alrm_ctrl;
326
327 spin_lock_irqsave(&priv->lock, flags);
328
329 rtc7301_select_bank(priv, 1);
330
331 alrm_ctrl = rtc7301_read(priv, RTC7301_ALARM_CONTROL);
332 if (alrm_ctrl & RTC7301_ALARM_CONTROL_AF) {
333 ret = IRQ_HANDLED;
334 rtc7301_alarm_irq(priv, false);
335 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
336 }
337
338 spin_unlock_irqrestore(&priv->lock, flags);
339
340 return ret;
341}
342
343static void rtc7301_init(struct rtc7301_priv *priv)
344{
345 unsigned long flags;
346
347 spin_lock_irqsave(&priv->lock, flags);
348
349 rtc7301_select_bank(priv, 2);
350 rtc7301_write(priv, 0, RTC7301_TIMER_CONTROL);
351
352 spin_unlock_irqrestore(&priv->lock, flags);
353}
354
355static int __init rtc7301_rtc_probe(struct platform_device *dev)
356{
357 void __iomem *regs;
358 struct rtc7301_priv *priv;
359 struct rtc_device *rtc;
360 int ret;
361
362 priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
363 if (!priv)
364 return -ENOMEM;
365
366 regs = devm_platform_ioremap_resource(dev, 0);
367 if (IS_ERR(regs))
368 return PTR_ERR(regs);
369
370 priv->regmap = devm_regmap_init_mmio(&dev->dev, regs,
371 &rtc7301_regmap_config);
372 if (IS_ERR(priv->regmap))
373 return PTR_ERR(priv->regmap);
374
375 priv->irq = platform_get_irq(dev, 0);
376
377 spin_lock_init(&priv->lock);
378 priv->bank = -1;
379
380 rtc7301_init(priv);
381
382 platform_set_drvdata(dev, priv);
383
384 rtc = devm_rtc_device_register(&dev->dev, DRV_NAME, &rtc7301_rtc_ops,
385 THIS_MODULE);
386 if (IS_ERR(rtc))
387 return PTR_ERR(rtc);
388
389 if (priv->irq > 0) {
390 ret = devm_request_irq(&dev->dev, priv->irq,
391 rtc7301_irq_handler, IRQF_SHARED,
392 dev_name(&dev->dev), rtc);
393 if (ret) {
394 priv->irq = 0;
395 dev_err(&dev->dev, "unable to request IRQ\n");
396 } else {
397 device_set_wakeup_capable(&dev->dev, true);
398 }
399 }
400
401 return 0;
402}
403
404#ifdef CONFIG_PM_SLEEP
405
406static int rtc7301_suspend(struct device *dev)
407{
408 struct rtc7301_priv *priv = dev_get_drvdata(dev);
409
410 if (device_may_wakeup(dev))
411 enable_irq_wake(priv->irq);
412
413 return 0;
414}
415
416static int rtc7301_resume(struct device *dev)
417{
418 struct rtc7301_priv *priv = dev_get_drvdata(dev);
419
420 if (device_may_wakeup(dev))
421 disable_irq_wake(priv->irq);
422
423 return 0;
424}
425
426#endif
427
428static SIMPLE_DEV_PM_OPS(rtc7301_pm_ops, rtc7301_suspend, rtc7301_resume);
429
430static const struct of_device_id rtc7301_dt_match[] = {
431 { .compatible = "epson,rtc7301sf" },
432 { .compatible = "epson,rtc7301dg" },
433 {}
434};
435MODULE_DEVICE_TABLE(of, rtc7301_dt_match);
436
437static struct platform_driver rtc7301_rtc_driver = {
438 .driver = {
439 .name = DRV_NAME,
440 .of_match_table = rtc7301_dt_match,
441 .pm = &rtc7301_pm_ops,
442 },
443};
444
445module_platform_driver_probe(rtc7301_rtc_driver, rtc7301_rtc_probe);
446
447MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
448MODULE_LICENSE("GPL");
449MODULE_DESCRIPTION("EPSON TOYOCOM RTC-7301SF/DG Driver");
450MODULE_ALIAS("platform:rtc-r7301");