1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ST M48T59 RTC driver
4 *
5 * Copyright (c) 2007 Wind River Systems, Inc.
6 *
7 * Author: Mark Zhan <rongkai.zhan@windriver.com>
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/io.h>
14 #include <linux/device.h>
15 #include <linux/platform_device.h>
16 #include <linux/rtc.h>
17 #include <linux/rtc/m48t59.h>
18 #include <linux/bcd.h>
19 #include <linux/slab.h>
20
21 #ifndef NO_IRQ
22 #define NO_IRQ (-1)
23 #endif
24
25 #define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
26 #define M48T59_WRITE(val, reg) \
27 (pdata->write_byte(dev, pdata->offset + reg, val))
28
29 #define M48T59_SET_BITS(mask, reg) \
30 M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
31 #define M48T59_CLEAR_BITS(mask, reg) \
32 M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))
33
34 struct m48t59_private {
35 void __iomem *ioaddr;
36 int irq;
37 struct rtc_device *rtc;
38 spinlock_t lock; /* serialize the NVRAM and RTC access */
39 };
40
41 /*
42 * This is the generic access method when the chip is memory-mapped
43 */
44 static void
m48t59_mem_writeb(struct device * dev,u32 ofs,u8 val)45 m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
46 {
47 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
48
49 writeb(val, m48t59->ioaddr+ofs);
50 }
51
52 static u8
m48t59_mem_readb(struct device * dev,u32 ofs)53 m48t59_mem_readb(struct device *dev, u32 ofs)
54 {
55 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
56
57 return readb(m48t59->ioaddr+ofs);
58 }
59
60 /*
61 * NOTE: M48T59 only uses BCD mode
62 */
m48t59_rtc_read_time(struct device * dev,struct rtc_time * tm)63 static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
64 {
65 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
66 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
67 unsigned long flags;
68 u8 val;
69
70 spin_lock_irqsave(&m48t59->lock, flags);
71 /* Issue the READ command */
72 M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
73
74 tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
75 /* tm_mon is 0-11 */
76 tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
77 tm->tm_mday = bcd2bin(M48T59_READ(M48T59_MDAY));
78
79 val = M48T59_READ(M48T59_WDAY);
80 if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
81 (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
82 dev_dbg(dev, "Century bit is enabled\n");
83 tm->tm_year += 100; /* one century */
84 }
85 #ifdef CONFIG_SPARC
86 /* Sun SPARC machines count years since 1968 */
87 tm->tm_year += 68;
88 #endif
89
90 tm->tm_wday = bcd2bin(val & 0x07);
91 tm->tm_hour = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
92 tm->tm_min = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
93 tm->tm_sec = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
94
95 /* Clear the READ bit */
96 M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
97 spin_unlock_irqrestore(&m48t59->lock, flags);
98
99 dev_dbg(dev, "RTC read time %ptR\n", tm);
100 return 0;
101 }
102
m48t59_rtc_set_time(struct device * dev,struct rtc_time * tm)103 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
104 {
105 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
106 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
107 unsigned long flags;
108 u8 val = 0;
109 int year = tm->tm_year;
110
111 #ifdef CONFIG_SPARC
112 /* Sun SPARC machines count years since 1968 */
113 year -= 68;
114 #endif
115
116 dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
117 year + 1900, tm->tm_mon, tm->tm_mday,
118 tm->tm_hour, tm->tm_min, tm->tm_sec);
119
120 if (year < 0)
121 return -EINVAL;
122
123 spin_lock_irqsave(&m48t59->lock, flags);
124 /* Issue the WRITE command */
125 M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
126
127 M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
128 M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
129 M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
130 M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
131 /* tm_mon is 0-11 */
132 M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
133 M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
134
135 if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
136 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
137 val |= (bin2bcd(tm->tm_wday) & 0x07);
138 M48T59_WRITE(val, M48T59_WDAY);
139
140 /* Clear the WRITE bit */
141 M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
142 spin_unlock_irqrestore(&m48t59->lock, flags);
143 return 0;
144 }
145
146 /*
147 * Read alarm time and date in RTC
148 */
m48t59_rtc_readalarm(struct device * dev,struct rtc_wkalrm * alrm)149 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
150 {
151 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
152 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
153 struct rtc_time *tm = &alrm->time;
154 unsigned long flags;
155 u8 val;
156
157 /* If no irq, we don't support ALARM */
158 if (m48t59->irq == NO_IRQ)
159 return -EIO;
160
161 spin_lock_irqsave(&m48t59->lock, flags);
162 /* Issue the READ command */
163 M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
164
165 tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
166 #ifdef CONFIG_SPARC
167 /* Sun SPARC machines count years since 1968 */
168 tm->tm_year += 68;
169 #endif
170 /* tm_mon is 0-11 */
171 tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
172
173 val = M48T59_READ(M48T59_WDAY);
174 if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
175 tm->tm_year += 100; /* one century */
176
177 tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
178 tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
179 tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
180 tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
181
182 /* Clear the READ bit */
183 M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
184 spin_unlock_irqrestore(&m48t59->lock, flags);
185
186 dev_dbg(dev, "RTC read alarm time %ptR\n", tm);
187 return rtc_valid_tm(tm);
188 }
189
190 /*
191 * Set alarm time and date in RTC
192 */
m48t59_rtc_setalarm(struct device * dev,struct rtc_wkalrm * alrm)193 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
194 {
195 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
196 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
197 struct rtc_time *tm = &alrm->time;
198 u8 mday, hour, min, sec;
199 unsigned long flags;
200 int year = tm->tm_year;
201
202 #ifdef CONFIG_SPARC
203 /* Sun SPARC machines count years since 1968 */
204 year -= 68;
205 #endif
206
207 /* If no irq, we don't support ALARM */
208 if (m48t59->irq == NO_IRQ)
209 return -EIO;
210
211 if (year < 0)
212 return -EINVAL;
213
214 /*
215 * 0xff means "always match"
216 */
217 mday = tm->tm_mday;
218 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
219 if (mday == 0xff)
220 mday = M48T59_READ(M48T59_MDAY);
221
222 hour = tm->tm_hour;
223 hour = (hour < 24) ? bin2bcd(hour) : 0x00;
224
225 min = tm->tm_min;
226 min = (min < 60) ? bin2bcd(min) : 0x00;
227
228 sec = tm->tm_sec;
229 sec = (sec < 60) ? bin2bcd(sec) : 0x00;
230
231 spin_lock_irqsave(&m48t59->lock, flags);
232 /* Issue the WRITE command */
233 M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
234
235 M48T59_WRITE(mday, M48T59_ALARM_DATE);
236 M48T59_WRITE(hour, M48T59_ALARM_HOUR);
237 M48T59_WRITE(min, M48T59_ALARM_MIN);
238 M48T59_WRITE(sec, M48T59_ALARM_SEC);
239
240 /* Clear the WRITE bit */
241 M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
242 spin_unlock_irqrestore(&m48t59->lock, flags);
243
244 dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
245 year + 1900, tm->tm_mon, tm->tm_mday,
246 tm->tm_hour, tm->tm_min, tm->tm_sec);
247 return 0;
248 }
249
250 /*
251 * Handle commands from user-space
252 */
m48t59_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)253 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
254 {
255 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
256 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
257 unsigned long flags;
258
259 spin_lock_irqsave(&m48t59->lock, flags);
260 if (enabled)
261 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
262 else
263 M48T59_WRITE(0x00, M48T59_INTR);
264 spin_unlock_irqrestore(&m48t59->lock, flags);
265
266 return 0;
267 }
268
m48t59_rtc_proc(struct device * dev,struct seq_file * seq)269 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
270 {
271 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
272 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
273 unsigned long flags;
274 u8 val;
275
276 spin_lock_irqsave(&m48t59->lock, flags);
277 val = M48T59_READ(M48T59_FLAGS);
278 spin_unlock_irqrestore(&m48t59->lock, flags);
279
280 seq_printf(seq, "battery\t\t: %s\n",
281 (val & M48T59_FLAGS_BF) ? "low" : "normal");
282 return 0;
283 }
284
285 /*
286 * IRQ handler for the RTC
287 */
m48t59_rtc_interrupt(int irq,void * dev_id)288 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
289 {
290 struct device *dev = (struct device *)dev_id;
291 struct m48t59_plat_data *pdata = dev_get_platdata(dev);
292 struct m48t59_private *m48t59 = dev_get_drvdata(dev);
293 u8 event;
294
295 spin_lock(&m48t59->lock);
296 event = M48T59_READ(M48T59_FLAGS);
297 spin_unlock(&m48t59->lock);
298
299 if (event & M48T59_FLAGS_AF) {
300 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
301 return IRQ_HANDLED;
302 }
303
304 return IRQ_NONE;
305 }
306
307 static const struct rtc_class_ops m48t59_rtc_ops = {
308 .read_time = m48t59_rtc_read_time,
309 .set_time = m48t59_rtc_set_time,
310 .read_alarm = m48t59_rtc_readalarm,
311 .set_alarm = m48t59_rtc_setalarm,
312 .proc = m48t59_rtc_proc,
313 .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
314 };
315
316 static const struct rtc_class_ops m48t02_rtc_ops = {
317 .read_time = m48t59_rtc_read_time,
318 .set_time = m48t59_rtc_set_time,
319 };
320
m48t59_nvram_read(void * priv,unsigned int offset,void * val,size_t size)321 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val,
322 size_t size)
323 {
324 struct platform_device *pdev = priv;
325 struct device *dev = &pdev->dev;
326 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
327 struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
328 ssize_t cnt = 0;
329 unsigned long flags;
330 u8 *buf = val;
331
332 spin_lock_irqsave(&m48t59->lock, flags);
333
334 for (; cnt < size; cnt++)
335 *buf++ = M48T59_READ(cnt);
336
337 spin_unlock_irqrestore(&m48t59->lock, flags);
338
339 return 0;
340 }
341
m48t59_nvram_write(void * priv,unsigned int offset,void * val,size_t size)342 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val,
343 size_t size)
344 {
345 struct platform_device *pdev = priv;
346 struct device *dev = &pdev->dev;
347 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
348 struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
349 ssize_t cnt = 0;
350 unsigned long flags;
351 u8 *buf = val;
352
353 spin_lock_irqsave(&m48t59->lock, flags);
354
355 for (; cnt < size; cnt++)
356 M48T59_WRITE(*buf++, cnt);
357
358 spin_unlock_irqrestore(&m48t59->lock, flags);
359
360 return 0;
361 }
362
m48t59_rtc_probe(struct platform_device * pdev)363 static int m48t59_rtc_probe(struct platform_device *pdev)
364 {
365 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
366 struct m48t59_private *m48t59 = NULL;
367 struct resource *res;
368 int ret = -ENOMEM;
369 const struct rtc_class_ops *ops;
370 struct nvmem_config nvmem_cfg = {
371 .name = "m48t59-",
372 .word_size = 1,
373 .stride = 1,
374 .reg_read = m48t59_nvram_read,
375 .reg_write = m48t59_nvram_write,
376 .priv = pdev,
377 };
378
379 /* This chip could be memory-mapped or I/O-mapped */
380 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
381 if (!res) {
382 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
383 if (!res)
384 return -EINVAL;
385 }
386
387 if (res->flags & IORESOURCE_IO) {
388 /* If we are I/O-mapped, the platform should provide
389 * the operations accessing chip registers.
390 */
391 if (!pdata || !pdata->write_byte || !pdata->read_byte)
392 return -EINVAL;
393 } else if (res->flags & IORESOURCE_MEM) {
394 /* we are memory-mapped */
395 if (!pdata) {
396 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
397 GFP_KERNEL);
398 if (!pdata)
399 return -ENOMEM;
400 /* Ensure we only kmalloc platform data once */
401 pdev->dev.platform_data = pdata;
402 }
403 if (!pdata->type)
404 pdata->type = M48T59RTC_TYPE_M48T59;
405
406 /* Try to use the generic memory read/write ops */
407 if (!pdata->write_byte)
408 pdata->write_byte = m48t59_mem_writeb;
409 if (!pdata->read_byte)
410 pdata->read_byte = m48t59_mem_readb;
411 }
412
413 m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
414 if (!m48t59)
415 return -ENOMEM;
416
417 m48t59->ioaddr = pdata->ioaddr;
418
419 if (!m48t59->ioaddr) {
420 /* ioaddr not mapped externally */
421 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
422 resource_size(res));
423 if (!m48t59->ioaddr)
424 return ret;
425 }
426
427 /* Try to get irq number. We also can work in
428 * the mode without IRQ.
429 */
430 m48t59->irq = platform_get_irq(pdev, 0);
431 if (m48t59->irq <= 0)
432 m48t59->irq = NO_IRQ;
433
434 if (m48t59->irq != NO_IRQ) {
435 ret = devm_request_irq(&pdev->dev, m48t59->irq,
436 m48t59_rtc_interrupt, IRQF_SHARED,
437 "rtc-m48t59", &pdev->dev);
438 if (ret)
439 return ret;
440 }
441 switch (pdata->type) {
442 case M48T59RTC_TYPE_M48T59:
443 ops = &m48t59_rtc_ops;
444 pdata->offset = 0x1ff0;
445 break;
446 case M48T59RTC_TYPE_M48T02:
447 ops = &m48t02_rtc_ops;
448 pdata->offset = 0x7f0;
449 break;
450 case M48T59RTC_TYPE_M48T08:
451 ops = &m48t02_rtc_ops;
452 pdata->offset = 0x1ff0;
453 break;
454 default:
455 dev_err(&pdev->dev, "Unknown RTC type\n");
456 return -ENODEV;
457 }
458
459 spin_lock_init(&m48t59->lock);
460 platform_set_drvdata(pdev, m48t59);
461
462 m48t59->rtc = devm_rtc_allocate_device(&pdev->dev);
463 if (IS_ERR(m48t59->rtc))
464 return PTR_ERR(m48t59->rtc);
465
466 m48t59->rtc->nvram_old_abi = true;
467 m48t59->rtc->ops = ops;
468
469 nvmem_cfg.size = pdata->offset;
470 ret = rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
471 if (ret)
472 return ret;
473
474 ret = rtc_register_device(m48t59->rtc);
475 if (ret)
476 return ret;
477
478 return 0;
479 }
480
481 /* work with hotplug and coldplug */
482 MODULE_ALIAS("platform:rtc-m48t59");
483
484 static struct platform_driver m48t59_rtc_driver = {
485 .driver = {
486 .name = "rtc-m48t59",
487 },
488 .probe = m48t59_rtc_probe,
489 };
490
491 module_platform_driver(m48t59_rtc_driver);
492
493 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
494 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
495 MODULE_LICENSE("GPL");
496