1/*
2 * ST M48T59 RTC driver
3 *
4 * Copyright (c) 2007 Wind River Systems, Inc.
5 *
6 * Author: Mark Zhan <rongkai.zhan@windriver.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/io.h>
17#include <linux/device.h>
18#include <linux/platform_device.h>
19#include <linux/rtc.h>
20#include <linux/rtc/m48t59.h>
21#include <linux/bcd.h>
22#include <linux/slab.h>
23
24#ifndef NO_IRQ
25#define NO_IRQ	(-1)
26#endif
27
28#define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
29#define M48T59_WRITE(val, reg) \
30	(pdata->write_byte(dev, pdata->offset + reg, val))
31
32#define M48T59_SET_BITS(mask, reg)	\
33	M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
34#define M48T59_CLEAR_BITS(mask, reg)	\
35	M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))
36
37struct m48t59_private {
38	void __iomem *ioaddr;
39	int irq;
40	struct rtc_device *rtc;
41	spinlock_t lock; /* serialize the NVRAM and RTC access */
42};
43
44/*
45 * This is the generic access method when the chip is memory-mapped
46 */
47static void
48m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
49{
50	struct platform_device *pdev = to_platform_device(dev);
51	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
52
53	writeb(val, m48t59->ioaddr+ofs);
54}
55
56static u8
57m48t59_mem_readb(struct device *dev, u32 ofs)
58{
59	struct platform_device *pdev = to_platform_device(dev);
60	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
61
62	return readb(m48t59->ioaddr+ofs);
63}
64
65/*
66 * NOTE: M48T59 only uses BCD mode
67 */
68static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
69{
70	struct platform_device *pdev = to_platform_device(dev);
71	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
72	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
73	unsigned long flags;
74	u8 val;
75
76	spin_lock_irqsave(&m48t59->lock, flags);
77	/* Issue the READ command */
78	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
79
80	tm->tm_year	= bcd2bin(M48T59_READ(M48T59_YEAR));
81	/* tm_mon is 0-11 */
82	tm->tm_mon	= bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
83	tm->tm_mday	= bcd2bin(M48T59_READ(M48T59_MDAY));
84
85	val = M48T59_READ(M48T59_WDAY);
86	if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
87	    (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
88		dev_dbg(dev, "Century bit is enabled\n");
89		tm->tm_year += 100;	/* one century */
90	}
91#ifdef CONFIG_SPARC
92	/* Sun SPARC machines count years since 1968 */
93	tm->tm_year += 68;
94#endif
95
96	tm->tm_wday	= bcd2bin(val & 0x07);
97	tm->tm_hour	= bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
98	tm->tm_min	= bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
99	tm->tm_sec	= bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
100
101	/* Clear the READ bit */
102	M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
103	spin_unlock_irqrestore(&m48t59->lock, flags);
104
105	dev_dbg(dev, "RTC read time %04d-%02d-%02d %02d/%02d/%02d\n",
106		tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
107		tm->tm_hour, tm->tm_min, tm->tm_sec);
108	return rtc_valid_tm(tm);
109}
110
111static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
112{
113	struct platform_device *pdev = to_platform_device(dev);
114	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
115	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
116	unsigned long flags;
117	u8 val = 0;
118	int year = tm->tm_year;
119
120#ifdef CONFIG_SPARC
121	/* Sun SPARC machines count years since 1968 */
122	year -= 68;
123#endif
124
125	dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
126		year + 1900, tm->tm_mon, tm->tm_mday,
127		tm->tm_hour, tm->tm_min, tm->tm_sec);
128
129	if (year < 0)
130		return -EINVAL;
131
132	spin_lock_irqsave(&m48t59->lock, flags);
133	/* Issue the WRITE command */
134	M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
135
136	M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
137	M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
138	M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
139	M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
140	/* tm_mon is 0-11 */
141	M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
142	M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
143
144	if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
145		val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
146	val |= (bin2bcd(tm->tm_wday) & 0x07);
147	M48T59_WRITE(val, M48T59_WDAY);
148
149	/* Clear the WRITE bit */
150	M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
151	spin_unlock_irqrestore(&m48t59->lock, flags);
152	return 0;
153}
154
155/*
156 * Read alarm time and date in RTC
157 */
158static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
159{
160	struct platform_device *pdev = to_platform_device(dev);
161	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
162	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
163	struct rtc_time *tm = &alrm->time;
164	unsigned long flags;
165	u8 val;
166
167	/* If no irq, we don't support ALARM */
168	if (m48t59->irq == NO_IRQ)
169		return -EIO;
170
171	spin_lock_irqsave(&m48t59->lock, flags);
172	/* Issue the READ command */
173	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
174
175	tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
176#ifdef CONFIG_SPARC
177	/* Sun SPARC machines count years since 1968 */
178	tm->tm_year += 68;
179#endif
180	/* tm_mon is 0-11 */
181	tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
182
183	val = M48T59_READ(M48T59_WDAY);
184	if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
185		tm->tm_year += 100;	/* one century */
186
187	tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
188	tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
189	tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
190	tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
191
192	/* Clear the READ bit */
193	M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
194	spin_unlock_irqrestore(&m48t59->lock, flags);
195
196	dev_dbg(dev, "RTC read alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
197		tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
198		tm->tm_hour, tm->tm_min, tm->tm_sec);
199	return rtc_valid_tm(tm);
200}
201
202/*
203 * Set alarm time and date in RTC
204 */
205static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
206{
207	struct platform_device *pdev = to_platform_device(dev);
208	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
209	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
210	struct rtc_time *tm = &alrm->time;
211	u8 mday, hour, min, sec;
212	unsigned long flags;
213	int year = tm->tm_year;
214
215#ifdef CONFIG_SPARC
216	/* Sun SPARC machines count years since 1968 */
217	year -= 68;
218#endif
219
220	/* If no irq, we don't support ALARM */
221	if (m48t59->irq == NO_IRQ)
222		return -EIO;
223
224	if (year < 0)
225		return -EINVAL;
226
227	/*
228	 * 0xff means "always match"
229	 */
230	mday = tm->tm_mday;
231	mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
232	if (mday == 0xff)
233		mday = M48T59_READ(M48T59_MDAY);
234
235	hour = tm->tm_hour;
236	hour = (hour < 24) ? bin2bcd(hour) : 0x00;
237
238	min = tm->tm_min;
239	min = (min < 60) ? bin2bcd(min) : 0x00;
240
241	sec = tm->tm_sec;
242	sec = (sec < 60) ? bin2bcd(sec) : 0x00;
243
244	spin_lock_irqsave(&m48t59->lock, flags);
245	/* Issue the WRITE command */
246	M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
247
248	M48T59_WRITE(mday, M48T59_ALARM_DATE);
249	M48T59_WRITE(hour, M48T59_ALARM_HOUR);
250	M48T59_WRITE(min, M48T59_ALARM_MIN);
251	M48T59_WRITE(sec, M48T59_ALARM_SEC);
252
253	/* Clear the WRITE bit */
254	M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
255	spin_unlock_irqrestore(&m48t59->lock, flags);
256
257	dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
258		year + 1900, tm->tm_mon, tm->tm_mday,
259		tm->tm_hour, tm->tm_min, tm->tm_sec);
260	return 0;
261}
262
263/*
264 * Handle commands from user-space
265 */
266static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
267{
268	struct platform_device *pdev = to_platform_device(dev);
269	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
270	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
271	unsigned long flags;
272
273	spin_lock_irqsave(&m48t59->lock, flags);
274	if (enabled)
275		M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
276	else
277		M48T59_WRITE(0x00, M48T59_INTR);
278	spin_unlock_irqrestore(&m48t59->lock, flags);
279
280	return 0;
281}
282
283static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
284{
285	struct platform_device *pdev = to_platform_device(dev);
286	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
287	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
288	unsigned long flags;
289	u8 val;
290
291	spin_lock_irqsave(&m48t59->lock, flags);
292	val = M48T59_READ(M48T59_FLAGS);
293	spin_unlock_irqrestore(&m48t59->lock, flags);
294
295	seq_printf(seq, "battery\t\t: %s\n",
296		 (val & M48T59_FLAGS_BF) ? "low" : "normal");
297	return 0;
298}
299
300/*
301 * IRQ handler for the RTC
302 */
303static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
304{
305	struct device *dev = (struct device *)dev_id;
306	struct platform_device *pdev = to_platform_device(dev);
307	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
308	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
309	u8 event;
310
311	spin_lock(&m48t59->lock);
312	event = M48T59_READ(M48T59_FLAGS);
313	spin_unlock(&m48t59->lock);
314
315	if (event & M48T59_FLAGS_AF) {
316		rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
317		return IRQ_HANDLED;
318	}
319
320	return IRQ_NONE;
321}
322
323static const struct rtc_class_ops m48t59_rtc_ops = {
324	.read_time	= m48t59_rtc_read_time,
325	.set_time	= m48t59_rtc_set_time,
326	.read_alarm	= m48t59_rtc_readalarm,
327	.set_alarm	= m48t59_rtc_setalarm,
328	.proc		= m48t59_rtc_proc,
329	.alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
330};
331
332static const struct rtc_class_ops m48t02_rtc_ops = {
333	.read_time	= m48t59_rtc_read_time,
334	.set_time	= m48t59_rtc_set_time,
335};
336
337static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,
338				struct bin_attribute *bin_attr,
339				char *buf, loff_t pos, size_t size)
340{
341	struct device *dev = container_of(kobj, struct device, kobj);
342	struct platform_device *pdev = to_platform_device(dev);
343	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
344	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
345	ssize_t cnt = 0;
346	unsigned long flags;
347
348	for (; size > 0 && pos < pdata->offset; cnt++, size--) {
349		spin_lock_irqsave(&m48t59->lock, flags);
350		*buf++ = M48T59_READ(cnt);
351		spin_unlock_irqrestore(&m48t59->lock, flags);
352	}
353
354	return cnt;
355}
356
357static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,
358				struct bin_attribute *bin_attr,
359				char *buf, loff_t pos, size_t size)
360{
361	struct device *dev = container_of(kobj, struct device, kobj);
362	struct platform_device *pdev = to_platform_device(dev);
363	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
364	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
365	ssize_t cnt = 0;
366	unsigned long flags;
367
368	for (; size > 0 && pos < pdata->offset; cnt++, size--) {
369		spin_lock_irqsave(&m48t59->lock, flags);
370		M48T59_WRITE(*buf++, cnt);
371		spin_unlock_irqrestore(&m48t59->lock, flags);
372	}
373
374	return cnt;
375}
376
377static struct bin_attribute m48t59_nvram_attr = {
378	.attr = {
379		.name = "nvram",
380		.mode = S_IRUGO | S_IWUSR,
381	},
382	.read = m48t59_nvram_read,
383	.write = m48t59_nvram_write,
384};
385
386static int m48t59_rtc_probe(struct platform_device *pdev)
387{
388	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
389	struct m48t59_private *m48t59 = NULL;
390	struct resource *res;
391	int ret = -ENOMEM;
392	char *name;
393	const struct rtc_class_ops *ops;
394
395	/* This chip could be memory-mapped or I/O-mapped */
396	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
397	if (!res) {
398		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
399		if (!res)
400			return -EINVAL;
401	}
402
403	if (res->flags & IORESOURCE_IO) {
404		/* If we are I/O-mapped, the platform should provide
405		 * the operations accessing chip registers.
406		 */
407		if (!pdata || !pdata->write_byte || !pdata->read_byte)
408			return -EINVAL;
409	} else if (res->flags & IORESOURCE_MEM) {
410		/* we are memory-mapped */
411		if (!pdata) {
412			pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
413						GFP_KERNEL);
414			if (!pdata)
415				return -ENOMEM;
416			/* Ensure we only kmalloc platform data once */
417			pdev->dev.platform_data = pdata;
418		}
419		if (!pdata->type)
420			pdata->type = M48T59RTC_TYPE_M48T59;
421
422		/* Try to use the generic memory read/write ops */
423		if (!pdata->write_byte)
424			pdata->write_byte = m48t59_mem_writeb;
425		if (!pdata->read_byte)
426			pdata->read_byte = m48t59_mem_readb;
427	}
428
429	m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
430	if (!m48t59)
431		return -ENOMEM;
432
433	m48t59->ioaddr = pdata->ioaddr;
434
435	if (!m48t59->ioaddr) {
436		/* ioaddr not mapped externally */
437		m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
438						resource_size(res));
439		if (!m48t59->ioaddr)
440			return ret;
441	}
442
443	/* Try to get irq number. We also can work in
444	 * the mode without IRQ.
445	 */
446	m48t59->irq = platform_get_irq(pdev, 0);
447	if (m48t59->irq <= 0)
448		m48t59->irq = NO_IRQ;
449
450	if (m48t59->irq != NO_IRQ) {
451		ret = devm_request_irq(&pdev->dev, m48t59->irq,
452				m48t59_rtc_interrupt, IRQF_SHARED,
453				"rtc-m48t59", &pdev->dev);
454		if (ret)
455			return ret;
456	}
457	switch (pdata->type) {
458	case M48T59RTC_TYPE_M48T59:
459		name = "m48t59";
460		ops = &m48t59_rtc_ops;
461		pdata->offset = 0x1ff0;
462		break;
463	case M48T59RTC_TYPE_M48T02:
464		name = "m48t02";
465		ops = &m48t02_rtc_ops;
466		pdata->offset = 0x7f0;
467		break;
468	case M48T59RTC_TYPE_M48T08:
469		name = "m48t08";
470		ops = &m48t02_rtc_ops;
471		pdata->offset = 0x1ff0;
472		break;
473	default:
474		dev_err(&pdev->dev, "Unknown RTC type\n");
475		return -ENODEV;
476	}
477
478	spin_lock_init(&m48t59->lock);
479	platform_set_drvdata(pdev, m48t59);
480
481	m48t59->rtc = devm_rtc_device_register(&pdev->dev, name, ops,
482						THIS_MODULE);
483	if (IS_ERR(m48t59->rtc))
484		return PTR_ERR(m48t59->rtc);
485
486	m48t59_nvram_attr.size = pdata->offset;
487
488	ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
489	if (ret)
490		return ret;
491
492	return 0;
493}
494
495static int m48t59_rtc_remove(struct platform_device *pdev)
496{
497	sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
498	return 0;
499}
500
501/* work with hotplug and coldplug */
502MODULE_ALIAS("platform:rtc-m48t59");
503
504static struct platform_driver m48t59_rtc_driver = {
505	.driver		= {
506		.name	= "rtc-m48t59",
507		.owner	= THIS_MODULE,
508	},
509	.probe		= m48t59_rtc_probe,
510	.remove		= m48t59_rtc_remove,
511};
512
513module_platform_driver(m48t59_rtc_driver);
514
515MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
516MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
517MODULE_LICENSE("GPL");
518