1/*
2 * An rtc driver for the Dallas DS1553
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/bcd.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/delay.h>
15#include <linux/jiffies.h>
16#include <linux/interrupt.h>
17#include <linux/rtc.h>
18#include <linux/platform_device.h>
19#include <linux/io.h>
20
21#define DRV_VERSION "0.2"
22
23#define RTC_REG_SIZE		0x2000
24#define RTC_OFFSET		0x1ff0
25
26#define RTC_FLAGS		(RTC_OFFSET + 0)
27#define RTC_SECONDS_ALARM	(RTC_OFFSET + 2)
28#define RTC_MINUTES_ALARM	(RTC_OFFSET + 3)
29#define RTC_HOURS_ALARM		(RTC_OFFSET + 4)
30#define RTC_DATE_ALARM		(RTC_OFFSET + 5)
31#define RTC_INTERRUPTS		(RTC_OFFSET + 6)
32#define RTC_WATCHDOG		(RTC_OFFSET + 7)
33#define RTC_CONTROL		(RTC_OFFSET + 8)
34#define RTC_CENTURY		(RTC_OFFSET + 8)
35#define RTC_SECONDS		(RTC_OFFSET + 9)
36#define RTC_MINUTES		(RTC_OFFSET + 10)
37#define RTC_HOURS		(RTC_OFFSET + 11)
38#define RTC_DAY			(RTC_OFFSET + 12)
39#define RTC_DATE		(RTC_OFFSET + 13)
40#define RTC_MONTH		(RTC_OFFSET + 14)
41#define RTC_YEAR		(RTC_OFFSET + 15)
42
43#define RTC_CENTURY_MASK	0x3f
44#define RTC_SECONDS_MASK	0x7f
45#define RTC_DAY_MASK		0x07
46
47/* Bits in the Control/Century register */
48#define RTC_WRITE		0x80
49#define RTC_READ		0x40
50
51/* Bits in the Seconds register */
52#define RTC_STOP		0x80
53
54/* Bits in the Flags register */
55#define RTC_FLAGS_AF		0x40
56#define RTC_FLAGS_BLF		0x10
57
58/* Bits in the Interrupts register */
59#define RTC_INTS_AE		0x80
60
61struct rtc_plat_data {
62	struct rtc_device *rtc;
63	void __iomem *ioaddr;
64	unsigned long baseaddr;
65	unsigned long last_jiffies;
66	int irq;
67	unsigned int irqen;
68	int alrm_sec;
69	int alrm_min;
70	int alrm_hour;
71	int alrm_mday;
72};
73
74static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
75{
76	struct platform_device *pdev = to_platform_device(dev);
77	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
78	void __iomem *ioaddr = pdata->ioaddr;
79	u8 century;
80
81	century = BIN2BCD((tm->tm_year + 1900) / 100);
82
83	writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
84
85	writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);
86	writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);
87	writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
88	writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);
89	writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);
90	writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);
91	writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
92
93	/* RTC_CENTURY and RTC_CONTROL share same register */
94	writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
95	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
96	return 0;
97}
98
99static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
100{
101	struct platform_device *pdev = to_platform_device(dev);
102	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
103	void __iomem *ioaddr = pdata->ioaddr;
104	unsigned int year, month, day, hour, minute, second, week;
105	unsigned int century;
106
107	/* give enough time to update RTC in case of continuous read */
108	if (pdata->last_jiffies == jiffies)
109		msleep(1);
110	pdata->last_jiffies = jiffies;
111	writeb(RTC_READ, ioaddr + RTC_CONTROL);
112	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
113	minute = readb(ioaddr + RTC_MINUTES);
114	hour = readb(ioaddr + RTC_HOURS);
115	day = readb(ioaddr + RTC_DATE);
116	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
117	month = readb(ioaddr + RTC_MONTH);
118	year = readb(ioaddr + RTC_YEAR);
119	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
120	writeb(0, ioaddr + RTC_CONTROL);
121	tm->tm_sec = BCD2BIN(second);
122	tm->tm_min = BCD2BIN(minute);
123	tm->tm_hour = BCD2BIN(hour);
124	tm->tm_mday = BCD2BIN(day);
125	tm->tm_wday = BCD2BIN(week);
126	tm->tm_mon = BCD2BIN(month) - 1;
127	/* year is 1900 + tm->tm_year */
128	tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
129
130	if (rtc_valid_tm(tm) < 0) {
131		dev_err(dev, "retrieved date/time is not valid.\n");
132		rtc_time_to_tm(0, tm);
133	}
134	return 0;
135}
136
137static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
138{
139	void __iomem *ioaddr = pdata->ioaddr;
140	unsigned long flags;
141
142	spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
143	writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
144	       0x80 : BIN2BCD(pdata->alrm_mday),
145	       ioaddr + RTC_DATE_ALARM);
146	writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
147	       0x80 : BIN2BCD(pdata->alrm_hour),
148	       ioaddr + RTC_HOURS_ALARM);
149	writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
150	       0x80 : BIN2BCD(pdata->alrm_min),
151	       ioaddr + RTC_MINUTES_ALARM);
152	writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
153	       0x80 : BIN2BCD(pdata->alrm_sec),
154	       ioaddr + RTC_SECONDS_ALARM);
155	writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
156	readb(ioaddr + RTC_FLAGS);	/* clear interrupts */
157	spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
158}
159
160static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
161{
162	struct platform_device *pdev = to_platform_device(dev);
163	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
164
165	if (pdata->irq < 0)
166		return -EINVAL;
167	pdata->alrm_mday = alrm->time.tm_mday;
168	pdata->alrm_hour = alrm->time.tm_hour;
169	pdata->alrm_min = alrm->time.tm_min;
170	pdata->alrm_sec = alrm->time.tm_sec;
171	if (alrm->enabled)
172		pdata->irqen |= RTC_AF;
173	ds1553_rtc_update_alarm(pdata);
174	return 0;
175}
176
177static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
178{
179	struct platform_device *pdev = to_platform_device(dev);
180	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
181
182	if (pdata->irq < 0)
183		return -EINVAL;
184	alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
185	alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
186	alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
187	alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
188	alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
189	return 0;
190}
191
192static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
193{
194	struct platform_device *pdev = dev_id;
195	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
196	void __iomem *ioaddr = pdata->ioaddr;
197	unsigned long events = RTC_IRQF;
198
199	/* read and clear interrupt */
200	if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
201		return IRQ_NONE;
202	if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
203		events |= RTC_UF;
204	else
205		events |= RTC_AF;
206	rtc_update_irq(pdata->rtc, 1, events);
207	return IRQ_HANDLED;
208}
209
210static void ds1553_rtc_release(struct device *dev)
211{
212	struct platform_device *pdev = to_platform_device(dev);
213	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
214
215	if (pdata->irq >= 0) {
216		pdata->irqen = 0;
217		ds1553_rtc_update_alarm(pdata);
218	}
219}
220
221static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
222			    unsigned long arg)
223{
224	struct platform_device *pdev = to_platform_device(dev);
225	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
226
227	if (pdata->irq < 0)
228		return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
229	switch (cmd) {
230	case RTC_AIE_OFF:
231		pdata->irqen &= ~RTC_AF;
232		ds1553_rtc_update_alarm(pdata);
233		break;
234	case RTC_AIE_ON:
235		pdata->irqen |= RTC_AF;
236		ds1553_rtc_update_alarm(pdata);
237		break;
238	case RTC_UIE_OFF:
239		pdata->irqen &= ~RTC_UF;
240		ds1553_rtc_update_alarm(pdata);
241		break;
242	case RTC_UIE_ON:
243		pdata->irqen |= RTC_UF;
244		ds1553_rtc_update_alarm(pdata);
245		break;
246	default:
247		return -ENOIOCTLCMD;
248	}
249	return 0;
250}
251
252static const struct rtc_class_ops ds1553_rtc_ops = {
253	.read_time	= ds1553_rtc_read_time,
254	.set_time	= ds1553_rtc_set_time,
255	.read_alarm	= ds1553_rtc_read_alarm,
256	.set_alarm	= ds1553_rtc_set_alarm,
257	.release	= ds1553_rtc_release,
258	.ioctl		= ds1553_rtc_ioctl,
259};
260
261static ssize_t ds1553_nvram_read(struct kobject *kobj, char *buf,
262				 loff_t pos, size_t size)
263{
264	struct platform_device *pdev =
265		to_platform_device(container_of(kobj, struct device, kobj));
266	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
267	void __iomem *ioaddr = pdata->ioaddr;
268	ssize_t count;
269
270	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
271		*buf++ = readb(ioaddr + pos++);
272	return count;
273}
274
275static ssize_t ds1553_nvram_write(struct kobject *kobj, char *buf,
276				  loff_t pos, size_t size)
277{
278	struct platform_device *pdev =
279		to_platform_device(container_of(kobj, struct device, kobj));
280	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
281	void __iomem *ioaddr = pdata->ioaddr;
282	ssize_t count;
283
284	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
285		writeb(*buf++, ioaddr + pos++);
286	return count;
287}
288
289static struct bin_attribute ds1553_nvram_attr = {
290	.attr = {
291		.name = "nvram",
292		.mode = S_IRUGO | S_IWUGO,
293		.owner = THIS_MODULE,
294	},
295	.size = RTC_OFFSET,
296	.read = ds1553_nvram_read,
297	.write = ds1553_nvram_write,
298};
299
300static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
301{
302	struct rtc_device *rtc;
303	struct resource *res;
304	unsigned int cen, sec;
305	struct rtc_plat_data *pdata = NULL;
306	void __iomem *ioaddr = NULL;
307	int ret = 0;
308
309	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
310	if (!res)
311		return -ENODEV;
312	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
313	if (!pdata)
314		return -ENOMEM;
315	pdata->irq = -1;
316	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
317		ret = -EBUSY;
318		goto out;
319	}
320	pdata->baseaddr = res->start;
321	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
322	if (!ioaddr) {
323		ret = -ENOMEM;
324		goto out;
325	}
326	pdata->ioaddr = ioaddr;
327	pdata->irq = platform_get_irq(pdev, 0);
328
329	/* turn RTC on if it was not on */
330	sec = readb(ioaddr + RTC_SECONDS);
331	if (sec & RTC_STOP) {
332		sec &= RTC_SECONDS_MASK;
333		cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
334		writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
335		writeb(sec, ioaddr + RTC_SECONDS);
336		writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
337	}
338	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
339		dev_warn(&pdev->dev, "voltage-low detected.\n");
340
341	if (pdata->irq >= 0) {
342		writeb(0, ioaddr + RTC_INTERRUPTS);
343		if (request_irq(pdata->irq, ds1553_rtc_interrupt,
344				IRQF_DISABLED | IRQF_SHARED,
345				pdev->name, pdev) < 0) {
346			dev_warn(&pdev->dev, "interrupt not available.\n");
347			pdata->irq = -1;
348		}
349	}
350
351	rtc = rtc_device_register(pdev->name, &pdev->dev,
352				  &ds1553_rtc_ops, THIS_MODULE);
353	if (IS_ERR(rtc)) {
354		ret = PTR_ERR(rtc);
355		goto out;
356	}
357	pdata->rtc = rtc;
358	pdata->last_jiffies = jiffies;
359	platform_set_drvdata(pdev, pdata);
360	ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
361	if (ret)
362		goto out;
363	return 0;
364 out:
365	if (pdata->rtc)
366		rtc_device_unregister(pdata->rtc);
367	if (pdata->irq >= 0)
368		free_irq(pdata->irq, pdev);
369	if (ioaddr)
370		iounmap(ioaddr);
371	if (pdata->baseaddr)
372		release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
373	kfree(pdata);
374	return ret;
375}
376
377static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
378{
379	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
380
381	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
382	rtc_device_unregister(pdata->rtc);
383	if (pdata->irq >= 0) {
384		writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
385		free_irq(pdata->irq, pdev);
386	}
387	iounmap(pdata->ioaddr);
388	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
389	kfree(pdata);
390	return 0;
391}
392
393static struct platform_driver ds1553_rtc_driver = {
394	.probe		= ds1553_rtc_probe,
395	.remove		= __devexit_p(ds1553_rtc_remove),
396	.driver		= {
397		.name	= "ds1553",
398		.owner	= THIS_MODULE,
399	},
400};
401
402static __init int ds1553_init(void)
403{
404	return platform_driver_register(&ds1553_rtc_driver);
405}
406
407static __exit void ds1553_exit(void)
408{
409	return platform_driver_unregister(&ds1553_rtc_driver);
410}
411
412module_init(ds1553_init);
413module_exit(ds1553_exit);
414
415MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
416MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
417MODULE_LICENSE("GPL");
418MODULE_VERSION(DRV_VERSION);
419