1/*
  2 * Copyright (c) 2008-2009 Nuvoton technology corporation.
  3 *
  4 * Wan ZongShun <mcuos.com@gmail.com>
  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 as published by
  8 * the Free Software Foundation;version 2 of the License.
  9 *
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/init.h>
 14#include <linux/platform_device.h>
 15#include <linux/slab.h>
 16#include <linux/rtc.h>
 17#include <linux/delay.h>
 18#include <linux/io.h>
 19#include <linux/bcd.h>
 20
 21/* RTC Control Registers */
 22#define REG_RTC_INIR		0x00
 23#define REG_RTC_AER		0x04
 24#define REG_RTC_FCR		0x08
 25#define REG_RTC_TLR		0x0C
 26#define REG_RTC_CLR		0x10
 27#define REG_RTC_TSSR		0x14
 28#define REG_RTC_DWR		0x18
 29#define REG_RTC_TAR		0x1C
 30#define REG_RTC_CAR		0x20
 31#define REG_RTC_LIR		0x24
 32#define REG_RTC_RIER		0x28
 33#define REG_RTC_RIIR		0x2C
 34#define REG_RTC_TTR		0x30
 35
 36#define RTCSET			0x01
 37#define AERRWENB		0x10000
 38#define INIRRESET		0xa5eb1357
 39#define AERPOWERON		0xA965
 40#define AERPOWEROFF		0x0000
 41#define LEAPYEAR		0x0001
 42#define TICKENB			0x80
 43#define TICKINTENB		0x0002
 44#define ALARMINTENB		0x0001
 45#define MODE24			0x0001
 46
 47struct nuc900_rtc {
 48	int			irq_num;
 49	void __iomem		*rtc_reg;
 50	struct rtc_device	*rtcdev;
 51};
 52
 53struct nuc900_bcd_time {
 54	int bcd_sec;
 55	int bcd_min;
 56	int bcd_hour;
 57	int bcd_mday;
 58	int bcd_mon;
 59	int bcd_year;
 60};
 61
 62static irqreturn_t nuc900_rtc_interrupt(int irq, void *_rtc)
 63{
 64	struct nuc900_rtc *rtc = _rtc;
 65	unsigned long events = 0, rtc_irq;
 66
 67	rtc_irq = __raw_readl(rtc->rtc_reg + REG_RTC_RIIR);
 68
 69	if (rtc_irq & ALARMINTENB) {
 70		rtc_irq &= ~ALARMINTENB;
 71		__raw_writel(rtc_irq, rtc->rtc_reg + REG_RTC_RIIR);
 72		events |= RTC_AF | RTC_IRQF;
 73	}
 74
 75	if (rtc_irq & TICKINTENB) {
 76		rtc_irq &= ~TICKINTENB;
 77		__raw_writel(rtc_irq, rtc->rtc_reg + REG_RTC_RIIR);
 78		events |= RTC_UF | RTC_IRQF;
 79	}
 80
 81	rtc_update_irq(rtc->rtcdev, 1, events);
 82
 83	return IRQ_HANDLED;
 84}
 85
 86static int *check_rtc_access_enable(struct nuc900_rtc *nuc900_rtc)
 87{
 88	unsigned int timeout = 0x1000;
 89	__raw_writel(INIRRESET, nuc900_rtc->rtc_reg + REG_RTC_INIR);
 90
 91	mdelay(10);
 92
 93	__raw_writel(AERPOWERON, nuc900_rtc->rtc_reg + REG_RTC_AER);
 94
 95	while (!(__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_AER) & AERRWENB)
 96								&& timeout--)
 97		mdelay(1);
 98
 99	if (!timeout)
100		return ERR_PTR(-EPERM);
101
102	return NULL;
103}
104
105static int nuc900_rtc_bcd2bin(unsigned int timereg,
106				unsigned int calreg, struct rtc_time *tm)
107{
108	tm->tm_mday	= bcd2bin(calreg >> 0);
109	tm->tm_mon	= bcd2bin(calreg >> 8);
110	tm->tm_year	= bcd2bin(calreg >> 16) + 100;
111
112	tm->tm_sec	= bcd2bin(timereg >> 0);
113	tm->tm_min	= bcd2bin(timereg >> 8);
114	tm->tm_hour	= bcd2bin(timereg >> 16);
115
116	return rtc_valid_tm(tm);
117}
118
119static void nuc900_rtc_bin2bcd(struct device *dev, struct rtc_time *settm,
120						struct nuc900_bcd_time *gettm)
121{
122	gettm->bcd_mday = bin2bcd(settm->tm_mday) << 0;
123	gettm->bcd_mon  = bin2bcd(settm->tm_mon) << 8;
124
125	if (settm->tm_year < 100) {
126		dev_warn(dev, "The year will be between 1970-1999, right?\n");
127		gettm->bcd_year = bin2bcd(settm->tm_year) << 16;
128	} else {
129		gettm->bcd_year = bin2bcd(settm->tm_year - 100) << 16;
130	}
131
132	gettm->bcd_sec  = bin2bcd(settm->tm_sec) << 0;
133	gettm->bcd_min  = bin2bcd(settm->tm_min) << 8;
134	gettm->bcd_hour = bin2bcd(settm->tm_hour) << 16;
135}
136
137static int nuc900_alarm_irq_enable(struct device *dev, unsigned int enabled)
138{
139	struct nuc900_rtc *rtc = dev_get_drvdata(dev);
140
141	if (enabled)
142		__raw_writel(__raw_readl(rtc->rtc_reg + REG_RTC_RIER)|
143				(ALARMINTENB), rtc->rtc_reg + REG_RTC_RIER);
144	else
145		__raw_writel(__raw_readl(rtc->rtc_reg + REG_RTC_RIER)&
146				(~ALARMINTENB), rtc->rtc_reg + REG_RTC_RIER);
147
148	return 0;
149}
150
151static int nuc900_rtc_read_time(struct device *dev, struct rtc_time *tm)
152{
153	struct nuc900_rtc *rtc = dev_get_drvdata(dev);
154	unsigned int timeval, clrval;
155
156	timeval = __raw_readl(rtc->rtc_reg + REG_RTC_TLR);
157	clrval	= __raw_readl(rtc->rtc_reg + REG_RTC_CLR);
158
159	return nuc900_rtc_bcd2bin(timeval, clrval, tm);
160}
161
162static int nuc900_rtc_set_time(struct device *dev, struct rtc_time *tm)
163{
164	struct nuc900_rtc *rtc = dev_get_drvdata(dev);
165	struct nuc900_bcd_time gettm;
166	unsigned long val;
167	int *err;
168
169	nuc900_rtc_bin2bcd(dev, tm, &gettm);
170
171	err = check_rtc_access_enable(rtc);
172	if (IS_ERR(err))
173		return PTR_ERR(err);
174
175	val = gettm.bcd_mday | gettm.bcd_mon | gettm.bcd_year;
176	__raw_writel(val, rtc->rtc_reg + REG_RTC_CLR);
177
178	val = gettm.bcd_sec | gettm.bcd_min | gettm.bcd_hour;
179	__raw_writel(val, rtc->rtc_reg + REG_RTC_TLR);
180
181	return 0;
182}
183
184static int nuc900_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
185{
186	struct nuc900_rtc *rtc = dev_get_drvdata(dev);
187	unsigned int timeval, carval;
188
189	timeval = __raw_readl(rtc->rtc_reg + REG_RTC_TAR);
190	carval	= __raw_readl(rtc->rtc_reg + REG_RTC_CAR);
191
192	return nuc900_rtc_bcd2bin(timeval, carval, &alrm->time);
193}
194
195static int nuc900_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
196{
197	struct nuc900_rtc *rtc = dev_get_drvdata(dev);
198	struct nuc900_bcd_time tm;
199	unsigned long val;
200	int *err;
201
202	nuc900_rtc_bin2bcd(dev, &alrm->time, &tm);
203
204	err = check_rtc_access_enable(rtc);
205	if (IS_ERR(err))
206		return PTR_ERR(err);
207
208	val = tm.bcd_mday | tm.bcd_mon | tm.bcd_year;
209	__raw_writel(val, rtc->rtc_reg + REG_RTC_CAR);
210
211	val = tm.bcd_sec | tm.bcd_min | tm.bcd_hour;
212	__raw_writel(val, rtc->rtc_reg + REG_RTC_TAR);
213
214	return 0;
215}
216
217static struct rtc_class_ops nuc900_rtc_ops = {
218	.read_time = nuc900_rtc_read_time,
219	.set_time = nuc900_rtc_set_time,
220	.read_alarm = nuc900_rtc_read_alarm,
221	.set_alarm = nuc900_rtc_set_alarm,
222	.alarm_irq_enable = nuc900_alarm_irq_enable,
223};
224
225static int __init nuc900_rtc_probe(struct platform_device *pdev)
226{
227	struct resource *res;
228	struct nuc900_rtc *nuc900_rtc;
229
230	nuc900_rtc = devm_kzalloc(&pdev->dev, sizeof(struct nuc900_rtc),
231				GFP_KERNEL);
232	if (!nuc900_rtc)
233		return -ENOMEM;
234
235	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
236	nuc900_rtc->rtc_reg = devm_ioremap_resource(&pdev->dev, res);
237	if (IS_ERR(nuc900_rtc->rtc_reg))
238		return PTR_ERR(nuc900_rtc->rtc_reg);
239
240	platform_set_drvdata(pdev, nuc900_rtc);
241
242	nuc900_rtc->rtcdev = devm_rtc_device_register(&pdev->dev, pdev->name,
243						&nuc900_rtc_ops, THIS_MODULE);
244	if (IS_ERR(nuc900_rtc->rtcdev)) {
245		dev_err(&pdev->dev, "rtc device register failed\n");
246		return PTR_ERR(nuc900_rtc->rtcdev);
247	}
248
249	__raw_writel(__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_TSSR) | MODE24,
250					nuc900_rtc->rtc_reg + REG_RTC_TSSR);
251
252	nuc900_rtc->irq_num = platform_get_irq(pdev, 0);
253	if (devm_request_irq(&pdev->dev, nuc900_rtc->irq_num,
254			nuc900_rtc_interrupt, 0, "nuc900rtc", nuc900_rtc)) {
255		dev_err(&pdev->dev, "NUC900 RTC request irq failed\n");
256		return -EBUSY;
257	}
258
259	return 0;
260}
261
262static struct platform_driver nuc900_rtc_driver = {
263	.driver		= {
264		.name	= "nuc900-rtc",
265	},
266};
267
268module_platform_driver_probe(nuc900_rtc_driver, nuc900_rtc_probe);
269
270MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
271MODULE_DESCRIPTION("nuc910/nuc920 RTC driver");
272MODULE_LICENSE("GPL");
273MODULE_ALIAS("platform:nuc900-rtc");