1/*
2 * Dallas DS1302 RTC Support
3 *
4 *  Copyright (C) 2002 David McCullough
5 *  Copyright (C) 2003 - 2007 Paul Mundt
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License version 2. See the file "COPYING" in the main directory of
9 * this archive for more details.
10 */
11
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/kernel.h>
15#include <linux/platform_device.h>
16#include <linux/rtc.h>
17#include <linux/io.h>
18#include <linux/bcd.h>
19
20#define DRV_NAME	"rtc-ds1302"
21#define DRV_VERSION	"0.1.1"
22
23#define	RTC_CMD_READ	0x81		/* Read command */
24#define	RTC_CMD_WRITE	0x80		/* Write command */
25
26#define	RTC_CMD_WRITE_ENABLE	0x00		/* Write enable */
27#define	RTC_CMD_WRITE_DISABLE	0x80		/* Write disable */
28
29#define RTC_ADDR_RAM0	0x20		/* Address of RAM0 */
30#define RTC_ADDR_TCR	0x08		/* Address of trickle charge register */
31#define	RTC_ADDR_CTRL	0x07		/* Address of control register */
32#define	RTC_ADDR_YEAR	0x06		/* Address of year register */
33#define	RTC_ADDR_DAY	0x05		/* Address of day of week register */
34#define	RTC_ADDR_MON	0x04		/* Address of month register */
35#define	RTC_ADDR_DATE	0x03		/* Address of day of month register */
36#define	RTC_ADDR_HOUR	0x02		/* Address of hour register */
37#define	RTC_ADDR_MIN	0x01		/* Address of minute register */
38#define	RTC_ADDR_SEC	0x00		/* Address of second register */
39
40#ifdef CONFIG_SH_SECUREEDGE5410
41#include <asm/rtc.h>
42#include <mach/secureedge5410.h>
43
44#define	RTC_RESET	0x1000
45#define	RTC_IODATA	0x0800
46#define	RTC_SCLK	0x0400
47
48#define set_dp(x)	SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
49#define get_dp()	SECUREEDGE_READ_IOPORT()
50#define ds1302_set_tx()
51#define ds1302_set_rx()
52
53static inline int ds1302_hw_init(void)
54{
55	return 0;
56}
57
58static inline void ds1302_reset(void)
59{
60	set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
61}
62
63static inline void ds1302_clock(void)
64{
65	set_dp(get_dp() | RTC_SCLK);	/* clock high */
66	set_dp(get_dp() & ~RTC_SCLK);	/* clock low */
67}
68
69static inline void ds1302_start(void)
70{
71	set_dp(get_dp() | RTC_RESET);
72}
73
74static inline void ds1302_stop(void)
75{
76	set_dp(get_dp() & ~RTC_RESET);
77}
78
79static inline void ds1302_txbit(int bit)
80{
81	set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0));
82}
83
84static inline int ds1302_rxbit(void)
85{
86	return !!(get_dp() & RTC_IODATA);
87}
88
89#else
90#error "Add support for your platform"
91#endif
92
93static void ds1302_sendbits(unsigned int val)
94{
95	int i;
96
97	ds1302_set_tx();
98
99	for (i = 8; (i); i--, val >>= 1) {
100		ds1302_txbit(val & 0x1);
101		ds1302_clock();
102	}
103}
104
105static unsigned int ds1302_recvbits(void)
106{
107	unsigned int val;
108	int i;
109
110	ds1302_set_rx();
111
112	for (i = 0, val = 0; (i < 8); i++) {
113		val |= (ds1302_rxbit() << i);
114		ds1302_clock();
115	}
116
117	return val;
118}
119
120static unsigned int ds1302_readbyte(unsigned int addr)
121{
122	unsigned int val;
123
124	ds1302_reset();
125
126	ds1302_start();
127	ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
128	val = ds1302_recvbits();
129	ds1302_stop();
130
131	return val;
132}
133
134static void ds1302_writebyte(unsigned int addr, unsigned int val)
135{
136	ds1302_reset();
137
138	ds1302_start();
139	ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
140	ds1302_sendbits(val);
141	ds1302_stop();
142}
143
144static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm)
145{
146	tm->tm_sec	= bcd2bin(ds1302_readbyte(RTC_ADDR_SEC));
147	tm->tm_min	= bcd2bin(ds1302_readbyte(RTC_ADDR_MIN));
148	tm->tm_hour	= bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR));
149	tm->tm_wday	= bcd2bin(ds1302_readbyte(RTC_ADDR_DAY));
150	tm->tm_mday	= bcd2bin(ds1302_readbyte(RTC_ADDR_DATE));
151	tm->tm_mon	= bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1;
152	tm->tm_year	= bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR));
153
154	if (tm->tm_year < 70)
155		tm->tm_year += 100;
156
157	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
158		"mday=%d, mon=%d, year=%d, wday=%d\n",
159		__func__,
160		tm->tm_sec, tm->tm_min, tm->tm_hour,
161		tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
162
163	return rtc_valid_tm(tm);
164}
165
166static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm)
167{
168	ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_ENABLE);
169	/* Stop RTC */
170	ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
171
172	ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec));
173	ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min));
174	ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour));
175	ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday));
176	ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday));
177	ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1));
178	ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100));
179
180	/* Start RTC */
181	ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
182
183	ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_DISABLE);
184
185	return 0;
186}
187
188static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd,
189			    unsigned long arg)
190{
191	switch (cmd) {
192#ifdef RTC_SET_CHARGE
193	case RTC_SET_CHARGE:
194	{
195		int tcs_val;
196
197		if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int)))
198			return -EFAULT;
199
200		ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf));
201		return 0;
202	}
203#endif
204	}
205
206	return -ENOIOCTLCMD;
207}
208
209static struct rtc_class_ops ds1302_rtc_ops = {
210	.read_time	= ds1302_rtc_read_time,
211	.set_time	= ds1302_rtc_set_time,
212	.ioctl		= ds1302_rtc_ioctl,
213};
214
215static int __init ds1302_rtc_probe(struct platform_device *pdev)
216{
217	struct rtc_device *rtc;
218
219	if (ds1302_hw_init()) {
220		dev_err(&pdev->dev, "Failed to init communication channel");
221		return -EINVAL;
222	}
223
224	/* Reset */
225	ds1302_reset();
226
227	/* Write a magic value to the DS1302 RAM, and see if it sticks. */
228	ds1302_writebyte(RTC_ADDR_RAM0, 0x42);
229	if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) {
230		dev_err(&pdev->dev, "Failed to probe");
231		return -ENODEV;
232	}
233
234	rtc = devm_rtc_device_register(&pdev->dev, "ds1302",
235					   &ds1302_rtc_ops, THIS_MODULE);
236	if (IS_ERR(rtc))
237		return PTR_ERR(rtc);
238
239	platform_set_drvdata(pdev, rtc);
240
241	return 0;
242}
243
244static struct platform_driver ds1302_platform_driver = {
245	.driver		= {
246		.name	= DRV_NAME,
247	},
248};
249
250module_platform_driver_probe(ds1302_platform_driver, ds1302_rtc_probe);
251
252MODULE_DESCRIPTION("Dallas DS1302 RTC driver");
253MODULE_VERSION(DRV_VERSION);
254MODULE_AUTHOR("Paul Mundt, David McCullough");
255MODULE_LICENSE("GPL v2");
256