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path: root/drivers/rtc/rtc-ds3234.c
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Diffstat (limited to 'drivers/rtc/rtc-ds3234.c')
-rw-r--r--drivers/rtc/rtc-ds3234.c290
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds3234.c b/drivers/rtc/rtc-ds3234.c
new file mode 100644
index 000000000000..37d131d03f33
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+++ b/drivers/rtc/rtc-ds3234.c
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1/* drivers/rtc/rtc-ds3234.c
2 *
3 * Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal
4 * and SRAM.
5 *
6 * Copyright (C) 2008 MIMOMax Wireless Ltd.
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 * Changelog:
13 *
14 * 07-May-2008: Dennis Aberilla <denzzzhome@yahoo.com>
15 * - Created based on the max6902 code. Only implements the
16 * date/time keeping functions; no SRAM yet.
17 */
18
19#include <linux/device.h>
20#include <linux/platform_device.h>
21#include <linux/rtc.h>
22#include <linux/spi/spi.h>
23#include <linux/bcd.h>
24
25#define DS3234_REG_SECONDS 0x00
26#define DS3234_REG_MINUTES 0x01
27#define DS3234_REG_HOURS 0x02
28#define DS3234_REG_DAY 0x03
29#define DS3234_REG_DATE 0x04
30#define DS3234_REG_MONTH 0x05
31#define DS3234_REG_YEAR 0x06
32#define DS3234_REG_CENTURY (1 << 7) /* Bit 7 of the Month register */
33
34#define DS3234_REG_CONTROL 0x0E
35#define DS3234_REG_CONT_STAT 0x0F
36
37#undef DS3234_DEBUG
38
39struct ds3234 {
40 struct rtc_device *rtc;
41 u8 buf[8]; /* Burst read: addr + 7 regs */
42 u8 tx_buf[2];
43 u8 rx_buf[2];
44};
45
46static void ds3234_set_reg(struct device *dev, unsigned char address,
47 unsigned char data)
48{
49 struct spi_device *spi = to_spi_device(dev);
50 unsigned char buf[2];
51
52 /* MSB must be '1' to indicate write */
53 buf[0] = address | 0x80;
54 buf[1] = data;
55
56 spi_write(spi, buf, 2);
57}
58
59static int ds3234_get_reg(struct device *dev, unsigned char address,
60 unsigned char *data)
61{
62 struct spi_device *spi = to_spi_device(dev);
63 struct ds3234 *chip = dev_get_drvdata(dev);
64 struct spi_message message;
65 struct spi_transfer xfer;
66 int status;
67
68 if (!data)
69 return -EINVAL;
70
71 /* Build our spi message */
72 spi_message_init(&message);
73 memset(&xfer, 0, sizeof(xfer));
74
75 /* Address + dummy tx byte */
76 xfer.len = 2;
77 xfer.tx_buf = chip->tx_buf;
78 xfer.rx_buf = chip->rx_buf;
79
80 chip->tx_buf[0] = address;
81 chip->tx_buf[1] = 0xff;
82
83 spi_message_add_tail(&xfer, &message);
84
85 /* do the i/o */
86 status = spi_sync(spi, &message);
87 if (status == 0)
88 status = message.status;
89 else
90 return status;
91
92 *data = chip->rx_buf[1];
93
94 return status;
95}
96
97static int ds3234_get_datetime(struct device *dev, struct rtc_time *dt)
98{
99 struct spi_device *spi = to_spi_device(dev);
100 struct ds3234 *chip = dev_get_drvdata(dev);
101 struct spi_message message;
102 struct spi_transfer xfer;
103 int status;
104
105 /* build the message */
106 spi_message_init(&message);
107 memset(&xfer, 0, sizeof(xfer));
108 xfer.len = 1 + 7; /* Addr + 7 registers */
109 xfer.tx_buf = chip->buf;
110 xfer.rx_buf = chip->buf;
111 chip->buf[0] = 0x00; /* Start address */
112 spi_message_add_tail(&xfer, &message);
113
114 /* do the i/o */
115 status = spi_sync(spi, &message);
116 if (status == 0)
117 status = message.status;
118 else
119 return status;
120
121 /* Seconds, Minutes, Hours, Day, Date, Month, Year */
122 dt->tm_sec = bcd2bin(chip->buf[1]);
123 dt->tm_min = bcd2bin(chip->buf[2]);
124 dt->tm_hour = bcd2bin(chip->buf[3] & 0x3f);
125 dt->tm_wday = bcd2bin(chip->buf[4]) - 1; /* 0 = Sun */
126 dt->tm_mday = bcd2bin(chip->buf[5]);
127 dt->tm_mon = bcd2bin(chip->buf[6] & 0x1f) - 1; /* 0 = Jan */
128 dt->tm_year = bcd2bin(chip->buf[7] & 0xff) + 100; /* Assume 20YY */
129
130#ifdef DS3234_DEBUG
131 dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
132 dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
133 dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
134 dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
135 dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
136 dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
137 dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
138 dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
139#endif
140
141 return 0;
142}
143
144static int ds3234_set_datetime(struct device *dev, struct rtc_time *dt)
145{
146#ifdef DS3234_DEBUG
147 dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
148 dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
149 dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
150 dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
151 dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
152 dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
153 dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
154 dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
155#endif
156
157 ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec));
158 ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min));
159 ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f);
160
161 /* 0 = Sun */
162 ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1));
163 ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday));
164
165 /* 0 = Jan */
166 ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1));
167
168 /* Assume 20YY although we just want to make sure not to go negative. */
169 if (dt->tm_year > 100)
170 dt->tm_year -= 100;
171
172 ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year));
173
174 return 0;
175}
176
177static int ds3234_read_time(struct device *dev, struct rtc_time *tm)
178{
179 return ds3234_get_datetime(dev, tm);
180}
181
182static int ds3234_set_time(struct device *dev, struct rtc_time *tm)
183{
184 return ds3234_set_datetime(dev, tm);
185}
186
187static const struct rtc_class_ops ds3234_rtc_ops = {
188 .read_time = ds3234_read_time,
189 .set_time = ds3234_set_time,
190};
191
192static int ds3234_probe(struct spi_device *spi)
193{
194 struct rtc_device *rtc;
195 unsigned char tmp;
196 struct ds3234 *chip;
197 int res;
198
199 rtc = rtc_device_register("ds3234",
200 &spi->dev, &ds3234_rtc_ops, THIS_MODULE);
201 if (IS_ERR(rtc))
202 return PTR_ERR(rtc);
203
204 spi->mode = SPI_MODE_3;
205 spi->bits_per_word = 8;
206 spi_setup(spi);
207
208 chip = kzalloc(sizeof(struct ds3234), GFP_KERNEL);
209 if (!chip) {
210 rtc_device_unregister(rtc);
211 return -ENOMEM;
212 }
213 chip->rtc = rtc;
214 dev_set_drvdata(&spi->dev, chip);
215
216 res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp);
217 if (res) {
218 rtc_device_unregister(rtc);
219 return res;
220 }
221
222 /* Control settings
223 *
224 * CONTROL_REG
225 * BIT 7 6 5 4 3 2 1 0
226 * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE
227 *
228 * 0 0 0 1 1 1 0 0
229 *
230 * CONTROL_STAT_REG
231 * BIT 7 6 5 4 3 2 1 0
232 * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F
233 *
234 * 1 0 0 0 1 0 0 0
235 */
236 ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
237 ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c);
238
239 ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
240 ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88);
241
242 /* Print our settings */
243 ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
244 dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
245
246 ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
247 dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
248
249 return 0;
250}
251
252static int __exit ds3234_remove(struct spi_device *spi)
253{
254 struct ds3234 *chip = platform_get_drvdata(spi);
255 struct rtc_device *rtc = chip->rtc;
256
257 if (rtc)
258 rtc_device_unregister(rtc);
259
260 kfree(chip);
261
262 return 0;
263}
264
265static struct spi_driver ds3234_driver = {
266 .driver = {
267 .name = "ds3234",
268 .bus = &spi_bus_type,
269 .owner = THIS_MODULE,
270 },
271 .probe = ds3234_probe,
272 .remove = __devexit_p(ds3234_remove),
273};
274
275static __init int ds3234_init(void)
276{
277 printk(KERN_INFO "DS3234 SPI RTC Driver\n");
278 return spi_register_driver(&ds3234_driver);
279}
280module_init(ds3234_init);
281
282static __exit void ds3234_exit(void)
283{
284 spi_unregister_driver(&ds3234_driver);
285}
286module_exit(ds3234_exit);
287
288MODULE_DESCRIPTION("DS3234 SPI RTC driver");
289MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
290MODULE_LICENSE("GPL");
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