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authorRaphael Assenat <raph@raphnet.net>2006-06-25 08:48:23 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-25 13:01:14 -0400
commit8e12ecc2b5a4521a338d7681e7d5547080fc6f71 (patch)
treeffa6cfbbc2d461bb965b97482fc53c02cf3e7733 /drivers/rtc
parent110d693d5898649da606cd6e5f6af4d7f70a405f (diff)
[PATCH] Add max6902 RTC support
Add support for the MAX6902 SPI RTC chip. Tested on a pxa2xx cpu. The compulab code comes from the kernel patch the produce for their cn-x255 board. (inside a zip file on the http://www.compulab.co.il/x255/html/x255-developer.htm) The original file (drivers/char/max6902.c) was GPL, which is of course an appropriate licence: /* * max6902.c * * Driver for MAX6902 RTC * * Copyright (C) 2004 Compulab Ltd. * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * */ For reference, you can get the original file here: http://raph.people.8d.com/misc/max6902.c [akpm@osdl.org: cleanups] Signed-off-by: Raphael Assenat <raph@raphnet.net> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/Kconfig10
-rw-r--r--drivers/rtc/Makefile1
-rw-r--r--drivers/rtc/rtc-max6902.c286
3 files changed, 297 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 37ee69f57a0b..94746cfac7b5 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -217,4 +217,14 @@ config RTC_DRV_TEST
217 This driver can also be built as a module. If so, the module 217 This driver can also be built as a module. If so, the module
218 will be called rtc-test. 218 will be called rtc-test.
219 219
220config RTC_DRV_MAX6902
221 tristate "Maxim 6902"
222 depends on RTC_CLASS && SPI
223 help
224 If you say yes here you will get support for the
225 Maxim MAX6902 spi RTC chip.
226
227 This driver can also be built as a module. If so, the module
228 will be called rtc-max6902.
229
220endmenu 230endmenu
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 090f197f07e8..dd480d6bcdf8 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
23obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o 23obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
24obj-$(CONFIG_RTC_DRV_VR41XX) += rtc-vr41xx.o 24obj-$(CONFIG_RTC_DRV_VR41XX) += rtc-vr41xx.o
25obj-$(CONFIG_RTC_DRV_PL031) += rtc-pl031.o 25obj-$(CONFIG_RTC_DRV_PL031) += rtc-pl031.o
26obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
diff --git a/drivers/rtc/rtc-max6902.c b/drivers/rtc/rtc-max6902.c
new file mode 100644
index 000000000000..2c9739562b5c
--- /dev/null
+++ b/drivers/rtc/rtc-max6902.c
@@ -0,0 +1,286 @@
1/* drivers/char/max6902.c
2 *
3 * Copyright (C) 2006 8D Technologies inc.
4 * Copyright (C) 2004 Compulab Ltd.
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 * Driver for MAX6902 spi RTC
11 *
12 * Changelog:
13 *
14 * 24-May-2006: Raphael Assenat <raph@8d.com>
15 * - Major rework
16 * Converted to rtc_device and uses the SPI layer.
17 *
18 * ??-???-2005: Someone at Compulab
19 * - Initial driver creation.
20 */
21
22#include <linux/config.h>
23#include <linux/module.h>
24#include <linux/version.h>
25
26#include <linux/kernel.h>
27#include <linux/platform_device.h>
28#include <linux/init.h>
29#include <linux/rtc.h>
30#include <linux/spi/spi.h>
31#include <linux/bcd.h>
32#include <linux/delay.h>
33
34#define MAX6902_REG_SECONDS 0x01
35#define MAX6902_REG_MINUTES 0x03
36#define MAX6902_REG_HOURS 0x05
37#define MAX6902_REG_DATE 0x07
38#define MAX6902_REG_MONTH 0x09
39#define MAX6902_REG_DAY 0x0B
40#define MAX6902_REG_YEAR 0x0D
41#define MAX6902_REG_CONTROL 0x0F
42#define MAX6902_REG_CENTURY 0x13
43
44#undef MAX6902_DEBUG
45
46struct max6902 {
47 struct rtc_device *rtc;
48 u8 buf[9]; /* Burst read cmd + 8 registers */
49 u8 tx_buf[2];
50 u8 rx_buf[2];
51};
52
53static void max6902_set_reg(struct device *dev, unsigned char address,
54 unsigned char data)
55{
56 struct spi_device *spi = to_spi_device(dev);
57 unsigned char buf[2];
58
59 /* MSB must be '0' to write */
60 buf[0] = address & 0x7f;
61 buf[1] = data;
62
63 spi_write(spi, buf, 2);
64}
65
66static int max6902_get_reg(struct device *dev, unsigned char address,
67 unsigned char *data)
68{
69 struct spi_device *spi = to_spi_device(dev);
70 struct max6902 *chip = dev_get_drvdata(dev);
71 struct spi_message message;
72 struct spi_transfer xfer;
73 int status;
74
75 if (!data)
76 return -EINVAL;
77
78 /* Build our spi message */
79 spi_message_init(&message);
80 memset(&xfer, 0, sizeof(xfer));
81 xfer.len = 2;
82 /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
83 xfer.tx_buf = chip->tx_buf;
84 xfer.rx_buf = chip->rx_buf;
85
86 /* Set MSB to indicate read */
87 chip->tx_buf[0] = address | 0x80;
88
89 spi_message_add_tail(&xfer, &message);
90
91 /* do the i/o */
92 status = spi_sync(spi, &message);
93 if (status == 0)
94 status = message.status;
95 else
96 return status;
97
98 *data = chip->rx_buf[1];
99
100 return status;
101}
102
103static int max6902_get_datetime(struct device *dev, struct rtc_time *dt)
104{
105 unsigned char tmp;
106 int century;
107 int err;
108 struct spi_device *spi = to_spi_device(dev);
109 struct max6902 *chip = dev_get_drvdata(dev);
110 struct spi_message message;
111 struct spi_transfer xfer;
112 int status;
113
114 err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp);
115 if (err)
116 return err;
117
118 /* build the message */
119 spi_message_init(&message);
120 memset(&xfer, 0, sizeof(xfer));
121 xfer.len = 1 + 7; /* Burst read command + 7 registers */
122 xfer.tx_buf = chip->buf;
123 xfer.rx_buf = chip->buf;
124 chip->buf[0] = 0xbf; /* Burst read */
125 spi_message_add_tail(&xfer, &message);
126
127 /* do the i/o */
128 status = spi_sync(spi, &message);
129 if (status == 0)
130 status = message.status;
131 else
132 return status;
133
134 /* The chip sends data in this order:
135 * Seconds, Minutes, Hours, Date, Month, Day, Year */
136 dt->tm_sec = BCD2BIN(chip->buf[1]);
137 dt->tm_min = BCD2BIN(chip->buf[2]);
138 dt->tm_hour = BCD2BIN(chip->buf[3]);
139 dt->tm_mday = BCD2BIN(chip->buf[4]);
140 dt->tm_mon = BCD2BIN(chip->buf[5] - 1);
141 dt->tm_wday = BCD2BIN(chip->buf[6]);
142 dt->tm_year = BCD2BIN(chip->buf[7]);
143
144 century = BCD2BIN(tmp) * 100;
145
146 dt->tm_year += century;
147 dt->tm_year -= 1900;
148
149#ifdef MAX6902_DEBUG
150 printk("\n%s : Read RTC values\n",__FUNCTION__);
151 printk("tm_hour: %i\n",dt->tm_hour);
152 printk("tm_min : %i\n",dt->tm_min);
153 printk("tm_sec : %i\n",dt->tm_sec);
154 printk("tm_year: %i\n",dt->tm_year);
155 printk("tm_mon : %i\n",dt->tm_mon);
156 printk("tm_mday: %i\n",dt->tm_mday);
157 printk("tm_wday: %i\n",dt->tm_wday);
158#endif
159
160 return 0;
161}
162
163static int max6902_set_datetime(struct device *dev, struct rtc_time *dt)
164{
165 dt->tm_year = dt->tm_year+1900;
166
167#ifdef MAX6902_DEBUG
168 printk("\n%s : Setting RTC values\n",__FUNCTION__);
169 printk("tm_sec : %i\n",dt->tm_sec);
170 printk("tm_min : %i\n",dt->tm_min);
171 printk("tm_hour: %i\n",dt->tm_hour);
172 printk("tm_mday: %i\n",dt->tm_mday);
173 printk("tm_wday: %i\n",dt->tm_wday);
174 printk("tm_year: %i\n",dt->tm_year);
175#endif
176
177 /* Remove write protection */
178 max6902_set_reg(dev, 0xF, 0);
179
180 max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec));
181 max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min));
182 max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour));
183
184 max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday));
185 max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1));
186 max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday));
187 max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100));
188 max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100));
189
190 /* Compulab used a delay here. However, the datasheet
191 * does not mention a delay being required anywhere... */
192 /* delay(2000); */
193
194 /* Write protect */
195 max6902_set_reg(dev, 0xF, 0x80);
196
197 return 0;
198}
199
200static int max6902_read_time(struct device *dev, struct rtc_time *tm)
201{
202 return max6902_get_datetime(dev, tm);
203}
204
205static int max6902_set_time(struct device *dev, struct rtc_time *tm)
206{
207 return max6902_set_datetime(dev, tm);
208}
209
210static struct rtc_class_ops max6902_rtc_ops = {
211 .read_time = max6902_read_time,
212 .set_time = max6902_set_time,
213};
214
215static int __devinit max6902_probe(struct spi_device *spi)
216{
217 struct rtc_device *rtc;
218 unsigned char tmp;
219 struct max6902 *chip;
220 int res;
221
222 rtc = rtc_device_register("max6902",
223 &spi->dev, &max6902_rtc_ops, THIS_MODULE);
224 if (IS_ERR(rtc))
225 return PTR_ERR(rtc);
226
227 spi->mode = SPI_MODE_3;
228 spi->bits_per_word = 8;
229 spi_setup(spi);
230
231 chip = kzalloc(sizeof *chip, GFP_KERNEL);
232 if (!chip) {
233 rtc_device_unregister(rtc);
234 return -ENOMEM;
235 }
236 chip->rtc = rtc;
237 dev_set_drvdata(&spi->dev, chip);
238
239 res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
240 if (res) {
241 rtc_device_unregister(rtc);
242 return res;
243 }
244
245 return 0;
246}
247
248static int __devexit max6902_remove(struct spi_device *spi)
249{
250 struct max6902 *chip = platform_get_drvdata(spi);
251 struct rtc_device *rtc = chip->rtc;
252
253 if (rtc)
254 rtc_device_unregister(rtc);
255
256 kfree(chip);
257
258 return 0;
259}
260
261static struct spi_driver max6902_driver = {
262 .driver = {
263 .name = "max6902",
264 .bus = &spi_bus_type,
265 .owner = THIS_MODULE,
266 },
267 .probe = max6902_probe,
268 .remove = __devexit_p(max6902_remove),
269};
270
271static __init int max6902_init(void)
272{
273 printk("max6902 spi driver\n");
274 return spi_register_driver(&max6902_driver);
275}
276module_init(max6902_init);
277
278static __exit void max6902_exit(void)
279{
280 spi_unregister_driver(&max6902_driver);
281}
282module_exit(max6902_exit);
283
284MODULE_DESCRIPTION ("max6902 spi RTC driver");
285MODULE_AUTHOR ("Raphael Assenat");
286MODULE_LICENSE ("GPL");