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authorChris Verges <chrisv@cyberswitching.com>2009-09-22 19:46:20 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 10:39:44 -0400
commit7f3923a184bb8e7ede5e5f58f1114bf7b8c611ea (patch)
tree6c11806b0f93fd2a20758c2b40883d0067d81e59 /drivers/rtc/rtc-pcf2123.c
parent568d0697f42771425ae9f1e9a3db769fef7e10b6 (diff)
rtc: Philips PCF2123 RTC SPI driver
Add support for the Philips/NXP PCF2123 RTC. Signed-off: Chris Verges <chrisv@cyberswitching.com> Tested-by: Chris Verges <chrisv@cyberswitching.com> Signed-off: Christian Pellegrin <chripell@fsfe.org> Tested-by: Christian Pellegrin <chripell@fsfe.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/rtc/rtc-pcf2123.c')
-rw-r--r--drivers/rtc/rtc-pcf2123.c344
1 files changed, 344 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
new file mode 100644
index 000000000000..d07b199a0c94
--- /dev/null
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -0,0 +1,344 @@
1/*
2 * An SPI driver for the Philips PCF2123 RTC
3 * Copyright 2009 Cyber Switching, Inc.
4 *
5 * Author: Chris Verges <chrisv@cyberswitching.com>
6 * Maintainers: http://www.cyberswitching.com
7 *
8 * based on the RS5C348 driver in this same directory.
9 *
10 * Thanks to Christian Pellegrin <chripell@fsfe.org> for
11 * the sysfs contributions to this driver.
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 *
17 * Please note that the CS is active high, so platform data
18 * should look something like:
19 *
20 * static struct spi_board_info ek_spi_devices[] = {
21 * ...
22 * {
23 * .modalias = "rtc-pcf2123",
24 * .chip_select = 1,
25 * .controller_data = (void *)AT91_PIN_PA10,
26 * .max_speed_hz = 1000 * 1000,
27 * .mode = SPI_CS_HIGH,
28 * .bus_num = 0,
29 * },
30 * ...
31 *};
32 *
33 */
34
35#include <linux/bcd.h>
36#include <linux/delay.h>
37#include <linux/device.h>
38#include <linux/errno.h>
39#include <linux/init.h>
40#include <linux/kernel.h>
41#include <linux/string.h>
42#include <linux/rtc.h>
43#include <linux/spi/spi.h>
44
45#define DRV_VERSION "0.5"
46
47#define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */
48#define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */
49#define PCF2123_REG_SC (0x02) /* datetime */
50#define PCF2123_REG_MN (0x03)
51#define PCF2123_REG_HR (0x04)
52#define PCF2123_REG_DM (0x05)
53#define PCF2123_REG_DW (0x06)
54#define PCF2123_REG_MO (0x07)
55#define PCF2123_REG_YR (0x08)
56
57#define PCF2123_SUBADDR (1 << 4)
58#define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR)
59#define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR)
60
61static struct spi_driver pcf2123_driver;
62
63struct pcf2123_sysfs_reg {
64 struct device_attribute attr; /* must be first */
65 char name[2];
66};
67
68struct pcf2123_plat_data {
69 struct rtc_device *rtc;
70 struct pcf2123_sysfs_reg regs[16];
71};
72
73/*
74 * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select
75 * is released properly after an SPI write. This function should be
76 * called after EVERY read/write call over SPI.
77 */
78static inline void pcf2123_delay_trec(void)
79{
80 ndelay(30);
81}
82
83static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
84 char *buffer)
85{
86 struct spi_device *spi = to_spi_device(dev);
87 struct pcf2123_sysfs_reg *r = (struct pcf2123_sysfs_reg *) attr;
88 u8 txbuf[1], rxbuf[1];
89 int ret;
90
91 txbuf[0] = PCF2123_READ | simple_strtoul(r->name, NULL, 16);
92 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
93 if (ret < 0)
94 return sprintf(buffer, "error: %d", ret);
95 pcf2123_delay_trec();
96 return sprintf(buffer, "0x%x", rxbuf[0]);
97}
98
99static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
100 const char *buffer, size_t count) {
101 struct spi_device *spi = to_spi_device(dev);
102 struct pcf2123_sysfs_reg *r = (struct pcf2123_sysfs_reg *) attr;
103 u8 txbuf[2];
104 int ret;
105
106 txbuf[0] = PCF2123_WRITE | simple_strtoul(r->name, NULL, 16);
107 txbuf[1] = simple_strtoul(buffer, NULL, 0);
108 ret = spi_write(spi, txbuf, sizeof(txbuf));
109 if (ret < 0)
110 return -EIO;
111 pcf2123_delay_trec();
112 return count;
113}
114
115static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
116{
117 struct spi_device *spi = to_spi_device(dev);
118 u8 txbuf[1], rxbuf[7];
119 int ret;
120
121 txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
122 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
123 rxbuf, sizeof(rxbuf));
124 if (ret < 0)
125 return ret;
126 pcf2123_delay_trec();
127
128 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
129 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
130 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */
131 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
132 tm->tm_wday = rxbuf[4] & 0x07;
133 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */
134 tm->tm_year = bcd2bin(rxbuf[6]);
135 if (tm->tm_year < 70)
136 tm->tm_year += 100; /* assume we are in 1970...2069 */
137
138 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
139 "mday=%d, mon=%d, year=%d, wday=%d\n",
140 __func__,
141 tm->tm_sec, tm->tm_min, tm->tm_hour,
142 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
143
144 /* the clock can give out invalid datetime, but we cannot return
145 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
146 */
147 if (rtc_valid_tm(tm) < 0)
148 dev_err(dev, "retrieved date/time is not valid.\n");
149
150 return 0;
151}
152
153static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
154{
155 struct spi_device *spi = to_spi_device(dev);
156 u8 txbuf[8];
157 int ret;
158
159 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
160 "mday=%d, mon=%d, year=%d, wday=%d\n",
161 __func__,
162 tm->tm_sec, tm->tm_min, tm->tm_hour,
163 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
164
165 /* Stop the counter first */
166 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
167 txbuf[1] = 0x20;
168 ret = spi_write(spi, txbuf, 2);
169 if (ret < 0)
170 return ret;
171 pcf2123_delay_trec();
172
173 /* Set the new time */
174 txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
175 txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
176 txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
177 txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
178 txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);
179 txbuf[5] = tm->tm_wday & 0x07;
180 txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
181 txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
182
183 ret = spi_write(spi, txbuf, sizeof(txbuf));
184 if (ret < 0)
185 return ret;
186 pcf2123_delay_trec();
187
188 /* Start the counter */
189 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
190 txbuf[1] = 0x00;
191 ret = spi_write(spi, txbuf, 2);
192 if (ret < 0)
193 return ret;
194 pcf2123_delay_trec();
195
196 return 0;
197}
198
199static const struct rtc_class_ops pcf2123_rtc_ops = {
200 .read_time = pcf2123_rtc_read_time,
201 .set_time = pcf2123_rtc_set_time,
202};
203
204static int __devinit pcf2123_probe(struct spi_device *spi)
205{
206 struct rtc_device *rtc;
207 struct pcf2123_plat_data *pdata;
208 u8 txbuf[2], rxbuf[2];
209 int ret, i;
210
211 pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL);
212 if (!pdata)
213 return -ENOMEM;
214 spi->dev.platform_data = pdata;
215
216 /* Send a software reset command */
217 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
218 txbuf[1] = 0x58;
219 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
220 txbuf[0], txbuf[1]);
221 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
222 if (ret < 0)
223 return ret;
224 pcf2123_delay_trec();
225
226 /* Stop the counter */
227 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
228 txbuf[1] = 0x20;
229 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
230 txbuf[0], txbuf[1]);
231 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
232 if (ret < 0)
233 return ret;
234 pcf2123_delay_trec();
235
236 /* See if the counter was actually stopped */
237 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
238 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
239 txbuf[0]);
240 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
241 rxbuf, 2 * sizeof(u8));
242 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
243 rxbuf[0], rxbuf[1]);
244 if (ret < 0)
245 goto kfree_exit;
246 pcf2123_delay_trec();
247
248 if (!(rxbuf[0] & 0x20)) {
249 dev_err(&spi->dev, "chip not found\n");
250 goto kfree_exit;
251 }
252
253 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
254 dev_info(&spi->dev, "spiclk %u KHz.\n",
255 (spi->max_speed_hz + 500) / 1000);
256
257 /* Start the counter */
258 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
259 txbuf[1] = 0x00;
260 ret = spi_write(spi, txbuf, sizeof(txbuf));
261 if (ret < 0)
262 goto kfree_exit;
263 pcf2123_delay_trec();
264
265 /* Finalize the initialization */
266 rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev,
267 &pcf2123_rtc_ops, THIS_MODULE);
268
269 if (IS_ERR(rtc)) {
270 dev_err(&spi->dev, "failed to register.\n");
271 ret = PTR_ERR(rtc);
272 goto kfree_exit;
273 }
274
275 pdata->rtc = rtc;
276
277 for (i = 0; i < 16; i++) {
278 sprintf(pdata->regs[i].name, "%1x", i);
279 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
280 pdata->regs[i].attr.attr.name = pdata->regs[i].name;
281 pdata->regs[i].attr.show = pcf2123_show;
282 pdata->regs[i].attr.store = pcf2123_store;
283 ret = device_create_file(&spi->dev, &pdata->regs[i].attr);
284 if (ret) {
285 dev_err(&spi->dev, "Unable to create sysfs %s\n",
286 pdata->regs[i].name);
287 pdata->regs[i].name[0] = '\0';
288 }
289 }
290
291 return 0;
292kfree_exit:
293 kfree(pdata);
294 spi->dev.platform_data = NULL;
295 return ret;
296}
297
298static int pcf2123_remove(struct spi_device *spi)
299{
300 struct pcf2123_plat_data *pdata = spi->dev.platform_data;
301 int i;
302
303 if (pdata) {
304 struct rtc_device *rtc = pdata->rtc;
305
306 if (rtc)
307 rtc_device_unregister(rtc);
308 for (i = 0; i < 16; i++)
309 if (pdata->regs[i].name[0])
310 device_remove_file(&spi->dev,
311 &pdata->regs[i].attr);
312 kfree(pdata);
313 }
314
315 return 0;
316}
317
318static struct spi_driver pcf2123_driver = {
319 .driver = {
320 .name = "rtc-pcf2123",
321 .bus = &spi_bus_type,
322 .owner = THIS_MODULE,
323 },
324 .probe = pcf2123_probe,
325 .remove = __devexit_p(pcf2123_remove),
326};
327
328static int __init pcf2123_init(void)
329{
330 return spi_register_driver(&pcf2123_driver);
331}
332
333static void __exit pcf2123_exit(void)
334{
335 spi_unregister_driver(&pcf2123_driver);
336}
337
338MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
339MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
340MODULE_LICENSE("GPL");
341MODULE_VERSION(DRV_VERSION);
342
343module_init(pcf2123_init);
344module_exit(pcf2123_exit);