Merge branch 'origin' into for-linus
[linux-2.6.git] / drivers / rtc / rtc-pcf2123.c
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 "0.6"
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
61 static struct spi_driver pcf2123_driver;
62
63 struct pcf2123_sysfs_reg {
64         struct device_attribute attr;
65         char name[2];
66 };
67
68 struct 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  */
78 static inline void pcf2123_delay_trec(void)
79 {
80         ndelay(30);
81 }
82
83 static 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;
88         u8 txbuf[1], rxbuf[1];
89         unsigned long reg;
90         int ret;
91
92         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
93
94         if (strict_strtoul(r->name, 16, &reg))
95                 return -EINVAL;
96
97         txbuf[0] = PCF2123_READ | reg;
98         ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
99         if (ret < 0)
100                 return -EIO;
101         pcf2123_delay_trec();
102         return sprintf(buffer, "0x%x\n", rxbuf[0]);
103 }
104
105 static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
106                              const char *buffer, size_t count) {
107         struct spi_device *spi = to_spi_device(dev);
108         struct pcf2123_sysfs_reg *r;
109         u8 txbuf[2];
110         unsigned long reg;
111         unsigned long val;
112
113         int ret;
114
115         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
116
117         if (strict_strtoul(r->name, 16, &reg)
118                 || strict_strtoul(buffer, 10, &val))
119                 return -EINVAL;
120
121         txbuf[0] = PCF2123_WRITE | reg;
122         txbuf[1] = val;
123         ret = spi_write(spi, txbuf, sizeof(txbuf));
124         if (ret < 0)
125                 return -EIO;
126         pcf2123_delay_trec();
127         return count;
128 }
129
130 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
131 {
132         struct spi_device *spi = to_spi_device(dev);
133         u8 txbuf[1], rxbuf[7];
134         int ret;
135
136         txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
137         ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
138                         rxbuf, sizeof(rxbuf));
139         if (ret < 0)
140                 return ret;
141         pcf2123_delay_trec();
142
143         tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
144         tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
145         tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */
146         tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
147         tm->tm_wday = rxbuf[4] & 0x07;
148         tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */
149         tm->tm_year = bcd2bin(rxbuf[6]);
150         if (tm->tm_year < 70)
151                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
152
153         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
154                         "mday=%d, mon=%d, year=%d, wday=%d\n",
155                         __func__,
156                         tm->tm_sec, tm->tm_min, tm->tm_hour,
157                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
158
159         /* the clock can give out invalid datetime, but we cannot return
160          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
161          */
162         if (rtc_valid_tm(tm) < 0)
163                 dev_err(dev, "retrieved date/time is not valid.\n");
164
165         return 0;
166 }
167
168 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
169 {
170         struct spi_device *spi = to_spi_device(dev);
171         u8 txbuf[8];
172         int ret;
173
174         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
175                         "mday=%d, mon=%d, year=%d, wday=%d\n",
176                         __func__,
177                         tm->tm_sec, tm->tm_min, tm->tm_hour,
178                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
179
180         /* Stop the counter first */
181         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
182         txbuf[1] = 0x20;
183         ret = spi_write(spi, txbuf, 2);
184         if (ret < 0)
185                 return ret;
186         pcf2123_delay_trec();
187
188         /* Set the new time */
189         txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
190         txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
191         txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
192         txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
193         txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);
194         txbuf[5] = tm->tm_wday & 0x07;
195         txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
196         txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
197
198         ret = spi_write(spi, txbuf, sizeof(txbuf));
199         if (ret < 0)
200                 return ret;
201         pcf2123_delay_trec();
202
203         /* Start the counter */
204         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
205         txbuf[1] = 0x00;
206         ret = spi_write(spi, txbuf, 2);
207         if (ret < 0)
208                 return ret;
209         pcf2123_delay_trec();
210
211         return 0;
212 }
213
214 static const struct rtc_class_ops pcf2123_rtc_ops = {
215         .read_time      = pcf2123_rtc_read_time,
216         .set_time       = pcf2123_rtc_set_time,
217 };
218
219 static int __devinit pcf2123_probe(struct spi_device *spi)
220 {
221         struct rtc_device *rtc;
222         struct pcf2123_plat_data *pdata;
223         u8 txbuf[2], rxbuf[2];
224         int ret, i;
225
226         pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL);
227         if (!pdata)
228                 return -ENOMEM;
229         spi->dev.platform_data = pdata;
230
231         /* Send a software reset command */
232         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
233         txbuf[1] = 0x58;
234         dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
235                         txbuf[0], txbuf[1]);
236         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
237         if (ret < 0)
238                 goto kfree_exit;
239         pcf2123_delay_trec();
240
241         /* Stop the counter */
242         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
243         txbuf[1] = 0x20;
244         dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
245                         txbuf[0], txbuf[1]);
246         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
247         if (ret < 0)
248                 goto kfree_exit;
249         pcf2123_delay_trec();
250
251         /* See if the counter was actually stopped */
252         txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
253         dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
254                         txbuf[0]);
255         ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
256                                         rxbuf, 2 * sizeof(u8));
257         dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
258                         rxbuf[0], rxbuf[1]);
259         if (ret < 0)
260                 goto kfree_exit;
261         pcf2123_delay_trec();
262
263         if (!(rxbuf[0] & 0x20)) {
264                 dev_err(&spi->dev, "chip not found\n");
265                 goto kfree_exit;
266         }
267
268         dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
269         dev_info(&spi->dev, "spiclk %u KHz.\n",
270                         (spi->max_speed_hz + 500) / 1000);
271
272         /* Start the counter */
273         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
274         txbuf[1] = 0x00;
275         ret = spi_write(spi, txbuf, sizeof(txbuf));
276         if (ret < 0)
277                 goto kfree_exit;
278         pcf2123_delay_trec();
279
280         /* Finalize the initialization */
281         rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev,
282                         &pcf2123_rtc_ops, THIS_MODULE);
283
284         if (IS_ERR(rtc)) {
285                 dev_err(&spi->dev, "failed to register.\n");
286                 ret = PTR_ERR(rtc);
287                 goto kfree_exit;
288         }
289
290         pdata->rtc = rtc;
291
292         for (i = 0; i < 16; i++) {
293                 sprintf(pdata->regs[i].name, "%1x", i);
294                 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
295                 pdata->regs[i].attr.attr.name = pdata->regs[i].name;
296                 pdata->regs[i].attr.show = pcf2123_show;
297                 pdata->regs[i].attr.store = pcf2123_store;
298                 ret = device_create_file(&spi->dev, &pdata->regs[i].attr);
299                 if (ret) {
300                         dev_err(&spi->dev, "Unable to create sysfs %s\n",
301                                 pdata->regs[i].name);
302                         goto sysfs_exit;
303                 }
304         }
305
306         return 0;
307
308 sysfs_exit:
309         for (i--; i >= 0; i--)
310                 device_remove_file(&spi->dev, &pdata->regs[i].attr);
311
312 kfree_exit:
313         kfree(pdata);
314         spi->dev.platform_data = NULL;
315         return ret;
316 }
317
318 static int pcf2123_remove(struct spi_device *spi)
319 {
320         struct pcf2123_plat_data *pdata = spi->dev.platform_data;
321         int i;
322
323         if (pdata) {
324                 struct rtc_device *rtc = pdata->rtc;
325
326                 if (rtc)
327                         rtc_device_unregister(rtc);
328                 for (i = 0; i < 16; i++)
329                         if (pdata->regs[i].name[0])
330                                 device_remove_file(&spi->dev,
331                                                    &pdata->regs[i].attr);
332                 kfree(pdata);
333         }
334
335         return 0;
336 }
337
338 static struct spi_driver pcf2123_driver = {
339         .driver = {
340                         .name   = "rtc-pcf2123",
341                         .bus    = &spi_bus_type,
342                         .owner  = THIS_MODULE,
343         },
344         .probe  = pcf2123_probe,
345         .remove = __devexit_p(pcf2123_remove),
346 };
347
348 static int __init pcf2123_init(void)
349 {
350         return spi_register_driver(&pcf2123_driver);
351 }
352
353 static void __exit pcf2123_exit(void)
354 {
355         spi_unregister_driver(&pcf2123_driver);
356 }
357
358 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
359 MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
360 MODULE_LICENSE("GPL");
361 MODULE_VERSION(DRV_VERSION);
362
363 module_init(pcf2123_init);
364 module_exit(pcf2123_exit);