2ee3bbf7e5ea03df488233c61b659c4909219335
[~shefty/rdma-dev.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/slab.h>
43 #include <linux/rtc.h>
44 #include <linux/spi/spi.h>
45 #include <linux/module.h>
46
47 #define DRV_VERSION "0.6"
48
49 #define PCF2123_REG_CTRL1       (0x00)  /* Control Register 1 */
50 #define PCF2123_REG_CTRL2       (0x01)  /* Control Register 2 */
51 #define PCF2123_REG_SC          (0x02)  /* datetime */
52 #define PCF2123_REG_MN          (0x03)
53 #define PCF2123_REG_HR          (0x04)
54 #define PCF2123_REG_DM          (0x05)
55 #define PCF2123_REG_DW          (0x06)
56 #define PCF2123_REG_MO          (0x07)
57 #define PCF2123_REG_YR          (0x08)
58
59 #define PCF2123_SUBADDR         (1 << 4)
60 #define PCF2123_WRITE           ((0 << 7) | PCF2123_SUBADDR)
61 #define PCF2123_READ            ((1 << 7) | PCF2123_SUBADDR)
62
63 static struct spi_driver pcf2123_driver;
64
65 struct pcf2123_sysfs_reg {
66         struct device_attribute attr;
67         char name[2];
68 };
69
70 struct pcf2123_plat_data {
71         struct rtc_device *rtc;
72         struct pcf2123_sysfs_reg regs[16];
73 };
74
75 /*
76  * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select
77  * is released properly after an SPI write.  This function should be
78  * called after EVERY read/write call over SPI.
79  */
80 static inline void pcf2123_delay_trec(void)
81 {
82         ndelay(30);
83 }
84
85 static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
86                             char *buffer)
87 {
88         struct spi_device *spi = to_spi_device(dev);
89         struct pcf2123_sysfs_reg *r;
90         u8 txbuf[1], rxbuf[1];
91         unsigned long reg;
92         int ret;
93
94         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
95
96         if (strict_strtoul(r->name, 16, &reg))
97                 return -EINVAL;
98
99         txbuf[0] = PCF2123_READ | reg;
100         ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
101         if (ret < 0)
102                 return -EIO;
103         pcf2123_delay_trec();
104         return sprintf(buffer, "0x%x\n", rxbuf[0]);
105 }
106
107 static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
108                              const char *buffer, size_t count) {
109         struct spi_device *spi = to_spi_device(dev);
110         struct pcf2123_sysfs_reg *r;
111         u8 txbuf[2];
112         unsigned long reg;
113         unsigned long val;
114
115         int ret;
116
117         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
118
119         if (strict_strtoul(r->name, 16, &reg)
120                 || strict_strtoul(buffer, 10, &val))
121                 return -EINVAL;
122
123         txbuf[0] = PCF2123_WRITE | reg;
124         txbuf[1] = val;
125         ret = spi_write(spi, txbuf, sizeof(txbuf));
126         if (ret < 0)
127                 return -EIO;
128         pcf2123_delay_trec();
129         return count;
130 }
131
132 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
133 {
134         struct spi_device *spi = to_spi_device(dev);
135         u8 txbuf[1], rxbuf[7];
136         int ret;
137
138         txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
139         ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
140                         rxbuf, sizeof(rxbuf));
141         if (ret < 0)
142                 return ret;
143         pcf2123_delay_trec();
144
145         tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
146         tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
147         tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */
148         tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
149         tm->tm_wday = rxbuf[4] & 0x07;
150         tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */
151         tm->tm_year = bcd2bin(rxbuf[6]);
152         if (tm->tm_year < 70)
153                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
154
155         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
156                         "mday=%d, mon=%d, year=%d, wday=%d\n",
157                         __func__,
158                         tm->tm_sec, tm->tm_min, tm->tm_hour,
159                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
160
161         /* the clock can give out invalid datetime, but we cannot return
162          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
163          */
164         if (rtc_valid_tm(tm) < 0)
165                 dev_err(dev, "retrieved date/time is not valid.\n");
166
167         return 0;
168 }
169
170 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
171 {
172         struct spi_device *spi = to_spi_device(dev);
173         u8 txbuf[8];
174         int ret;
175
176         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
177                         "mday=%d, mon=%d, year=%d, wday=%d\n",
178                         __func__,
179                         tm->tm_sec, tm->tm_min, tm->tm_hour,
180                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
181
182         /* Stop the counter first */
183         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
184         txbuf[1] = 0x20;
185         ret = spi_write(spi, txbuf, 2);
186         if (ret < 0)
187                 return ret;
188         pcf2123_delay_trec();
189
190         /* Set the new time */
191         txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
192         txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
193         txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
194         txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
195         txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);
196         txbuf[5] = tm->tm_wday & 0x07;
197         txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
198         txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
199
200         ret = spi_write(spi, txbuf, sizeof(txbuf));
201         if (ret < 0)
202                 return ret;
203         pcf2123_delay_trec();
204
205         /* Start the counter */
206         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
207         txbuf[1] = 0x00;
208         ret = spi_write(spi, txbuf, 2);
209         if (ret < 0)
210                 return ret;
211         pcf2123_delay_trec();
212
213         return 0;
214 }
215
216 static const struct rtc_class_ops pcf2123_rtc_ops = {
217         .read_time      = pcf2123_rtc_read_time,
218         .set_time       = pcf2123_rtc_set_time,
219 };
220
221 static int __devinit pcf2123_probe(struct spi_device *spi)
222 {
223         struct rtc_device *rtc;
224         struct pcf2123_plat_data *pdata;
225         u8 txbuf[2], rxbuf[2];
226         int ret, i;
227
228         pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL);
229         if (!pdata)
230                 return -ENOMEM;
231         spi->dev.platform_data = pdata;
232
233         /* Send a software reset command */
234         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
235         txbuf[1] = 0x58;
236         dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
237                         txbuf[0], txbuf[1]);
238         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
239         if (ret < 0)
240                 goto kfree_exit;
241         pcf2123_delay_trec();
242
243         /* Stop the counter */
244         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
245         txbuf[1] = 0x20;
246         dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
247                         txbuf[0], txbuf[1]);
248         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
249         if (ret < 0)
250                 goto kfree_exit;
251         pcf2123_delay_trec();
252
253         /* See if the counter was actually stopped */
254         txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
255         dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
256                         txbuf[0]);
257         ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
258                                         rxbuf, 2 * sizeof(u8));
259         dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
260                         rxbuf[0], rxbuf[1]);
261         if (ret < 0)
262                 goto kfree_exit;
263         pcf2123_delay_trec();
264
265         if (!(rxbuf[0] & 0x20)) {
266                 dev_err(&spi->dev, "chip not found\n");
267                 goto kfree_exit;
268         }
269
270         dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
271         dev_info(&spi->dev, "spiclk %u KHz.\n",
272                         (spi->max_speed_hz + 500) / 1000);
273
274         /* Start the counter */
275         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
276         txbuf[1] = 0x00;
277         ret = spi_write(spi, txbuf, sizeof(txbuf));
278         if (ret < 0)
279                 goto kfree_exit;
280         pcf2123_delay_trec();
281
282         /* Finalize the initialization */
283         rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev,
284                         &pcf2123_rtc_ops, THIS_MODULE);
285
286         if (IS_ERR(rtc)) {
287                 dev_err(&spi->dev, "failed to register.\n");
288                 ret = PTR_ERR(rtc);
289                 goto kfree_exit;
290         }
291
292         pdata->rtc = rtc;
293
294         for (i = 0; i < 16; i++) {
295                 sprintf(pdata->regs[i].name, "%1x", i);
296                 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
297                 pdata->regs[i].attr.attr.name = pdata->regs[i].name;
298                 pdata->regs[i].attr.show = pcf2123_show;
299                 pdata->regs[i].attr.store = pcf2123_store;
300                 ret = device_create_file(&spi->dev, &pdata->regs[i].attr);
301                 if (ret) {
302                         dev_err(&spi->dev, "Unable to create sysfs %s\n",
303                                 pdata->regs[i].name);
304                         goto sysfs_exit;
305                 }
306         }
307
308         return 0;
309
310 sysfs_exit:
311         for (i--; i >= 0; i--)
312                 device_remove_file(&spi->dev, &pdata->regs[i].attr);
313
314 kfree_exit:
315         kfree(pdata);
316         spi->dev.platform_data = NULL;
317         return ret;
318 }
319
320 static int __devexit pcf2123_remove(struct spi_device *spi)
321 {
322         struct pcf2123_plat_data *pdata = spi->dev.platform_data;
323         int i;
324
325         if (pdata) {
326                 struct rtc_device *rtc = pdata->rtc;
327
328                 if (rtc)
329                         rtc_device_unregister(rtc);
330                 for (i = 0; i < 16; i++)
331                         if (pdata->regs[i].name[0])
332                                 device_remove_file(&spi->dev,
333                                                    &pdata->regs[i].attr);
334                 kfree(pdata);
335         }
336
337         return 0;
338 }
339
340 static struct spi_driver pcf2123_driver = {
341         .driver = {
342                         .name   = "rtc-pcf2123",
343                         .bus    = &spi_bus_type,
344                         .owner  = THIS_MODULE,
345         },
346         .probe  = pcf2123_probe,
347         .remove = __devexit_p(pcf2123_remove),
348 };
349
350 static int __init pcf2123_init(void)
351 {
352         return spi_register_driver(&pcf2123_driver);
353 }
354
355 static void __exit pcf2123_exit(void)
356 {
357         spi_unregister_driver(&pcf2123_driver);
358 }
359
360 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
361 MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
362 MODULE_LICENSE("GPL");
363 MODULE_VERSION(DRV_VERSION);
364
365 module_init(pcf2123_init);
366 module_exit(pcf2123_exit);