ARM: tegra30: pm: flush L1 data before exit coherency on secondary CPU
[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/slab.h>
43 #include <linux/rtc.h>
44 #include <linux/spi/spi.h>
45
46 #define DRV_VERSION "0.6"
47
48 #define PCF2123_REG_CTRL1       (0x00)  /* Control Register 1 */
49 #define PCF2123_REG_CTRL2       (0x01)  /* Control Register 2 */
50 #define PCF2123_REG_SC          (0x02)  /* datetime */
51 #define PCF2123_REG_MN          (0x03)
52 #define PCF2123_REG_HR          (0x04)
53 #define PCF2123_REG_DM          (0x05)
54 #define PCF2123_REG_DW          (0x06)
55 #define PCF2123_REG_MO          (0x07)
56 #define PCF2123_REG_YR          (0x08)
57
58 #define PCF2123_SUBADDR         (1 << 4)
59 #define PCF2123_WRITE           ((0 << 7) | PCF2123_SUBADDR)
60 #define PCF2123_READ            ((1 << 7) | PCF2123_SUBADDR)
61
62 static struct spi_driver pcf2123_driver;
63
64 struct pcf2123_sysfs_reg {
65         struct device_attribute attr;
66         char name[2];
67 };
68
69 struct pcf2123_plat_data {
70         struct rtc_device *rtc;
71         struct pcf2123_sysfs_reg regs[16];
72 };
73
74 /*
75  * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select
76  * is released properly after an SPI write.  This function should be
77  * called after EVERY read/write call over SPI.
78  */
79 static inline void pcf2123_delay_trec(void)
80 {
81         ndelay(30);
82 }
83
84 static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
85                             char *buffer)
86 {
87         struct spi_device *spi = to_spi_device(dev);
88         struct pcf2123_sysfs_reg *r;
89         u8 txbuf[1], rxbuf[1];
90         unsigned long reg;
91         int ret;
92
93         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
94
95         if (strict_strtoul(r->name, 16, &reg))
96                 return -EINVAL;
97
98         txbuf[0] = PCF2123_READ | reg;
99         ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
100         if (ret < 0)
101                 return -EIO;
102         pcf2123_delay_trec();
103         return sprintf(buffer, "0x%x\n", rxbuf[0]);
104 }
105
106 static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
107                              const char *buffer, size_t count) {
108         struct spi_device *spi = to_spi_device(dev);
109         struct pcf2123_sysfs_reg *r;
110         u8 txbuf[2];
111         unsigned long reg;
112         unsigned long val;
113
114         int ret;
115
116         r = container_of(attr, struct pcf2123_sysfs_reg, attr);
117
118         if (strict_strtoul(r->name, 16, &reg)
119                 || strict_strtoul(buffer, 10, &val))
120                 return -EINVAL;
121
122         txbuf[0] = PCF2123_WRITE | reg;
123         txbuf[1] = val;
124         ret = spi_write(spi, txbuf, sizeof(txbuf));
125         if (ret < 0)
126                 return -EIO;
127         pcf2123_delay_trec();
128         return count;
129 }
130
131 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
132 {
133         struct spi_device *spi = to_spi_device(dev);
134         u8 txbuf[1], rxbuf[7];
135         int ret;
136
137         txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
138         ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
139                         rxbuf, sizeof(rxbuf));
140         if (ret < 0)
141                 return ret;
142         pcf2123_delay_trec();
143
144         tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
145         tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
146         tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */
147         tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
148         tm->tm_wday = rxbuf[4] & 0x07;
149         tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */
150         tm->tm_year = bcd2bin(rxbuf[6]);
151         if (tm->tm_year < 70)
152                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
153
154         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
155                         "mday=%d, mon=%d, year=%d, wday=%d\n",
156                         __func__,
157                         tm->tm_sec, tm->tm_min, tm->tm_hour,
158                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
159
160         /* the clock can give out invalid datetime, but we cannot return
161          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
162          */
163         if (rtc_valid_tm(tm) < 0)
164                 dev_err(dev, "retrieved date/time is not valid.\n");
165
166         return 0;
167 }
168
169 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
170 {
171         struct spi_device *spi = to_spi_device(dev);
172         u8 txbuf[8];
173         int ret;
174
175         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
176                         "mday=%d, mon=%d, year=%d, wday=%d\n",
177                         __func__,
178                         tm->tm_sec, tm->tm_min, tm->tm_hour,
179                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
180
181         /* Stop the counter first */
182         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
183         txbuf[1] = 0x20;
184         ret = spi_write(spi, txbuf, 2);
185         if (ret < 0)
186                 return ret;
187         pcf2123_delay_trec();
188
189         /* Set the new time */
190         txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
191         txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
192         txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
193         txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
194         txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);
195         txbuf[5] = tm->tm_wday & 0x07;
196         txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */
197         txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
198
199         ret = spi_write(spi, txbuf, sizeof(txbuf));
200         if (ret < 0)
201                 return ret;
202         pcf2123_delay_trec();
203
204         /* Start the counter */
205         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
206         txbuf[1] = 0x00;
207         ret = spi_write(spi, txbuf, 2);
208         if (ret < 0)
209                 return ret;
210         pcf2123_delay_trec();
211
212         return 0;
213 }
214
215 static const struct rtc_class_ops pcf2123_rtc_ops = {
216         .read_time      = pcf2123_rtc_read_time,
217         .set_time       = pcf2123_rtc_set_time,
218 };
219
220 static int __devinit pcf2123_probe(struct spi_device *spi)
221 {
222         struct rtc_device *rtc;
223         struct pcf2123_plat_data *pdata;
224         u8 txbuf[2], rxbuf[2];
225         int ret, i;
226
227         pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL);
228         if (!pdata)
229                 return -ENOMEM;
230         spi->dev.platform_data = pdata;
231
232         /* Send a software reset command */
233         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
234         txbuf[1] = 0x58;
235         dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
236                         txbuf[0], txbuf[1]);
237         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
238         if (ret < 0)
239                 goto kfree_exit;
240         pcf2123_delay_trec();
241
242         /* Stop the counter */
243         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
244         txbuf[1] = 0x20;
245         dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
246                         txbuf[0], txbuf[1]);
247         ret = spi_write(spi, txbuf, 2 * sizeof(u8));
248         if (ret < 0)
249                 goto kfree_exit;
250         pcf2123_delay_trec();
251
252         /* See if the counter was actually stopped */
253         txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
254         dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
255                         txbuf[0]);
256         ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
257                                         rxbuf, 2 * sizeof(u8));
258         dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
259                         rxbuf[0], rxbuf[1]);
260         if (ret < 0)
261                 goto kfree_exit;
262         pcf2123_delay_trec();
263
264         if (!(rxbuf[0] & 0x20)) {
265                 dev_err(&spi->dev, "chip not found\n");
266                 goto kfree_exit;
267         }
268
269         dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
270         dev_info(&spi->dev, "spiclk %u KHz.\n",
271                         (spi->max_speed_hz + 500) / 1000);
272
273         /* Start the counter */
274         txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
275         txbuf[1] = 0x00;
276         ret = spi_write(spi, txbuf, sizeof(txbuf));
277         if (ret < 0)
278                 goto kfree_exit;
279         pcf2123_delay_trec();
280
281         /* Finalize the initialization */
282         rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev,
283                         &pcf2123_rtc_ops, THIS_MODULE);
284
285         if (IS_ERR(rtc)) {
286                 dev_err(&spi->dev, "failed to register.\n");
287                 ret = PTR_ERR(rtc);
288                 goto kfree_exit;
289         }
290
291         pdata->rtc = rtc;
292
293         for (i = 0; i < 16; i++) {
294                 sprintf(pdata->regs[i].name, "%1x", i);
295                 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
296                 pdata->regs[i].attr.attr.name = pdata->regs[i].name;
297                 pdata->regs[i].attr.show = pcf2123_show;
298                 pdata->regs[i].attr.store = pcf2123_store;
299                 ret = device_create_file(&spi->dev, &pdata->regs[i].attr);
300                 if (ret) {
301                         dev_err(&spi->dev, "Unable to create sysfs %s\n",
302                                 pdata->regs[i].name);
303                         goto sysfs_exit;
304                 }
305         }
306
307         return 0;
308
309 sysfs_exit:
310         for (i--; i >= 0; i--)
311                 device_remove_file(&spi->dev, &pdata->regs[i].attr);
312
313 kfree_exit:
314         kfree(pdata);
315         spi->dev.platform_data = NULL;
316         return ret;
317 }
318
319 static int __devexit pcf2123_remove(struct spi_device *spi)
320 {
321         struct pcf2123_plat_data *pdata = spi->dev.platform_data;
322         int i;
323
324         if (pdata) {
325                 struct rtc_device *rtc = pdata->rtc;
326
327                 if (rtc)
328                         rtc_device_unregister(rtc);
329                 for (i = 0; i < 16; i++)
330                         if (pdata->regs[i].name[0])
331                                 device_remove_file(&spi->dev,
332                                                    &pdata->regs[i].attr);
333                 kfree(pdata);
334         }
335
336         return 0;
337 }
338
339 static struct spi_driver pcf2123_driver = {
340         .driver = {
341                         .name   = "rtc-pcf2123",
342                         .bus    = &spi_bus_type,
343                         .owner  = THIS_MODULE,
344         },
345         .probe  = pcf2123_probe,
346         .remove = __devexit_p(pcf2123_remove),
347 };
348
349 static int __init pcf2123_init(void)
350 {
351         return spi_register_driver(&pcf2123_driver);
352 }
353
354 static void __exit pcf2123_exit(void)
355 {
356         spi_unregister_driver(&pcf2123_driver);
357 }
358
359 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
360 MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
361 MODULE_LICENSE("GPL");
362 MODULE_VERSION(DRV_VERSION);
363
364 module_init(pcf2123_init);
365 module_exit(pcf2123_exit);