2 * An SPI driver for the Philips PCF2123 RTC
3 * Copyright 2009 Cyber Switching, Inc.
5 * Author: Chris Verges <chrisv@cyberswitching.com>
6 * Maintainers: http://www.cyberswitching.com
8 * based on the RS5C348 driver in this same directory.
10 * Thanks to Christian Pellegrin <chripell@fsfe.org> for
11 * the sysfs contributions to this driver.
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.
17 * Please note that the CS is active high, so platform data
18 * should look something like:
20 * static struct spi_board_info ek_spi_devices[] = {
23 * .modalias = "rtc-pcf2123",
25 * .controller_data = (void *)AT91_PIN_PA10,
26 * .max_speed_hz = 1000 * 1000,
27 * .mode = SPI_CS_HIGH,
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>
46 #define DRV_VERSION "0.6"
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)
58 #define PCF2123_SUBADDR (1 << 4)
59 #define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR)
60 #define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR)
62 static struct spi_driver pcf2123_driver;
64 struct pcf2123_sysfs_reg {
65 struct device_attribute attr;
69 struct pcf2123_plat_data {
70 struct rtc_device *rtc;
71 struct pcf2123_sysfs_reg regs[16];
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.
79 static inline void pcf2123_delay_trec(void)
84 static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
87 struct spi_device *spi = to_spi_device(dev);
88 struct pcf2123_sysfs_reg *r;
89 u8 txbuf[1], rxbuf[1];
93 r = container_of(attr, struct pcf2123_sysfs_reg, attr);
95 if (strict_strtoul(r->name, 16, ®))
98 txbuf[0] = PCF2123_READ | reg;
99 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
102 pcf2123_delay_trec();
103 return sprintf(buffer, "0x%x\n", rxbuf[0]);
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;
116 r = container_of(attr, struct pcf2123_sysfs_reg, attr);
118 if (strict_strtoul(r->name, 16, ®)
119 || strict_strtoul(buffer, 10, &val))
122 txbuf[0] = PCF2123_WRITE | reg;
124 ret = spi_write(spi, txbuf, sizeof(txbuf));
127 pcf2123_delay_trec();
131 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
133 struct spi_device *spi = to_spi_device(dev);
134 u8 txbuf[1], rxbuf[7];
137 txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
138 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
139 rxbuf, sizeof(rxbuf));
142 pcf2123_delay_trec();
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 */
154 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
155 "mday=%d, mon=%d, year=%d, wday=%d\n",
157 tm->tm_sec, tm->tm_min, tm->tm_hour,
158 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
160 /* the clock can give out invalid datetime, but we cannot return
161 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
163 if (rtc_valid_tm(tm) < 0)
164 dev_err(dev, "retrieved date/time is not valid.\n");
169 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
171 struct spi_device *spi = to_spi_device(dev);
175 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
176 "mday=%d, mon=%d, year=%d, wday=%d\n",
178 tm->tm_sec, tm->tm_min, tm->tm_hour,
179 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
181 /* Stop the counter first */
182 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
184 ret = spi_write(spi, txbuf, 2);
187 pcf2123_delay_trec();
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);
199 ret = spi_write(spi, txbuf, sizeof(txbuf));
202 pcf2123_delay_trec();
204 /* Start the counter */
205 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
207 ret = spi_write(spi, txbuf, 2);
210 pcf2123_delay_trec();
215 static const struct rtc_class_ops pcf2123_rtc_ops = {
216 .read_time = pcf2123_rtc_read_time,
217 .set_time = pcf2123_rtc_set_time,
220 static int __devinit pcf2123_probe(struct spi_device *spi)
222 struct rtc_device *rtc;
223 struct pcf2123_plat_data *pdata;
224 u8 txbuf[2], rxbuf[2];
227 pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL);
230 spi->dev.platform_data = pdata;
232 /* Send a software reset command */
233 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
235 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
237 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
240 pcf2123_delay_trec();
242 /* Stop the counter */
243 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
245 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
247 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
250 pcf2123_delay_trec();
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",
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",
262 pcf2123_delay_trec();
264 if (!(rxbuf[0] & 0x20)) {
265 dev_err(&spi->dev, "chip not found\n");
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);
273 /* Start the counter */
274 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
276 ret = spi_write(spi, txbuf, sizeof(txbuf));
279 pcf2123_delay_trec();
281 /* Finalize the initialization */
282 rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev,
283 &pcf2123_rtc_ops, THIS_MODULE);
286 dev_err(&spi->dev, "failed to register.\n");
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);
301 dev_err(&spi->dev, "Unable to create sysfs %s\n",
302 pdata->regs[i].name);
310 for (i--; i >= 0; i--)
311 device_remove_file(&spi->dev, &pdata->regs[i].attr);
315 spi->dev.platform_data = NULL;
319 static int __devexit pcf2123_remove(struct spi_device *spi)
321 struct pcf2123_plat_data *pdata = spi->dev.platform_data;
325 struct rtc_device *rtc = pdata->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);
339 static struct spi_driver pcf2123_driver = {
341 .name = "rtc-pcf2123",
342 .bus = &spi_bus_type,
343 .owner = THIS_MODULE,
345 .probe = pcf2123_probe,
346 .remove = __devexit_p(pcf2123_remove),
349 static int __init pcf2123_init(void)
351 return spi_register_driver(&pcf2123_driver);
354 static void __exit pcf2123_exit(void)
356 spi_unregister_driver(&pcf2123_driver);
359 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
360 MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
361 MODULE_LICENSE("GPL");
362 MODULE_VERSION(DRV_VERSION);
364 module_init(pcf2123_init);
365 module_exit(pcf2123_exit);