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Chris Verges7f3923a2009-09-22 16:46:20 -07001/*
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
Chris Vergesf3d2570a2009-09-22 16:46:22 -070045#define DRV_VERSION "0.6"
Chris Verges7f3923a2009-09-22 16:46:20 -070046
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 {
Chris Vergesf3d2570a2009-09-22 16:46:22 -070064 struct device_attribute attr;
Chris Verges7f3923a2009-09-22 16:46:20 -070065 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);
Chris Vergesf3d2570a2009-09-22 16:46:22 -070087 struct pcf2123_sysfs_reg *r;
Chris Verges7f3923a2009-09-22 16:46:20 -070088 u8 txbuf[1], rxbuf[1];
Chris Vergesf3d2570a2009-09-22 16:46:22 -070089 unsigned long reg;
Chris Verges7f3923a2009-09-22 16:46:20 -070090 int ret;
91
Chris Vergesf3d2570a2009-09-22 16:46:22 -070092 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;
Chris Verges7f3923a2009-09-22 16:46:20 -070098 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
99 if (ret < 0)
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700100 return -EIO;
Chris Verges7f3923a2009-09-22 16:46:20 -0700101 pcf2123_delay_trec();
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700102 return sprintf(buffer, "0x%x\n", rxbuf[0]);
Chris Verges7f3923a2009-09-22 16:46:20 -0700103}
104
105static 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);
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700108 struct pcf2123_sysfs_reg *r;
Chris Verges7f3923a2009-09-22 16:46:20 -0700109 u8 txbuf[2];
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700110 unsigned long reg;
111 unsigned long val;
112
Chris Verges7f3923a2009-09-22 16:46:20 -0700113 int ret;
114
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700115 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;
Chris Verges7f3923a2009-09-22 16:46:20 -0700123 ret = spi_write(spi, txbuf, sizeof(txbuf));
124 if (ret < 0)
125 return -EIO;
126 pcf2123_delay_trec();
127 return count;
128}
129
130static 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
168static 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
214static const struct rtc_class_ops pcf2123_rtc_ops = {
215 .read_time = pcf2123_rtc_read_time,
216 .set_time = pcf2123_rtc_set_time,
217};
218
219static 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)
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700238 goto kfree_exit;
Chris Verges7f3923a2009-09-22 16:46:20 -0700239 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)
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700248 goto kfree_exit;
Chris Verges7f3923a2009-09-22 16:46:20 -0700249 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);
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700302 goto sysfs_exit;
Chris Verges7f3923a2009-09-22 16:46:20 -0700303 }
304 }
305
306 return 0;
Chris Vergesf3d2570a2009-09-22 16:46:22 -0700307
308sysfs_exit:
309 for (i--; i >= 0; i--)
310 device_remove_file(&spi->dev, &pdata->regs[i].attr);
311
Chris Verges7f3923a2009-09-22 16:46:20 -0700312kfree_exit:
313 kfree(pdata);
314 spi->dev.platform_data = NULL;
315 return ret;
316}
317
318static 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
338static 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
348static int __init pcf2123_init(void)
349{
350 return spi_register_driver(&pcf2123_driver);
351}
352
353static void __exit pcf2123_exit(void)
354{
355 spi_unregister_driver(&pcf2123_driver);
356}
357
358MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
359MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
360MODULE_LICENSE("GPL");
361MODULE_VERSION(DRV_VERSION);
362
363module_init(pcf2123_init);
364module_exit(pcf2123_exit);