2 * I2C client/driver for the ST M41T00 family of i2c rtc chips.
4 * Author: Mark A. Greer <mgreer@mvista.com>
6 * 2005, 2006 (c) MontaVista Software, Inc. This file is licensed under
7 * the terms of the GNU General Public License version 2. This program
8 * is licensed "as is" without any warranty of any kind, whether express
12 * This i2c client/driver wedges between the drivers/char/genrtc.c RTC
13 * interface and the SMBus interface of the i2c subsystem.
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/interrupt.h>
19 #include <linux/i2c.h>
20 #include <linux/rtc.h>
21 #include <linux/bcd.h>
22 #include <linux/workqueue.h>
23 #include <linux/platform_device.h>
24 #include <linux/m41t00.h>
28 static struct i2c_driver m41t00_driver;
29 static struct i2c_client *save_client;
31 static unsigned short ignore[] = { I2C_CLIENT_END };
32 static unsigned short normal_addr[] = { I2C_CLIENT_END, I2C_CLIENT_END };
34 static struct i2c_client_address_data addr_data = {
35 .normal_i2c = normal_addr,
40 struct m41t00_chip_info {
44 u8 sec; /* Offsets for chip regs */
56 static struct m41t00_chip_info m41t00_chip_info_tbl[] = {
58 .type = M41T00_TYPE_M41T00,
69 .type = M41T00_TYPE_M41T81,
83 .type = M41T00_TYPE_M41T85,
97 static struct m41t00_chip_info *m41t00_chip;
100 m41t00_get_rtc_time(void)
102 s32 sec, min, hour, day, mon, year;
103 s32 sec1, min1, hour1, day1, mon1, year1;
105 u8 buf[8], msgbuf[1] = { 0 }; /* offset into rtc's regs */
106 struct i2c_msg msgs[] = {
108 .addr = save_client->addr,
114 .addr = save_client->addr,
121 sec = min = hour = day = mon = year = 0;
124 if (i2c_transfer(save_client->adapter, msgs, 2) < 0)
134 sec = buf[m41t00_chip->sec] & 0x7f;
135 min = buf[m41t00_chip->min] & 0x7f;
136 hour = buf[m41t00_chip->hour] & 0x3f;
137 day = buf[m41t00_chip->day] & 0x3f;
138 mon = buf[m41t00_chip->mon] & 0x1f;
139 year = buf[m41t00_chip->year];
140 } while ((++reads < m41t00_chip->read_limit) && ((sec != sec1)
141 || (min != min1) || (hour != hour1) || (day != day1)
142 || (mon != mon1) || (year != year1)));
144 if ((m41t00_chip->read_limit > 1) && ((sec != sec1) || (min != min1)
145 || (hour != hour1) || (day != day1) || (mon != mon1)
151 hour = BCD2BIN(hour);
154 year = BCD2BIN(year);
160 return mktime(year, mon, day, hour, min, sec);
163 dev_err(&save_client->dev, "m41t00_get_rtc_time: Read error\n");
166 EXPORT_SYMBOL_GPL(m41t00_get_rtc_time);
169 m41t00_set(void *arg)
172 int nowtime = *(int *)arg;
173 s32 sec, min, hour, day, mon, year;
174 u8 wbuf[9], *buf = &wbuf[1], msgbuf[1] = { 0 };
175 struct i2c_msg msgs[] = {
177 .addr = save_client->addr,
183 .addr = save_client->addr,
191 tm.tm_year = (tm.tm_year - 1900) % 100;
193 sec = BIN2BCD(tm.tm_sec);
194 min = BIN2BCD(tm.tm_min);
195 hour = BIN2BCD(tm.tm_hour);
196 day = BIN2BCD(tm.tm_mday);
197 mon = BIN2BCD(tm.tm_mon);
198 year = BIN2BCD(tm.tm_year);
200 /* Read reg values into buf[0..7]/wbuf[1..8] */
201 if (i2c_transfer(save_client->adapter, msgs, 2) < 0) {
202 dev_err(&save_client->dev, "m41t00_set: Read error\n");
206 wbuf[0] = 0; /* offset into rtc's regs */
207 buf[m41t00_chip->sec] = (buf[m41t00_chip->sec] & ~0x7f) | (sec & 0x7f);
208 buf[m41t00_chip->min] = (buf[m41t00_chip->min] & ~0x7f) | (min & 0x7f);
209 buf[m41t00_chip->hour] = (buf[m41t00_chip->hour] & ~0x3f) | (hour& 0x3f);
210 buf[m41t00_chip->day] = (buf[m41t00_chip->day] & ~0x3f) | (day & 0x3f);
211 buf[m41t00_chip->mon] = (buf[m41t00_chip->mon] & ~0x1f) | (mon & 0x1f);
213 if (i2c_master_send(save_client, wbuf, 9) < 0)
214 dev_err(&save_client->dev, "m41t00_set: Write error\n");
217 static ulong new_time;
218 /* well, isn't this API just _lovely_? */
220 m41t00_barf(struct work_struct *unusable)
222 m41t00_set(&new_time);
225 static struct workqueue_struct *m41t00_wq;
226 static DECLARE_WORK(m41t00_work, m41t00_barf);
229 m41t00_set_rtc_time(ulong nowtime)
234 queue_work(m41t00_wq, &m41t00_work);
236 m41t00_set(&new_time);
240 EXPORT_SYMBOL_GPL(m41t00_set_rtc_time);
243 *****************************************************************************
245 * platform_data Driver Interface
247 *****************************************************************************
250 m41t00_platform_probe(struct platform_device *pdev)
252 struct m41t00_platform_data *pdata;
255 if (pdev && (pdata = pdev->dev.platform_data)) {
256 normal_addr[0] = pdata->i2c_addr;
258 for (i=0; i<ARRAY_SIZE(m41t00_chip_info_tbl); i++)
259 if (m41t00_chip_info_tbl[i].type == pdata->type) {
260 m41t00_chip = &m41t00_chip_info_tbl[i];
261 m41t00_chip->sqw_freq = pdata->sqw_freq;
269 m41t00_platform_remove(struct platform_device *pdev)
274 static struct platform_driver m41t00_platform_driver = {
275 .probe = m41t00_platform_probe,
276 .remove = m41t00_platform_remove,
278 .owner = THIS_MODULE,
279 .name = M41T00_DRV_NAME,
284 *****************************************************************************
288 *****************************************************************************
291 m41t00_probe(struct i2c_adapter *adap, int addr, int kind)
293 struct i2c_client *client;
296 if (!i2c_check_functionality(adap, I2C_FUNC_I2C
297 | I2C_FUNC_SMBUS_BYTE_DATA))
300 client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
304 strlcpy(client->name, m41t00_chip->name, I2C_NAME_SIZE);
306 client->adapter = adap;
307 client->driver = &m41t00_driver;
309 if ((rc = i2c_attach_client(client)))
312 if (m41t00_chip->type != M41T00_TYPE_M41T00) {
313 /* If asked, disable SQW, set SQW frequency & re-enable */
314 if (m41t00_chip->sqw_freq)
315 if (((rc = i2c_smbus_read_byte_data(client,
316 m41t00_chip->alarm_mon)) < 0)
317 || ((rc = i2c_smbus_write_byte_data(client,
318 m41t00_chip->alarm_mon, rc & ~0x40)) <0)
319 || ((rc = i2c_smbus_write_byte_data(client,
321 m41t00_chip->sqw_freq)) < 0)
322 || ((rc = i2c_smbus_write_byte_data(client,
323 m41t00_chip->alarm_mon, rc | 0x40)) <0))
326 /* Make sure HT (Halt Update) bit is cleared */
327 if ((rc = i2c_smbus_read_byte_data(client,
328 m41t00_chip->alarm_hour)) < 0)
332 if ((rc = i2c_smbus_write_byte_data(client,
333 m41t00_chip->alarm_hour, rc & ~0x40))<0)
337 /* Make sure ST (stop) bit is cleared */
338 if ((rc = i2c_smbus_read_byte_data(client, m41t00_chip->sec)) < 0)
342 if ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->sec,
346 m41t00_wq = create_singlethread_workqueue(m41t00_chip->name);
347 save_client = client;
351 dev_err(&client->dev, "m41t00_probe: Can't clear ST bit\n");
354 dev_err(&client->dev, "m41t00_probe: Can't clear HT bit\n");
357 dev_err(&client->dev, "m41t00_probe: Can't set SQW Frequency\n");
364 m41t00_attach(struct i2c_adapter *adap)
366 return i2c_probe(adap, &addr_data, m41t00_probe);
370 m41t00_detach(struct i2c_client *client)
374 if ((rc = i2c_detach_client(client)) == 0) {
376 destroy_workqueue(m41t00_wq);
381 static struct i2c_driver m41t00_driver = {
383 .name = M41T00_DRV_NAME,
385 .id = I2C_DRIVERID_STM41T00,
386 .attach_adapter = m41t00_attach,
387 .detach_client = m41t00_detach,
395 if (!(rc = platform_driver_register(&m41t00_platform_driver)))
396 rc = i2c_add_driver(&m41t00_driver);
403 i2c_del_driver(&m41t00_driver);
404 platform_driver_unregister(&m41t00_platform_driver);
407 module_init(m41t00_init);
408 module_exit(m41t00_exit);
410 MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
411 MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver");
412 MODULE_LICENSE("GPL");