2 * Seiko Instruments S-35390A RTC Driver
4 * Copyright (c) 2007 Byron Bradley
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/rtc.h>
14 #include <linux/i2c.h>
15 #include <linux/bitrev.h>
16 #include <linux/bcd.h>
17 #include <linux/slab.h>
19 #define S35390A_CMD_STATUS1 0
20 #define S35390A_CMD_STATUS2 1
21 #define S35390A_CMD_TIME1 2
23 #define S35390A_BYTE_YEAR 0
24 #define S35390A_BYTE_MONTH 1
25 #define S35390A_BYTE_DAY 2
26 #define S35390A_BYTE_WDAY 3
27 #define S35390A_BYTE_HOURS 4
28 #define S35390A_BYTE_MINS 5
29 #define S35390A_BYTE_SECS 6
31 #define S35390A_FLAG_POC 0x01
32 #define S35390A_FLAG_BLD 0x02
33 #define S35390A_FLAG_24H 0x40
34 #define S35390A_FLAG_RESET 0x80
35 #define S35390A_FLAG_TEST 0x01
37 static const struct i2c_device_id s35390a_id[] = {
41 MODULE_DEVICE_TABLE(i2c, s35390a_id);
44 struct i2c_client *client[8];
45 struct rtc_device *rtc;
49 static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
51 struct i2c_client *client = s35390a->client[reg];
52 struct i2c_msg msg[] = {
60 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
66 static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
68 struct i2c_client *client = s35390a->client[reg];
69 struct i2c_msg msg[] = {
78 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
84 static int s35390a_reset(struct s35390a *s35390a)
88 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
91 if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
94 buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
96 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
99 static int s35390a_disable_test_mode(struct s35390a *s35390a)
103 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
106 if (!(buf[0] & S35390A_FLAG_TEST))
109 buf[0] &= ~S35390A_FLAG_TEST;
110 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
113 static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
115 if (s35390a->twentyfourhour)
116 return bin2bcd(hour);
119 return bin2bcd(hour);
121 return 0x40 | bin2bcd(hour - 12);
124 static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
128 if (s35390a->twentyfourhour)
129 return bcd2bin(reg & 0x3f);
131 hour = bcd2bin(reg & 0x3f);
138 static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
140 struct s35390a *s35390a = i2c_get_clientdata(client);
144 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
145 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
146 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
149 buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
150 buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
151 buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
152 buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
153 buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
154 buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
155 buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
157 /* This chip expects the bits of each byte to be in reverse order */
158 for (i = 0; i < 7; ++i)
159 buf[i] = bitrev8(buf[i]);
161 err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
166 static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
168 struct s35390a *s35390a = i2c_get_clientdata(client);
172 err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
176 /* This chip returns the bits of each byte in reverse order */
177 for (i = 0; i < 7; ++i)
178 buf[i] = bitrev8(buf[i]);
180 tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
181 tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
182 tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
183 tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
184 tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
185 tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
186 tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
188 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
189 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
190 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
193 return rtc_valid_tm(tm);
196 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
198 return s35390a_get_datetime(to_i2c_client(dev), tm);
201 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
203 return s35390a_set_datetime(to_i2c_client(dev), tm);
206 static const struct rtc_class_ops s35390a_rtc_ops = {
207 .read_time = s35390a_rtc_read_time,
208 .set_time = s35390a_rtc_set_time,
211 static struct i2c_driver s35390a_driver;
213 static int s35390a_probe(struct i2c_client *client,
214 const struct i2c_device_id *id)
218 struct s35390a *s35390a;
222 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
227 s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL);
233 s35390a->client[0] = client;
234 i2c_set_clientdata(client, s35390a);
236 /* This chip uses multiple addresses, use dummy devices for them */
237 for (i = 1; i < 8; ++i) {
238 s35390a->client[i] = i2c_new_dummy(client->adapter,
240 if (!s35390a->client[i]) {
241 dev_err(&client->dev, "Address %02x unavailable\n",
248 err = s35390a_reset(s35390a);
250 dev_err(&client->dev, "error resetting chip\n");
254 err = s35390a_disable_test_mode(s35390a);
256 dev_err(&client->dev, "error disabling test mode\n");
260 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
262 dev_err(&client->dev, "error checking 12/24 hour mode\n");
265 if (buf[0] & S35390A_FLAG_24H)
266 s35390a->twentyfourhour = 1;
268 s35390a->twentyfourhour = 0;
270 if (s35390a_get_datetime(client, &tm) < 0)
271 dev_warn(&client->dev, "clock needs to be set\n");
273 s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,
274 &client->dev, &s35390a_rtc_ops, THIS_MODULE);
276 if (IS_ERR(s35390a->rtc)) {
277 err = PTR_ERR(s35390a->rtc);
283 for (i = 1; i < 8; ++i)
284 if (s35390a->client[i])
285 i2c_unregister_device(s35390a->client[i]);
292 static int s35390a_remove(struct i2c_client *client)
296 struct s35390a *s35390a = i2c_get_clientdata(client);
297 for (i = 1; i < 8; ++i)
298 if (s35390a->client[i])
299 i2c_unregister_device(s35390a->client[i]);
301 rtc_device_unregister(s35390a->rtc);
307 static struct i2c_driver s35390a_driver = {
309 .name = "rtc-s35390a",
311 .probe = s35390a_probe,
312 .remove = s35390a_remove,
313 .id_table = s35390a_id,
316 module_i2c_driver(s35390a_driver);
318 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
319 MODULE_DESCRIPTION("S35390A RTC driver");
320 MODULE_LICENSE("GPL");