Pull Kconfig into release branch
[linux-2.6] / drivers / i2c / chips / m41t00.c
1 /*
2  * drivers/i2c/chips/m41t00.c
3  *
4  * I2C client/driver for the ST M41T00 Real-Time Clock chip.
5  *
6  * Author: Mark A. Greer <mgreer@mvista.com>
7  *
8  * 2005 (c) MontaVista Software, Inc. This file is licensed under
9  * the terms of the GNU General Public License version 2. This program
10  * is licensed "as is" without any warranty of any kind, whether express
11  * or implied.
12  */
13 /*
14  * This i2c client/driver wedges between the drivers/char/genrtc.c RTC
15  * interface and the SMBus interface of the i2c subsystem.
16  * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
17  * recommened in .../Documentation/i2c/writing-clients section
18  * "Sending and receiving", using SMBus level communication is preferred.
19  */
20
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/interrupt.h>
24 #include <linux/i2c.h>
25 #include <linux/rtc.h>
26 #include <linux/bcd.h>
27 #include <linux/mutex.h>
28 #include <linux/workqueue.h>
29
30 #include <asm/time.h>
31 #include <asm/rtc.h>
32
33 #define M41T00_DRV_NAME         "m41t00"
34
35 static DEFINE_MUTEX(m41t00_mutex);
36
37 static struct i2c_driver m41t00_driver;
38 static struct i2c_client *save_client;
39
40 static unsigned short ignore[] = { I2C_CLIENT_END };
41 static unsigned short normal_addr[] = { 0x68, I2C_CLIENT_END };
42
43 static struct i2c_client_address_data addr_data = {
44         .normal_i2c             = normal_addr,
45         .probe                  = ignore,
46         .ignore                 = ignore,
47 };
48
49 ulong
50 m41t00_get_rtc_time(void)
51 {
52         s32     sec, min, hour, day, mon, year;
53         s32     sec1, min1, hour1, day1, mon1, year1;
54         ulong   limit = 10;
55
56         sec = min = hour = day = mon = year = 0;
57         sec1 = min1 = hour1 = day1 = mon1 = year1 = 0;
58
59         mutex_lock(&m41t00_mutex);
60         do {
61                 if (((sec = i2c_smbus_read_byte_data(save_client, 0)) >= 0)
62                         && ((min = i2c_smbus_read_byte_data(save_client, 1))
63                                 >= 0)
64                         && ((hour = i2c_smbus_read_byte_data(save_client, 2))
65                                 >= 0)
66                         && ((day = i2c_smbus_read_byte_data(save_client, 4))
67                                 >= 0)
68                         && ((mon = i2c_smbus_read_byte_data(save_client, 5))
69                                 >= 0)
70                         && ((year = i2c_smbus_read_byte_data(save_client, 6))
71                                 >= 0)
72                         && ((sec == sec1) && (min == min1) && (hour == hour1)
73                                 && (day == day1) && (mon == mon1)
74                                 && (year == year1)))
75
76                                 break;
77
78                 sec1 = sec;
79                 min1 = min;
80                 hour1 = hour;
81                 day1 = day;
82                 mon1 = mon;
83                 year1 = year;
84         } while (--limit > 0);
85         mutex_unlock(&m41t00_mutex);
86
87         if (limit == 0) {
88                 dev_warn(&save_client->dev,
89                         "m41t00: can't read rtc chip\n");
90                 sec = min = hour = day = mon = year = 0;
91         }
92
93         sec &= 0x7f;
94         min &= 0x7f;
95         hour &= 0x3f;
96         day &= 0x3f;
97         mon &= 0x1f;
98         year &= 0xff;
99
100         BCD_TO_BIN(sec);
101         BCD_TO_BIN(min);
102         BCD_TO_BIN(hour);
103         BCD_TO_BIN(day);
104         BCD_TO_BIN(mon);
105         BCD_TO_BIN(year);
106
107         year += 1900;
108         if (year < 1970)
109                 year += 100;
110
111         return mktime(year, mon, day, hour, min, sec);
112 }
113
114 static void
115 m41t00_set(void *arg)
116 {
117         struct rtc_time tm;
118         ulong   nowtime = *(ulong *)arg;
119
120         to_tm(nowtime, &tm);
121         tm.tm_year = (tm.tm_year - 1900) % 100;
122
123         BIN_TO_BCD(tm.tm_sec);
124         BIN_TO_BCD(tm.tm_min);
125         BIN_TO_BCD(tm.tm_hour);
126         BIN_TO_BCD(tm.tm_mon);
127         BIN_TO_BCD(tm.tm_mday);
128         BIN_TO_BCD(tm.tm_year);
129
130         mutex_lock(&m41t00_mutex);
131         if ((i2c_smbus_write_byte_data(save_client, 0, tm.tm_sec & 0x7f) < 0)
132                 || (i2c_smbus_write_byte_data(save_client, 1, tm.tm_min & 0x7f)
133                         < 0)
134                 || (i2c_smbus_write_byte_data(save_client, 2, tm.tm_hour & 0x3f)
135                         < 0)
136                 || (i2c_smbus_write_byte_data(save_client, 4, tm.tm_mday & 0x3f)
137                         < 0)
138                 || (i2c_smbus_write_byte_data(save_client, 5, tm.tm_mon & 0x1f)
139                         < 0)
140                 || (i2c_smbus_write_byte_data(save_client, 6, tm.tm_year & 0xff)
141                         < 0))
142
143                 dev_warn(&save_client->dev,"m41t00: can't write to rtc chip\n");
144
145         mutex_unlock(&m41t00_mutex);
146         return;
147 }
148
149 static ulong new_time;
150 static struct workqueue_struct *m41t00_wq;
151 static DECLARE_WORK(m41t00_work, m41t00_set, &new_time);
152
153 int
154 m41t00_set_rtc_time(ulong nowtime)
155 {
156         new_time = nowtime;
157
158         if (in_interrupt())
159                 queue_work(m41t00_wq, &m41t00_work);
160         else
161                 m41t00_set(&new_time);
162
163         return 0;
164 }
165
166 /*
167  *****************************************************************************
168  *
169  *      Driver Interface
170  *
171  *****************************************************************************
172  */
173 static int
174 m41t00_probe(struct i2c_adapter *adap, int addr, int kind)
175 {
176         struct i2c_client *client;
177         int rc;
178
179         client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
180         if (!client)
181                 return -ENOMEM;
182
183         strncpy(client->name, M41T00_DRV_NAME, I2C_NAME_SIZE);
184         client->addr = addr;
185         client->adapter = adap;
186         client->driver = &m41t00_driver;
187
188         if ((rc = i2c_attach_client(client)) != 0) {
189                 kfree(client);
190                 return rc;
191         }
192
193         m41t00_wq = create_singlethread_workqueue("m41t00");
194         save_client = client;
195         return 0;
196 }
197
198 static int
199 m41t00_attach(struct i2c_adapter *adap)
200 {
201         return i2c_probe(adap, &addr_data, m41t00_probe);
202 }
203
204 static int
205 m41t00_detach(struct i2c_client *client)
206 {
207         int     rc;
208
209         if ((rc = i2c_detach_client(client)) == 0) {
210                 kfree(client);
211                 destroy_workqueue(m41t00_wq);
212         }
213         return rc;
214 }
215
216 static struct i2c_driver m41t00_driver = {
217         .driver = {
218                 .name   = M41T00_DRV_NAME,
219         },
220         .id             = I2C_DRIVERID_STM41T00,
221         .attach_adapter = m41t00_attach,
222         .detach_client  = m41t00_detach,
223 };
224
225 static int __init
226 m41t00_init(void)
227 {
228         return i2c_add_driver(&m41t00_driver);
229 }
230
231 static void __exit
232 m41t00_exit(void)
233 {
234         i2c_del_driver(&m41t00_driver);
235         return;
236 }
237
238 module_init(m41t00_init);
239 module_exit(m41t00_exit);
240
241 MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
242 MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver");
243 MODULE_LICENSE("GPL");