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-rw-r--r--drivers/i2c/chips/m41t00.c246
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diff --git a/drivers/i2c/chips/m41t00.c b/drivers/i2c/chips/m41t00.c
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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
28#include <asm/time.h>
29#include <asm/rtc.h>
30
31#define M41T00_DRV_NAME "m41t00"
32
33static DECLARE_MUTEX(m41t00_mutex);
34
35static struct i2c_driver m41t00_driver;
36static struct i2c_client *save_client;
37
38static unsigned short ignore[] = { I2C_CLIENT_END };
39static unsigned short normal_addr[] = { 0x68, I2C_CLIENT_END };
40
41static struct i2c_client_address_data addr_data = {
42 .normal_i2c = normal_addr,
43 .normal_i2c_range = ignore,
44 .probe = ignore,
45 .probe_range = ignore,
46 .ignore = ignore,
47 .ignore_range = ignore,
48 .force = ignore,
49};
50
51ulong
52m41t00_get_rtc_time(void)
53{
54 s32 sec, min, hour, day, mon, year;
55 s32 sec1, min1, hour1, day1, mon1, year1;
56 ulong limit = 10;
57
58 sec = min = hour = day = mon = year = 0;
59 sec1 = min1 = hour1 = day1 = mon1 = year1 = 0;
60
61 down(&m41t00_mutex);
62 do {
63 if (((sec = i2c_smbus_read_byte_data(save_client, 0)) >= 0)
64 && ((min = i2c_smbus_read_byte_data(save_client, 1))
65 >= 0)
66 && ((hour = i2c_smbus_read_byte_data(save_client, 2))
67 >= 0)
68 && ((day = i2c_smbus_read_byte_data(save_client, 4))
69 >= 0)
70 && ((mon = i2c_smbus_read_byte_data(save_client, 5))
71 >= 0)
72 && ((year = i2c_smbus_read_byte_data(save_client, 6))
73 >= 0)
74 && ((sec == sec1) && (min == min1) && (hour == hour1)
75 && (day == day1) && (mon == mon1)
76 && (year == year1)))
77
78 break;
79
80 sec1 = sec;
81 min1 = min;
82 hour1 = hour;
83 day1 = day;
84 mon1 = mon;
85 year1 = year;
86 } while (--limit > 0);
87 up(&m41t00_mutex);
88
89 if (limit == 0) {
90 dev_warn(&save_client->dev,
91 "m41t00: can't read rtc chip\n");
92 sec = min = hour = day = mon = year = 0;
93 }
94
95 sec &= 0x7f;
96 min &= 0x7f;
97 hour &= 0x3f;
98 day &= 0x3f;
99 mon &= 0x1f;
100 year &= 0xff;
101
102 BCD_TO_BIN(sec);
103 BCD_TO_BIN(min);
104 BCD_TO_BIN(hour);
105 BCD_TO_BIN(day);
106 BCD_TO_BIN(mon);
107 BCD_TO_BIN(year);
108
109 year += 1900;
110 if (year < 1970)
111 year += 100;
112
113 return mktime(year, mon, day, hour, min, sec);
114}
115
116static void
117m41t00_set_tlet(ulong arg)
118{
119 struct rtc_time tm;
120 ulong nowtime = *(ulong *)arg;
121
122 to_tm(nowtime, &tm);
123 tm.tm_year = (tm.tm_year - 1900) % 100;
124
125 BIN_TO_BCD(tm.tm_sec);
126 BIN_TO_BCD(tm.tm_min);
127 BIN_TO_BCD(tm.tm_hour);
128 BIN_TO_BCD(tm.tm_mon);
129 BIN_TO_BCD(tm.tm_mday);
130 BIN_TO_BCD(tm.tm_year);
131
132 down(&m41t00_mutex);
133 if ((i2c_smbus_write_byte_data(save_client, 0, tm.tm_sec & 0x7f) < 0)
134 || (i2c_smbus_write_byte_data(save_client, 1, tm.tm_min & 0x7f)
135 < 0)
136 || (i2c_smbus_write_byte_data(save_client, 2, tm.tm_hour & 0x7f)
137 < 0)
138 || (i2c_smbus_write_byte_data(save_client, 4, tm.tm_mday & 0x7f)
139 < 0)
140 || (i2c_smbus_write_byte_data(save_client, 5, tm.tm_mon & 0x7f)
141 < 0)
142 || (i2c_smbus_write_byte_data(save_client, 6, tm.tm_year & 0x7f)
143 < 0))
144
145 dev_warn(&save_client->dev,"m41t00: can't write to rtc chip\n");
146
147 up(&m41t00_mutex);
148 return;
149}
150
151ulong new_time;
152
153DECLARE_TASKLET_DISABLED(m41t00_tasklet, m41t00_set_tlet, (ulong)&new_time);
154
155int
156m41t00_set_rtc_time(ulong nowtime)
157{
158 new_time = nowtime;
159
160 if (in_interrupt())
161 tasklet_schedule(&m41t00_tasklet);
162 else
163 m41t00_set_tlet((ulong)&new_time);
164
165 return 0;
166}
167
168/*
169 *****************************************************************************
170 *
171 * Driver Interface
172 *
173 *****************************************************************************
174 */
175static int
176m41t00_probe(struct i2c_adapter *adap, int addr, int kind)
177{
178 struct i2c_client *client;
179 int rc;
180
181 client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
182 if (!client)
183 return -ENOMEM;
184
185 memset(client, 0, sizeof(struct i2c_client));
186 strncpy(client->name, M41T00_DRV_NAME, I2C_NAME_SIZE);
187 client->flags = I2C_DF_NOTIFY;
188 client->addr = addr;
189 client->adapter = adap;
190 client->driver = &m41t00_driver;
191
192 if ((rc = i2c_attach_client(client)) != 0) {
193 kfree(client);
194 return rc;
195 }
196
197 save_client = client;
198 return 0;
199}
200
201static int
202m41t00_attach(struct i2c_adapter *adap)
203{
204 return i2c_probe(adap, &addr_data, m41t00_probe);
205}
206
207static int
208m41t00_detach(struct i2c_client *client)
209{
210 int rc;
211
212 if ((rc = i2c_detach_client(client)) == 0) {
213 kfree(i2c_get_clientdata(client));
214 tasklet_kill(&m41t00_tasklet);
215 }
216 return rc;
217}
218
219static struct i2c_driver m41t00_driver = {
220 .owner = THIS_MODULE,
221 .name = M41T00_DRV_NAME,
222 .id = I2C_DRIVERID_STM41T00,
223 .flags = I2C_DF_NOTIFY,
224 .attach_adapter = m41t00_attach,
225 .detach_client = m41t00_detach,
226};
227
228static int __init
229m41t00_init(void)
230{
231 return i2c_add_driver(&m41t00_driver);
232}
233
234static void __exit
235m41t00_exit(void)
236{
237 i2c_del_driver(&m41t00_driver);
238 return;
239}
240
241module_init(m41t00_init);
242module_exit(m41t00_exit);
243
244MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
245MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver");
246MODULE_LICENSE("GPL");