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/drivers/i2c/chips/m41t00.c

https://bitbucket.org/evzijst/gittest
C | 246 lines | 179 code | 41 blank | 26 comment | 34 complexity | 287e3e269cd50b2d37254d6d8b67b84b MD5 | raw file
  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");