summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/chips/m41t00.c
blob: 420377c86422b229008e11361e079cca6556346e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
/*
 * I2C client/driver for the ST M41T00 family of i2c rtc chips.
 *
 * Author: Mark A. Greer <mgreer@mvista.com>
 *
 * 2005, 2006 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
/*
 * This i2c client/driver wedges between the drivers/char/genrtc.c RTC
 * interface and the SMBus interface of the i2c subsystem.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/m41t00.h>
#include <asm/time.h>
#include <asm/rtc.h>

static struct i2c_driver m41t00_driver;
static struct i2c_client *save_client;

static unsigned short ignore[] = { I2C_CLIENT_END };
static unsigned short normal_addr[] = { I2C_CLIENT_END, I2C_CLIENT_END };

static struct i2c_client_address_data addr_data = {
	.normal_i2c	= normal_addr,
	.probe		= ignore,
	.ignore		= ignore,
};

struct m41t00_chip_info {
	u8	type;
	char	*name;
	u8	read_limit;
	u8	sec;		/* Offsets for chip regs */
	u8	min;
	u8	hour;
	u8	day;
	u8	mon;
	u8	year;
	u8	alarm_mon;
	u8	alarm_hour;
	u8	sqw;
	u8	sqw_freq;
};

static struct m41t00_chip_info m41t00_chip_info_tbl[] = {
	{
		.type		= M41T00_TYPE_M41T00,
		.name		= "m41t00",
		.read_limit	= 5,
		.sec		= 0,
		.min		= 1,
		.hour		= 2,
		.day		= 4,
		.mon		= 5,
		.year		= 6,
	},
	{
		.type		= M41T00_TYPE_M41T81,
		.name		= "m41t81",
		.read_limit	= 1,
		.sec		= 1,
		.min		= 2,
		.hour		= 3,
		.day		= 5,
		.mon		= 6,
		.year		= 7,
		.alarm_mon	= 0xa,
		.alarm_hour	= 0xc,
		.sqw		= 0x13,
	},
	{
		.type		= M41T00_TYPE_M41T85,
		.name		= "m41t85",
		.read_limit	= 1,
		.sec		= 1,
		.min		= 2,
		.hour		= 3,
		.day		= 5,
		.mon		= 6,
		.year		= 7,
		.alarm_mon	= 0xa,
		.alarm_hour	= 0xc,
		.sqw		= 0x13,
	},
};
static struct m41t00_chip_info *m41t00_chip;

ulong
m41t00_get_rtc_time(void)
{
	s32 sec, min, hour, day, mon, year;
	s32 sec1, min1, hour1, day1, mon1, year1;
	u8 reads = 0;
	u8 buf[8], msgbuf[1] = { 0 }; /* offset into rtc's regs */
	struct i2c_msg msgs[] = {
		{
			.addr	= save_client->addr,
			.flags	= 0,
			.len	= 1,
			.buf	= msgbuf,
		},
		{
			.addr	= save_client->addr,
			.flags	= I2C_M_RD,
			.len	= 8,
			.buf	= buf,
		},
	};

	sec = min = hour = day = mon = year = 0;

	do {
		if (i2c_transfer(save_client->adapter, msgs, 2) < 0)
			goto read_err;

		sec1 = sec;
		min1 = min;
		hour1 = hour;
		day1 = day;
		mon1 = mon;
		year1 = year;

		sec = buf[m41t00_chip->sec] & 0x7f;
		min = buf[m41t00_chip->min] & 0x7f;
		hour = buf[m41t00_chip->hour] & 0x3f;
		day = buf[m41t00_chip->day] & 0x3f;
		mon = buf[m41t00_chip->mon] & 0x1f;
		year = buf[m41t00_chip->year];
	} while ((++reads < m41t00_chip->read_limit) && ((sec != sec1)
			|| (min != min1) || (hour != hour1) || (day != day1)
			|| (mon != mon1) || (year != year1)));

	if ((m41t00_chip->read_limit > 1) && ((sec != sec1) || (min != min1)
			|| (hour != hour1) || (day != day1) || (mon != mon1)
			|| (year != year1)))
		goto read_err;

	sec = BCD2BIN(sec);
	min = BCD2BIN(min);
	hour = BCD2BIN(hour);
	day = BCD2BIN(day);
	mon = BCD2BIN(mon);
	year = BCD2BIN(year);

	year += 1900;
	if (year < 1970)
		year += 100;

	return mktime(year, mon, day, hour, min, sec);

read_err:
	dev_err(&save_client->dev, "m41t00_get_rtc_time: Read error\n");
	return 0;
}
EXPORT_SYMBOL_GPL(m41t00_get_rtc_time);

static void
m41t00_set(void *arg)
{
	struct rtc_time	tm;
	int nowtime = *(int *)arg;
	s32 sec, min, hour, day, mon, year;
	u8 wbuf[9], *buf = &wbuf[1], msgbuf[1] = { 0 };
	struct i2c_msg msgs[] = {
		{
			.addr	= save_client->addr,
			.flags	= 0,
			.len	= 1,
			.buf	= msgbuf,
		},
		{
			.addr	= save_client->addr,
			.flags	= I2C_M_RD,
			.len	= 8,
			.buf	= buf,
		},
	};

	to_tm(nowtime, &tm);
	tm.tm_year = (tm.tm_year - 1900) % 100;

	sec = BIN2BCD(tm.tm_sec);
	min = BIN2BCD(tm.tm_min);
	hour = BIN2BCD(tm.tm_hour);
	day = BIN2BCD(tm.tm_mday);
	mon = BIN2BCD(tm.tm_mon);
	year = BIN2BCD(tm.tm_year);

	/* Read reg values into buf[0..7]/wbuf[1..8] */
	if (i2c_transfer(save_client->adapter, msgs, 2) < 0) {
		dev_err(&save_client->dev, "m41t00_set: Read error\n");
		return;
	}

	wbuf[0] = 0; /* offset into rtc's regs */
	buf[m41t00_chip->sec] = (buf[m41t00_chip->sec] & ~0x7f) | (sec & 0x7f);
	buf[m41t00_chip->min] = (buf[m41t00_chip->min] & ~0x7f) | (min & 0x7f);
	buf[m41t00_chip->hour] = (buf[m41t00_chip->hour] & ~0x3f) | (hour& 0x3f);
	buf[m41t00_chip->day] = (buf[m41t00_chip->day] & ~0x3f) | (day & 0x3f);
	buf[m41t00_chip->mon] = (buf[m41t00_chip->mon] & ~0x1f) | (mon & 0x1f);

	if (i2c_master_send(save_client, wbuf, 9) < 0)
		dev_err(&save_client->dev, "m41t00_set: Write error\n");
}

static ulong new_time;
/* well, isn't this API just _lovely_? */
static void
m41t00_barf(struct work_struct *unusable)
{
	m41t00_set(&new_time);
}

static struct workqueue_struct *m41t00_wq;
static DECLARE_WORK(m41t00_work, m41t00_barf);

int
m41t00_set_rtc_time(ulong nowtime)
{
	new_time = nowtime;

	if (in_interrupt())
		queue_work(m41t00_wq, &m41t00_work);
	else
		m41t00_set(&new_time);

	return 0;
}
EXPORT_SYMBOL_GPL(m41t00_set_rtc_time);

/*
 *****************************************************************************
 *
 *	platform_data Driver Interface
 *
 *****************************************************************************
 */
static int __init
m41t00_platform_probe(struct platform_device *pdev)
{
	struct m41t00_platform_data *pdata;
	int i;

	if (pdev && (pdata = pdev->dev.platform_data)) {
		normal_addr[0] = pdata->i2c_addr;

		for (i=0; i<ARRAY_SIZE(m41t00_chip_info_tbl); i++)
			if (m41t00_chip_info_tbl[i].type == pdata->type) {
				m41t00_chip = &m41t00_chip_info_tbl[i];
				m41t00_chip->sqw_freq = pdata->sqw_freq;
				return 0;
			}
	}
	return -ENODEV;
}

static int __exit
m41t00_platform_remove(struct platform_device *pdev)
{
	return 0;
}

static struct platform_driver m41t00_platform_driver = {
	.probe  = m41t00_platform_probe,
	.remove = m41t00_platform_remove,
	.driver = {
		.owner = THIS_MODULE,
		.name  = M41T00_DRV_NAME,
	},
};

/*
 *****************************************************************************
 *
 *	Driver Interface
 *
 *****************************************************************************
 */
static int
m41t00_probe(struct i2c_adapter *adap, int addr, int kind)
{
	struct i2c_client *client;
	int rc;

	if (!i2c_check_functionality(adap, I2C_FUNC_I2C
			| I2C_FUNC_SMBUS_BYTE_DATA))
		return 0;

	client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
	if (!client)
		return -ENOMEM;

	strlcpy(client->name, m41t00_chip->name, I2C_NAME_SIZE);
	client->addr = addr;
	client->adapter = adap;
	client->driver = &m41t00_driver;

	if ((rc = i2c_attach_client(client)))
		goto attach_err;

	if (m41t00_chip->type != M41T00_TYPE_M41T00) {
		/* If asked, disable SQW, set SQW frequency & re-enable */
		if (m41t00_chip->sqw_freq)
			if (((rc = i2c_smbus_read_byte_data(client,
					m41t00_chip->alarm_mon)) < 0)
			 || ((rc = i2c_smbus_write_byte_data(client,
					m41t00_chip->alarm_mon, rc & ~0x40)) <0)
			 || ((rc = i2c_smbus_write_byte_data(client,
					m41t00_chip->sqw,
					m41t00_chip->sqw_freq)) < 0)
			 || ((rc = i2c_smbus_write_byte_data(client,
					m41t00_chip->alarm_mon, rc | 0x40)) <0))
				goto sqw_err;

		/* Make sure HT (Halt Update) bit is cleared */
		if ((rc = i2c_smbus_read_byte_data(client,
				m41t00_chip->alarm_hour)) < 0)
			goto ht_err;

		if (rc & 0x40)
			if ((rc = i2c_smbus_write_byte_data(client,
					m41t00_chip->alarm_hour, rc & ~0x40))<0)
				goto ht_err;
	}

	/* Make sure ST (stop) bit is cleared */
	if ((rc = i2c_smbus_read_byte_data(client, m41t00_chip->sec)) < 0)
		goto st_err;

	if (rc & 0x80)
		if ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->sec,
				rc & ~0x80)) < 0)
			goto st_err;

	m41t00_wq = create_singlethread_workqueue(m41t00_chip->name);
	save_client = client;
	return 0;

st_err:
	dev_err(&client->dev, "m41t00_probe: Can't clear ST bit\n");
	goto attach_err;
ht_err:
	dev_err(&client->dev, "m41t00_probe: Can't clear HT bit\n");
	goto attach_err;
sqw_err:
	dev_err(&client->dev, "m41t00_probe: Can't set SQW Frequency\n");
attach_err:
	kfree(client);
	return rc;
}

static int
m41t00_attach(struct i2c_adapter *adap)
{
	return i2c_probe(adap, &addr_data, m41t00_probe);
}

static int
m41t00_detach(struct i2c_client *client)
{
	int rc;

	if ((rc = i2c_detach_client(client)) == 0) {
		kfree(client);
		destroy_workqueue(m41t00_wq);
	}
	return rc;
}

static struct i2c_driver m41t00_driver = {
	.driver = {
		.name	= M41T00_DRV_NAME,
	},
	.id		= I2C_DRIVERID_STM41T00,
	.attach_adapter	= m41t00_attach,
	.detach_client	= m41t00_detach,
};

static int __init
m41t00_init(void)
{
	int rc;

	if (!(rc = platform_driver_register(&m41t00_platform_driver)))
		rc = i2c_add_driver(&m41t00_driver);
	return rc;
}

static void __exit
m41t00_exit(void)
{
	i2c_del_driver(&m41t00_driver);
	platform_driver_unregister(&m41t00_platform_driver);
}

module_init(m41t00_init);
module_exit(m41t00_exit);

MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver");
MODULE_LICENSE("GPL");