aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/i2c/chips/tsl2550.c
blob: aa96bd2d27ead9452d08da3bb62065468f1822f2 (plain) (blame)
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
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
/*
 *  tsl2550.c - Linux kernel modules for ambient light sensor
 *
 *  Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it>
 *  Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

#define TSL2550_DRV_NAME	"tsl2550"
#define DRIVER_VERSION		"1.2"

/*
 * Defines
 */

#define TSL2550_POWER_DOWN		0x00
#define TSL2550_POWER_UP		0x03
#define TSL2550_STANDARD_RANGE		0x18
#define TSL2550_EXTENDED_RANGE		0x1d
#define TSL2550_READ_ADC0		0x43
#define TSL2550_READ_ADC1		0x83

/*
 * Structs
 */

struct tsl2550_data {
	struct i2c_client *client;
	struct mutex update_lock;

	unsigned int power_state : 1;
	unsigned int operating_mode : 1;
};

/*
 * Global data
 */

static const u8 TSL2550_MODE_RANGE[2] = {
	TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE,
};

/*
 * Management functions
 */

static int tsl2550_set_operating_mode(struct i2c_client *client, int mode)
{
	struct tsl2550_data *data = i2c_get_clientdata(client);

	int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]);

	data->operating_mode = mode;

	return ret;
}

static int tsl2550_set_power_state(struct i2c_client *client, int state)
{
	struct tsl2550_data *data = i2c_get_clientdata(client);
	int ret;

	if (state == 0)
		ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN);
	else {
		ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP);

		/* On power up we should reset operating mode also... */
		tsl2550_set_operating_mode(client, data->operating_mode);
	}

	data->power_state = state;

	return ret;
}

static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd)
{
	int ret;

	ret = i2c_smbus_read_byte_data(client, cmd);
	if (ret < 0)
		return ret;
	if (!(ret & 0x80))
		return -EAGAIN;
	return ret & 0x7f;	/* remove the "valid" bit */
}

/*
 * LUX calculation
 */

#define	TSL2550_MAX_LUX		1846

static const u8 ratio_lut[] = {
	100, 100, 100, 100, 100, 100, 100, 100,
	100, 100, 100, 100, 100, 100, 99, 99,
	99, 99, 99, 99, 99, 99, 99, 99,
	99, 99, 99, 98, 98, 98, 98, 98,
	98, 98, 97, 97, 97, 97, 97, 96,
	96, 96, 96, 95, 95, 95, 94, 94,
	93, 93, 93, 92, 92, 91, 91, 90,
	89, 89, 88, 87, 87, 86, 85, 84,
	83, 82, 81, 80, 79, 78, 77, 75,
	74, 73, 71, 69, 68, 66, 64, 62,
	60, 58, 56, 54, 52, 49, 47, 44,
	42, 41, 40, 40, 39, 39, 38, 38,
	37, 37, 37, 36, 36, 36, 35, 35,
	35, 35, 34, 34, 34, 34, 33, 33,
	33, 33, 32, 32, 32, 32, 32, 31,
	31, 31, 31, 31, 30, 30, 30, 30,
	30,
};

static const u16 count_lut[] = {
	0, 1, 2, 3, 4, 5, 6, 7,
	8, 9, 10, 11, 12, 13, 14, 15,
	16, 18, 20, 22, 24, 26, 28, 30,
	32, 34, 36, 38, 40, 42, 44, 46,
	49, 53, 57, 61, 65, 69, 73, 77,
	81, 85, 89, 93, 97, 101, 105, 109,
	115, 123, 131, 139, 147, 155, 163, 171,
	179, 187, 195, 203, 211, 219, 227, 235,
	247, 263, 279, 295, 311, 327, 343, 359,
	375, 391, 407, 423, 439, 455, 471, 487,
	511, 543, 575, 607, 639, 671, 703, 735,
	767, 799, 831, 863, 895, 927, 959, 991,
	1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487,
	1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999,
	2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991,
	3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015,
};

/*
 * This function is described into Taos TSL2550 Designer's Notebook
 * pages 2, 3.
 */
static int tsl2550_calculate_lux(u8 ch0, u8 ch1)
{
	unsigned int lux;

	/* Look up count from channel values */
	u16 c0 = count_lut[ch0];
	u16 c1 = count_lut[ch1];

	/*
	 * Calculate ratio.
	 * Note: the "128" is a scaling factor
	 */
	u8 r = 128;

	/* Avoid division by 0 and count 1 cannot be greater than count 0 */
	if (c1 <= c0)
		if (c0) {
			r = c1 * 128 / c0;

			/* Calculate LUX */
			lux = ((c0 - c1) * ratio_lut[r]) / 256;
		} else
			lux = 0;
	else
		return -EAGAIN;

	/* LUX range check */
	return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;
}

/*
 * SysFS support
 */

static ssize_t tsl2550_show_power_state(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));

	return sprintf(buf, "%u\n", data->power_state);
}

static ssize_t tsl2550_store_power_state(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tsl2550_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10);
	int ret;

	if (val < 0 || val > 1)
		return -EINVAL;

	mutex_lock(&data->update_lock);
	ret = tsl2550_set_power_state(client, val);
	mutex_unlock(&data->update_lock);

	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
		   tsl2550_show_power_state, tsl2550_store_power_state);

static ssize_t tsl2550_show_operating_mode(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));

	return sprintf(buf, "%u\n", data->operating_mode);
}

static ssize_t tsl2550_store_operating_mode(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tsl2550_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10);
	int ret;

	if (val < 0 || val > 1)
		return -EINVAL;

	if (data->power_state == 0)
		return -EBUSY;

	mutex_lock(&data->update_lock);
	ret = tsl2550_set_operating_mode(client, val);
	mutex_unlock(&data->update_lock);

	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO,
		   tsl2550_show_operating_mode, tsl2550_store_operating_mode);

static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf)
{
	u8 ch0, ch1;
	int ret;

	ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0);
	if (ret < 0)
		return ret;
	ch0 = ret;

	ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1);
	if (ret < 0)
		return ret;
	ch1 = ret;

	/* Do the job */
	ret = tsl2550_calculate_lux(ch0, ch1);
	if (ret < 0)
		return ret;

	return sprintf(buf, "%d\n", ret);
}

static ssize_t tsl2550_show_lux1_input(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tsl2550_data *data = i2c_get_clientdata(client);
	int ret;

	/* No LUX data if not operational */
	if (!data->power_state)
		return -EBUSY;

	mutex_lock(&data->update_lock);
	ret = __tsl2550_show_lux(client, buf);
	mutex_unlock(&data->update_lock);

	return ret;
}

static DEVICE_ATTR(lux1_input, S_IRUGO,
		   tsl2550_show_lux1_input, NULL);

static struct attribute *tsl2550_attributes[] = {
	&dev_attr_power_state.attr,
	&dev_attr_operating_mode.attr,
	&dev_attr_lux1_input.attr,
	NULL
};

static const struct attribute_group tsl2550_attr_group = {
	.attrs = tsl2550_attributes,
};

/*
 * Initialization function
 */

static int tsl2550_init_client(struct i2c_client *client)
{
	struct tsl2550_data *data = i2c_get_clientdata(client);
	int err;

	/*
	 * Probe the chip. To do so we try to power up the device and then to
	 * read back the 0x03 code
	 */
	err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP);
	if (err < 0)
		return err;
	if (err != TSL2550_POWER_UP)
		return -ENODEV;
	data->power_state = 1;

	/* Set the default operating mode */
	err = i2c_smbus_write_byte(client,
				   TSL2550_MODE_RANGE[data->operating_mode]);
	if (err < 0)
		return err;

	return 0;
}

/*
 * I2C init/probing/exit functions
 */

static struct i2c_driver tsl2550_driver;
static int __devinit tsl2550_probe(struct i2c_client *client,
				   const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
	struct tsl2550_data *data;
	int *opmode, err = 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE
					    | I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
		err = -EIO;
		goto exit;
	}

	data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}
	data->client = client;
	i2c_set_clientdata(client, data);

	/* Check platform data */
	opmode = client->dev.platform_data;
	if (opmode) {
		if (*opmode < 0 || *opmode > 1) {
			dev_err(&client->dev, "invalid operating_mode (%d)\n",
					*opmode);
			err = -EINVAL;
			goto exit_kfree;
		}
		data->operating_mode = *opmode;
	} else
		data->operating_mode = 0;	/* default mode is standard */
	dev_info(&client->dev, "%s operating mode\n",
			data->operating_mode ? "extended" : "standard");

	mutex_init(&data->update_lock);

	/* Initialize the TSL2550 chip */
	err = tsl2550_init_client(client);
	if (err)
		goto exit_kfree;

	/* Register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group);
	if (err)
		goto exit_kfree;

	dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);

	return 0;

exit_kfree:
	kfree(data);
exit:
	return err;
}

static int __devexit tsl2550_remove(struct i2c_client *client)
{
	sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);

	/* Power down the device */
	tsl2550_set_power_state(client, 0);

	kfree(i2c_get_clientdata(client));

	return 0;
}

#ifdef CONFIG_PM

static int tsl2550_suspend(struct i2c_client *client, pm_message_t mesg)
{
	return tsl2550_set_power_state(client, 0);
}

static int tsl2550_resume(struct i2c_client *client)
{
	return tsl2550_set_power_state(client, 1);
}

#else

#define tsl2550_suspend		NULL
#define tsl2550_resume		NULL

#endif /* CONFIG_PM */

static const struct i2c_device_id tsl2550_id[] = {
	{ "tsl2550", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tsl2550_id);

static struct i2c_driver tsl2550_driver = {
	.driver = {
		.name	= TSL2550_DRV_NAME,
		.owner	= THIS_MODULE,
	},
	.suspend = tsl2550_suspend,
	.resume	= tsl2550_resume,
	.probe	= tsl2550_probe,
	.remove	= __devexit_p(tsl2550_remove),
	.id_table = tsl2550_id,
};

static int __init tsl2550_init(void)
{
	return i2c_add_driver(&tsl2550_driver);
}

static void __exit tsl2550_exit(void)
{
	i2c_del_driver(&tsl2550_driver);
}

MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRIVER_VERSION);

module_init(tsl2550_init);
module_exit(tsl2550_exit);