Free Electrons

Embedded Linux Experts

  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
/*
 * CM3232 Ambient Light Sensor
 *
 * Copyright (C) 2014-2015 Capella Microsystems Inc.
 * Author: Kevin Tsai <ktsai@capellamicro.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2, as published
 * by the Free Software Foundation.
 *
 * IIO driver for CM3232 (7-bit I2C slave address 0x10).
 */

#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/init.h>

/* Registers Address */
#define CM3232_REG_ADDR_CMD		0x00
#define CM3232_REG_ADDR_ALS		0x50
#define CM3232_REG_ADDR_ID		0x53

#define CM3232_CMD_ALS_DISABLE		BIT(0)

#define CM3232_CMD_ALS_IT_SHIFT		2
#define CM3232_CMD_ALS_IT_MASK		(BIT(2) | BIT(3) | BIT(4))
#define CM3232_CMD_ALS_IT_DEFAULT	(0x01 << CM3232_CMD_ALS_IT_SHIFT)

#define CM3232_CMD_ALS_RESET		BIT(6)

#define CM3232_CMD_DEFAULT		CM3232_CMD_ALS_IT_DEFAULT

#define CM3232_HW_ID			0x32
#define CM3232_CALIBSCALE_DEFAULT	100000
#define CM3232_CALIBSCALE_RESOLUTION	100000
#define CM3232_MLUX_PER_LUX		1000

#define CM3232_MLUX_PER_BIT_DEFAULT	64
#define CM3232_MLUX_PER_BIT_BASE_IT	100000

static const struct {
	int val;
	int val2;
	u8 it;
} cm3232_als_it_scales[] = {
	{0, 100000, 0},	/* 0.100000 */
	{0, 200000, 1},	/* 0.200000 */
	{0, 400000, 2},	/* 0.400000 */
	{0, 800000, 3},	/* 0.800000 */
	{1, 600000, 4},	/* 1.600000 */
	{3, 200000, 5},	/* 3.200000 */
};

struct cm3232_als_info {
	u8 regs_cmd_default;
	u8 hw_id;
	int calibscale;
	int mlux_per_bit;
	int mlux_per_bit_base_it;
};

static struct cm3232_als_info cm3232_als_info_default = {
	.regs_cmd_default = CM3232_CMD_DEFAULT,
	.hw_id = CM3232_HW_ID,
	.calibscale = CM3232_CALIBSCALE_DEFAULT,
	.mlux_per_bit = CM3232_MLUX_PER_BIT_DEFAULT,
	.mlux_per_bit_base_it = CM3232_MLUX_PER_BIT_BASE_IT,
};

struct cm3232_chip {
	struct i2c_client *client;
	struct cm3232_als_info *als_info;
	u8 regs_cmd;
	u16 regs_als;
};

/**
 * cm3232_reg_init() - Initialize CM3232
 * @chip:	pointer of struct cm3232_chip.
 *
 * Check and initialize CM3232 ambient light sensor.
 *
 * Return: 0 for success; otherwise for error code.
 */
static int cm3232_reg_init(struct cm3232_chip *chip)
{
	struct i2c_client *client = chip->client;
	s32 ret;

	chip->als_info = &cm3232_als_info_default;

	/* Identify device */
	ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID);
	if (ret < 0) {
		dev_err(&chip->client->dev, "Error reading addr_id\n");
		return ret;
	}

	if ((ret & 0xFF) != chip->als_info->hw_id)
		return -ENODEV;

	/* Disable and reset device */
	chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET;
	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
					chip->regs_cmd);
	if (ret < 0) {
		dev_err(&chip->client->dev, "Error writing reg_cmd\n");
		return ret;
	}

	/* Register default value */
	chip->regs_cmd = chip->als_info->regs_cmd_default;

	/* Configure register */
	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
					chip->regs_cmd);
	if (ret < 0)
		dev_err(&chip->client->dev, "Error writing reg_cmd\n");

	return ret;
}

/**
 *  cm3232_read_als_it() - Get sensor integration time
 *  @chip:	pointer of struct cm3232_chip
 *  @val:	pointer of int to load the integration (sec).
 *  @val2:	pointer of int to load the integration time (microsecond).
 *
 *  Report the current integration time.
 *
 *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 */
static int cm3232_read_als_it(struct cm3232_chip *chip, int *val, int *val2)
{
	u16 als_it;
	int i;

	als_it = chip->regs_cmd;
	als_it &= CM3232_CMD_ALS_IT_MASK;
	als_it >>= CM3232_CMD_ALS_IT_SHIFT;
	for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
		if (als_it == cm3232_als_it_scales[i].it) {
			*val = cm3232_als_it_scales[i].val;
			*val2 = cm3232_als_it_scales[i].val2;
			return IIO_VAL_INT_PLUS_MICRO;
		}
	}

	return -EINVAL;
}

/**
 * cm3232_write_als_it() - Write sensor integration time
 * @chip:	pointer of struct cm3232_chip.
 * @val:	integration time in second.
 * @val2:	integration time in microsecond.
 *
 * Convert integration time to sensor value.
 *
 * Return: i2c_smbus_write_byte_data command return value.
 */
static int cm3232_write_als_it(struct cm3232_chip *chip, int val, int val2)
{
	struct i2c_client *client = chip->client;
	u16 als_it, cmd;
	int i;
	s32 ret;

	for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
		if (val == cm3232_als_it_scales[i].val &&
			val2 == cm3232_als_it_scales[i].val2) {

			als_it = cm3232_als_it_scales[i].it;
			als_it <<= CM3232_CMD_ALS_IT_SHIFT;

			cmd = chip->regs_cmd & ~CM3232_CMD_ALS_IT_MASK;
			cmd |= als_it;
			ret = i2c_smbus_write_byte_data(client,
							CM3232_REG_ADDR_CMD,
							cmd);
			if (ret < 0)
				return ret;
			chip->regs_cmd = cmd;
			return 0;
		}
	}
	return -EINVAL;
}

/**
 * cm3232_get_lux() - report current lux value
 * @chip:	pointer of struct cm3232_chip.
 *
 * Convert sensor data to lux.  It depends on integration
 * time and calibscale variable.
 *
 * Return: Zero or positive value is lux, otherwise error code.
 */
static int cm3232_get_lux(struct cm3232_chip *chip)
{
	struct i2c_client *client = chip->client;
	struct cm3232_als_info *als_info = chip->als_info;
	int ret;
	int val, val2;
	int als_it;
	u64 lux;

	/* Calculate mlux per bit based on als_it */
	ret = cm3232_read_als_it(chip, &val, &val2);
	if (ret < 0)
		return -EINVAL;
	als_it = val * 1000000 + val2;
	lux = (__force u64)als_info->mlux_per_bit;
	lux *= als_info->mlux_per_bit_base_it;
	lux = div_u64(lux, als_it);

	ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ALS);
	if (ret < 0) {
		dev_err(&client->dev, "Error reading reg_addr_als\n");
		return ret;
	}

	chip->regs_als = (u16)ret;
	lux *= chip->regs_als;
	lux *= als_info->calibscale;
	lux = div_u64(lux, CM3232_CALIBSCALE_RESOLUTION);
	lux = div_u64(lux, CM3232_MLUX_PER_LUX);

	if (lux > 0xFFFF)
		lux = 0xFFFF;

	return (int)lux;
}

static int cm3232_read_raw(struct iio_dev *indio_dev,
			struct iio_chan_spec const *chan,
			int *val, int *val2, long mask)
{
	struct cm3232_chip *chip = iio_priv(indio_dev);
	struct cm3232_als_info *als_info = chip->als_info;
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_PROCESSED:
		ret = cm3232_get_lux(chip);
		if (ret < 0)
			return ret;
		*val = ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_CALIBSCALE:
		*val = als_info->calibscale;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_INT_TIME:
		return cm3232_read_als_it(chip, val, val2);
	}

	return -EINVAL;
}

static int cm3232_write_raw(struct iio_dev *indio_dev,
			struct iio_chan_spec const *chan,
			int val, int val2, long mask)
{
	struct cm3232_chip *chip = iio_priv(indio_dev);
	struct cm3232_als_info *als_info = chip->als_info;

	switch (mask) {
	case IIO_CHAN_INFO_CALIBSCALE:
		als_info->calibscale = val;
		return 0;
	case IIO_CHAN_INFO_INT_TIME:
		return cm3232_write_als_it(chip, val, val2);
	}

	return -EINVAL;
}

/**
 * cm3232_get_it_available() - Get available ALS IT value
 * @dev:	pointer of struct device.
 * @attr:	pointer of struct device_attribute.
 * @buf:	pointer of return string buffer.
 *
 * Display the available integration time in second.
 *
 * Return: string length.
 */
static ssize_t cm3232_get_it_available(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	int i, len;

	for (i = 0, len = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++)
		len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
			cm3232_als_it_scales[i].val,
			cm3232_als_it_scales[i].val2);
	return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
}

static const struct iio_chan_spec cm3232_channels[] = {
	{
		.type = IIO_LIGHT,
		.info_mask_separate =
			BIT(IIO_CHAN_INFO_PROCESSED) |
			BIT(IIO_CHAN_INFO_CALIBSCALE) |
			BIT(IIO_CHAN_INFO_INT_TIME),
	}
};

static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
			S_IRUGO, cm3232_get_it_available, NULL, 0);

static struct attribute *cm3232_attributes[] = {
	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group cm3232_attribute_group = {
	.attrs = cm3232_attributes
};

static const struct iio_info cm3232_info = {
	.driver_module		= THIS_MODULE,
	.read_raw		= &cm3232_read_raw,
	.write_raw		= &cm3232_write_raw,
	.attrs			= &cm3232_attribute_group,
};

static int cm3232_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct cm3232_chip *chip;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
	if (!indio_dev)
		return -ENOMEM;

	chip = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	chip->client = client;

	indio_dev->dev.parent = &client->dev;
	indio_dev->channels = cm3232_channels;
	indio_dev->num_channels = ARRAY_SIZE(cm3232_channels);
	indio_dev->info = &cm3232_info;
	indio_dev->name = id->name;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = cm3232_reg_init(chip);
	if (ret) {
		dev_err(&client->dev,
			"%s: register init failed\n",
			__func__);
		return ret;
	}

	return iio_device_register(indio_dev);
}

static int cm3232_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
		CM3232_CMD_ALS_DISABLE);

	iio_device_unregister(indio_dev);

	return 0;
}

static const struct i2c_device_id cm3232_id[] = {
	{"cm3232", 0},
	{}
};

#ifdef CONFIG_PM_SLEEP
static int cm3232_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct cm3232_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;
	int ret;

	chip->regs_cmd |= CM3232_CMD_ALS_DISABLE;
	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
					chip->regs_cmd);

	return ret;
}

static int cm3232_resume(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct cm3232_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;
	int ret;

	chip->regs_cmd &= ~CM3232_CMD_ALS_DISABLE;
	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
					chip->regs_cmd | CM3232_CMD_ALS_RESET);

	return ret;
}

static const struct dev_pm_ops cm3232_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(cm3232_suspend, cm3232_resume)};
#endif

MODULE_DEVICE_TABLE(i2c, cm3232_id);

static const struct of_device_id cm3232_of_match[] = {
	{.compatible = "capella,cm3232"},
	{}
};
MODULE_DEVICE_TABLE(of, cm3232_of_match);

static struct i2c_driver cm3232_driver = {
	.driver = {
		.name	= "cm3232",
		.of_match_table = of_match_ptr(cm3232_of_match),
#ifdef CONFIG_PM_SLEEP
		.pm	= &cm3232_pm_ops,
#endif
	},
	.id_table	= cm3232_id,
	.probe		= cm3232_probe,
	.remove		= cm3232_remove,
};

module_i2c_driver(cm3232_driver);

MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
MODULE_DESCRIPTION("CM3232 ambient light sensor driver");
MODULE_LICENSE("GPL");