summaryrefslogtreecommitdiffstats
path: root/drivers/iio/light/cm32181.c
blob: aebf7dd071af1fe3691a70a4d689931d3c223ccf (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
/*
 * Copyright (C) 2013 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.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/init.h>

/* Registers Address */
#define CM32181_REG_ADDR_CMD		0x00
#define CM32181_REG_ADDR_ALS		0x04
#define CM32181_REG_ADDR_STATUS		0x06
#define CM32181_REG_ADDR_ID		0x07

/* Number of Configurable Registers */
#define CM32181_CONF_REG_NUM		0x01

/* CMD register */
#define CM32181_CMD_ALS_ENABLE		0x00
#define CM32181_CMD_ALS_DISABLE		0x01
#define CM32181_CMD_ALS_INT_EN		0x02

#define CM32181_CMD_ALS_IT_SHIFT	6
#define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)
#define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)

#define CM32181_CMD_ALS_SM_SHIFT	11
#define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)
#define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)

#define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */
#define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */
#define	CM32181_CALIBSCALE_DEFAULT	1000
#define CM32181_CALIBSCALE_RESOLUTION	1000
#define MLUX_PER_LUX			1000

static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
	CM32181_REG_ADDR_CMD,
};

static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
	800000};

struct cm32181_chip {
	struct i2c_client *client;
	struct mutex lock;
	u16 conf_regs[CM32181_CONF_REG_NUM];
	int calibscale;
};

/**
 * cm32181_reg_init() - Initialize CM32181 registers
 * @cm32181:	pointer of struct cm32181.
 *
 * Initialize CM32181 ambient light sensor register to default values.
 *
 * Return: 0 for success; otherwise for error code.
 */
static int cm32181_reg_init(struct cm32181_chip *cm32181)
{
	struct i2c_client *client = cm32181->client;
	int i;
	s32 ret;

	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
	if (ret < 0)
		return ret;

	/* check device ID */
	if ((ret & 0xFF) != 0x81)
		return -ENODEV;

	/* Default Values */
	cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;

	/* Initialize registers*/
	for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
		ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
			cm32181->conf_regs[i]);
		if (ret < 0)
			return ret;
	}

	return 0;
}

/**
 *  cm32181_read_als_it() - Get sensor integration time (ms)
 *  @cm32181:	pointer of struct cm32181
 *  @val2:	pointer of int to load the als_it value.
 *
 *  Report the current integartion time by millisecond.
 *
 *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 */
static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
{
	u16 als_it;
	int i;

	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
	als_it &= CM32181_CMD_ALS_IT_MASK;
	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
		if (als_it == als_it_bits[i]) {
			*val2 = als_it_value[i];
			return IIO_VAL_INT_PLUS_MICRO;
		}
	}

	return -EINVAL;
}

/**
 * cm32181_write_als_it() - Write sensor integration time
 * @cm32181:	pointer of struct cm32181.
 * @val:	integration time by millisecond.
 *
 * Convert integration time (ms) to sensor value.
 *
 * Return: i2c_smbus_write_word_data command return value.
 */
static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
{
	struct i2c_client *client = cm32181->client;
	u16 als_it;
	int ret, i, n;

	n = ARRAY_SIZE(als_it_value);
	for (i = 0; i < n; i++)
		if (val <= als_it_value[i])
			break;
	if (i >= n)
		i = n - 1;

	als_it = als_it_bits[i];
	als_it <<= CM32181_CMD_ALS_IT_SHIFT;

	mutex_lock(&cm32181->lock);
	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
		~CM32181_CMD_ALS_IT_MASK;
	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
		als_it;
	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
	mutex_unlock(&cm32181->lock);

	return ret;
}

/**
 * cm32181_get_lux() - report current lux value
 * @cm32181:	pointer of struct cm32181.
 *
 * Convert sensor raw data to lux.  It depends on integration
 * time and calibscale variable.
 *
 * Return: Positive value is lux, otherwise is error code.
 */
static int cm32181_get_lux(struct cm32181_chip *cm32181)
{
	struct i2c_client *client = cm32181->client;
	int ret;
	int als_it;
	unsigned long lux;

	ret = cm32181_read_als_it(cm32181, &als_it);
	if (ret < 0)
		return -EINVAL;

	lux = CM32181_MLUX_PER_BIT;
	lux *= CM32181_MLUX_PER_BIT_BASE_IT;
	lux /= als_it;

	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
	if (ret < 0)
		return ret;

	lux *= ret;
	lux *= cm32181->calibscale;
	lux /= CM32181_CALIBSCALE_RESOLUTION;
	lux /= MLUX_PER_LUX;

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

	return lux;
}

static int cm32181_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_PROCESSED:
		ret = cm32181_get_lux(cm32181);
		if (ret < 0)
			return ret;
		*val = ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_CALIBSCALE:
		*val = cm32181->calibscale;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_INT_TIME:
		*val = 0;
		ret = cm32181_read_als_it(cm32181, val2);
		return ret;
	}

	return -EINVAL;
}

static int cm32181_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_CALIBSCALE:
		cm32181->calibscale = val;
		return val;
	case IIO_CHAN_INFO_INT_TIME:
		ret = cm32181_write_als_it(cm32181, val2);
		return ret;
	}

	return -EINVAL;
}

/**
 * cm32181_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 values by millisecond.
 *
 * Return: string length.
 */
static ssize_t cm32181_get_it_available(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	int i, n, len;

	n = ARRAY_SIZE(als_it_value);
	for (i = 0, len = 0; i < n; i++)
		len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
	return len + sprintf(buf + len, "\n");
}

static const struct iio_chan_spec cm32181_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, cm32181_get_it_available, NULL, 0);

static struct attribute *cm32181_attributes[] = {
	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group cm32181_attribute_group = {
	.attrs = cm32181_attributes
};

static const struct iio_info cm32181_info = {
	.read_raw		= &cm32181_read_raw,
	.write_raw		= &cm32181_write_raw,
	.attrs			= &cm32181_attribute_group,
};

static int cm32181_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct cm32181_chip *cm32181;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
	if (!indio_dev) {
		dev_err(&client->dev, "devm_iio_device_alloc failed\n");
		return -ENOMEM;
	}

	cm32181 = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	cm32181->client = client;

	mutex_init(&cm32181->lock);
	indio_dev->dev.parent = &client->dev;
	indio_dev->channels = cm32181_channels;
	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
	indio_dev->info = &cm32181_info;
	indio_dev->name = id->name;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = cm32181_reg_init(cm32181);
	if (ret) {
		dev_err(&client->dev,
			"%s: register init failed\n",
			__func__);
		return ret;
	}

	ret = devm_iio_device_register(&client->dev, indio_dev);
	if (ret) {
		dev_err(&client->dev,
			"%s: regist device failed\n",
			__func__);
		return ret;
	}

	return 0;
}

static const struct i2c_device_id cm32181_id[] = {
	{ "cm32181", 0 },
	{ }
};

MODULE_DEVICE_TABLE(i2c, cm32181_id);

static const struct of_device_id cm32181_of_match[] = {
	{ .compatible = "capella,cm32181" },
	{ }
};
MODULE_DEVICE_TABLE(of, cm32181_of_match);

static struct i2c_driver cm32181_driver = {
	.driver = {
		.name	= "cm32181",
		.of_match_table = of_match_ptr(cm32181_of_match),
	},
	.id_table       = cm32181_id,
	.probe		= cm32181_probe,
};

module_i2c_driver(cm32181_driver);

MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
MODULE_LICENSE("GPL");