1/*
2 * Copyright (C) 2013 Capella Microsystems Inc.
3 * Author: Kevin Tsai <ktsai@capellamicro.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2, as published
7 * by the Free Software Foundation.
8 */
9
10#include <linux/delay.h>
11#include <linux/err.h>
12#include <linux/i2c.h>
13#include <linux/mutex.h>
14#include <linux/module.h>
15#include <linux/interrupt.h>
16#include <linux/regulator/consumer.h>
17#include <linux/iio/iio.h>
18#include <linux/iio/sysfs.h>
19#include <linux/iio/events.h>
20#include <linux/init.h>
21
22/* Registers Address */
23#define CM32181_REG_ADDR_CMD		0x00
24#define CM32181_REG_ADDR_ALS		0x04
25#define CM32181_REG_ADDR_STATUS		0x06
26#define CM32181_REG_ADDR_ID		0x07
27
28/* Number of Configurable Registers */
29#define CM32181_CONF_REG_NUM		0x01
30
31/* CMD register */
32#define CM32181_CMD_ALS_ENABLE		0x00
33#define CM32181_CMD_ALS_DISABLE		0x01
34#define CM32181_CMD_ALS_INT_EN		0x02
35
36#define CM32181_CMD_ALS_IT_SHIFT	6
37#define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)
38#define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)
39
40#define CM32181_CMD_ALS_SM_SHIFT	11
41#define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)
42#define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)
43
44#define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */
45#define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */
46#define	CM32181_CALIBSCALE_DEFAULT	1000
47#define CM32181_CALIBSCALE_RESOLUTION	1000
48#define MLUX_PER_LUX			1000
49
50static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
51	CM32181_REG_ADDR_CMD,
52};
53
54static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
55static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
56	800000};
57
58struct cm32181_chip {
59	struct i2c_client *client;
60	struct mutex lock;
61	u16 conf_regs[CM32181_CONF_REG_NUM];
62	int calibscale;
63};
64
65/**
66 * cm32181_reg_init() - Initialize CM32181 registers
67 * @cm32181:	pointer of struct cm32181.
68 *
69 * Initialize CM32181 ambient light sensor register to default values.
70 *
71 * Return: 0 for success; otherwise for error code.
72 */
73static int cm32181_reg_init(struct cm32181_chip *cm32181)
74{
75	struct i2c_client *client = cm32181->client;
76	int i;
77	s32 ret;
78
79	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
80	if (ret < 0)
81		return ret;
82
83	/* check device ID */
84	if ((ret & 0xFF) != 0x81)
85		return -ENODEV;
86
87	/* Default Values */
88	cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
89			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
90	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
91
92	/* Initialize registers*/
93	for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
94		ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
95			cm32181->conf_regs[i]);
96		if (ret < 0)
97			return ret;
98	}
99
100	return 0;
101}
102
103/**
104 *  cm32181_read_als_it() - Get sensor integration time (ms)
105 *  @cm32181:	pointer of struct cm32181
106 *  @val2:	pointer of int to load the als_it value.
107 *
108 *  Report the current integartion time by millisecond.
109 *
110 *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
111 */
112static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
113{
114	u16 als_it;
115	int i;
116
117	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
118	als_it &= CM32181_CMD_ALS_IT_MASK;
119	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
120	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
121		if (als_it == als_it_bits[i]) {
122			*val2 = als_it_value[i];
123			return IIO_VAL_INT_PLUS_MICRO;
124		}
125	}
126
127	return -EINVAL;
128}
129
130/**
131 * cm32181_write_als_it() - Write sensor integration time
132 * @cm32181:	pointer of struct cm32181.
133 * @val:	integration time by millisecond.
134 *
135 * Convert integration time (ms) to sensor value.
136 *
137 * Return: i2c_smbus_write_word_data command return value.
138 */
139static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
140{
141	struct i2c_client *client = cm32181->client;
142	u16 als_it;
143	int ret, i, n;
144
145	n = ARRAY_SIZE(als_it_value);
146	for (i = 0; i < n; i++)
147		if (val <= als_it_value[i])
148			break;
149	if (i >= n)
150		i = n - 1;
151
152	als_it = als_it_bits[i];
153	als_it <<= CM32181_CMD_ALS_IT_SHIFT;
154
155	mutex_lock(&cm32181->lock);
156	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
157		~CM32181_CMD_ALS_IT_MASK;
158	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
159		als_it;
160	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
161			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
162	mutex_unlock(&cm32181->lock);
163
164	return ret;
165}
166
167/**
168 * cm32181_get_lux() - report current lux value
169 * @cm32181:	pointer of struct cm32181.
170 *
171 * Convert sensor raw data to lux.  It depends on integration
172 * time and calibscale variable.
173 *
174 * Return: Positive value is lux, otherwise is error code.
175 */
176static int cm32181_get_lux(struct cm32181_chip *cm32181)
177{
178	struct i2c_client *client = cm32181->client;
179	int ret;
180	int als_it;
181	unsigned long lux;
182
183	ret = cm32181_read_als_it(cm32181, &als_it);
184	if (ret < 0)
185		return -EINVAL;
186
187	lux = CM32181_MLUX_PER_BIT;
188	lux *= CM32181_MLUX_PER_BIT_BASE_IT;
189	lux /= als_it;
190
191	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
192	if (ret < 0)
193		return ret;
194
195	lux *= ret;
196	lux *= cm32181->calibscale;
197	lux /= CM32181_CALIBSCALE_RESOLUTION;
198	lux /= MLUX_PER_LUX;
199
200	if (lux > 0xFFFF)
201		lux = 0xFFFF;
202
203	return lux;
204}
205
206static int cm32181_read_raw(struct iio_dev *indio_dev,
207			    struct iio_chan_spec const *chan,
208			    int *val, int *val2, long mask)
209{
210	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
211	int ret;
212
213	switch (mask) {
214	case IIO_CHAN_INFO_PROCESSED:
215		ret = cm32181_get_lux(cm32181);
216		if (ret < 0)
217			return ret;
218		*val = ret;
219		return IIO_VAL_INT;
220	case IIO_CHAN_INFO_CALIBSCALE:
221		*val = cm32181->calibscale;
222		return IIO_VAL_INT;
223	case IIO_CHAN_INFO_INT_TIME:
224		*val = 0;
225		ret = cm32181_read_als_it(cm32181, val2);
226		return ret;
227	}
228
229	return -EINVAL;
230}
231
232static int cm32181_write_raw(struct iio_dev *indio_dev,
233			     struct iio_chan_spec const *chan,
234			     int val, int val2, long mask)
235{
236	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
237	int ret;
238
239	switch (mask) {
240	case IIO_CHAN_INFO_CALIBSCALE:
241		cm32181->calibscale = val;
242		return val;
243	case IIO_CHAN_INFO_INT_TIME:
244		ret = cm32181_write_als_it(cm32181, val2);
245		return ret;
246	}
247
248	return -EINVAL;
249}
250
251/**
252 * cm32181_get_it_available() - Get available ALS IT value
253 * @dev:	pointer of struct device.
254 * @attr:	pointer of struct device_attribute.
255 * @buf:	pointer of return string buffer.
256 *
257 * Display the available integration time values by millisecond.
258 *
259 * Return: string length.
260 */
261static ssize_t cm32181_get_it_available(struct device *dev,
262			struct device_attribute *attr, char *buf)
263{
264	int i, n, len;
265
266	n = ARRAY_SIZE(als_it_value);
267	for (i = 0, len = 0; i < n; i++)
268		len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
269	return len + sprintf(buf + len, "\n");
270}
271
272static const struct iio_chan_spec cm32181_channels[] = {
273	{
274		.type = IIO_LIGHT,
275		.info_mask_separate =
276			BIT(IIO_CHAN_INFO_PROCESSED) |
277			BIT(IIO_CHAN_INFO_CALIBSCALE) |
278			BIT(IIO_CHAN_INFO_INT_TIME),
279	}
280};
281
282static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
283			S_IRUGO, cm32181_get_it_available, NULL, 0);
284
285static struct attribute *cm32181_attributes[] = {
286	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
287	NULL,
288};
289
290static const struct attribute_group cm32181_attribute_group = {
291	.attrs = cm32181_attributes
292};
293
294static const struct iio_info cm32181_info = {
295	.driver_module		= THIS_MODULE,
296	.read_raw		= &cm32181_read_raw,
297	.write_raw		= &cm32181_write_raw,
298	.attrs			= &cm32181_attribute_group,
299};
300
301static int cm32181_probe(struct i2c_client *client,
302			const struct i2c_device_id *id)
303{
304	struct cm32181_chip *cm32181;
305	struct iio_dev *indio_dev;
306	int ret;
307
308	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
309	if (!indio_dev) {
310		dev_err(&client->dev, "devm_iio_device_alloc failed\n");
311		return -ENOMEM;
312	}
313
314	cm32181 = iio_priv(indio_dev);
315	i2c_set_clientdata(client, indio_dev);
316	cm32181->client = client;
317
318	mutex_init(&cm32181->lock);
319	indio_dev->dev.parent = &client->dev;
320	indio_dev->channels = cm32181_channels;
321	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
322	indio_dev->info = &cm32181_info;
323	indio_dev->name = id->name;
324	indio_dev->modes = INDIO_DIRECT_MODE;
325
326	ret = cm32181_reg_init(cm32181);
327	if (ret) {
328		dev_err(&client->dev,
329			"%s: register init failed\n",
330			__func__);
331		return ret;
332	}
333
334	ret = devm_iio_device_register(&client->dev, indio_dev);
335	if (ret) {
336		dev_err(&client->dev,
337			"%s: regist device failed\n",
338			__func__);
339		return ret;
340	}
341
342	return 0;
343}
344
345static const struct i2c_device_id cm32181_id[] = {
346	{ "cm32181", 0 },
347	{ }
348};
349
350MODULE_DEVICE_TABLE(i2c, cm32181_id);
351
352static const struct of_device_id cm32181_of_match[] = {
353	{ .compatible = "capella,cm32181" },
354	{ }
355};
356
357static struct i2c_driver cm32181_driver = {
358	.driver = {
359		.name	= "cm32181",
360		.of_match_table = of_match_ptr(cm32181_of_match),
361		.owner	= THIS_MODULE,
362	},
363	.id_table       = cm32181_id,
364	.probe		= cm32181_probe,
365};
366
367module_i2c_driver(cm32181_driver);
368
369MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
370MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
371MODULE_LICENSE("GPL");
372