xref: /openbmc/linux/drivers/iio/light/cm32181.c (revision c7b03852)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013 Capella Microsystems Inc.
4  * Author: Kevin Tsai <ktsai@capellamicro.com>
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/err.h>
9 #include <linux/i2c.h>
10 #include <linux/mutex.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/regulator/consumer.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/sysfs.h>
16 #include <linux/iio/events.h>
17 #include <linux/init.h>
18 
19 /* Registers Address */
20 #define CM32181_REG_ADDR_CMD		0x00
21 #define CM32181_REG_ADDR_ALS		0x04
22 #define CM32181_REG_ADDR_STATUS		0x06
23 #define CM32181_REG_ADDR_ID		0x07
24 
25 /* Number of Configurable Registers */
26 #define CM32181_CONF_REG_NUM		0x01
27 
28 /* CMD register */
29 #define CM32181_CMD_ALS_ENABLE		0x00
30 #define CM32181_CMD_ALS_DISABLE		0x01
31 #define CM32181_CMD_ALS_INT_EN		0x02
32 
33 #define CM32181_CMD_ALS_IT_SHIFT	6
34 #define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)
35 #define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)
36 
37 #define CM32181_CMD_ALS_SM_SHIFT	11
38 #define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)
39 #define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)
40 
41 #define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */
42 #define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */
43 #define	CM32181_CALIBSCALE_DEFAULT	1000
44 #define CM32181_CALIBSCALE_RESOLUTION	1000
45 #define MLUX_PER_LUX			1000
46 
47 static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
48 	CM32181_REG_ADDR_CMD,
49 };
50 
51 static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
52 static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
53 	800000};
54 
55 struct cm32181_chip {
56 	struct i2c_client *client;
57 	struct mutex lock;
58 	u16 conf_regs[CM32181_CONF_REG_NUM];
59 	int calibscale;
60 };
61 
62 /**
63  * cm32181_reg_init() - Initialize CM32181 registers
64  * @cm32181:	pointer of struct cm32181.
65  *
66  * Initialize CM32181 ambient light sensor register to default values.
67  *
68  * Return: 0 for success; otherwise for error code.
69  */
70 static int cm32181_reg_init(struct cm32181_chip *cm32181)
71 {
72 	struct i2c_client *client = cm32181->client;
73 	int i;
74 	s32 ret;
75 
76 	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
77 	if (ret < 0)
78 		return ret;
79 
80 	/* check device ID */
81 	if ((ret & 0xFF) != 0x81)
82 		return -ENODEV;
83 
84 	/* Default Values */
85 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
86 			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
87 	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
88 
89 	/* Initialize registers*/
90 	for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
91 		ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
92 			cm32181->conf_regs[i]);
93 		if (ret < 0)
94 			return ret;
95 	}
96 
97 	return 0;
98 }
99 
100 /**
101  *  cm32181_read_als_it() - Get sensor integration time (ms)
102  *  @cm32181:	pointer of struct cm32181
103  *  @val2:	pointer of int to load the als_it value.
104  *
105  *  Report the current integartion time by millisecond.
106  *
107  *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
108  */
109 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
110 {
111 	u16 als_it;
112 	int i;
113 
114 	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
115 	als_it &= CM32181_CMD_ALS_IT_MASK;
116 	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
117 	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
118 		if (als_it == als_it_bits[i]) {
119 			*val2 = als_it_value[i];
120 			return IIO_VAL_INT_PLUS_MICRO;
121 		}
122 	}
123 
124 	return -EINVAL;
125 }
126 
127 /**
128  * cm32181_write_als_it() - Write sensor integration time
129  * @cm32181:	pointer of struct cm32181.
130  * @val:	integration time by millisecond.
131  *
132  * Convert integration time (ms) to sensor value.
133  *
134  * Return: i2c_smbus_write_word_data command return value.
135  */
136 static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
137 {
138 	struct i2c_client *client = cm32181->client;
139 	u16 als_it;
140 	int ret, i, n;
141 
142 	n = ARRAY_SIZE(als_it_value);
143 	for (i = 0; i < n; i++)
144 		if (val <= als_it_value[i])
145 			break;
146 	if (i >= n)
147 		i = n - 1;
148 
149 	als_it = als_it_bits[i];
150 	als_it <<= CM32181_CMD_ALS_IT_SHIFT;
151 
152 	mutex_lock(&cm32181->lock);
153 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
154 		~CM32181_CMD_ALS_IT_MASK;
155 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
156 		als_it;
157 	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
158 			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
159 	mutex_unlock(&cm32181->lock);
160 
161 	return ret;
162 }
163 
164 /**
165  * cm32181_get_lux() - report current lux value
166  * @cm32181:	pointer of struct cm32181.
167  *
168  * Convert sensor raw data to lux.  It depends on integration
169  * time and calibscale variable.
170  *
171  * Return: Positive value is lux, otherwise is error code.
172  */
173 static int cm32181_get_lux(struct cm32181_chip *cm32181)
174 {
175 	struct i2c_client *client = cm32181->client;
176 	int ret;
177 	int als_it;
178 	unsigned long lux;
179 
180 	ret = cm32181_read_als_it(cm32181, &als_it);
181 	if (ret < 0)
182 		return -EINVAL;
183 
184 	lux = CM32181_MLUX_PER_BIT;
185 	lux *= CM32181_MLUX_PER_BIT_BASE_IT;
186 	lux /= als_it;
187 
188 	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
189 	if (ret < 0)
190 		return ret;
191 
192 	lux *= ret;
193 	lux *= cm32181->calibscale;
194 	lux /= CM32181_CALIBSCALE_RESOLUTION;
195 	lux /= MLUX_PER_LUX;
196 
197 	if (lux > 0xFFFF)
198 		lux = 0xFFFF;
199 
200 	return lux;
201 }
202 
203 static int cm32181_read_raw(struct iio_dev *indio_dev,
204 			    struct iio_chan_spec const *chan,
205 			    int *val, int *val2, long mask)
206 {
207 	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
208 	int ret;
209 
210 	switch (mask) {
211 	case IIO_CHAN_INFO_PROCESSED:
212 		ret = cm32181_get_lux(cm32181);
213 		if (ret < 0)
214 			return ret;
215 		*val = ret;
216 		return IIO_VAL_INT;
217 	case IIO_CHAN_INFO_CALIBSCALE:
218 		*val = cm32181->calibscale;
219 		return IIO_VAL_INT;
220 	case IIO_CHAN_INFO_INT_TIME:
221 		*val = 0;
222 		ret = cm32181_read_als_it(cm32181, val2);
223 		return ret;
224 	}
225 
226 	return -EINVAL;
227 }
228 
229 static int cm32181_write_raw(struct iio_dev *indio_dev,
230 			     struct iio_chan_spec const *chan,
231 			     int val, int val2, long mask)
232 {
233 	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
234 	int ret;
235 
236 	switch (mask) {
237 	case IIO_CHAN_INFO_CALIBSCALE:
238 		cm32181->calibscale = val;
239 		return val;
240 	case IIO_CHAN_INFO_INT_TIME:
241 		ret = cm32181_write_als_it(cm32181, val2);
242 		return ret;
243 	}
244 
245 	return -EINVAL;
246 }
247 
248 /**
249  * cm32181_get_it_available() - Get available ALS IT value
250  * @dev:	pointer of struct device.
251  * @attr:	pointer of struct device_attribute.
252  * @buf:	pointer of return string buffer.
253  *
254  * Display the available integration time values by millisecond.
255  *
256  * Return: string length.
257  */
258 static ssize_t cm32181_get_it_available(struct device *dev,
259 			struct device_attribute *attr, char *buf)
260 {
261 	int i, n, len;
262 
263 	n = ARRAY_SIZE(als_it_value);
264 	for (i = 0, len = 0; i < n; i++)
265 		len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
266 	return len + sprintf(buf + len, "\n");
267 }
268 
269 static const struct iio_chan_spec cm32181_channels[] = {
270 	{
271 		.type = IIO_LIGHT,
272 		.info_mask_separate =
273 			BIT(IIO_CHAN_INFO_PROCESSED) |
274 			BIT(IIO_CHAN_INFO_CALIBSCALE) |
275 			BIT(IIO_CHAN_INFO_INT_TIME),
276 	}
277 };
278 
279 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
280 			S_IRUGO, cm32181_get_it_available, NULL, 0);
281 
282 static struct attribute *cm32181_attributes[] = {
283 	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
284 	NULL,
285 };
286 
287 static const struct attribute_group cm32181_attribute_group = {
288 	.attrs = cm32181_attributes
289 };
290 
291 static const struct iio_info cm32181_info = {
292 	.read_raw		= &cm32181_read_raw,
293 	.write_raw		= &cm32181_write_raw,
294 	.attrs			= &cm32181_attribute_group,
295 };
296 
297 static int cm32181_probe(struct i2c_client *client,
298 			const struct i2c_device_id *id)
299 {
300 	struct cm32181_chip *cm32181;
301 	struct iio_dev *indio_dev;
302 	int ret;
303 
304 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
305 	if (!indio_dev) {
306 		dev_err(&client->dev, "devm_iio_device_alloc failed\n");
307 		return -ENOMEM;
308 	}
309 
310 	cm32181 = iio_priv(indio_dev);
311 	i2c_set_clientdata(client, indio_dev);
312 	cm32181->client = client;
313 
314 	mutex_init(&cm32181->lock);
315 	indio_dev->dev.parent = &client->dev;
316 	indio_dev->channels = cm32181_channels;
317 	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
318 	indio_dev->info = &cm32181_info;
319 	indio_dev->name = id->name;
320 	indio_dev->modes = INDIO_DIRECT_MODE;
321 
322 	ret = cm32181_reg_init(cm32181);
323 	if (ret) {
324 		dev_err(&client->dev,
325 			"%s: register init failed\n",
326 			__func__);
327 		return ret;
328 	}
329 
330 	ret = devm_iio_device_register(&client->dev, indio_dev);
331 	if (ret) {
332 		dev_err(&client->dev,
333 			"%s: regist device failed\n",
334 			__func__);
335 		return ret;
336 	}
337 
338 	return 0;
339 }
340 
341 static const struct i2c_device_id cm32181_id[] = {
342 	{ "cm32181", 0 },
343 	{ }
344 };
345 
346 MODULE_DEVICE_TABLE(i2c, cm32181_id);
347 
348 static const struct of_device_id cm32181_of_match[] = {
349 	{ .compatible = "capella,cm32181" },
350 	{ }
351 };
352 MODULE_DEVICE_TABLE(of, cm32181_of_match);
353 
354 static struct i2c_driver cm32181_driver = {
355 	.driver = {
356 		.name	= "cm32181",
357 		.of_match_table = of_match_ptr(cm32181_of_match),
358 	},
359 	.id_table       = cm32181_id,
360 	.probe		= cm32181_probe,
361 };
362 
363 module_i2c_driver(cm32181_driver);
364 
365 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
366 MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
367 MODULE_LICENSE("GPL");
368