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1/*
2 * CM3232 Ambient Light Sensor
3 *
4 * Copyright (C) 2014-2015 Capella Microsystems Inc.
5 * Author: Kevin Tsai <ktsai@capellamicro.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2, as published
9 * by the Free Software Foundation.
10 *
11 * IIO driver for CM3232 (7-bit I2C slave address 0x10).
12 */
13
14#include <linux/i2c.h>
15#include <linux/module.h>
16#include <linux/iio/iio.h>
17#include <linux/iio/sysfs.h>
18#include <linux/init.h>
19
20/* Registers Address */
21#define CM3232_REG_ADDR_CMD 0x00
22#define CM3232_REG_ADDR_ALS 0x50
23#define CM3232_REG_ADDR_ID 0x53
24
25#define CM3232_CMD_ALS_DISABLE BIT(0)
26
27#define CM3232_CMD_ALS_IT_SHIFT 2
28#define CM3232_CMD_ALS_IT_MASK (BIT(2) | BIT(3) | BIT(4))
29#define CM3232_CMD_ALS_IT_DEFAULT (0x01 << CM3232_CMD_ALS_IT_SHIFT)
30
31#define CM3232_CMD_ALS_RESET BIT(6)
32
33#define CM3232_CMD_DEFAULT CM3232_CMD_ALS_IT_DEFAULT
34
35#define CM3232_HW_ID 0x32
36#define CM3232_CALIBSCALE_DEFAULT 100000
37#define CM3232_CALIBSCALE_RESOLUTION 100000
38#define CM3232_MLUX_PER_LUX 1000
39
40#define CM3232_MLUX_PER_BIT_DEFAULT 64
41#define CM3232_MLUX_PER_BIT_BASE_IT 100000
42
43static const struct {
44 int val;
45 int val2;
46 u8 it;
47} cm3232_als_it_scales[] = {
48 {0, 100000, 0}, /* 0.100000 */
49 {0, 200000, 1}, /* 0.200000 */
50 {0, 400000, 2}, /* 0.400000 */
51 {0, 800000, 3}, /* 0.800000 */
52 {1, 600000, 4}, /* 1.600000 */
53 {3, 200000, 5}, /* 3.200000 */
54};
55
56struct cm3232_als_info {
57 u8 regs_cmd_default;
58 u8 hw_id;
59 int calibscale;
60 int mlux_per_bit;
61 int mlux_per_bit_base_it;
62};
63
64static struct cm3232_als_info cm3232_als_info_default = {
65 .regs_cmd_default = CM3232_CMD_DEFAULT,
66 .hw_id = CM3232_HW_ID,
67 .calibscale = CM3232_CALIBSCALE_DEFAULT,
68 .mlux_per_bit = CM3232_MLUX_PER_BIT_DEFAULT,
69 .mlux_per_bit_base_it = CM3232_MLUX_PER_BIT_BASE_IT,
70};
71
72struct cm3232_chip {
73 struct i2c_client *client;
74 struct cm3232_als_info *als_info;
75 u8 regs_cmd;
76 u16 regs_als;
77};
78
79/**
80 * cm3232_reg_init() - Initialize CM3232
81 * @chip: pointer of struct cm3232_chip.
82 *
83 * Check and initialize CM3232 ambient light sensor.
84 *
85 * Return: 0 for success; otherwise for error code.
86 */
87static int cm3232_reg_init(struct cm3232_chip *chip)
88{
89 struct i2c_client *client = chip->client;
90 s32 ret;
91
92 chip->als_info = &cm3232_als_info_default;
93
94 /* Identify device */
95 ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID);
96 if (ret < 0) {
97 dev_err(&chip->client->dev, "Error reading addr_id\n");
98 return ret;
99 }
100
101 if ((ret & 0xFF) != chip->als_info->hw_id)
102 return -ENODEV;
103
104 /* Disable and reset device */
105 chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET;
106 ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
107 chip->regs_cmd);
108 if (ret < 0) {
109 dev_err(&chip->client->dev, "Error writing reg_cmd\n");
110 return ret;
111 }
112
113 /* Register default value */
114 chip->regs_cmd = chip->als_info->regs_cmd_default;
115
116 /* Configure register */
117 ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
118 chip->regs_cmd);
119 if (ret < 0)
120 dev_err(&chip->client->dev, "Error writing reg_cmd\n");
121
122 return 0;
123}
124
125/**
126 * cm3232_read_als_it() - Get sensor integration time
127 * @chip: pointer of struct cm3232_chip
128 * @val: pointer of int to load the integration (sec).
129 * @val2: pointer of int to load the integration time (microsecond).
130 *
131 * Report the current integration time.
132 *
133 * Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
134 */
135static int cm3232_read_als_it(struct cm3232_chip *chip, int *val, int *val2)
136{
137 u16 als_it;
138 int i;
139
140 als_it = chip->regs_cmd;
141 als_it &= CM3232_CMD_ALS_IT_MASK;
142 als_it >>= CM3232_CMD_ALS_IT_SHIFT;
143 for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
144 if (als_it == cm3232_als_it_scales[i].it) {
145 *val = cm3232_als_it_scales[i].val;
146 *val2 = cm3232_als_it_scales[i].val2;
147 return IIO_VAL_INT_PLUS_MICRO;
148 }
149 }
150
151 return -EINVAL;
152}
153
154/**
155 * cm3232_write_als_it() - Write sensor integration time
156 * @chip: pointer of struct cm3232_chip.
157 * @val: integration time in second.
158 * @val2: integration time in microsecond.
159 *
160 * Convert integration time to sensor value.
161 *
162 * Return: i2c_smbus_write_byte_data command return value.
163 */
164static int cm3232_write_als_it(struct cm3232_chip *chip, int val, int val2)
165{
166 struct i2c_client *client = chip->client;
167 u16 als_it, cmd;
168 int i;
169 s32 ret;
170
171 for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
172 if (val == cm3232_als_it_scales[i].val &&
173 val2 == cm3232_als_it_scales[i].val2) {
174
175 als_it = cm3232_als_it_scales[i].it;
176 als_it <<= CM3232_CMD_ALS_IT_SHIFT;
177
178 cmd = chip->regs_cmd & ~CM3232_CMD_ALS_IT_MASK;
179 cmd |= als_it;
180 ret = i2c_smbus_write_byte_data(client,
181 CM3232_REG_ADDR_CMD,
182 cmd);
183 if (ret < 0)
184 return ret;
185 chip->regs_cmd = cmd;
186 return 0;
187 }
188 }
189 return -EINVAL;
190}
191
192/**
193 * cm3232_get_lux() - report current lux value
194 * @chip: pointer of struct cm3232_chip.
195 *
196 * Convert sensor data to lux. It depends on integration
197 * time and calibscale variable.
198 *
199 * Return: Zero or positive value is lux, otherwise error code.
200 */
201static int cm3232_get_lux(struct cm3232_chip *chip)
202{
203 struct i2c_client *client = chip->client;
204 struct cm3232_als_info *als_info = chip->als_info;
205 int ret;
206 int val, val2;
207 int als_it;
208 u64 lux;
209
210 /* Calculate mlux per bit based on als_it */
211 ret = cm3232_read_als_it(chip, &val, &val2);
212 if (ret < 0)
213 return -EINVAL;
214 als_it = val * 1000000 + val2;
215 lux = (__force u64)als_info->mlux_per_bit;
216 lux *= als_info->mlux_per_bit_base_it;
217 lux = div_u64(lux, als_it);
218
219 ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ALS);
220 if (ret < 0) {
221 dev_err(&client->dev, "Error reading reg_addr_als\n");
222 return ret;
223 }
224
225 chip->regs_als = (u16)ret;
226 lux *= chip->regs_als;
227 lux *= als_info->calibscale;
228 lux = div_u64(lux, CM3232_CALIBSCALE_RESOLUTION);
229 lux = div_u64(lux, CM3232_MLUX_PER_LUX);
230
231 if (lux > 0xFFFF)
232 lux = 0xFFFF;
233
234 return (int)lux;
235}
236
237static int cm3232_read_raw(struct iio_dev *indio_dev,
238 struct iio_chan_spec const *chan,
239 int *val, int *val2, long mask)
240{
241 struct cm3232_chip *chip = iio_priv(indio_dev);
242 struct cm3232_als_info *als_info = chip->als_info;
243 int ret;
244
245 switch (mask) {
246 case IIO_CHAN_INFO_PROCESSED:
247 ret = cm3232_get_lux(chip);
248 if (ret < 0)
249 return ret;
250 *val = ret;
251 return IIO_VAL_INT;
252 case IIO_CHAN_INFO_CALIBSCALE:
253 *val = als_info->calibscale;
254 return IIO_VAL_INT;
255 case IIO_CHAN_INFO_INT_TIME:
256 return cm3232_read_als_it(chip, val, val2);
257 }
258
259 return -EINVAL;
260}
261
262static int cm3232_write_raw(struct iio_dev *indio_dev,
263 struct iio_chan_spec const *chan,
264 int val, int val2, long mask)
265{
266 struct cm3232_chip *chip = iio_priv(indio_dev);
267 struct cm3232_als_info *als_info = chip->als_info;
268
269 switch (mask) {
270 case IIO_CHAN_INFO_CALIBSCALE:
271 als_info->calibscale = val;
272 return 0;
273 case IIO_CHAN_INFO_INT_TIME:
274 return cm3232_write_als_it(chip, val, val2);
275 }
276
277 return -EINVAL;
278}
279
280/**
281 * cm3232_get_it_available() - Get available ALS IT value
282 * @dev: pointer of struct device.
283 * @attr: pointer of struct device_attribute.
284 * @buf: pointer of return string buffer.
285 *
286 * Display the available integration time in second.
287 *
288 * Return: string length.
289 */
290static ssize_t cm3232_get_it_available(struct device *dev,
291 struct device_attribute *attr, char *buf)
292{
293 int i, len;
294
295 for (i = 0, len = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++)
296 len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
297 cm3232_als_it_scales[i].val,
298 cm3232_als_it_scales[i].val2);
299 return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
300}
301
302static const struct iio_chan_spec cm3232_channels[] = {
303 {
304 .type = IIO_LIGHT,
305 .info_mask_separate =
306 BIT(IIO_CHAN_INFO_PROCESSED) |
307 BIT(IIO_CHAN_INFO_CALIBSCALE) |
308 BIT(IIO_CHAN_INFO_INT_TIME),
309 }
310};
311
312static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
313 S_IRUGO, cm3232_get_it_available, NULL, 0);
314
315static struct attribute *cm3232_attributes[] = {
316 &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
317 NULL,
318};
319
320static const struct attribute_group cm3232_attribute_group = {
321 .attrs = cm3232_attributes
322};
323
324static const struct iio_info cm3232_info = {
325 .driver_module = THIS_MODULE,
326 .read_raw = &cm3232_read_raw,
327 .write_raw = &cm3232_write_raw,
328 .attrs = &cm3232_attribute_group,
329};
330
331static int cm3232_probe(struct i2c_client *client,
332 const struct i2c_device_id *id)
333{
334 struct cm3232_chip *chip;
335 struct iio_dev *indio_dev;
336 int ret;
337
338 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
339 if (!indio_dev)
340 return -ENOMEM;
341
342 chip = iio_priv(indio_dev);
343 i2c_set_clientdata(client, indio_dev);
344 chip->client = client;
345
346 indio_dev->dev.parent = &client->dev;
347 indio_dev->channels = cm3232_channels;
348 indio_dev->num_channels = ARRAY_SIZE(cm3232_channels);
349 indio_dev->info = &cm3232_info;
350 indio_dev->name = id->name;
351 indio_dev->modes = INDIO_DIRECT_MODE;
352
353 ret = cm3232_reg_init(chip);
354 if (ret) {
355 dev_err(&client->dev,
356 "%s: register init failed\n",
357 __func__);
358 return ret;
359 }
360
361 return iio_device_register(indio_dev);
362}
363
364static int cm3232_remove(struct i2c_client *client)
365{
366 struct iio_dev *indio_dev = i2c_get_clientdata(client);
367
368 i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
369 CM3232_CMD_ALS_DISABLE);
370
371 iio_device_unregister(indio_dev);
372
373 return 0;
374}
375
376static const struct i2c_device_id cm3232_id[] = {
377 {"cm3232", 0},
378 {}
379};
380
381#ifdef CONFIG_PM_SLEEP
382static int cm3232_suspend(struct device *dev)
383{
384 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
385 struct cm3232_chip *chip = iio_priv(indio_dev);
386 struct i2c_client *client = chip->client;
387 int ret;
388
389 chip->regs_cmd |= CM3232_CMD_ALS_DISABLE;
390 ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
391 chip->regs_cmd);
392
393 return ret;
394}
395
396static int cm3232_resume(struct device *dev)
397{
398 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
399 struct cm3232_chip *chip = iio_priv(indio_dev);
400 struct i2c_client *client = chip->client;
401 int ret;
402
403 chip->regs_cmd &= ~CM3232_CMD_ALS_DISABLE;
404 ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
405 chip->regs_cmd | CM3232_CMD_ALS_RESET);
406
407 return ret;
408}
409
410static const struct dev_pm_ops cm3232_pm_ops = {
411 SET_SYSTEM_SLEEP_PM_OPS(cm3232_suspend, cm3232_resume)};
412#endif
413
414MODULE_DEVICE_TABLE(i2c, cm3232_id);
415
416static const struct of_device_id cm3232_of_match[] = {
417 {.compatible = "capella,cm3232"},
418 {}
419};
420MODULE_DEVICE_TABLE(of, cm3232_of_match);
421
422static struct i2c_driver cm3232_driver = {
423 .driver = {
424 .name = "cm3232",
425 .of_match_table = of_match_ptr(cm3232_of_match),
426#ifdef CONFIG_PM_SLEEP
427 .pm = &cm3232_pm_ops,
428#endif
429 },
430 .id_table = cm3232_id,
431 .probe = cm3232_probe,
432 .remove = cm3232_remove,
433};
434
435module_i2c_driver(cm3232_driver);
436
437MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
438MODULE_DESCRIPTION("CM3232 ambient light sensor driver");
439MODULE_LICENSE("GPL");