xref: /linux/drivers/iio/light/cm32181.c (revision 2a2dfc869d3345ccdd91322b023f4b0da84acbe7) 
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/acpi.h>
8 #include <linux/delay.h>
9 #include <linux/err.h>
10 #include <linux/i2c.h>
11 #include <linux/mutex.h>
12 #include <linux/module.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/interrupt.h>
15 #include <linux/regulator/consumer.h>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
18 #include <linux/iio/events.h>
19 #include <linux/init.h>
20 
21 /* Registers Address */
22 #define CM32181_REG_ADDR_CMD		0x00
23 #define CM32181_REG_ADDR_WH		0x01
24 #define CM32181_REG_ADDR_WL		0x02
25 #define CM32181_REG_ADDR_TEST		0x03
26 #define CM32181_REG_ADDR_ALS		0x04
27 #define CM32181_REG_ADDR_STATUS		0x06
28 #define CM32181_REG_ADDR_ID		0x07
29 
30 /* Number of Configurable Registers */
31 #define CM32181_CONF_REG_NUM		4
32 
33 /* CMD register */
34 #define CM32181_CMD_ALS_DISABLE		BIT(0)
35 #define CM32181_CMD_ALS_INT_EN		BIT(1)
36 #define CM32181_CMD_ALS_THRES_WINDOW	BIT(2)
37 
38 #define CM32181_CMD_ALS_PERS_SHIFT	4
39 #define CM32181_CMD_ALS_PERS_MASK	(0x03 << CM32181_CMD_ALS_PERS_SHIFT)
40 #define CM32181_CMD_ALS_PERS_DEFAULT	(0x01 << CM32181_CMD_ALS_PERS_SHIFT)
41 
42 #define CM32181_CMD_ALS_IT_SHIFT	6
43 #define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)
44 #define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)
45 
46 #define CM32181_CMD_ALS_SM_SHIFT	11
47 #define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)
48 #define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)
49 
50 #define CM32181_LUX_PER_BIT		500	/* ALS_SM=01 IT=800ms */
51 #define CM32181_LUX_PER_BIT_RESOLUTION	100000
52 #define CM32181_LUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */
53 #define CM32181_CALIBSCALE_DEFAULT	100000
54 #define CM32181_CALIBSCALE_RESOLUTION	100000
55 
56 #define SMBUS_ALERT_RESPONSE_ADDRESS	0x0c
57 
58 /* CPM0 Index 0: device-id (3218 or 32181), 1: Unknown, 2: init_regs_bitmap */
59 #define CPM0_REGS_BITMAP		2
60 #define CPM0_HEADER_SIZE		3
61 
62 /* CPM1 Index 0: lux_per_bit, 1: calibscale, 2: resolution (100000) */
63 #define CPM1_LUX_PER_BIT		0
64 #define CPM1_CALIBSCALE			1
65 #define CPM1_SIZE			3
66 
67 /* CM3218 Family */
68 static const int cm3218_als_it_bits[] = { 0, 1, 2, 3 };
69 static const int cm3218_als_it_values[] = { 100000, 200000, 400000, 800000 };
70 
71 /* CM32181 Family */
72 static const int cm32181_als_it_bits[] = { 12, 8, 0, 1, 2, 3 };
73 static const int cm32181_als_it_values[] = {
74 	25000, 50000, 100000, 200000, 400000, 800000
75 };
76 
77 struct cm32181_chip {
78 	struct i2c_client *client;
79 	struct device *dev;
80 	struct mutex lock;
81 	u16 conf_regs[CM32181_CONF_REG_NUM];
82 	unsigned long init_regs_bitmap;
83 	int calibscale;
84 	int lux_per_bit;
85 	int lux_per_bit_base_it;
86 	int num_als_it;
87 	const int *als_it_bits;
88 	const int *als_it_values;
89 };
90 
91 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2);
92 
93 #ifdef CONFIG_ACPI
94 /**
95  * cm32181_acpi_get_cpm() - Get CPM object from ACPI
96  * @dev:	pointer of struct device.
97  * @obj_name:	pointer of ACPI object name.
98  * @values:	pointer of array for return elements.
99  * @count:	maximum size of return array.
100  *
101  * Convert ACPI CPM table to array.
102  *
103  * Return: -ENODEV for fail.  Otherwise is number of elements.
104  */
105 static int cm32181_acpi_get_cpm(struct device *dev, char *obj_name,
106 				u64 *values, int count)
107 {
108 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
109 	union acpi_object *cpm, *elem;
110 	acpi_handle handle;
111 	acpi_status status;
112 	int i;
113 
114 	handle = ACPI_HANDLE(dev);
115 	if (!handle)
116 		return -ENODEV;
117 
118 	status = acpi_evaluate_object(handle, obj_name, NULL, &buffer);
119 	if (ACPI_FAILURE(status)) {
120 		dev_err(dev, "object %s not found\n", obj_name);
121 		return -ENODEV;
122 	}
123 
124 	cpm = buffer.pointer;
125 	if (cpm->package.count > count)
126 		dev_warn(dev, "%s table contains %u values, only using first %d values\n",
127 			 obj_name, cpm->package.count, count);
128 
129 	count = min_t(int, cpm->package.count, count);
130 	for (i = 0; i < count; i++) {
131 		elem = &(cpm->package.elements[i]);
132 		values[i] = elem->integer.value;
133 	}
134 
135 	kfree(buffer.pointer);
136 
137 	return count;
138 }
139 
140 static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181)
141 {
142 	u64 vals[CPM0_HEADER_SIZE + CM32181_CONF_REG_NUM];
143 	struct device *dev = cm32181->dev;
144 	int i, count;
145 
146 	count = cm32181_acpi_get_cpm(dev, "CPM0", vals, ARRAY_SIZE(vals));
147 	if (count <= CPM0_HEADER_SIZE)
148 		return;
149 
150 	count -= CPM0_HEADER_SIZE;
151 
152 	cm32181->init_regs_bitmap = vals[CPM0_REGS_BITMAP];
153 	cm32181->init_regs_bitmap &= GENMASK(count - 1, 0);
154 	for_each_set_bit(i, &cm32181->init_regs_bitmap, count)
155 		cm32181->conf_regs[i] =	vals[CPM0_HEADER_SIZE + i];
156 
157 	count = cm32181_acpi_get_cpm(dev, "CPM1", vals, ARRAY_SIZE(vals));
158 	if (count != CPM1_SIZE)
159 		return;
160 
161 	cm32181->lux_per_bit = vals[CPM1_LUX_PER_BIT];
162 
163 	/* Check for uncalibrated devices */
164 	if (vals[CPM1_CALIBSCALE] == CM32181_CALIBSCALE_DEFAULT)
165 		return;
166 
167 	cm32181->calibscale = vals[CPM1_CALIBSCALE];
168 	/* CPM1 lux_per_bit is for the current it value */
169 	cm32181_read_als_it(cm32181, &cm32181->lux_per_bit_base_it);
170 }
171 #else
172 static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181)
173 {
174 }
175 #endif /* CONFIG_ACPI */
176 
177 /**
178  * cm32181_reg_init() - Initialize CM32181 registers
179  * @cm32181:	pointer of struct cm32181.
180  *
181  * Initialize CM32181 ambient light sensor register to default values.
182  *
183  * Return: 0 for success; otherwise for error code.
184  */
185 static int cm32181_reg_init(struct cm32181_chip *cm32181)
186 {
187 	struct i2c_client *client = cm32181->client;
188 	int i;
189 	s32 ret;
190 
191 	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
192 	if (ret < 0)
193 		return ret;
194 
195 	/* check device ID */
196 	switch (ret & 0xFF) {
197 	case 0x18: /* CM3218 */
198 		cm32181->num_als_it = ARRAY_SIZE(cm3218_als_it_bits);
199 		cm32181->als_it_bits = cm3218_als_it_bits;
200 		cm32181->als_it_values = cm3218_als_it_values;
201 		break;
202 	case 0x81: /* CM32181 */
203 	case 0x82: /* CM32182, fully compat. with CM32181 */
204 		cm32181->num_als_it = ARRAY_SIZE(cm32181_als_it_bits);
205 		cm32181->als_it_bits = cm32181_als_it_bits;
206 		cm32181->als_it_values = cm32181_als_it_values;
207 		break;
208 	default:
209 		return -ENODEV;
210 	}
211 
212 	/* Default Values */
213 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] =
214 			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
215 	cm32181->init_regs_bitmap = BIT(CM32181_REG_ADDR_CMD);
216 	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
217 	cm32181->lux_per_bit = CM32181_LUX_PER_BIT;
218 	cm32181->lux_per_bit_base_it = CM32181_LUX_PER_BIT_BASE_IT;
219 
220 	if (ACPI_HANDLE(cm32181->dev))
221 		cm32181_acpi_parse_cpm_tables(cm32181);
222 
223 	/* Initialize registers*/
224 	for_each_set_bit(i, &cm32181->init_regs_bitmap, CM32181_CONF_REG_NUM) {
225 		ret = i2c_smbus_write_word_data(client, i,
226 						cm32181->conf_regs[i]);
227 		if (ret < 0)
228 			return ret;
229 	}
230 
231 	return 0;
232 }
233 
234 /**
235  *  cm32181_read_als_it() - Get sensor integration time (ms)
236  *  @cm32181:	pointer of struct cm32181
237  *  @val2:	pointer of int to load the als_it value.
238  *
239  *  Report the current integration time in milliseconds.
240  *
241  *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
242  */
243 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
244 {
245 	u16 als_it;
246 	int i;
247 
248 	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
249 	als_it &= CM32181_CMD_ALS_IT_MASK;
250 	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
251 	for (i = 0; i < cm32181->num_als_it; i++) {
252 		if (als_it == cm32181->als_it_bits[i]) {
253 			*val2 = cm32181->als_it_values[i];
254 			return IIO_VAL_INT_PLUS_MICRO;
255 		}
256 	}
257 
258 	return -EINVAL;
259 }
260 
261 /**
262  * cm32181_write_als_it() - Write sensor integration time
263  * @cm32181:	pointer of struct cm32181.
264  * @val:	integration time by millisecond.
265  *
266  * Convert integration time (ms) to sensor value.
267  *
268  * Return: i2c_smbus_write_word_data command return value.
269  */
270 static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
271 {
272 	struct i2c_client *client = cm32181->client;
273 	u16 als_it;
274 	int ret, i, n;
275 
276 	n = cm32181->num_als_it;
277 	for (i = 0; i < n; i++)
278 		if (val <= cm32181->als_it_values[i])
279 			break;
280 	if (i >= n)
281 		i = n - 1;
282 
283 	als_it = cm32181->als_it_bits[i];
284 	als_it <<= CM32181_CMD_ALS_IT_SHIFT;
285 
286 	mutex_lock(&cm32181->lock);
287 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
288 		~CM32181_CMD_ALS_IT_MASK;
289 	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
290 		als_it;
291 	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
292 			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
293 	mutex_unlock(&cm32181->lock);
294 
295 	return ret;
296 }
297 
298 /**
299  * cm32181_get_lux() - report current lux value
300  * @cm32181:	pointer of struct cm32181.
301  *
302  * Convert sensor raw data to lux.  It depends on integration
303  * time and calibscale variable.
304  *
305  * Return: Positive value is lux, otherwise is error code.
306  */
307 static int cm32181_get_lux(struct cm32181_chip *cm32181)
308 {
309 	struct i2c_client *client = cm32181->client;
310 	int ret;
311 	int als_it;
312 	u64 lux;
313 
314 	ret = cm32181_read_als_it(cm32181, &als_it);
315 	if (ret < 0)
316 		return -EINVAL;
317 
318 	lux = cm32181->lux_per_bit;
319 	lux *= cm32181->lux_per_bit_base_it;
320 	lux = div_u64(lux, als_it);
321 
322 	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
323 	if (ret < 0)
324 		return ret;
325 
326 	lux *= ret;
327 	lux *= cm32181->calibscale;
328 	lux = div_u64(lux, CM32181_CALIBSCALE_RESOLUTION);
329 	lux = div_u64(lux, CM32181_LUX_PER_BIT_RESOLUTION);
330 
331 	if (lux > 0xFFFF)
332 		lux = 0xFFFF;
333 
334 	return lux;
335 }
336 
337 static int cm32181_read_raw(struct iio_dev *indio_dev,
338 			    struct iio_chan_spec const *chan,
339 			    int *val, int *val2, long mask)
340 {
341 	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
342 	int ret;
343 
344 	switch (mask) {
345 	case IIO_CHAN_INFO_PROCESSED:
346 		ret = cm32181_get_lux(cm32181);
347 		if (ret < 0)
348 			return ret;
349 		*val = ret;
350 		return IIO_VAL_INT;
351 	case IIO_CHAN_INFO_CALIBSCALE:
352 		*val = cm32181->calibscale;
353 		return IIO_VAL_INT;
354 	case IIO_CHAN_INFO_INT_TIME:
355 		*val = 0;
356 		ret = cm32181_read_als_it(cm32181, val2);
357 		return ret;
358 	}
359 
360 	return -EINVAL;
361 }
362 
363 static int cm32181_write_raw(struct iio_dev *indio_dev,
364 			     struct iio_chan_spec const *chan,
365 			     int val, int val2, long mask)
366 {
367 	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
368 	int ret;
369 
370 	switch (mask) {
371 	case IIO_CHAN_INFO_CALIBSCALE:
372 		cm32181->calibscale = val;
373 		return val;
374 	case IIO_CHAN_INFO_INT_TIME:
375 		ret = cm32181_write_als_it(cm32181, val2);
376 		return ret;
377 	}
378 
379 	return -EINVAL;
380 }
381 
382 /**
383  * cm32181_get_it_available() - Get available ALS IT value
384  * @dev:	pointer of struct device.
385  * @attr:	pointer of struct device_attribute.
386  * @buf:	pointer of return string buffer.
387  *
388  * Display the available integration time values by millisecond.
389  *
390  * Return: string length.
391  */
392 static ssize_t cm32181_get_it_available(struct device *dev,
393 			struct device_attribute *attr, char *buf)
394 {
395 	struct cm32181_chip *cm32181 = iio_priv(dev_to_iio_dev(dev));
396 	int i, n, len;
397 
398 	n = cm32181->num_als_it;
399 	for (i = 0, len = 0; i < n; i++)
400 		len += sprintf(buf + len, "0.%06u ", cm32181->als_it_values[i]);
401 	return len + sprintf(buf + len, "\n");
402 }
403 
404 static const struct iio_chan_spec cm32181_channels[] = {
405 	{
406 		.type = IIO_LIGHT,
407 		.info_mask_separate =
408 			BIT(IIO_CHAN_INFO_PROCESSED) |
409 			BIT(IIO_CHAN_INFO_CALIBSCALE) |
410 			BIT(IIO_CHAN_INFO_INT_TIME),
411 	}
412 };
413 
414 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
415 			S_IRUGO, cm32181_get_it_available, NULL, 0);
416 
417 static struct attribute *cm32181_attributes[] = {
418 	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
419 	NULL,
420 };
421 
422 static const struct attribute_group cm32181_attribute_group = {
423 	.attrs = cm32181_attributes
424 };
425 
426 static const struct iio_info cm32181_info = {
427 	.read_raw		= &cm32181_read_raw,
428 	.write_raw		= &cm32181_write_raw,
429 	.attrs			= &cm32181_attribute_group,
430 };
431 
432 static int cm32181_probe(struct i2c_client *client)
433 {
434 	struct device *dev = &client->dev;
435 	struct cm32181_chip *cm32181;
436 	struct iio_dev *indio_dev;
437 	int ret;
438 
439 	indio_dev = devm_iio_device_alloc(dev, sizeof(*cm32181));
440 	if (!indio_dev)
441 		return -ENOMEM;
442 
443 	/*
444 	 * Some ACPI systems list 2 I2C resources for the CM3218 sensor, the
445 	 * SMBus Alert Response Address (ARA, 0x0c) and the actual I2C address.
446 	 * Detect this and take the following step to deal with it:
447 	 * 1. When a SMBus Alert capable sensor has an Alert asserted, it will
448 	 *    not respond on its actual I2C address. Read a byte from the ARA
449 	 *    to clear any pending Alerts.
450 	 * 2. Create a "dummy" client for the actual I2C address and
451 	 *    use that client to communicate with the sensor.
452 	 */
453 	if (ACPI_HANDLE(dev) && client->addr == SMBUS_ALERT_RESPONSE_ADDRESS) {
454 		struct i2c_board_info board_info = { .type = "dummy" };
455 
456 		i2c_smbus_read_byte(client);
457 
458 		client = i2c_acpi_new_device(dev, 1, &board_info);
459 		if (IS_ERR(client))
460 			return PTR_ERR(client);
461 	}
462 
463 	i2c_set_clientdata(client, indio_dev);
464 
465 	cm32181 = iio_priv(indio_dev);
466 	cm32181->client = client;
467 	cm32181->dev = dev;
468 
469 	mutex_init(&cm32181->lock);
470 	indio_dev->channels = cm32181_channels;
471 	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
472 	indio_dev->info = &cm32181_info;
473 	indio_dev->name = dev_name(dev);
474 	indio_dev->modes = INDIO_DIRECT_MODE;
475 
476 	ret = cm32181_reg_init(cm32181);
477 	if (ret) {
478 		dev_err(dev, "%s: register init failed\n", __func__);
479 		return ret;
480 	}
481 
482 	ret = devm_iio_device_register(dev, indio_dev);
483 	if (ret) {
484 		dev_err(dev, "%s: regist device failed\n", __func__);
485 		return ret;
486 	}
487 
488 	return 0;
489 }
490 
491 static int cm32181_suspend(struct device *dev)
492 {
493 	struct i2c_client *client = to_i2c_client(dev);
494 
495 	return i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
496 					 CM32181_CMD_ALS_DISABLE);
497 }
498 
499 static int cm32181_resume(struct device *dev)
500 {
501 	struct i2c_client *client = to_i2c_client(dev);
502 	struct cm32181_chip *cm32181 = iio_priv(dev_get_drvdata(dev));
503 
504 	return i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
505 					 cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
506 }
507 
508 DEFINE_SIMPLE_DEV_PM_OPS(cm32181_pm_ops, cm32181_suspend, cm32181_resume);
509 
510 static const struct of_device_id cm32181_of_match[] = {
511 	{ .compatible = "capella,cm3218" },
512 	{ .compatible = "capella,cm32181" },
513 	{ }
514 };
515 MODULE_DEVICE_TABLE(of, cm32181_of_match);
516 
517 #ifdef CONFIG_ACPI
518 static const struct acpi_device_id cm32181_acpi_match[] = {
519 	{ "CPLM3218", 0 },
520 	{ }
521 };
522 MODULE_DEVICE_TABLE(acpi, cm32181_acpi_match);
523 #endif
524 
525 static struct i2c_driver cm32181_driver = {
526 	.driver = {
527 		.name	= "cm32181",
528 		.acpi_match_table = ACPI_PTR(cm32181_acpi_match),
529 		.of_match_table = cm32181_of_match,
530 		.pm = pm_sleep_ptr(&cm32181_pm_ops),
531 	},
532 	.probe_new	= cm32181_probe,
533 };
534 
535 module_i2c_driver(cm32181_driver);
536 
537 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
538 MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
539 MODULE_LICENSE("GPL");
540