cm3232.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * CM3232 Ambient Light Sensor
  4 *
  5 * Copyright (C) 2014-2015 Capella Microsystems Inc.
  6 * Author: Kevin Tsai <ktsai@capellamicro.com>
  7 *
  8 * IIO driver for CM3232 (7-bit I2C slave address 0x10).
  9 */
 10
 11#include <linux/i2c.h>
 12#include <linux/module.h>
 13#include <linux/mod_devicetable.h>
 14#include <linux/iio/iio.h>
 15#include <linux/iio/sysfs.h>
 16#include <linux/init.h>
 17
 18/* Registers Address */
 19#define CM3232_REG_ADDR_CMD		0x00
 20#define CM3232_REG_ADDR_ALS		0x50
 21#define CM3232_REG_ADDR_ID		0x53
 22
 23#define CM3232_CMD_ALS_DISABLE		BIT(0)
 24
 25#define CM3232_CMD_ALS_IT_SHIFT		2
 26#define CM3232_CMD_ALS_IT_MASK		(BIT(2) | BIT(3) | BIT(4))
 27#define CM3232_CMD_ALS_IT_DEFAULT	(0x01 << CM3232_CMD_ALS_IT_SHIFT)
 28
 29#define CM3232_CMD_ALS_RESET		BIT(6)
 30
 31#define CM3232_CMD_DEFAULT		CM3232_CMD_ALS_IT_DEFAULT
 32
 33#define CM3232_HW_ID			0x32
 34#define CM3232_CALIBSCALE_DEFAULT	100000
 35#define CM3232_CALIBSCALE_RESOLUTION	100000
 36#define CM3232_MLUX_PER_LUX		1000
 37
 38#define CM3232_MLUX_PER_BIT_DEFAULT	64
 39#define CM3232_MLUX_PER_BIT_BASE_IT	100000
 40
 41static const struct {
 42	int val;
 43	int val2;
 44	u8 it;
 45} cm3232_als_it_scales[] = {
 46	{0, 100000, 0},	/* 0.100000 */
 47	{0, 200000, 1},	/* 0.200000 */
 48	{0, 400000, 2},	/* 0.400000 */
 49	{0, 800000, 3},	/* 0.800000 */
 50	{1, 600000, 4},	/* 1.600000 */
 51	{3, 200000, 5},	/* 3.200000 */
 52};
 53
 54struct cm3232_als_info {
 55	u8 regs_cmd_default;
 56	u8 hw_id;
 57	int mlux_per_bit;
 58	int mlux_per_bit_base_it;
 59};
 60
 61static const struct cm3232_als_info cm3232_als_info_default = {
 62	.regs_cmd_default = CM3232_CMD_DEFAULT,
 63	.hw_id = CM3232_HW_ID,
 64	.mlux_per_bit = CM3232_MLUX_PER_BIT_DEFAULT,
 65	.mlux_per_bit_base_it = CM3232_MLUX_PER_BIT_BASE_IT,
 66};
 67
 68struct cm3232_chip {
 69	struct i2c_client *client;
 70	const struct cm3232_als_info *als_info;
 71	int calibscale;
 72	u8 regs_cmd;
 73	u16 regs_als;
 74};
 75
 76/**
 77 * cm3232_reg_init() - Initialize CM3232
 78 * @chip:	pointer of struct cm3232_chip.
 79 *
 80 * Check and initialize CM3232 ambient light sensor.
 81 *
 82 * Return: 0 for success; otherwise for error code.
 83 */
 84static int cm3232_reg_init(struct cm3232_chip *chip)
 85{
 86	struct i2c_client *client = chip->client;
 87	s32 ret;
 88
 89	chip->als_info = &cm3232_als_info_default;
 90
 91	/* Disable and reset device */
 92	chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET;
 93	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 94					chip->regs_cmd);
 95	if (ret < 0) {
 96		dev_err(&chip->client->dev, "Error writing reg_cmd\n");
 97		return ret;
 98	}
 99
100	/* Identify device */
101	ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID);
102	if (ret < 0) {
103		dev_err(&chip->client->dev, "Error reading addr_id\n");
104		return ret;
105	}
106
107	if ((ret & 0xFF) != chip->als_info->hw_id)
108		return -ENODEV;
109
110	/* Register default value */
111	chip->regs_cmd = chip->als_info->regs_cmd_default;
112
113	/* Configure register */
114	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
115					chip->regs_cmd);
116	if (ret < 0)
117		dev_err(&chip->client->dev, "Error writing reg_cmd\n");
118
119	return ret;
120}
121
122/**
123 *  cm3232_read_als_it() - Get sensor integration time
124 *  @chip:	pointer of struct cm3232_chip
125 *  @val:	pointer of int to load the integration (sec).
126 *  @val2:	pointer of int to load the integration time (microsecond).
127 *
128 *  Report the current integration time.
129 *
130 *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
131 */
132static int cm3232_read_als_it(struct cm3232_chip *chip, int *val, int *val2)
133{
134	u16 als_it;
135	int i;
136
137	als_it = chip->regs_cmd;
138	als_it &= CM3232_CMD_ALS_IT_MASK;
139	als_it >>= CM3232_CMD_ALS_IT_SHIFT;
140	for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
141		if (als_it == cm3232_als_it_scales[i].it) {
142			*val = cm3232_als_it_scales[i].val;
143			*val2 = cm3232_als_it_scales[i].val2;
144			return IIO_VAL_INT_PLUS_MICRO;
145		}
146	}
147
148	return -EINVAL;
149}
150
151/**
152 * cm3232_write_als_it() - Write sensor integration time
153 * @chip:	pointer of struct cm3232_chip.
154 * @val:	integration time in second.
155 * @val2:	integration time in microsecond.
156 *
157 * Convert integration time to sensor value.
158 *
159 * Return: i2c_smbus_write_byte_data command return value.
160 */
161static int cm3232_write_als_it(struct cm3232_chip *chip, int val, int val2)
162{
163	struct i2c_client *client = chip->client;
164	u16 als_it, cmd;
165	int i;
166	s32 ret;
167
168	for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
169		if (val == cm3232_als_it_scales[i].val &&
170			val2 == cm3232_als_it_scales[i].val2) {
171
172			als_it = cm3232_als_it_scales[i].it;
173			als_it <<= CM3232_CMD_ALS_IT_SHIFT;
174
175			cmd = chip->regs_cmd & ~CM3232_CMD_ALS_IT_MASK;
176			cmd |= als_it;
177			ret = i2c_smbus_write_byte_data(client,
178							CM3232_REG_ADDR_CMD,
179							cmd);
180			if (ret < 0)
181				return ret;
182			chip->regs_cmd = cmd;
183			return 0;
184		}
185	}
186	return -EINVAL;
187}
188
189/**
190 * cm3232_get_lux() - report current lux value
191 * @chip:	pointer of struct cm3232_chip.
192 *
193 * Convert sensor data to lux.  It depends on integration
194 * time and calibscale variable.
195 *
196 * Return: Zero or positive value is lux, otherwise error code.
197 */
198static int cm3232_get_lux(struct cm3232_chip *chip)
199{
200	struct i2c_client *client = chip->client;
201	const struct cm3232_als_info *als_info = chip->als_info;
202	int ret;
203	int val, val2;
204	int als_it;
205	u64 lux;
206
207	/* Calculate mlux per bit based on als_it */
208	ret = cm3232_read_als_it(chip, &val, &val2);
209	if (ret < 0)
210		return -EINVAL;
211	als_it = val * 1000000 + val2;
212	lux = (__force u64)als_info->mlux_per_bit;
213	lux *= als_info->mlux_per_bit_base_it;
214	lux = div_u64(lux, als_it);
215
216	ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ALS);
217	if (ret < 0) {
218		dev_err(&client->dev, "Error reading reg_addr_als\n");
219		return ret;
220	}
221
222	chip->regs_als = (u16)ret;
223	lux *= chip->regs_als;
224	lux *= chip->calibscale;
225	lux = div_u64(lux, CM3232_CALIBSCALE_RESOLUTION);
226	lux = div_u64(lux, CM3232_MLUX_PER_LUX);
227
228	if (lux > 0xFFFF)
229		lux = 0xFFFF;
230
231	return (int)lux;
232}
233
234static int cm3232_read_raw(struct iio_dev *indio_dev,
235			struct iio_chan_spec const *chan,
236			int *val, int *val2, long mask)
237{
238	struct cm3232_chip *chip = iio_priv(indio_dev);
239	int ret;
240
241	switch (mask) {
242	case IIO_CHAN_INFO_PROCESSED:
243		ret = cm3232_get_lux(chip);
244		if (ret < 0)
245			return ret;
246		*val = ret;
247		return IIO_VAL_INT;
248	case IIO_CHAN_INFO_CALIBSCALE:
249		*val = chip->calibscale;
250		return IIO_VAL_INT;
251	case IIO_CHAN_INFO_INT_TIME:
252		return cm3232_read_als_it(chip, val, val2);
253	}
254
255	return -EINVAL;
256}
257
258static int cm3232_write_raw(struct iio_dev *indio_dev,
259			struct iio_chan_spec const *chan,
260			int val, int val2, long mask)
261{
262	struct cm3232_chip *chip = iio_priv(indio_dev);
263
264	switch (mask) {
265	case IIO_CHAN_INFO_CALIBSCALE:
266		chip->calibscale = val;
267		return 0;
268	case IIO_CHAN_INFO_INT_TIME:
269		return cm3232_write_als_it(chip, val, val2);
270	}
271
272	return -EINVAL;
273}
274
275/**
276 * cm3232_get_it_available() - Get available ALS IT value
277 * @dev:	pointer of struct device.
278 * @attr:	pointer of struct device_attribute.
279 * @buf:	pointer of return string buffer.
280 *
281 * Display the available integration time in second.
282 *
283 * Return: string length.
284 */
285static ssize_t cm3232_get_it_available(struct device *dev,
286			struct device_attribute *attr, char *buf)
287{
288	int i, len;
289
290	for (i = 0, len = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++)
291		len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
292			cm3232_als_it_scales[i].val,
293			cm3232_als_it_scales[i].val2);
294	return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
295}
296
297static const struct iio_chan_spec cm3232_channels[] = {
298	{
299		.type = IIO_LIGHT,
300		.info_mask_separate =
301			BIT(IIO_CHAN_INFO_PROCESSED) |
302			BIT(IIO_CHAN_INFO_CALIBSCALE) |
303			BIT(IIO_CHAN_INFO_INT_TIME),
304	}
305};
306
307static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
308			S_IRUGO, cm3232_get_it_available, NULL, 0);
309
310static struct attribute *cm3232_attributes[] = {
311	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
312	NULL,
313};
314
315static const struct attribute_group cm3232_attribute_group = {
316	.attrs = cm3232_attributes
317};
318
319static const struct iio_info cm3232_info = {
320	.read_raw		= &cm3232_read_raw,
321	.write_raw		= &cm3232_write_raw,
322	.attrs			= &cm3232_attribute_group,
323};
324
325static int cm3232_probe(struct i2c_client *client)
326{
327	const struct i2c_device_id *id = i2c_client_get_device_id(client);
328	struct cm3232_chip *chip;
329	struct iio_dev *indio_dev;
330	int ret;
331
332	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
333	if (!indio_dev)
334		return -ENOMEM;
335
336	chip = iio_priv(indio_dev);
337	i2c_set_clientdata(client, indio_dev);
338	chip->client = client;
339	chip->calibscale = CM3232_CALIBSCALE_DEFAULT;
340
341	indio_dev->channels = cm3232_channels;
342	indio_dev->num_channels = ARRAY_SIZE(cm3232_channels);
343	indio_dev->info = &cm3232_info;
344	indio_dev->name = id->name;
345	indio_dev->modes = INDIO_DIRECT_MODE;
346
347	ret = cm3232_reg_init(chip);
348	if (ret) {
349		dev_err(&client->dev,
350			"%s: register init failed\n",
351			__func__);
352		return ret;
353	}
354
355	return iio_device_register(indio_dev);
356}
357
358static void cm3232_remove(struct i2c_client *client)
359{
360	struct iio_dev *indio_dev = i2c_get_clientdata(client);
361
362	i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
363		CM3232_CMD_ALS_DISABLE);
364
365	iio_device_unregister(indio_dev);
366}
367
368static const struct i2c_device_id cm3232_id[] = {
369	{ "cm3232" },
370	{ }
371};
372
373static int cm3232_suspend(struct device *dev)
374{
375	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
376	struct cm3232_chip *chip = iio_priv(indio_dev);
377	struct i2c_client *client = chip->client;
378	int ret;
379
380	chip->regs_cmd |= CM3232_CMD_ALS_DISABLE;
381	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
382					chip->regs_cmd);
383
384	return ret;
385}
386
387static int cm3232_resume(struct device *dev)
388{
389	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
390	struct cm3232_chip *chip = iio_priv(indio_dev);
391	struct i2c_client *client = chip->client;
392	int ret;
393
394	chip->regs_cmd &= ~CM3232_CMD_ALS_DISABLE;
395	ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
396					chip->regs_cmd | CM3232_CMD_ALS_RESET);
397
398	return ret;
399}
400
401static DEFINE_SIMPLE_DEV_PM_OPS(cm3232_pm_ops, cm3232_suspend, cm3232_resume);
402
403MODULE_DEVICE_TABLE(i2c, cm3232_id);
404
405static const struct of_device_id cm3232_of_match[] = {
406	{.compatible = "capella,cm3232"},
407	{ }
408};
409MODULE_DEVICE_TABLE(of, cm3232_of_match);
410
411static struct i2c_driver cm3232_driver = {
412	.driver = {
413		.name	= "cm3232",
414		.of_match_table = cm3232_of_match,
415		.pm	= pm_sleep_ptr(&cm3232_pm_ops),
416	},
417	.id_table	= cm3232_id,
418	.probe		= cm3232_probe,
419	.remove		= cm3232_remove,
420};
421
422module_i2c_driver(cm3232_driver);
423
424MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
425MODULE_DESCRIPTION("CM3232 ambient light sensor driver");
426MODULE_LICENSE("GPL");