1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light sensor driver
4 *
5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 *
7 * Data sheets:
8 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1710fvc-e.pdf
9 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1715fvc-e.pdf
10 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf
11 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
12 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1751fvi-e.pdf
13 *
14 * 7-bit I2C slave addresses:
15 *  0x23 (ADDR pin low)
16 *  0x5C (ADDR pin high)
17 *
18 */
19
20#include <linux/delay.h>
21#include <linux/i2c.h>
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24#include <linux/module.h>
25
26#define BH1750_POWER_DOWN		0x00
27#define BH1750_ONE_TIME_H_RES_MODE	0x20 /* auto-mode for BH1721 */
28#define BH1750_CHANGE_INT_TIME_H_BIT	0x40
29#define BH1750_CHANGE_INT_TIME_L_BIT	0x60
30
31enum {
32	BH1710,
33	BH1721,
34	BH1750,
35};
36
37struct bh1750_chip_info;
38struct bh1750_data {
39	struct i2c_client *client;
40	struct mutex lock;
41	const struct bh1750_chip_info *chip_info;
42	u16 mtreg;
43};
44
45struct bh1750_chip_info {
46	u16 mtreg_min;
47	u16 mtreg_max;
48	u16 mtreg_default;
49	int mtreg_to_usec;
50	int mtreg_to_scale;
51
52	/*
53	 * For BH1710/BH1721 all possible integration time values won't fit
54	 * into one page so displaying is limited to every second one.
55	 * Note, that user can still write proper values which were not
56	 * listed.
57	 */
58	int inc;
59
60	u16 int_time_low_mask;
61	u16 int_time_high_mask;
62};
63
64static const struct bh1750_chip_info bh1750_chip_info_tbl[] = {
65	[BH1710] = { 140, 1022, 300, 400,  250000000, 2, 0x001F, 0x03E0 },
66	[BH1721] = { 140, 1020, 300, 400,  250000000, 2, 0x0010, 0x03E0 },
67	[BH1750] = { 31,  254,  69,  1740, 57500000,  1, 0x001F, 0x00E0 },
68};
69
70static int bh1750_change_int_time(struct bh1750_data *data, int usec)
71{
72	int ret;
73	u16 val;
74	u8 regval;
75	const struct bh1750_chip_info *chip_info = data->chip_info;
76
77	if ((usec % chip_info->mtreg_to_usec) != 0)
78		return -EINVAL;
79
80	val = usec / chip_info->mtreg_to_usec;
81	if (val < chip_info->mtreg_min || val > chip_info->mtreg_max)
82		return -EINVAL;
83
84	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
85	if (ret < 0)
86		return ret;
87
88	regval = (val & chip_info->int_time_high_mask) >> 5;
89	ret = i2c_smbus_write_byte(data->client,
90				   BH1750_CHANGE_INT_TIME_H_BIT | regval);
91	if (ret < 0)
92		return ret;
93
94	regval = val & chip_info->int_time_low_mask;
95	ret = i2c_smbus_write_byte(data->client,
96				   BH1750_CHANGE_INT_TIME_L_BIT | regval);
97	if (ret < 0)
98		return ret;
99
100	data->mtreg = val;
101
102	return 0;
103}
104
105static int bh1750_read(struct bh1750_data *data, int *val)
106{
107	int ret;
108	__be16 result;
109	const struct bh1750_chip_info *chip_info = data->chip_info;
110	unsigned long delay = chip_info->mtreg_to_usec * data->mtreg;
111
112	/*
113	 * BH1721 will enter continuous mode on receiving this command.
114	 * Note, that this eliminates need for bh1750_resume().
115	 */
116	ret = i2c_smbus_write_byte(data->client, BH1750_ONE_TIME_H_RES_MODE);
117	if (ret < 0)
118		return ret;
119
120	usleep_range(delay + 15000, delay + 40000);
121
122	ret = i2c_master_recv(data->client, (char *)&result, 2);
123	if (ret < 0)
124		return ret;
125
126	*val = be16_to_cpu(result);
127
128	return 0;
129}
130
131static int bh1750_read_raw(struct iio_dev *indio_dev,
132			   struct iio_chan_spec const *chan,
133			   int *val, int *val2, long mask)
134{
135	int ret, tmp;
136	struct bh1750_data *data = iio_priv(indio_dev);
137	const struct bh1750_chip_info *chip_info = data->chip_info;
138
139	switch (mask) {
140	case IIO_CHAN_INFO_RAW:
141		switch (chan->type) {
142		case IIO_LIGHT:
143			mutex_lock(&data->lock);
144			ret = bh1750_read(data, val);
145			mutex_unlock(&data->lock);
146			if (ret < 0)
147				return ret;
148
149			return IIO_VAL_INT;
150		default:
151			return -EINVAL;
152		}
153	case IIO_CHAN_INFO_SCALE:
154		tmp = chip_info->mtreg_to_scale / data->mtreg;
155		*val = tmp / 1000000;
156		*val2 = tmp % 1000000;
157		return IIO_VAL_INT_PLUS_MICRO;
158	case IIO_CHAN_INFO_INT_TIME:
159		*val = 0;
160		*val2 = chip_info->mtreg_to_usec * data->mtreg;
161		return IIO_VAL_INT_PLUS_MICRO;
162	default:
163		return -EINVAL;
164	}
165}
166
167static int bh1750_write_raw(struct iio_dev *indio_dev,
168			    struct iio_chan_spec const *chan,
169			    int val, int val2, long mask)
170{
171	int ret;
172	struct bh1750_data *data = iio_priv(indio_dev);
173
174	switch (mask) {
175	case IIO_CHAN_INFO_INT_TIME:
176		if (val != 0)
177			return -EINVAL;
178
179		mutex_lock(&data->lock);
180		ret = bh1750_change_int_time(data, val2);
181		mutex_unlock(&data->lock);
182		return ret;
183	default:
184		return -EINVAL;
185	}
186}
187
188static ssize_t bh1750_show_int_time_available(struct device *dev,
189		struct device_attribute *attr, char *buf)
190{
191	int i;
192	size_t len = 0;
193	struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev));
194	const struct bh1750_chip_info *chip_info = data->chip_info;
195
196	for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += chip_info->inc)
197		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ",
198				 chip_info->mtreg_to_usec * i);
199
200	buf[len - 1] = '\n';
201
202	return len;
203}
204
205static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available);
206
207static struct attribute *bh1750_attributes[] = {
208	&iio_dev_attr_integration_time_available.dev_attr.attr,
209	NULL,
210};
211
212static const struct attribute_group bh1750_attribute_group = {
213	.attrs = bh1750_attributes,
214};
215
216static const struct iio_info bh1750_info = {
217	.attrs = &bh1750_attribute_group,
218	.read_raw = bh1750_read_raw,
219	.write_raw = bh1750_write_raw,
220};
221
222static const struct iio_chan_spec bh1750_channels[] = {
223	{
224		.type = IIO_LIGHT,
225		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
226				      BIT(IIO_CHAN_INFO_SCALE) |
227				      BIT(IIO_CHAN_INFO_INT_TIME)
228	}
229};
230
231static int bh1750_probe(struct i2c_client *client)
232{
233	const struct i2c_device_id *id = i2c_client_get_device_id(client);
234	int ret, usec;
235	struct bh1750_data *data;
236	struct iio_dev *indio_dev;
237
238	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
239				I2C_FUNC_SMBUS_WRITE_BYTE))
240		return -EOPNOTSUPP;
241
242	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
243	if (!indio_dev)
244		return -ENOMEM;
245
246	data = iio_priv(indio_dev);
247	i2c_set_clientdata(client, indio_dev);
248	data->client = client;
249	data->chip_info = &bh1750_chip_info_tbl[id->driver_data];
250
251	usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default;
252	ret = bh1750_change_int_time(data, usec);
253	if (ret < 0)
254		return ret;
255
256	mutex_init(&data->lock);
257	indio_dev->info = &bh1750_info;
258	indio_dev->name = id->name;
259	indio_dev->channels = bh1750_channels;
260	indio_dev->num_channels = ARRAY_SIZE(bh1750_channels);
261	indio_dev->modes = INDIO_DIRECT_MODE;
262
263	return iio_device_register(indio_dev);
264}
265
266static void bh1750_remove(struct i2c_client *client)
267{
268	struct iio_dev *indio_dev = i2c_get_clientdata(client);
269	struct bh1750_data *data = iio_priv(indio_dev);
270
271	iio_device_unregister(indio_dev);
272
273	mutex_lock(&data->lock);
274	i2c_smbus_write_byte(client, BH1750_POWER_DOWN);
275	mutex_unlock(&data->lock);
276}
277
278static int bh1750_suspend(struct device *dev)
279{
280	int ret;
281	struct bh1750_data *data =
282		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
283
284	/*
285	 * This is mainly for BH1721 which doesn't enter power down
286	 * mode automatically.
287	 */
288	mutex_lock(&data->lock);
289	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
290	mutex_unlock(&data->lock);
291
292	return ret;
293}
294
295static DEFINE_SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL);
296
297static const struct i2c_device_id bh1750_id[] = {
298	{ "bh1710", BH1710 },
299	{ "bh1715", BH1750 },
300	{ "bh1721", BH1721 },
301	{ "bh1750", BH1750 },
302	{ "bh1751", BH1750 },
303	{ }
304};
305MODULE_DEVICE_TABLE(i2c, bh1750_id);
306
307static const struct of_device_id bh1750_of_match[] = {
308	{ .compatible = "rohm,bh1710", },
309	{ .compatible = "rohm,bh1715", },
310	{ .compatible = "rohm,bh1721", },
311	{ .compatible = "rohm,bh1750", },
312	{ .compatible = "rohm,bh1751", },
313	{ }
314};
315MODULE_DEVICE_TABLE(of, bh1750_of_match);
316
317static struct i2c_driver bh1750_driver = {
318	.driver = {
319		.name = "bh1750",
320		.of_match_table = bh1750_of_match,
321		.pm = pm_sleep_ptr(&bh1750_pm_ops),
322	},
323	.probe = bh1750_probe,
324	.remove = bh1750_remove,
325	.id_table = bh1750_id,
326
327};
328module_i2c_driver(bh1750_driver);
329
330MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
331MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver");
332MODULE_LICENSE("GPL v2");
333