1/*
2 * ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light sensor driver
3 *
4 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Data sheets:
11 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1710fvc-e.pdf
12 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1715fvc-e.pdf
13 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf
14 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
15 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1751fvi-e.pdf
16 *
17 * 7-bit I2C slave addresses:
18 *  0x23 (ADDR pin low)
19 *  0x5C (ADDR pin high)
20 *
21 */
22
23#include <linux/delay.h>
24#include <linux/i2c.h>
25#include <linux/iio/iio.h>
26#include <linux/iio/sysfs.h>
27#include <linux/module.h>
28
29#define BH1750_POWER_DOWN		0x00
30#define BH1750_ONE_TIME_H_RES_MODE	0x20 /* auto-mode for BH1721 */
31#define BH1750_CHANGE_INT_TIME_H_BIT	0x40
32#define BH1750_CHANGE_INT_TIME_L_BIT	0x60
33
34enum {
35	BH1710,
36	BH1721,
37	BH1750,
38};
39
40struct bh1750_chip_info;
41struct bh1750_data {
42	struct i2c_client *client;
43	struct mutex lock;
44	const struct bh1750_chip_info *chip_info;
45	u16 mtreg;
46};
47
48struct bh1750_chip_info {
49	u16 mtreg_min;
50	u16 mtreg_max;
51	u16 mtreg_default;
52	int mtreg_to_usec;
53	int mtreg_to_scale;
54
55	/*
56	 * For BH1710/BH1721 all possible integration time values won't fit
57	 * into one page so displaying is limited to every second one.
58	 * Note, that user can still write proper values which were not
59	 * listed.
60	 */
61	int inc;
62
63	u16 int_time_low_mask;
64	u16 int_time_high_mask;
65}
66
67static const bh1750_chip_info_tbl[] = {
68	[BH1710] = { 140, 1022, 300, 400,  250000000, 2, 0x001F, 0x03E0 },
69	[BH1721] = { 140, 1020, 300, 400,  250000000, 2, 0x0010, 0x03E0 },
70	[BH1750] = { 31,  254,  69,  1740, 57500000,  1, 0x001F, 0x00E0 },
71};
72
73static int bh1750_change_int_time(struct bh1750_data *data, int usec)
74{
75	int ret;
76	u16 val;
77	u8 regval;
78	const struct bh1750_chip_info *chip_info = data->chip_info;
79
80	if ((usec % chip_info->mtreg_to_usec) != 0)
81		return -EINVAL;
82
83	val = usec / chip_info->mtreg_to_usec;
84	if (val < chip_info->mtreg_min || val > chip_info->mtreg_max)
85		return -EINVAL;
86
87	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
88	if (ret < 0)
89		return ret;
90
91	regval = (val & chip_info->int_time_high_mask) >> 5;
92	ret = i2c_smbus_write_byte(data->client,
93				   BH1750_CHANGE_INT_TIME_H_BIT | regval);
94	if (ret < 0)
95		return ret;
96
97	regval = val & chip_info->int_time_low_mask;
98	ret = i2c_smbus_write_byte(data->client,
99				   BH1750_CHANGE_INT_TIME_L_BIT | regval);
100	if (ret < 0)
101		return ret;
102
103	data->mtreg = val;
104
105	return 0;
106}
107
108static int bh1750_read(struct bh1750_data *data, int *val)
109{
110	int ret;
111	__be16 result;
112	const struct bh1750_chip_info *chip_info = data->chip_info;
113	unsigned long delay = chip_info->mtreg_to_usec * data->mtreg;
114
115	/*
116	 * BH1721 will enter continuous mode on receiving this command.
117	 * Note, that this eliminates need for bh1750_resume().
118	 */
119	ret = i2c_smbus_write_byte(data->client, BH1750_ONE_TIME_H_RES_MODE);
120	if (ret < 0)
121		return ret;
122
123	usleep_range(delay + 15000, delay + 40000);
124
125	ret = i2c_master_recv(data->client, (char *)&result, 2);
126	if (ret < 0)
127		return ret;
128
129	*val = be16_to_cpu(result);
130
131	return 0;
132}
133
134static int bh1750_read_raw(struct iio_dev *indio_dev,
135			   struct iio_chan_spec const *chan,
136			   int *val, int *val2, long mask)
137{
138	int ret, tmp;
139	struct bh1750_data *data = iio_priv(indio_dev);
140	const struct bh1750_chip_info *chip_info = data->chip_info;
141
142	switch (mask) {
143	case IIO_CHAN_INFO_RAW:
144		switch (chan->type) {
145		case IIO_LIGHT:
146			mutex_lock(&data->lock);
147			ret = bh1750_read(data, val);
148			mutex_unlock(&data->lock);
149			if (ret < 0)
150				return ret;
151
152			return IIO_VAL_INT;
153		default:
154			return -EINVAL;
155		}
156	case IIO_CHAN_INFO_SCALE:
157		tmp = chip_info->mtreg_to_scale / data->mtreg;
158		*val = tmp / 1000000;
159		*val2 = tmp % 1000000;
160		return IIO_VAL_INT_PLUS_MICRO;
161	case IIO_CHAN_INFO_INT_TIME:
162		*val = 0;
163		*val2 = chip_info->mtreg_to_usec * data->mtreg;
164		return IIO_VAL_INT_PLUS_MICRO;
165	default:
166		return -EINVAL;
167	}
168}
169
170static int bh1750_write_raw(struct iio_dev *indio_dev,
171			    struct iio_chan_spec const *chan,
172			    int val, int val2, long mask)
173{
174	int ret;
175	struct bh1750_data *data = iio_priv(indio_dev);
176
177	switch (mask) {
178	case IIO_CHAN_INFO_INT_TIME:
179		if (val != 0)
180			return -EINVAL;
181
182		mutex_lock(&data->lock);
183		ret = bh1750_change_int_time(data, val2);
184		mutex_unlock(&data->lock);
185		return ret;
186	default:
187		return -EINVAL;
188	}
189}
190
191static ssize_t bh1750_show_int_time_available(struct device *dev,
192		struct device_attribute *attr, char *buf)
193{
194	int i;
195	size_t len = 0;
196	struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev));
197	const struct bh1750_chip_info *chip_info = data->chip_info;
198
199	for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += chip_info->inc)
200		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ",
201				 chip_info->mtreg_to_usec * i);
202
203	buf[len - 1] = '\n';
204
205	return len;
206}
207
208static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available);
209
210static struct attribute *bh1750_attributes[] = {
211	&iio_dev_attr_integration_time_available.dev_attr.attr,
212	NULL,
213};
214
215static struct attribute_group bh1750_attribute_group = {
216	.attrs = bh1750_attributes,
217};
218
219static const struct iio_info bh1750_info = {
220	.driver_module = THIS_MODULE,
221	.attrs = &bh1750_attribute_group,
222	.read_raw = bh1750_read_raw,
223	.write_raw = bh1750_write_raw,
224};
225
226static const struct iio_chan_spec bh1750_channels[] = {
227	{
228		.type = IIO_LIGHT,
229		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
230				      BIT(IIO_CHAN_INFO_SCALE) |
231				      BIT(IIO_CHAN_INFO_INT_TIME)
232	}
233};
234
235static int bh1750_probe(struct i2c_client *client,
236			const struct i2c_device_id *id)
237{
238	int ret, usec;
239	struct bh1750_data *data;
240	struct iio_dev *indio_dev;
241
242	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
243				I2C_FUNC_SMBUS_WRITE_BYTE))
244		return -ENODEV;
245
246	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
247	if (!indio_dev)
248		return -ENOMEM;
249
250	data = iio_priv(indio_dev);
251	i2c_set_clientdata(client, indio_dev);
252	data->client = client;
253	data->chip_info = &bh1750_chip_info_tbl[id->driver_data];
254
255	usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default;
256	ret = bh1750_change_int_time(data, usec);
257	if (ret < 0)
258		return ret;
259
260	mutex_init(&data->lock);
261	indio_dev->dev.parent = &client->dev;
262	indio_dev->info = &bh1750_info;
263	indio_dev->name = id->name;
264	indio_dev->channels = bh1750_channels;
265	indio_dev->num_channels = ARRAY_SIZE(bh1750_channels);
266	indio_dev->modes = INDIO_DIRECT_MODE;
267
268	return iio_device_register(indio_dev);
269}
270
271static int bh1750_remove(struct i2c_client *client)
272{
273	struct iio_dev *indio_dev = i2c_get_clientdata(client);
274	struct bh1750_data *data = iio_priv(indio_dev);
275
276	iio_device_unregister(indio_dev);
277
278	mutex_lock(&data->lock);
279	i2c_smbus_write_byte(client, BH1750_POWER_DOWN);
280	mutex_unlock(&data->lock);
281
282	return 0;
283}
284
285#ifdef CONFIG_PM_SLEEP
286static int bh1750_suspend(struct device *dev)
287{
288	int ret;
289	struct bh1750_data *data =
290		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
291
292	/*
293	 * This is mainly for BH1721 which doesn't enter power down
294	 * mode automatically.
295	 */
296	mutex_lock(&data->lock);
297	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
298	mutex_unlock(&data->lock);
299
300	return ret;
301}
302
303static SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL);
304#define BH1750_PM_OPS (&bh1750_pm_ops)
305#else
306#define BH1750_PM_OPS NULL
307#endif
308
309static const struct i2c_device_id bh1750_id[] = {
310	{ "bh1710", BH1710 },
311	{ "bh1715", BH1750 },
312	{ "bh1721", BH1721 },
313	{ "bh1750", BH1750 },
314	{ "bh1751", BH1750 },
315	{ }
316};
317MODULE_DEVICE_TABLE(i2c, bh1750_id);
318
319static struct i2c_driver bh1750_driver = {
320	.driver = {
321		.name = "bh1750",
322		.pm = BH1750_PM_OPS,
323	},
324	.probe = bh1750_probe,
325	.remove = bh1750_remove,
326	.id_table = bh1750_id,
327
328};
329module_i2c_driver(bh1750_driver);
330
331MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
332MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver");
333MODULE_LICENSE("GPL v2");
334