bh1750.c

  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#include <linux/gpio/consumer.h>
 26
 27#define BH1750_POWER_DOWN		0x00
 28#define BH1750_ONE_TIME_H_RES_MODE	0x20 /* auto-mode for BH1721 */
 29#define BH1750_CHANGE_INT_TIME_H_BIT	0x40
 30#define BH1750_CHANGE_INT_TIME_L_BIT	0x60
 31
 32/* Define the reset delay time in microseconds */
 33#define BH1750_RESET_DELAY_US 10000 /* 10ms */
 34
 35enum {
 36	BH1710,
 37	BH1721,
 38	BH1750,
 39};
 40
 41struct bh1750_chip_info;
 42struct bh1750_data {
 43	struct i2c_client *client;
 44	struct mutex lock;
 45	const struct bh1750_chip_info *chip_info;
 46	u16 mtreg;
 47	struct gpio_desc *reset_gpio;
 48};
 49
 50struct bh1750_chip_info {
 51	u16 mtreg_min;
 52	u16 mtreg_max;
 53	u16 mtreg_default;
 54	int mtreg_to_usec;
 55	int mtreg_to_scale;
 56
 57	/*
 58	 * For BH1710/BH1721 all possible integration time values won't fit
 59	 * into one page so displaying is limited to every second one.
 60	 * Note, that user can still write proper values which were not
 61	 * listed.
 62	 */
 63	int inc;
 64
 65	u16 int_time_low_mask;
 66	u16 int_time_high_mask;
 67};
 68
 69static const struct bh1750_chip_info bh1750_chip_info_tbl[] = {
 70	[BH1710] = { 140, 1022, 300, 400,  250000000, 2, 0x001F, 0x03E0 },
 71	[BH1721] = { 140, 1020, 300, 400,  250000000, 2, 0x0010, 0x03E0 },
 72	[BH1750] = { 31,  254,  69,  1740, 57500000,  1, 0x001F, 0x00E0 },
 73};
 74
 75static int bh1750_change_int_time(struct bh1750_data *data, int usec)
 76{
 77	int ret;
 78	u16 val;
 79	u8 regval;
 80	const struct bh1750_chip_info *chip_info = data->chip_info;
 81
 82	if ((usec % chip_info->mtreg_to_usec) != 0)
 83		return -EINVAL;
 84
 85	val = usec / chip_info->mtreg_to_usec;
 86	if (val < chip_info->mtreg_min || val > chip_info->mtreg_max)
 87		return -EINVAL;
 88
 89	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
 90	if (ret < 0)
 91		return ret;
 92
 93	regval = (val & chip_info->int_time_high_mask) >> 5;
 94	ret = i2c_smbus_write_byte(data->client,
 95				   BH1750_CHANGE_INT_TIME_H_BIT | regval);
 96	if (ret < 0)
 97		return ret;
 98
 99	regval = val & chip_info->int_time_low_mask;
100	ret = i2c_smbus_write_byte(data->client,
101				   BH1750_CHANGE_INT_TIME_L_BIT | regval);
102	if (ret < 0)
103		return ret;
104
105	data->mtreg = val;
106
107	return 0;
108}
109
110static int bh1750_read(struct bh1750_data *data, int *val)
111{
112	int ret;
113	__be16 result;
114	const struct bh1750_chip_info *chip_info = data->chip_info;
115	unsigned long delay = chip_info->mtreg_to_usec * data->mtreg;
116
117	/*
118	 * BH1721 will enter continuous mode on receiving this command.
119	 * Note, that this eliminates need for bh1750_resume().
120	 */
121	ret = i2c_smbus_write_byte(data->client, BH1750_ONE_TIME_H_RES_MODE);
122	if (ret < 0)
123		return ret;
124
125	usleep_range(delay + 15000, delay + 40000);
126
127	ret = i2c_master_recv(data->client, (char *)&result, 2);
128	if (ret < 0)
129		return ret;
130
131	*val = be16_to_cpu(result);
132
133	return 0;
134}
135
136static int bh1750_read_raw(struct iio_dev *indio_dev,
137			   struct iio_chan_spec const *chan,
138			   int *val, int *val2, long mask)
139{
140	int ret, tmp;
141	struct bh1750_data *data = iio_priv(indio_dev);
142	const struct bh1750_chip_info *chip_info = data->chip_info;
143
144	switch (mask) {
145	case IIO_CHAN_INFO_RAW:
146		switch (chan->type) {
147		case IIO_LIGHT:
148			mutex_lock(&data->lock);
149			ret = bh1750_read(data, val);
150			mutex_unlock(&data->lock);
151			if (ret < 0)
152				return ret;
153
154			return IIO_VAL_INT;
155		default:
156			return -EINVAL;
157		}
158	case IIO_CHAN_INFO_SCALE:
159		tmp = chip_info->mtreg_to_scale / data->mtreg;
160		*val = tmp / 1000000;
161		*val2 = tmp % 1000000;
162		return IIO_VAL_INT_PLUS_MICRO;
163	case IIO_CHAN_INFO_INT_TIME:
164		*val = 0;
165		*val2 = chip_info->mtreg_to_usec * data->mtreg;
166		return IIO_VAL_INT_PLUS_MICRO;
167	default:
168		return -EINVAL;
169	}
170}
171
172static int bh1750_write_raw(struct iio_dev *indio_dev,
173			    struct iio_chan_spec const *chan,
174			    int val, int val2, long mask)
175{
176	int ret;
177	struct bh1750_data *data = iio_priv(indio_dev);
178
179	switch (mask) {
180	case IIO_CHAN_INFO_INT_TIME:
181		if (val != 0)
182			return -EINVAL;
183
184		mutex_lock(&data->lock);
185		ret = bh1750_change_int_time(data, val2);
186		mutex_unlock(&data->lock);
187		return ret;
188	default:
189		return -EINVAL;
190	}
191}
192
193static ssize_t bh1750_show_int_time_available(struct device *dev,
194		struct device_attribute *attr, char *buf)
195{
196	int i;
197	size_t len = 0;
198	struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev));
199	const struct bh1750_chip_info *chip_info = data->chip_info;
200
201	for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += chip_info->inc)
202		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ",
203				 chip_info->mtreg_to_usec * i);
204
205	buf[len - 1] = '\n';
206
207	return len;
208}
209
210static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available);
211
212static struct attribute *bh1750_attributes[] = {
213	&iio_dev_attr_integration_time_available.dev_attr.attr,
214	NULL,
215};
216
217static const struct attribute_group bh1750_attribute_group = {
218	.attrs = bh1750_attributes,
219};
220
221static const struct iio_info bh1750_info = {
222	.attrs = &bh1750_attribute_group,
223	.read_raw = bh1750_read_raw,
224	.write_raw = bh1750_write_raw,
225};
226
227static const struct iio_chan_spec bh1750_channels[] = {
228	{
229		.type = IIO_LIGHT,
230		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
231				      BIT(IIO_CHAN_INFO_SCALE) |
232				      BIT(IIO_CHAN_INFO_INT_TIME)
233	}
234};
235
236static int bh1750_probe(struct i2c_client *client)
237{
238	const struct i2c_device_id *id = i2c_client_get_device_id(client);
239	int ret, usec;
240	struct bh1750_data *data;
241	struct iio_dev *indio_dev;
242
243	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
244				I2C_FUNC_SMBUS_WRITE_BYTE))
245		return -EOPNOTSUPP;
246
247	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
248	if (!indio_dev)
249		return -ENOMEM;
250
251	data = iio_priv(indio_dev);
252	i2c_set_clientdata(client, indio_dev);
253	data->client = client;
254	data->chip_info = &bh1750_chip_info_tbl[id->driver_data];
255
256	/* Get reset GPIO from device tree */
257	data->reset_gpio = devm_gpiod_get_optional(&client->dev,
258						   "reset", GPIOD_OUT_HIGH);
259
260	if (IS_ERR(data->reset_gpio))
261		return dev_err_probe(&client->dev, PTR_ERR(data->reset_gpio),
262				     "Failed to get reset GPIO\n");
263
264	/* Perform hardware reset if GPIO is provided */
265	if (data->reset_gpio) {
266		/* Perform reset sequence: low-high */
267		gpiod_set_value_cansleep(data->reset_gpio, 1);
268		fsleep(BH1750_RESET_DELAY_US);
269		gpiod_set_value_cansleep(data->reset_gpio, 0);
270		fsleep(BH1750_RESET_DELAY_US);
271
272		dev_dbg(&client->dev, "BH1750 reset completed via GPIO\n");
273	}
274
275	usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default;
276	ret = bh1750_change_int_time(data, usec);
277	if (ret < 0)
278		return ret;
279
280	mutex_init(&data->lock);
281	indio_dev->info = &bh1750_info;
282	indio_dev->name = id->name;
283	indio_dev->channels = bh1750_channels;
284	indio_dev->num_channels = ARRAY_SIZE(bh1750_channels);
285	indio_dev->modes = INDIO_DIRECT_MODE;
286
287	return iio_device_register(indio_dev);
288}
289
290static void bh1750_remove(struct i2c_client *client)
291{
292	struct iio_dev *indio_dev = i2c_get_clientdata(client);
293	struct bh1750_data *data = iio_priv(indio_dev);
294
295	iio_device_unregister(indio_dev);
296
297	mutex_lock(&data->lock);
298	i2c_smbus_write_byte(client, BH1750_POWER_DOWN);
299	mutex_unlock(&data->lock);
300}
301
302static int bh1750_suspend(struct device *dev)
303{
304	int ret;
305	struct bh1750_data *data =
306		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
307
308	/*
309	 * This is mainly for BH1721 which doesn't enter power down
310	 * mode automatically.
311	 */
312	mutex_lock(&data->lock);
313	ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
314	mutex_unlock(&data->lock);
315
316	return ret;
317}
318
319static DEFINE_SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL);
320
321static const struct i2c_device_id bh1750_id[] = {
322	{ "bh1710", BH1710 },
323	{ "bh1715", BH1750 },
324	{ "bh1721", BH1721 },
325	{ "bh1750", BH1750 },
326	{ "bh1751", BH1750 },
327	{ }
328};
329MODULE_DEVICE_TABLE(i2c, bh1750_id);
330
331static const struct of_device_id bh1750_of_match[] = {
332	{ .compatible = "rohm,bh1710", },
333	{ .compatible = "rohm,bh1715", },
334	{ .compatible = "rohm,bh1721", },
335	{ .compatible = "rohm,bh1750", },
336	{ .compatible = "rohm,bh1751", },
337	{ }
338};
339MODULE_DEVICE_TABLE(of, bh1750_of_match);
340
341static struct i2c_driver bh1750_driver = {
342	.driver = {
343		.name = "bh1750",
344		.of_match_table = bh1750_of_match,
345		.pm = pm_sleep_ptr(&bh1750_pm_ops),
346	},
347	.probe = bh1750_probe,
348	.remove = bh1750_remove,
349	.id_table = bh1750_id,
350
351};
352module_i2c_driver(bh1750_driver);
353
354MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
355MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver");
356MODULE_LICENSE("GPL v2");