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
31 enum {
32 BH1710,
33 BH1721,
34 BH1750,
35 };
36
37 struct bh1750_chip_info;
38 struct bh1750_data {
39 struct i2c_client *client;
40 struct mutex lock;
41 const struct bh1750_chip_info *chip_info;
42 u16 mtreg;
43 };
44
45 struct 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
64 static 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
bh1750_change_int_time(struct bh1750_data * data,int usec)70 static 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
bh1750_read(struct bh1750_data * data,int * val)105 static 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
bh1750_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)131 static 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
bh1750_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)167 static 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
bh1750_show_int_time_available(struct device * dev,struct device_attribute * attr,char * buf)188 static 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
205 static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available);
206
207 static struct attribute *bh1750_attributes[] = {
208 &iio_dev_attr_integration_time_available.dev_attr.attr,
209 NULL,
210 };
211
212 static const struct attribute_group bh1750_attribute_group = {
213 .attrs = bh1750_attributes,
214 };
215
216 static 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
222 static 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
bh1750_probe(struct i2c_client * client)231 static 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
bh1750_remove(struct i2c_client * client)266 static 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
bh1750_suspend(struct device * dev)278 static 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
295 static DEFINE_SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL);
296
297 static const struct i2c_device_id bh1750_id[] = {
298 { "bh1710", BH1710 },
299 { "bh1715", BH1750 },
300 { "bh1721", BH1721 },
301 { "bh1750", BH1750 },
302 { "bh1751", BH1750 },
303 { }
304 };
305 MODULE_DEVICE_TABLE(i2c, bh1750_id);
306
307 static 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 };
315 MODULE_DEVICE_TABLE(of, bh1750_of_match);
316
317 static 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 };
328 module_i2c_driver(bh1750_driver);
329
330 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
331 MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver");
332 MODULE_LICENSE("GPL v2");
333