1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * veml6070.c - Support for Vishay VEML6070 UV A light sensor
4 *
5 * Copyright 2016 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
6 *
7 * IIO driver for VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)
8 *
9 * TODO: ACK signal
10 */
11
12 #include <linux/bitfield.h>
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/mutex.h>
16 #include <linux/err.h>
17 #include <linux/delay.h>
18 #include <linux/units.h>
19
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22
23 #define VEML6070_DRV_NAME "veml6070"
24
25 #define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */
26 #define VEML6070_ADDR_DATA_LSB 0x39 /* LSB data */
27
28 #define VEML6070_COMMAND_ACK BIT(5) /* raise interrupt when over threshold */
29 #define VEML6070_COMMAND_IT GENMASK(3, 2) /* bit mask integration time */
30 #define VEML6070_COMMAND_RSRVD BIT(1) /* reserved, set to 1 */
31 #define VEML6070_COMMAND_SD BIT(0) /* shutdown mode when set */
32
33 #define VEML6070_IT_05 0x00
34 #define VEML6070_IT_10 0x01
35 #define VEML6070_IT_20 0x02
36 #define VEML6070_IT_40 0x03
37
38 #define VEML6070_MIN_RSET_KOHM 75
39 #define VEML6070_MIN_IT_US 15625 /* Rset = 75 kohm, IT = 1/2 */
40
41 struct veml6070_data {
42 struct i2c_client *client1;
43 struct i2c_client *client2;
44 u8 config;
45 struct mutex lock;
46 u32 rset;
47 int it[4][2];
48 };
49
veml6070_calc_it(struct device * dev,struct veml6070_data * data)50 static int veml6070_calc_it(struct device *dev, struct veml6070_data *data)
51 {
52 int i, tmp_it;
53
54 data->rset = 270000;
55 device_property_read_u32(dev, "vishay,rset-ohms", &data->rset);
56
57 if (data->rset < 75000 || data->rset > 1200000)
58 return dev_err_probe(dev, -EINVAL, "Rset out of range\n");
59
60 /*
61 * convert to kohm to avoid overflows and work with the same units as
62 * in the datasheet and simplify UVI operations.
63 */
64 data->rset /= KILO;
65
66 tmp_it = VEML6070_MIN_IT_US * data->rset / VEML6070_MIN_RSET_KOHM;
67 for (i = 0; i < ARRAY_SIZE(data->it); i++) {
68 data->it[i][0] = (tmp_it << i) / MICRO;
69 data->it[i][1] = (tmp_it << i) % MICRO;
70 }
71
72 return 0;
73 }
74
veml6070_get_it(struct veml6070_data * data,int * val,int * val2)75 static int veml6070_get_it(struct veml6070_data *data, int *val, int *val2)
76 {
77 int it_idx = FIELD_GET(VEML6070_COMMAND_IT, data->config);
78
79 *val = data->it[it_idx][0];
80 *val2 = data->it[it_idx][1];
81
82 return IIO_VAL_INT_PLUS_MICRO;
83 }
84
veml6070_set_it(struct veml6070_data * data,int val,int val2)85 static int veml6070_set_it(struct veml6070_data *data, int val, int val2)
86 {
87 int it_idx;
88
89 for (it_idx = 0; it_idx < ARRAY_SIZE(data->it); it_idx++) {
90 if (data->it[it_idx][0] == val && data->it[it_idx][1] == val2)
91 break;
92 }
93
94 if (it_idx >= ARRAY_SIZE(data->it))
95 return -EINVAL;
96
97 data->config = (data->config & ~VEML6070_COMMAND_IT) |
98 FIELD_PREP(VEML6070_COMMAND_IT, it_idx);
99
100 return i2c_smbus_write_byte(data->client1, data->config);
101 }
102
veml6070_read(struct veml6070_data * data)103 static int veml6070_read(struct veml6070_data *data)
104 {
105 int ret, it_ms, val, val2;
106 u8 msb, lsb;
107
108 guard(mutex)(&data->lock);
109
110 /* disable shutdown */
111 ret = i2c_smbus_write_byte(data->client1,
112 data->config & ~VEML6070_COMMAND_SD);
113 if (ret < 0)
114 return ret;
115
116 veml6070_get_it(data, &val, &val2);
117 it_ms = val * MILLI + val2 / (MICRO / MILLI);
118 msleep(it_ms + 10);
119
120 ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */
121 if (ret < 0)
122 return ret;
123
124 msb = ret;
125
126 ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */
127 if (ret < 0)
128 return ret;
129
130 lsb = ret;
131
132 /* shutdown again */
133 ret = i2c_smbus_write_byte(data->client1, data->config);
134 if (ret < 0)
135 return ret;
136
137 return (msb << 8) | lsb;
138 }
139
140 static const struct iio_chan_spec veml6070_channels[] = {
141 {
142 .type = IIO_INTENSITY,
143 .modified = 1,
144 .channel2 = IIO_MOD_LIGHT_UV,
145 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
146 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
147 .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
148 },
149 {
150 .type = IIO_UVINDEX,
151 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
152 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
153 .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
154 }
155 };
156
veml6070_to_uv_index(struct veml6070_data * data,unsigned int val)157 static int veml6070_to_uv_index(struct veml6070_data *data, unsigned int val)
158 {
159 /*
160 * conversion of raw UV intensity values to UV index depends on
161 * integration time (IT) and value of the resistor connected to
162 * the RSET pin.
163 */
164 unsigned int uvi[11] = {
165 187, 373, 560, /* low */
166 746, 933, 1120, /* moderate */
167 1308, 1494, /* high */
168 1681, 1868, 2054}; /* very high */
169 int i, it_idx;
170
171 it_idx = FIELD_GET(VEML6070_COMMAND_IT, data->config);
172
173 if (!it_idx)
174 val = (val * 270 / data->rset) << 1;
175 else
176 val = (val * 270 / data->rset) >> (it_idx - 1);
177
178 for (i = 0; i < ARRAY_SIZE(uvi); i++)
179 if (val <= uvi[i])
180 return i;
181
182 return 11; /* extreme */
183 }
184
veml6070_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)185 static int veml6070_read_raw(struct iio_dev *indio_dev,
186 struct iio_chan_spec const *chan,
187 int *val, int *val2, long mask)
188 {
189 struct veml6070_data *data = iio_priv(indio_dev);
190 int ret;
191
192 switch (mask) {
193 case IIO_CHAN_INFO_RAW:
194 case IIO_CHAN_INFO_PROCESSED:
195 ret = veml6070_read(data);
196 if (ret < 0)
197 return ret;
198 if (mask == IIO_CHAN_INFO_PROCESSED)
199 *val = veml6070_to_uv_index(data, ret);
200 else
201 *val = ret;
202 return IIO_VAL_INT;
203 case IIO_CHAN_INFO_INT_TIME:
204 return veml6070_get_it(data, val, val2);
205 default:
206 return -EINVAL;
207 }
208 }
209
veml6070_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)210 static int veml6070_read_avail(struct iio_dev *indio_dev,
211 struct iio_chan_spec const *chan,
212 const int **vals, int *type, int *length,
213 long mask)
214 {
215 struct veml6070_data *data = iio_priv(indio_dev);
216
217 switch (mask) {
218 case IIO_CHAN_INFO_INT_TIME:
219 *vals = (int *)data->it;
220 *length = 2 * ARRAY_SIZE(data->it);
221 *type = IIO_VAL_INT_PLUS_MICRO;
222 return IIO_AVAIL_LIST;
223 default:
224 return -EINVAL;
225 }
226 }
227
veml6070_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)228 static int veml6070_write_raw(struct iio_dev *indio_dev,
229 struct iio_chan_spec const *chan,
230 int val, int val2, long mask)
231 {
232 struct veml6070_data *data = iio_priv(indio_dev);
233
234 switch (mask) {
235 case IIO_CHAN_INFO_INT_TIME:
236 return veml6070_set_it(data, val, val2);
237 default:
238 return -EINVAL;
239 }
240 }
241
242 static const struct iio_info veml6070_info = {
243 .read_raw = veml6070_read_raw,
244 .read_avail = veml6070_read_avail,
245 .write_raw = veml6070_write_raw,
246 };
247
veml6070_i2c_unreg(void * p)248 static void veml6070_i2c_unreg(void *p)
249 {
250 struct veml6070_data *data = p;
251
252 i2c_unregister_device(data->client2);
253 }
254
veml6070_probe(struct i2c_client * client)255 static int veml6070_probe(struct i2c_client *client)
256 {
257 struct veml6070_data *data;
258 struct iio_dev *indio_dev;
259 int ret;
260
261 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
262 if (!indio_dev)
263 return -ENOMEM;
264
265 data = iio_priv(indio_dev);
266 i2c_set_clientdata(client, indio_dev);
267 data->client1 = client;
268 mutex_init(&data->lock);
269
270 indio_dev->info = &veml6070_info;
271 indio_dev->channels = veml6070_channels;
272 indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
273 indio_dev->name = VEML6070_DRV_NAME;
274 indio_dev->modes = INDIO_DIRECT_MODE;
275
276 ret = veml6070_calc_it(&client->dev, data);
277 if (ret < 0)
278 return ret;
279
280 ret = devm_regulator_get_enable(&client->dev, "vdd");
281 if (ret < 0)
282 return ret;
283
284 data->client2 = i2c_new_dummy_device(client->adapter, VEML6070_ADDR_DATA_LSB);
285 if (IS_ERR(data->client2))
286 return dev_err_probe(&client->dev, PTR_ERR(data->client2),
287 "i2c device for second chip address failed\n");
288
289 data->config = FIELD_PREP(VEML6070_COMMAND_IT, VEML6070_IT_10) |
290 VEML6070_COMMAND_RSRVD | VEML6070_COMMAND_SD;
291 ret = i2c_smbus_write_byte(data->client1, data->config);
292 if (ret < 0)
293 return ret;
294
295 ret = devm_add_action_or_reset(&client->dev, veml6070_i2c_unreg, data);
296 if (ret < 0)
297 return ret;
298
299 return devm_iio_device_register(&client->dev, indio_dev);
300 }
301
302 static const struct i2c_device_id veml6070_id[] = {
303 { "veml6070" },
304 { }
305 };
306 MODULE_DEVICE_TABLE(i2c, veml6070_id);
307
308 static const struct of_device_id veml6070_of_match[] = {
309 { .compatible = "vishay,veml6070" },
310 { }
311 };
312 MODULE_DEVICE_TABLE(of, veml6070_of_match);
313
314 static struct i2c_driver veml6070_driver = {
315 .driver = {
316 .name = VEML6070_DRV_NAME,
317 .of_match_table = veml6070_of_match,
318 },
319 .probe = veml6070_probe,
320 .id_table = veml6070_id,
321 };
322
323 module_i2c_driver(veml6070_driver);
324
325 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
326 MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
327 MODULE_LICENSE("GPL");
328