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: integration time, ACK signal
10 */
11
12 #include <linux/module.h>
13 #include <linux/i2c.h>
14 #include <linux/mutex.h>
15 #include <linux/err.h>
16 #include <linux/delay.h>
17
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20
21 #define VEML6070_DRV_NAME "veml6070"
22
23 #define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */
24 #define VEML6070_ADDR_DATA_LSB 0x39 /* LSB data */
25
26 #define VEML6070_COMMAND_ACK BIT(5) /* raise interrupt when over threshold */
27 #define VEML6070_COMMAND_IT GENMASK(3, 2) /* bit mask integration time */
28 #define VEML6070_COMMAND_RSRVD BIT(1) /* reserved, set to 1 */
29 #define VEML6070_COMMAND_SD BIT(0) /* shutdown mode when set */
30
31 #define VEML6070_IT_10 0x04 /* integration time 1x */
32
33 struct veml6070_data {
34 struct i2c_client *client1;
35 struct i2c_client *client2;
36 u8 config;
37 struct mutex lock;
38 };
39
veml6070_read(struct veml6070_data * data)40 static int veml6070_read(struct veml6070_data *data)
41 {
42 int ret;
43 u8 msb, lsb;
44
45 mutex_lock(&data->lock);
46
47 /* disable shutdown */
48 ret = i2c_smbus_write_byte(data->client1,
49 data->config & ~VEML6070_COMMAND_SD);
50 if (ret < 0)
51 goto out;
52
53 msleep(125 + 10); /* measurement takes up to 125 ms for IT 1x */
54
55 ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */
56 if (ret < 0)
57 goto out;
58 msb = ret;
59
60 ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */
61 if (ret < 0)
62 goto out;
63 lsb = ret;
64
65 /* shutdown again */
66 ret = i2c_smbus_write_byte(data->client1, data->config);
67 if (ret < 0)
68 goto out;
69
70 ret = (msb << 8) | lsb;
71
72 out:
73 mutex_unlock(&data->lock);
74 return ret;
75 }
76
77 static const struct iio_chan_spec veml6070_channels[] = {
78 {
79 .type = IIO_INTENSITY,
80 .modified = 1,
81 .channel2 = IIO_MOD_LIGHT_UV,
82 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
83 },
84 {
85 .type = IIO_UVINDEX,
86 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
87 }
88 };
89
veml6070_to_uv_index(unsigned val)90 static int veml6070_to_uv_index(unsigned val)
91 {
92 /*
93 * conversion of raw UV intensity values to UV index depends on
94 * integration time (IT) and value of the resistor connected to
95 * the RSET pin (default: 270 KOhm)
96 */
97 unsigned uvi[11] = {
98 187, 373, 560, /* low */
99 746, 933, 1120, /* moderate */
100 1308, 1494, /* high */
101 1681, 1868, 2054}; /* very high */
102 int i;
103
104 for (i = 0; i < ARRAY_SIZE(uvi); i++)
105 if (val <= uvi[i])
106 return i;
107
108 return 11; /* extreme */
109 }
110
veml6070_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)111 static int veml6070_read_raw(struct iio_dev *indio_dev,
112 struct iio_chan_spec const *chan,
113 int *val, int *val2, long mask)
114 {
115 struct veml6070_data *data = iio_priv(indio_dev);
116 int ret;
117
118 switch (mask) {
119 case IIO_CHAN_INFO_RAW:
120 case IIO_CHAN_INFO_PROCESSED:
121 ret = veml6070_read(data);
122 if (ret < 0)
123 return ret;
124 if (mask == IIO_CHAN_INFO_PROCESSED)
125 *val = veml6070_to_uv_index(ret);
126 else
127 *val = ret;
128 return IIO_VAL_INT;
129 default:
130 return -EINVAL;
131 }
132 }
133
134 static const struct iio_info veml6070_info = {
135 .read_raw = veml6070_read_raw,
136 };
137
veml6070_probe(struct i2c_client * client)138 static int veml6070_probe(struct i2c_client *client)
139 {
140 struct veml6070_data *data;
141 struct iio_dev *indio_dev;
142 int ret;
143
144 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
145 if (!indio_dev)
146 return -ENOMEM;
147
148 data = iio_priv(indio_dev);
149 i2c_set_clientdata(client, indio_dev);
150 data->client1 = client;
151 mutex_init(&data->lock);
152
153 indio_dev->info = &veml6070_info;
154 indio_dev->channels = veml6070_channels;
155 indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
156 indio_dev->name = VEML6070_DRV_NAME;
157 indio_dev->modes = INDIO_DIRECT_MODE;
158
159 data->client2 = i2c_new_dummy_device(client->adapter, VEML6070_ADDR_DATA_LSB);
160 if (IS_ERR(data->client2)) {
161 dev_err(&client->dev, "i2c device for second chip address failed\n");
162 return PTR_ERR(data->client2);
163 }
164
165 data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |
166 VEML6070_COMMAND_SD;
167 ret = i2c_smbus_write_byte(data->client1, data->config);
168 if (ret < 0)
169 goto fail;
170
171 ret = iio_device_register(indio_dev);
172 if (ret < 0)
173 goto fail;
174
175 return ret;
176
177 fail:
178 i2c_unregister_device(data->client2);
179 return ret;
180 }
181
veml6070_remove(struct i2c_client * client)182 static void veml6070_remove(struct i2c_client *client)
183 {
184 struct iio_dev *indio_dev = i2c_get_clientdata(client);
185 struct veml6070_data *data = iio_priv(indio_dev);
186
187 iio_device_unregister(indio_dev);
188 i2c_unregister_device(data->client2);
189 }
190
191 static const struct i2c_device_id veml6070_id[] = {
192 { "veml6070", 0 },
193 { }
194 };
195 MODULE_DEVICE_TABLE(i2c, veml6070_id);
196
197 static struct i2c_driver veml6070_driver = {
198 .driver = {
199 .name = VEML6070_DRV_NAME,
200 },
201 .probe = veml6070_probe,
202 .remove = veml6070_remove,
203 .id_table = veml6070_id,
204 };
205
206 module_i2c_driver(veml6070_driver);
207
208 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
209 MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
210 MODULE_LICENSE("GPL");
211