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,const struct i2c_device_id * id)138 static int veml6070_probe(struct i2c_client *client,
139 			  const struct i2c_device_id *id)
140 {
141 	struct veml6070_data *data;
142 	struct iio_dev *indio_dev;
143 	int ret;
144 
145 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
146 	if (!indio_dev)
147 		return -ENOMEM;
148 
149 	data = iio_priv(indio_dev);
150 	i2c_set_clientdata(client, indio_dev);
151 	data->client1 = client;
152 	mutex_init(&data->lock);
153 
154 	indio_dev->info = &veml6070_info;
155 	indio_dev->channels = veml6070_channels;
156 	indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
157 	indio_dev->name = VEML6070_DRV_NAME;
158 	indio_dev->modes = INDIO_DIRECT_MODE;
159 
160 	data->client2 = i2c_new_dummy_device(client->adapter, VEML6070_ADDR_DATA_LSB);
161 	if (IS_ERR(data->client2)) {
162 		dev_err(&client->dev, "i2c device for second chip address failed\n");
163 		return PTR_ERR(data->client2);
164 	}
165 
166 	data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |
167 		VEML6070_COMMAND_SD;
168 	ret = i2c_smbus_write_byte(data->client1, data->config);
169 	if (ret < 0)
170 		goto fail;
171 
172 	ret = iio_device_register(indio_dev);
173 	if (ret < 0)
174 		goto fail;
175 
176 	return ret;
177 
178 fail:
179 	i2c_unregister_device(data->client2);
180 	return ret;
181 }
182 
veml6070_remove(struct i2c_client * client)183 static int veml6070_remove(struct i2c_client *client)
184 {
185 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
186 	struct veml6070_data *data = iio_priv(indio_dev);
187 
188 	iio_device_unregister(indio_dev);
189 	i2c_unregister_device(data->client2);
190 
191 	return 0;
192 }
193 
194 static const struct i2c_device_id veml6070_id[] = {
195 	{ "veml6070", 0 },
196 	{ }
197 };
198 MODULE_DEVICE_TABLE(i2c, veml6070_id);
199 
200 static struct i2c_driver veml6070_driver = {
201 	.driver = {
202 		.name   = VEML6070_DRV_NAME,
203 	},
204 	.probe  = veml6070_probe,
205 	.remove  = veml6070_remove,
206 	.id_table = veml6070_id,
207 };
208 
209 module_i2c_driver(veml6070_driver);
210 
211 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
212 MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
213 MODULE_LICENSE("GPL");
214