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
33struct veml6070_data {
34	struct i2c_client *client1;
35	struct i2c_client *client2;
36	u8 config;
37	struct mutex lock;
38};
39
40static 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
72out:
73	mutex_unlock(&data->lock);
74	return ret;
75}
76
77static 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
90static 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
111static 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
134static const struct iio_info veml6070_info = {
135	.read_raw = veml6070_read_raw,
136};
137
138static 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
178fail:
179	i2c_unregister_device(data->client2);
180	return ret;
181}
182
183static 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
194static const struct i2c_device_id veml6070_id[] = {
195	{ "veml6070", 0 },
196	{ }
197};
198MODULE_DEVICE_TABLE(i2c, veml6070_id);
199
200static 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
209module_i2c_driver(veml6070_driver);
210
211MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
212MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
213MODULE_LICENSE("GPL");
214