1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * ams-iaq-core.c - Support for AMS iAQ-Core VOC sensors
  4 *
  5 * Copyright (C) 2015, 2018
  6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
  7 */
  8
  9#include <linux/module.h>
 10#include <linux/mutex.h>
 11#include <linux/init.h>
 12#include <linux/i2c.h>
 13#include <linux/iio/iio.h>
 14
 15#define AMS_IAQCORE_DATA_SIZE		9
 16
 17#define AMS_IAQCORE_VOC_CO2_IDX		0
 18#define AMS_IAQCORE_VOC_RESISTANCE_IDX	1
 19#define AMS_IAQCORE_VOC_TVOC_IDX	2
 20
 21struct ams_iaqcore_reading {
 22	__be16 co2_ppm;
 23	u8 status;
 24	__be32 resistance;
 25	__be16 voc_ppb;
 26} __attribute__((__packed__));
 27
 28struct ams_iaqcore_data {
 29	struct i2c_client *client;
 30	struct mutex lock;
 31	unsigned long last_update;
 32
 33	struct ams_iaqcore_reading buffer;
 34};
 35
 36static const struct iio_chan_spec ams_iaqcore_channels[] = {
 37	{
 38		.type = IIO_CONCENTRATION,
 39		.channel2 = IIO_MOD_CO2,
 40		.modified = 1,
 41		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 42		.address = AMS_IAQCORE_VOC_CO2_IDX,
 43	},
 44	{
 45		.type = IIO_RESISTANCE,
 46		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 47		.address = AMS_IAQCORE_VOC_RESISTANCE_IDX,
 48	},
 49	{
 50		.type = IIO_CONCENTRATION,
 51		.channel2 = IIO_MOD_VOC,
 52		.modified = 1,
 53		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 54		.address = AMS_IAQCORE_VOC_TVOC_IDX,
 55	},
 56};
 57
 58static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data)
 59{
 60	struct i2c_client *client = data->client;
 61	int ret;
 62
 63	struct i2c_msg msg = {
 64		.addr = client->addr,
 65		.flags = client->flags | I2C_M_RD,
 66		.len = AMS_IAQCORE_DATA_SIZE,
 67		.buf = (char *) &data->buffer,
 68	};
 69
 70	ret = i2c_transfer(client->adapter, &msg, 1);
 71
 72	return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret;
 73}
 74
 75static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data)
 76{
 77	int ret;
 78
 79	/* sensor can only be polled once a second max per datasheet */
 80	if (!time_after(jiffies, data->last_update + HZ))
 81		return 0;
 82
 83	ret = ams_iaqcore_read_measurement(data);
 84	if (ret < 0)
 85		return ret;
 86
 87	data->last_update = jiffies;
 88
 89	return 0;
 90}
 91
 92static int ams_iaqcore_read_raw(struct iio_dev *indio_dev,
 93				struct iio_chan_spec const *chan, int *val,
 94				int *val2, long mask)
 95{
 96	struct ams_iaqcore_data *data = iio_priv(indio_dev);
 97	int ret;
 98
 99	if (mask != IIO_CHAN_INFO_PROCESSED)
100		return -EINVAL;
101
102	mutex_lock(&data->lock);
103	ret = ams_iaqcore_get_measurement(data);
104
105	if (ret)
106		goto err_out;
107
108	switch (chan->address) {
109	case AMS_IAQCORE_VOC_CO2_IDX:
110		*val = 0;
111		*val2 = be16_to_cpu(data->buffer.co2_ppm);
112		ret = IIO_VAL_INT_PLUS_MICRO;
113		break;
114	case AMS_IAQCORE_VOC_RESISTANCE_IDX:
115		*val = be32_to_cpu(data->buffer.resistance);
116		ret = IIO_VAL_INT;
117		break;
118	case AMS_IAQCORE_VOC_TVOC_IDX:
119		*val = 0;
120		*val2 = be16_to_cpu(data->buffer.voc_ppb);
121		ret = IIO_VAL_INT_PLUS_NANO;
122		break;
123	default:
124		ret = -EINVAL;
125	}
126
127err_out:
128	mutex_unlock(&data->lock);
129
130	return ret;
131}
132
133static const struct iio_info ams_iaqcore_info = {
134	.read_raw	= ams_iaqcore_read_raw,
135};
136
137static int ams_iaqcore_probe(struct i2c_client *client,
138			     const struct i2c_device_id *id)
139{
140	struct iio_dev *indio_dev;
141	struct ams_iaqcore_data *data;
142
143	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
144	if (!indio_dev)
145		return -ENOMEM;
146
147	data = iio_priv(indio_dev);
148	i2c_set_clientdata(client, indio_dev);
149	data->client = client;
150
151	/* so initial reading will complete */
152	data->last_update = jiffies - HZ;
153	mutex_init(&data->lock);
154
155	indio_dev->info = &ams_iaqcore_info;
156	indio_dev->name = dev_name(&client->dev);
157	indio_dev->modes = INDIO_DIRECT_MODE;
158
159	indio_dev->channels = ams_iaqcore_channels;
160	indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels);
161
162	return devm_iio_device_register(&client->dev, indio_dev);
163}
164
165static const struct i2c_device_id ams_iaqcore_id[] = {
166	{ "ams-iaq-core", 0 },
167	{ }
168};
169MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id);
170
171static const struct of_device_id ams_iaqcore_dt_ids[] = {
172	{ .compatible = "ams,iaq-core" },
173	{ }
174};
175MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids);
176
177static struct i2c_driver ams_iaqcore_driver = {
178	.driver = {
179		.name	= "ams-iaq-core",
180		.of_match_table = of_match_ptr(ams_iaqcore_dt_ids),
181	},
182	.probe = ams_iaqcore_probe,
183	.id_table = ams_iaqcore_id,
184};
185module_i2c_driver(ams_iaqcore_driver);
186
187MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
188MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors");
189MODULE_LICENSE("GPL v2");