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/mod_devicetable.h>
11 #include <linux/mutex.h>
12 #include <linux/init.h>
13 #include <linux/i2c.h>
14 #include <linux/iio/iio.h>
15
16 #define AMS_IAQCORE_DATA_SIZE 9
17
18 #define AMS_IAQCORE_VOC_CO2_IDX 0
19 #define AMS_IAQCORE_VOC_RESISTANCE_IDX 1
20 #define AMS_IAQCORE_VOC_TVOC_IDX 2
21
22 struct ams_iaqcore_reading {
23 __be16 co2_ppm;
24 u8 status;
25 __be32 resistance;
26 __be16 voc_ppb;
27 } __attribute__((__packed__));
28
29 struct ams_iaqcore_data {
30 struct i2c_client *client;
31 struct mutex lock;
32 unsigned long last_update;
33
34 struct ams_iaqcore_reading buffer;
35 };
36
37 static const struct iio_chan_spec ams_iaqcore_channels[] = {
38 {
39 .type = IIO_CONCENTRATION,
40 .channel2 = IIO_MOD_CO2,
41 .modified = 1,
42 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
43 .address = AMS_IAQCORE_VOC_CO2_IDX,
44 },
45 {
46 .type = IIO_RESISTANCE,
47 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
48 .address = AMS_IAQCORE_VOC_RESISTANCE_IDX,
49 },
50 {
51 .type = IIO_CONCENTRATION,
52 .channel2 = IIO_MOD_VOC,
53 .modified = 1,
54 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
55 .address = AMS_IAQCORE_VOC_TVOC_IDX,
56 },
57 };
58
ams_iaqcore_read_measurement(struct ams_iaqcore_data * data)59 static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data)
60 {
61 struct i2c_client *client = data->client;
62 int ret;
63
64 struct i2c_msg msg = {
65 .addr = client->addr,
66 .flags = client->flags | I2C_M_RD,
67 .len = AMS_IAQCORE_DATA_SIZE,
68 .buf = (char *) &data->buffer,
69 };
70
71 ret = i2c_transfer(client->adapter, &msg, 1);
72
73 return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret;
74 }
75
ams_iaqcore_get_measurement(struct ams_iaqcore_data * data)76 static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data)
77 {
78 int ret;
79
80 /* sensor can only be polled once a second max per datasheet */
81 if (!time_after(jiffies, data->last_update + HZ))
82 return 0;
83
84 ret = ams_iaqcore_read_measurement(data);
85 if (ret < 0)
86 return ret;
87
88 data->last_update = jiffies;
89
90 return 0;
91 }
92
ams_iaqcore_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)93 static int ams_iaqcore_read_raw(struct iio_dev *indio_dev,
94 struct iio_chan_spec const *chan, int *val,
95 int *val2, long mask)
96 {
97 struct ams_iaqcore_data *data = iio_priv(indio_dev);
98 int ret;
99
100 if (mask != IIO_CHAN_INFO_PROCESSED)
101 return -EINVAL;
102
103 mutex_lock(&data->lock);
104 ret = ams_iaqcore_get_measurement(data);
105
106 if (ret)
107 goto err_out;
108
109 switch (chan->address) {
110 case AMS_IAQCORE_VOC_CO2_IDX:
111 *val = 0;
112 *val2 = be16_to_cpu(data->buffer.co2_ppm);
113 ret = IIO_VAL_INT_PLUS_MICRO;
114 break;
115 case AMS_IAQCORE_VOC_RESISTANCE_IDX:
116 *val = be32_to_cpu(data->buffer.resistance);
117 ret = IIO_VAL_INT;
118 break;
119 case AMS_IAQCORE_VOC_TVOC_IDX:
120 *val = 0;
121 *val2 = be16_to_cpu(data->buffer.voc_ppb);
122 ret = IIO_VAL_INT_PLUS_NANO;
123 break;
124 default:
125 ret = -EINVAL;
126 }
127
128 err_out:
129 mutex_unlock(&data->lock);
130
131 return ret;
132 }
133
134 static const struct iio_info ams_iaqcore_info = {
135 .read_raw = ams_iaqcore_read_raw,
136 };
137
ams_iaqcore_probe(struct i2c_client * client,const struct i2c_device_id * id)138 static int ams_iaqcore_probe(struct i2c_client *client,
139 const struct i2c_device_id *id)
140 {
141 struct iio_dev *indio_dev;
142 struct ams_iaqcore_data *data;
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->client = client;
151
152 /* so initial reading will complete */
153 data->last_update = jiffies - HZ;
154 mutex_init(&data->lock);
155
156 indio_dev->info = &ams_iaqcore_info;
157 indio_dev->name = dev_name(&client->dev);
158 indio_dev->modes = INDIO_DIRECT_MODE;
159
160 indio_dev->channels = ams_iaqcore_channels;
161 indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels);
162
163 return devm_iio_device_register(&client->dev, indio_dev);
164 }
165
166 static const struct i2c_device_id ams_iaqcore_id[] = {
167 { "ams-iaq-core", 0 },
168 { }
169 };
170 MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id);
171
172 static const struct of_device_id ams_iaqcore_dt_ids[] = {
173 { .compatible = "ams,iaq-core" },
174 { }
175 };
176 MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids);
177
178 static struct i2c_driver ams_iaqcore_driver = {
179 .driver = {
180 .name = "ams-iaq-core",
181 .of_match_table = ams_iaqcore_dt_ids,
182 },
183 .probe = ams_iaqcore_probe,
184 .id_table = ams_iaqcore_id,
185 };
186 module_i2c_driver(ams_iaqcore_driver);
187
188 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
189 MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors");
190 MODULE_LICENSE("GPL v2");
191