1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * atlas-ezo-sensor.c - Support for Atlas Scientific EZO sensors
4 *
5 * Copyright (C) 2020 Konsulko Group
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7 */
8
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/delay.h>
12 #include <linux/mutex.h>
13 #include <linux/err.h>
14 #include <linux/i2c.h>
15 #include <linux/of_device.h>
16 #include <linux/iio/iio.h>
17
18 #define ATLAS_EZO_DRV_NAME "atlas-ezo-sensor"
19 #define ATLAS_INT_TIME_IN_MS 950
20 #define ATLAS_INT_HUM_TIME_IN_MS 350
21
22 enum {
23 ATLAS_CO2_EZO,
24 ATLAS_O2_EZO,
25 ATLAS_HUM_EZO,
26 };
27
28 struct atlas_ezo_device {
29 const struct iio_chan_spec *channels;
30 int num_channels;
31 int delay;
32 };
33
34 struct atlas_ezo_data {
35 struct i2c_client *client;
36 struct atlas_ezo_device *chip;
37
38 /* lock to avoid multiple concurrent read calls */
39 struct mutex lock;
40
41 u8 buffer[8];
42 };
43
44 #define ATLAS_CONCENTRATION_CHANNEL(_modifier) \
45 { \
46 .type = IIO_CONCENTRATION, \
47 .modified = 1,\
48 .channel2 = _modifier, \
49 .info_mask_separate = \
50 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
51 .scan_index = 0, \
52 .scan_type = { \
53 .sign = 'u', \
54 .realbits = 32, \
55 .storagebits = 32, \
56 .endianness = IIO_CPU, \
57 }, \
58 }
59
60 static const struct iio_chan_spec atlas_co2_ezo_channels[] = {
61 ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_CO2),
62 };
63
64 static const struct iio_chan_spec atlas_o2_ezo_channels[] = {
65 ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_O2),
66 };
67
68 static const struct iio_chan_spec atlas_hum_ezo_channels[] = {
69 {
70 .type = IIO_HUMIDITYRELATIVE,
71 .info_mask_separate =
72 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
73 .scan_index = 0,
74 .scan_type = {
75 .sign = 'u',
76 .realbits = 32,
77 .storagebits = 32,
78 .endianness = IIO_CPU,
79 },
80 },
81 };
82
83 static struct atlas_ezo_device atlas_ezo_devices[] = {
84 [ATLAS_CO2_EZO] = {
85 .channels = atlas_co2_ezo_channels,
86 .num_channels = 1,
87 .delay = ATLAS_INT_TIME_IN_MS,
88 },
89 [ATLAS_O2_EZO] = {
90 .channels = atlas_o2_ezo_channels,
91 .num_channels = 1,
92 .delay = ATLAS_INT_TIME_IN_MS,
93 },
94 [ATLAS_HUM_EZO] = {
95 .channels = atlas_hum_ezo_channels,
96 .num_channels = 1,
97 .delay = ATLAS_INT_HUM_TIME_IN_MS,
98 },
99 };
100
atlas_ezo_sanitize(char * buf)101 static void atlas_ezo_sanitize(char *buf)
102 {
103 char *ptr = strchr(buf, '.');
104
105 if (!ptr)
106 return;
107
108 memmove(ptr, ptr + 1, strlen(ptr));
109 }
110
atlas_ezo_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)111 static int atlas_ezo_read_raw(struct iio_dev *indio_dev,
112 struct iio_chan_spec const *chan,
113 int *val, int *val2, long mask)
114 {
115 struct atlas_ezo_data *data = iio_priv(indio_dev);
116 struct i2c_client *client = data->client;
117
118 if (chan->type != IIO_CONCENTRATION)
119 return -EINVAL;
120
121 switch (mask) {
122 case IIO_CHAN_INFO_RAW: {
123 int ret;
124 long tmp;
125
126 mutex_lock(&data->lock);
127
128 tmp = i2c_smbus_write_byte(client, 'R');
129
130 if (tmp < 0) {
131 mutex_unlock(&data->lock);
132 return tmp;
133 }
134
135 msleep(data->chip->delay);
136
137 tmp = i2c_master_recv(client, data->buffer, sizeof(data->buffer));
138
139 if (tmp < 0 || data->buffer[0] != 1) {
140 mutex_unlock(&data->lock);
141 return -EBUSY;
142 }
143
144 /* removing floating point for fixed number representation */
145 atlas_ezo_sanitize(data->buffer + 2);
146
147 ret = kstrtol(data->buffer + 1, 10, &tmp);
148
149 *val = tmp;
150
151 mutex_unlock(&data->lock);
152
153 return ret ? ret : IIO_VAL_INT;
154 }
155 case IIO_CHAN_INFO_SCALE:
156 switch (chan->type) {
157 case IIO_HUMIDITYRELATIVE:
158 *val = 10;
159 return IIO_VAL_INT;
160 case IIO_CONCENTRATION:
161 break;
162 default:
163 return -EINVAL;
164 }
165
166 /* IIO_CONCENTRATION modifiers */
167 switch (chan->channel2) {
168 case IIO_MOD_CO2:
169 *val = 0;
170 *val2 = 100; /* 0.0001 */
171 return IIO_VAL_INT_PLUS_MICRO;
172 case IIO_MOD_O2:
173 *val = 100;
174 return IIO_VAL_INT;
175 }
176 return -EINVAL;
177 }
178
179 return 0;
180 }
181
182 static const struct iio_info atlas_info = {
183 .read_raw = atlas_ezo_read_raw,
184 };
185
186 static const struct i2c_device_id atlas_ezo_id[] = {
187 { "atlas-co2-ezo", ATLAS_CO2_EZO },
188 { "atlas-o2-ezo", ATLAS_O2_EZO },
189 { "atlas-hum-ezo", ATLAS_HUM_EZO },
190 {}
191 };
192 MODULE_DEVICE_TABLE(i2c, atlas_ezo_id);
193
194 static const struct of_device_id atlas_ezo_dt_ids[] = {
195 { .compatible = "atlas,co2-ezo", .data = (void *)ATLAS_CO2_EZO, },
196 { .compatible = "atlas,o2-ezo", .data = (void *)ATLAS_O2_EZO, },
197 { .compatible = "atlas,hum-ezo", .data = (void *)ATLAS_HUM_EZO, },
198 {}
199 };
200 MODULE_DEVICE_TABLE(of, atlas_ezo_dt_ids);
201
atlas_ezo_probe(struct i2c_client * client,const struct i2c_device_id * id)202 static int atlas_ezo_probe(struct i2c_client *client,
203 const struct i2c_device_id *id)
204 {
205 struct atlas_ezo_data *data;
206 struct atlas_ezo_device *chip;
207 const struct of_device_id *of_id;
208 struct iio_dev *indio_dev;
209
210 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
211 if (!indio_dev)
212 return -ENOMEM;
213
214 of_id = of_match_device(atlas_ezo_dt_ids, &client->dev);
215 if (!of_id)
216 chip = &atlas_ezo_devices[id->driver_data];
217 else
218 chip = &atlas_ezo_devices[(unsigned long)of_id->data];
219
220 indio_dev->info = &atlas_info;
221 indio_dev->name = ATLAS_EZO_DRV_NAME;
222 indio_dev->channels = chip->channels;
223 indio_dev->num_channels = chip->num_channels;
224 indio_dev->modes = INDIO_DIRECT_MODE;
225
226 data = iio_priv(indio_dev);
227 data->client = client;
228 data->chip = chip;
229 mutex_init(&data->lock);
230
231 return devm_iio_device_register(&client->dev, indio_dev);
232 };
233
234 static struct i2c_driver atlas_ezo_driver = {
235 .driver = {
236 .name = ATLAS_EZO_DRV_NAME,
237 .of_match_table = atlas_ezo_dt_ids,
238 },
239 .probe = atlas_ezo_probe,
240 .id_table = atlas_ezo_id,
241 };
242 module_i2c_driver(atlas_ezo_driver);
243
244 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
245 MODULE_DESCRIPTION("Atlas Scientific EZO sensors");
246 MODULE_LICENSE("GPL");
247
