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/init.h>
10 #include <linux/delay.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/property.h>
15 #include <linux/err.h>
16 #include <linux/i2c.h>
17
18 #include <linux/iio/iio.h>
19
20 #define ATLAS_EZO_DRV_NAME "atlas-ezo-sensor"
21 #define ATLAS_INT_TIME_IN_MS 950
22 #define ATLAS_INT_HUM_TIME_IN_MS 350
23
24 enum {
25 ATLAS_CO2_EZO,
26 ATLAS_O2_EZO,
27 ATLAS_HUM_EZO,
28 };
29
30 struct atlas_ezo_device {
31 const struct iio_chan_spec *channels;
32 int num_channels;
33 int delay;
34 };
35
36 struct atlas_ezo_data {
37 struct i2c_client *client;
38 const struct atlas_ezo_device *chip;
39
40 /* lock to avoid multiple concurrent read calls */
41 struct mutex lock;
42
43 u8 buffer[8];
44 };
45
46 #define ATLAS_CONCENTRATION_CHANNEL(_modifier) \
47 { \
48 .type = IIO_CONCENTRATION, \
49 .modified = 1,\
50 .channel2 = _modifier, \
51 .info_mask_separate = \
52 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
53 .scan_index = 0, \
54 .scan_type = { \
55 .sign = 'u', \
56 .realbits = 32, \
57 .storagebits = 32, \
58 .endianness = IIO_CPU, \
59 }, \
60 }
61
62 static const struct iio_chan_spec atlas_co2_ezo_channels[] = {
63 ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_CO2),
64 };
65
66 static const struct iio_chan_spec atlas_o2_ezo_channels[] = {
67 ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_O2),
68 };
69
70 static const struct iio_chan_spec atlas_hum_ezo_channels[] = {
71 {
72 .type = IIO_HUMIDITYRELATIVE,
73 .info_mask_separate =
74 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
75 .scan_index = 0,
76 .scan_type = {
77 .sign = 'u',
78 .realbits = 32,
79 .storagebits = 32,
80 .endianness = IIO_CPU,
81 },
82 },
83 };
84
85 static struct atlas_ezo_device atlas_ezo_devices[] = {
86 [ATLAS_CO2_EZO] = {
87 .channels = atlas_co2_ezo_channels,
88 .num_channels = 1,
89 .delay = ATLAS_INT_TIME_IN_MS,
90 },
91 [ATLAS_O2_EZO] = {
92 .channels = atlas_o2_ezo_channels,
93 .num_channels = 1,
94 .delay = ATLAS_INT_TIME_IN_MS,
95 },
96 [ATLAS_HUM_EZO] = {
97 .channels = atlas_hum_ezo_channels,
98 .num_channels = 1,
99 .delay = ATLAS_INT_HUM_TIME_IN_MS,
100 },
101 };
102
atlas_ezo_sanitize(char * buf)103 static void atlas_ezo_sanitize(char *buf)
104 {
105 char *ptr = strchr(buf, '.');
106
107 if (!ptr)
108 return;
109
110 memmove(ptr, ptr + 1, strlen(ptr));
111 }
112
atlas_ezo_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)113 static int atlas_ezo_read_raw(struct iio_dev *indio_dev,
114 struct iio_chan_spec const *chan,
115 int *val, int *val2, long mask)
116 {
117 struct atlas_ezo_data *data = iio_priv(indio_dev);
118 struct i2c_client *client = data->client;
119
120 if (chan->type != IIO_CONCENTRATION)
121 return -EINVAL;
122
123 switch (mask) {
124 case IIO_CHAN_INFO_RAW: {
125 int ret;
126 long tmp;
127
128 mutex_lock(&data->lock);
129
130 tmp = i2c_smbus_write_byte(client, 'R');
131
132 if (tmp < 0) {
133 mutex_unlock(&data->lock);
134 return tmp;
135 }
136
137 msleep(data->chip->delay);
138
139 tmp = i2c_master_recv(client, data->buffer, sizeof(data->buffer));
140
141 if (tmp < 0 || data->buffer[0] != 1) {
142 mutex_unlock(&data->lock);
143 return -EBUSY;
144 }
145
146 /* removing floating point for fixed number representation */
147 atlas_ezo_sanitize(data->buffer + 2);
148
149 ret = kstrtol(data->buffer + 1, 10, &tmp);
150
151 *val = tmp;
152
153 mutex_unlock(&data->lock);
154
155 return ret ? ret : IIO_VAL_INT;
156 }
157 case IIO_CHAN_INFO_SCALE:
158 switch (chan->type) {
159 case IIO_HUMIDITYRELATIVE:
160 *val = 10;
161 return IIO_VAL_INT;
162 case IIO_CONCENTRATION:
163 break;
164 default:
165 return -EINVAL;
166 }
167
168 /* IIO_CONCENTRATION modifiers */
169 switch (chan->channel2) {
170 case IIO_MOD_CO2:
171 *val = 0;
172 *val2 = 100; /* 0.0001 */
173 return IIO_VAL_INT_PLUS_MICRO;
174 case IIO_MOD_O2:
175 *val = 100;
176 return IIO_VAL_INT;
177 }
178 return -EINVAL;
179 }
180
181 return 0;
182 }
183
184 static const struct iio_info atlas_info = {
185 .read_raw = atlas_ezo_read_raw,
186 };
187
188 static const struct i2c_device_id atlas_ezo_id[] = {
189 { "atlas-co2-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_CO2_EZO] },
190 { "atlas-o2-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_O2_EZO] },
191 { "atlas-hum-ezo", (kernel_ulong_t)&atlas_ezo_devices[ATLAS_HUM_EZO] },
192 {}
193 };
194 MODULE_DEVICE_TABLE(i2c, atlas_ezo_id);
195
196 static const struct of_device_id atlas_ezo_dt_ids[] = {
197 { .compatible = "atlas,co2-ezo", .data = &atlas_ezo_devices[ATLAS_CO2_EZO], },
198 { .compatible = "atlas,o2-ezo", .data = &atlas_ezo_devices[ATLAS_O2_EZO], },
199 { .compatible = "atlas,hum-ezo", .data = &atlas_ezo_devices[ATLAS_HUM_EZO], },
200 {}
201 };
202 MODULE_DEVICE_TABLE(of, atlas_ezo_dt_ids);
203
atlas_ezo_probe(struct i2c_client * client)204 static int atlas_ezo_probe(struct i2c_client *client)
205 {
206 const struct atlas_ezo_device *chip;
207 struct atlas_ezo_data *data;
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 chip = i2c_get_match_data(client);
215 if (!chip)
216 return -EINVAL;
217
218 indio_dev->info = &atlas_info;
219 indio_dev->name = ATLAS_EZO_DRV_NAME;
220 indio_dev->channels = chip->channels;
221 indio_dev->num_channels = chip->num_channels;
222 indio_dev->modes = INDIO_DIRECT_MODE;
223
224 data = iio_priv(indio_dev);
225 data->client = client;
226 data->chip = chip;
227 mutex_init(&data->lock);
228
229 return devm_iio_device_register(&client->dev, indio_dev);
230 };
231
232 static struct i2c_driver atlas_ezo_driver = {
233 .driver = {
234 .name = ATLAS_EZO_DRV_NAME,
235 .of_match_table = atlas_ezo_dt_ids,
236 },
237 .probe = atlas_ezo_probe,
238 .id_table = atlas_ezo_id,
239 };
240 module_i2c_driver(atlas_ezo_driver);
241
242 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
243 MODULE_DESCRIPTION("Atlas Scientific EZO sensors");
244 MODULE_LICENSE("GPL");
245