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
24enum {
25	ATLAS_CO2_EZO,
26	ATLAS_O2_EZO,
27	ATLAS_HUM_EZO,
28};
29
30struct atlas_ezo_device {
31	const struct iio_chan_spec *channels;
32	int num_channels;
33	int delay;
34};
35
36struct 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
62static const struct iio_chan_spec atlas_co2_ezo_channels[] = {
63	ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_CO2),
64};
65
66static const struct iio_chan_spec atlas_o2_ezo_channels[] = {
67	ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_O2),
68};
69
70static 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
85static 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
103static 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
113static 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
184static const struct iio_info atlas_info = {
185	.read_raw = atlas_ezo_read_raw,
186};
187
188static 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};
194MODULE_DEVICE_TABLE(i2c, atlas_ezo_id);
195
196static 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};
202MODULE_DEVICE_TABLE(of, atlas_ezo_dt_ids);
203
204static 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
232static 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};
240module_i2c_driver(atlas_ezo_driver);
241
242MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
243MODULE_DESCRIPTION("Atlas Scientific EZO sensors");
244MODULE_LICENSE("GPL");
245