xref: /openbmc/linux/drivers/iio/humidity/hdc100x.c (revision d4b80afbba49e968623330f1336da8c724da8aad)
1 /*
2  * hdc100x.c - Support for the TI HDC100x temperature + humidity sensors
3  *
4  * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  */
17 
18 #include <linux/delay.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/i2c.h>
22 
23 #include <linux/iio/iio.h>
24 #include <linux/iio/sysfs.h>
25 
26 #define HDC100X_REG_TEMP			0x00
27 #define HDC100X_REG_HUMIDITY			0x01
28 
29 #define HDC100X_REG_CONFIG			0x02
30 #define HDC100X_REG_CONFIG_HEATER_EN		BIT(13)
31 
32 struct hdc100x_data {
33 	struct i2c_client *client;
34 	struct mutex lock;
35 	u16 config;
36 
37 	/* integration time of the sensor */
38 	int adc_int_us[2];
39 };
40 
41 /* integration time in us */
42 static const int hdc100x_int_time[][3] = {
43 	{ 6350, 3650, 0 },	/* IIO_TEMP channel*/
44 	{ 6500, 3850, 2500 },	/* IIO_HUMIDITYRELATIVE channel */
45 };
46 
47 /* HDC100X_REG_CONFIG shift and mask values */
48 static const struct {
49 	int shift;
50 	int mask;
51 } hdc100x_resolution_shift[2] = {
52 	{ /* IIO_TEMP channel */
53 		.shift = 10,
54 		.mask = 1
55 	},
56 	{ /* IIO_HUMIDITYRELATIVE channel */
57 		.shift = 8,
58 		.mask = 3,
59 	},
60 };
61 
62 static IIO_CONST_ATTR(temp_integration_time_available,
63 		"0.00365 0.00635");
64 
65 static IIO_CONST_ATTR(humidityrelative_integration_time_available,
66 		"0.0025 0.00385 0.0065");
67 
68 static IIO_CONST_ATTR(out_current_heater_raw_available,
69 		"0 1");
70 
71 static struct attribute *hdc100x_attributes[] = {
72 	&iio_const_attr_temp_integration_time_available.dev_attr.attr,
73 	&iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,
74 	&iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
75 	NULL
76 };
77 
78 static struct attribute_group hdc100x_attribute_group = {
79 	.attrs = hdc100x_attributes,
80 };
81 
82 static const struct iio_chan_spec hdc100x_channels[] = {
83 	{
84 		.type = IIO_TEMP,
85 		.address = HDC100X_REG_TEMP,
86 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
87 			BIT(IIO_CHAN_INFO_SCALE) |
88 			BIT(IIO_CHAN_INFO_INT_TIME) |
89 			BIT(IIO_CHAN_INFO_OFFSET),
90 	},
91 	{
92 		.type = IIO_HUMIDITYRELATIVE,
93 		.address = HDC100X_REG_HUMIDITY,
94 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
95 			BIT(IIO_CHAN_INFO_SCALE) |
96 			BIT(IIO_CHAN_INFO_INT_TIME)
97 	},
98 	{
99 		.type = IIO_CURRENT,
100 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
101 		.extend_name = "heater",
102 		.output = 1,
103 	},
104 };
105 
106 static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
107 {
108 	int tmp = (~mask & data->config) | val;
109 	int ret;
110 
111 	ret = i2c_smbus_write_word_swapped(data->client,
112 						HDC100X_REG_CONFIG, tmp);
113 	if (!ret)
114 		data->config = tmp;
115 
116 	return ret;
117 }
118 
119 static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)
120 {
121 	int shift = hdc100x_resolution_shift[chan].shift;
122 	int ret = -EINVAL;
123 	int i;
124 
125 	for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {
126 		if (val2 && val2 == hdc100x_int_time[chan][i]) {
127 			ret = hdc100x_update_config(data,
128 				hdc100x_resolution_shift[chan].mask << shift,
129 				i << shift);
130 			if (!ret)
131 				data->adc_int_us[chan] = val2;
132 			break;
133 		}
134 	}
135 
136 	return ret;
137 }
138 
139 static int hdc100x_get_measurement(struct hdc100x_data *data,
140 				   struct iio_chan_spec const *chan)
141 {
142 	struct i2c_client *client = data->client;
143 	int delay = data->adc_int_us[chan->address];
144 	int ret;
145 	__be16 val;
146 
147 	/* start measurement */
148 	ret = i2c_smbus_write_byte(client, chan->address);
149 	if (ret < 0) {
150 		dev_err(&client->dev, "cannot start measurement");
151 		return ret;
152 	}
153 
154 	/* wait for integration time to pass */
155 	usleep_range(delay, delay + 1000);
156 
157 	/* read measurement */
158 	ret = i2c_master_recv(data->client, (char *)&val, sizeof(val));
159 	if (ret < 0) {
160 		dev_err(&client->dev, "cannot read sensor data\n");
161 		return ret;
162 	}
163 	return be16_to_cpu(val);
164 }
165 
166 static int hdc100x_get_heater_status(struct hdc100x_data *data)
167 {
168 	return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);
169 }
170 
171 static int hdc100x_read_raw(struct iio_dev *indio_dev,
172 			    struct iio_chan_spec const *chan, int *val,
173 			    int *val2, long mask)
174 {
175 	struct hdc100x_data *data = iio_priv(indio_dev);
176 
177 	switch (mask) {
178 	case IIO_CHAN_INFO_RAW: {
179 		int ret;
180 
181 		mutex_lock(&data->lock);
182 		if (chan->type == IIO_CURRENT) {
183 			*val = hdc100x_get_heater_status(data);
184 			ret = IIO_VAL_INT;
185 		} else {
186 			ret = hdc100x_get_measurement(data, chan);
187 			if (ret >= 0) {
188 				*val = ret;
189 				ret = IIO_VAL_INT;
190 			}
191 		}
192 		mutex_unlock(&data->lock);
193 		return ret;
194 	}
195 	case IIO_CHAN_INFO_INT_TIME:
196 		*val = 0;
197 		*val2 = data->adc_int_us[chan->address];
198 		return IIO_VAL_INT_PLUS_MICRO;
199 	case IIO_CHAN_INFO_SCALE:
200 		if (chan->type == IIO_TEMP) {
201 			*val = 165000;
202 			*val2 = 65536;
203 			return IIO_VAL_FRACTIONAL;
204 		} else {
205 			*val = 100;
206 			*val2 = 65536;
207 			return IIO_VAL_FRACTIONAL;
208 		}
209 		break;
210 	case IIO_CHAN_INFO_OFFSET:
211 		*val = -15887;
212 		*val2 = 515151;
213 		return IIO_VAL_INT_PLUS_MICRO;
214 	default:
215 		return -EINVAL;
216 	}
217 }
218 
219 static int hdc100x_write_raw(struct iio_dev *indio_dev,
220 			     struct iio_chan_spec const *chan,
221 			     int val, int val2, long mask)
222 {
223 	struct hdc100x_data *data = iio_priv(indio_dev);
224 	int ret = -EINVAL;
225 
226 	switch (mask) {
227 	case IIO_CHAN_INFO_INT_TIME:
228 		if (val != 0)
229 			return -EINVAL;
230 
231 		mutex_lock(&data->lock);
232 		ret = hdc100x_set_it_time(data, chan->address, val2);
233 		mutex_unlock(&data->lock);
234 		return ret;
235 	case IIO_CHAN_INFO_RAW:
236 		if (chan->type != IIO_CURRENT || val2 != 0)
237 			return -EINVAL;
238 
239 		mutex_lock(&data->lock);
240 		ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
241 					val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
242 		mutex_unlock(&data->lock);
243 		return ret;
244 	default:
245 		return -EINVAL;
246 	}
247 }
248 
249 static const struct iio_info hdc100x_info = {
250 	.read_raw = hdc100x_read_raw,
251 	.write_raw = hdc100x_write_raw,
252 	.attrs = &hdc100x_attribute_group,
253 	.driver_module = THIS_MODULE,
254 };
255 
256 static int hdc100x_probe(struct i2c_client *client,
257 			 const struct i2c_device_id *id)
258 {
259 	struct iio_dev *indio_dev;
260 	struct hdc100x_data *data;
261 
262 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
263 				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
264 		return -EOPNOTSUPP;
265 
266 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
267 	if (!indio_dev)
268 		return -ENOMEM;
269 
270 	data = iio_priv(indio_dev);
271 	i2c_set_clientdata(client, indio_dev);
272 	data->client = client;
273 	mutex_init(&data->lock);
274 
275 	indio_dev->dev.parent = &client->dev;
276 	indio_dev->name = dev_name(&client->dev);
277 	indio_dev->modes = INDIO_DIRECT_MODE;
278 	indio_dev->info = &hdc100x_info;
279 
280 	indio_dev->channels = hdc100x_channels;
281 	indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);
282 
283 	/* be sure we are in a known state */
284 	hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]);
285 	hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]);
286 
287 	return devm_iio_device_register(&client->dev, indio_dev);
288 }
289 
290 static const struct i2c_device_id hdc100x_id[] = {
291 	{ "hdc100x", 0 },
292 	{ }
293 };
294 MODULE_DEVICE_TABLE(i2c, hdc100x_id);
295 
296 static struct i2c_driver hdc100x_driver = {
297 	.driver = {
298 		.name	= "hdc100x",
299 	},
300 	.probe = hdc100x_probe,
301 	.id_table = hdc100x_id,
302 };
303 module_i2c_driver(hdc100x_driver);
304 
305 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
306 MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver");
307 MODULE_LICENSE("GPL");
308