htu21.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * htu21.c - Support for Measurement-Specialties
  4 *           htu21 temperature & humidity sensor
  5 *	     and humidity part of MS8607 sensor
  6 *
  7 * Copyright (c) 2014 Measurement-Specialties
  8 *
  9 * (7-bit I2C slave address 0x40)
 10 *
 11 * Datasheet:
 12 *  http://www.meas-spec.com/downloads/HTU21D.pdf
 13 * Datasheet:
 14 *  http://www.meas-spec.com/downloads/MS8607-02BA01.pdf
 15 */
 16
 17#include <linux/init.h>
 18#include <linux/device.h>
 19#include <linux/kernel.h>
 20#include <linux/stat.h>
 21#include <linux/module.h>
 22#include <linux/mod_devicetable.h>
 23#include <linux/iio/iio.h>
 24#include <linux/iio/sysfs.h>
 25
 26#include "../common/ms_sensors/ms_sensors_i2c.h"
 27
 28#define HTU21_RESET				0xFE
 29
 30enum {
 31	HTU21,
 32	MS8607
 33};
 34
 35static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
 36/* String copy of the above const for readability purpose */
 37static const char htu21_show_samp_freq[] = "20 40 70 120";
 38
 39static int htu21_read_raw(struct iio_dev *indio_dev,
 40			  struct iio_chan_spec const *channel, int *val,
 41			  int *val2, long mask)
 42{
 43	int ret, temperature;
 44	unsigned int humidity;
 45	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
 46
 47	switch (mask) {
 48	case IIO_CHAN_INFO_PROCESSED:
 49		switch (channel->type) {
 50		case IIO_TEMP:	/* in milli °C */
 51			ret = ms_sensors_ht_read_temperature(dev_data,
 52							     &temperature);
 53			if (ret)
 54				return ret;
 55			*val = temperature;
 56
 57			return IIO_VAL_INT;
 58		case IIO_HUMIDITYRELATIVE:	/* in milli %RH */
 59			ret = ms_sensors_ht_read_humidity(dev_data,
 60							  &humidity);
 61			if (ret)
 62				return ret;
 63			*val = humidity;
 64
 65			return IIO_VAL_INT;
 66		default:
 67			return -EINVAL;
 68		}
 69	case IIO_CHAN_INFO_SAMP_FREQ:
 70		*val = htu21_samp_freq[dev_data->res_index];
 71
 72		return IIO_VAL_INT;
 73	default:
 74		return -EINVAL;
 75	}
 76}
 77
 78static int htu21_write_raw(struct iio_dev *indio_dev,
 79			   struct iio_chan_spec const *chan,
 80			   int val, int val2, long mask)
 81{
 82	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
 83	int i, ret;
 84
 85	switch (mask) {
 86	case IIO_CHAN_INFO_SAMP_FREQ:
 87		i = ARRAY_SIZE(htu21_samp_freq);
 88		while (i-- > 0)
 89			if (val == htu21_samp_freq[i])
 90				break;
 91		if (i < 0)
 92			return -EINVAL;
 93		mutex_lock(&dev_data->lock);
 94		dev_data->res_index = i;
 95		ret = ms_sensors_write_resolution(dev_data, i);
 96		mutex_unlock(&dev_data->lock);
 97
 98		return ret;
 99	default:
100		return -EINVAL;
101	}
102}
103
104static const struct iio_chan_spec htu21_channels[] = {
105	{
106		.type = IIO_TEMP,
107		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
108		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
109	 },
110	{
111		.type = IIO_HUMIDITYRELATIVE,
112		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
113		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
114	 }
115};
116
117/*
118 * Meas Spec recommendation is to not read temperature
119 * on this driver part for MS8607
120 */
121static const struct iio_chan_spec ms8607_channels[] = {
122	{
123		.type = IIO_HUMIDITYRELATIVE,
124		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
125		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
126	 }
127};
128
129static ssize_t htu21_show_battery_low(struct device *dev,
130				      struct device_attribute *attr, char *buf)
131{
132	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
133	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
134
135	return ms_sensors_show_battery_low(dev_data, buf);
136}
137
138static ssize_t htu21_show_heater(struct device *dev,
139				 struct device_attribute *attr, char *buf)
140{
141	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
142	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
143
144	return ms_sensors_show_heater(dev_data, buf);
145}
146
147static ssize_t htu21_write_heater(struct device *dev,
148				  struct device_attribute *attr,
149				  const char *buf, size_t len)
150{
151	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
152	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
153
154	return ms_sensors_write_heater(dev_data, buf, len);
155}
156
157static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
158static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
159		       htu21_show_battery_low, NULL, 0);
160static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
161		       htu21_show_heater, htu21_write_heater, 0);
162
163static struct attribute *htu21_attributes[] = {
164	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
165	&iio_dev_attr_battery_low.dev_attr.attr,
166	&iio_dev_attr_heater_enable.dev_attr.attr,
167	NULL,
168};
169
170static const struct attribute_group htu21_attribute_group = {
171	.attrs = htu21_attributes,
172};
173
174static const struct iio_info htu21_info = {
175	.read_raw = htu21_read_raw,
176	.write_raw = htu21_write_raw,
177	.attrs = &htu21_attribute_group,
178};
179
180static int htu21_probe(struct i2c_client *client)
181{
182	const struct i2c_device_id *id = i2c_client_get_device_id(client);
183	struct ms_ht_dev *dev_data;
184	struct iio_dev *indio_dev;
185	int ret;
186	u64 serial_number;
187
188	if (!i2c_check_functionality(client->adapter,
189				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
190				     I2C_FUNC_SMBUS_WRITE_BYTE |
191				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
192		dev_err(&client->dev,
193			"Adapter does not support some i2c transaction\n");
194		return -EOPNOTSUPP;
195	}
196
197	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
198	if (!indio_dev)
199		return -ENOMEM;
200
201	dev_data = iio_priv(indio_dev);
202	dev_data->client = client;
203	dev_data->res_index = 0;
204	mutex_init(&dev_data->lock);
205
206	indio_dev->info = &htu21_info;
207	indio_dev->name = id->name;
208	indio_dev->modes = INDIO_DIRECT_MODE;
209
210	if (id->driver_data == MS8607) {
211		indio_dev->channels = ms8607_channels;
212		indio_dev->num_channels = ARRAY_SIZE(ms8607_channels);
213	} else {
214		indio_dev->channels = htu21_channels;
215		indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
216	}
217
218	i2c_set_clientdata(client, indio_dev);
219
220	ret = ms_sensors_reset(client, HTU21_RESET, 15000);
221	if (ret)
222		return ret;
223
224	ret = ms_sensors_read_serial(client, &serial_number);
225	if (ret)
226		return ret;
227	dev_info(&client->dev, "Serial number : %llx", serial_number);
228
229	return devm_iio_device_register(&client->dev, indio_dev);
230}
231
232static const struct i2c_device_id htu21_id[] = {
233	{"htu21", HTU21},
234	{"ms8607-humidity", MS8607},
235	{ }
236};
237MODULE_DEVICE_TABLE(i2c, htu21_id);
238
239static const struct of_device_id htu21_of_match[] = {
240	{ .compatible = "meas,htu21", },
241	{ .compatible = "meas,ms8607-humidity", },
242	{ }
243};
244MODULE_DEVICE_TABLE(of, htu21_of_match);
245
246static struct i2c_driver htu21_driver = {
247	.probe = htu21_probe,
248	.id_table = htu21_id,
249	.driver = {
250		   .name = "htu21",
251		   .of_match_table = htu21_of_match,
252		   },
253};
254
255module_i2c_driver(htu21_driver);
256
257MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
258MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
259MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
260MODULE_LICENSE("GPL v2");
261MODULE_IMPORT_NS("IIO_MEAS_SPEC_SENSORS");