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 int 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 /* 158 * i2c_smbus_read_word_data cannot() be used here due to the command 159 * value not being understood and causes NAKs preventing any reading 160 * from being accessed. 161 */ 162 ret = i2c_smbus_read_byte(client); 163 if (ret < 0) { 164 dev_err(&client->dev, "cannot read high byte measurement"); 165 return ret; 166 } 167 val = ret << 8; 168 169 ret = i2c_smbus_read_byte(client); 170 if (ret < 0) { 171 dev_err(&client->dev, "cannot read low byte measurement"); 172 return ret; 173 } 174 val |= ret; 175 176 return val; 177 } 178 179 static int hdc100x_get_heater_status(struct hdc100x_data *data) 180 { 181 return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN); 182 } 183 184 static int hdc100x_read_raw(struct iio_dev *indio_dev, 185 struct iio_chan_spec const *chan, int *val, 186 int *val2, long mask) 187 { 188 struct hdc100x_data *data = iio_priv(indio_dev); 189 190 switch (mask) { 191 case IIO_CHAN_INFO_RAW: { 192 int ret; 193 194 mutex_lock(&data->lock); 195 if (chan->type == IIO_CURRENT) { 196 *val = hdc100x_get_heater_status(data); 197 ret = IIO_VAL_INT; 198 } else { 199 ret = hdc100x_get_measurement(data, chan); 200 if (ret >= 0) { 201 *val = ret; 202 ret = IIO_VAL_INT; 203 } 204 } 205 mutex_unlock(&data->lock); 206 return ret; 207 } 208 case IIO_CHAN_INFO_INT_TIME: 209 *val = 0; 210 *val2 = data->adc_int_us[chan->address]; 211 return IIO_VAL_INT_PLUS_MICRO; 212 case IIO_CHAN_INFO_SCALE: 213 if (chan->type == IIO_TEMP) { 214 *val = 165000; 215 *val2 = 65536; 216 return IIO_VAL_FRACTIONAL; 217 } else { 218 *val = 100; 219 *val2 = 65536; 220 return IIO_VAL_FRACTIONAL; 221 } 222 break; 223 case IIO_CHAN_INFO_OFFSET: 224 *val = -15887; 225 *val2 = 515151; 226 return IIO_VAL_INT_PLUS_MICRO; 227 default: 228 return -EINVAL; 229 } 230 } 231 232 static int hdc100x_write_raw(struct iio_dev *indio_dev, 233 struct iio_chan_spec const *chan, 234 int val, int val2, long mask) 235 { 236 struct hdc100x_data *data = iio_priv(indio_dev); 237 int ret = -EINVAL; 238 239 switch (mask) { 240 case IIO_CHAN_INFO_INT_TIME: 241 if (val != 0) 242 return -EINVAL; 243 244 mutex_lock(&data->lock); 245 ret = hdc100x_set_it_time(data, chan->address, val2); 246 mutex_unlock(&data->lock); 247 return ret; 248 case IIO_CHAN_INFO_RAW: 249 if (chan->type != IIO_CURRENT || val2 != 0) 250 return -EINVAL; 251 252 mutex_lock(&data->lock); 253 ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN, 254 val ? HDC100X_REG_CONFIG_HEATER_EN : 0); 255 mutex_unlock(&data->lock); 256 return ret; 257 default: 258 return -EINVAL; 259 } 260 } 261 262 static const struct iio_info hdc100x_info = { 263 .read_raw = hdc100x_read_raw, 264 .write_raw = hdc100x_write_raw, 265 .attrs = &hdc100x_attribute_group, 266 .driver_module = THIS_MODULE, 267 }; 268 269 static int hdc100x_probe(struct i2c_client *client, 270 const struct i2c_device_id *id) 271 { 272 struct iio_dev *indio_dev; 273 struct hdc100x_data *data; 274 275 if (!i2c_check_functionality(client->adapter, 276 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE)) 277 return -EOPNOTSUPP; 278 279 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 280 if (!indio_dev) 281 return -ENOMEM; 282 283 data = iio_priv(indio_dev); 284 i2c_set_clientdata(client, indio_dev); 285 data->client = client; 286 mutex_init(&data->lock); 287 288 indio_dev->dev.parent = &client->dev; 289 indio_dev->name = dev_name(&client->dev); 290 indio_dev->modes = INDIO_DIRECT_MODE; 291 indio_dev->info = &hdc100x_info; 292 293 indio_dev->channels = hdc100x_channels; 294 indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels); 295 296 /* be sure we are in a known state */ 297 hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]); 298 hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]); 299 300 return devm_iio_device_register(&client->dev, indio_dev); 301 } 302 303 static const struct i2c_device_id hdc100x_id[] = { 304 { "hdc100x", 0 }, 305 { } 306 }; 307 MODULE_DEVICE_TABLE(i2c, hdc100x_id); 308 309 static struct i2c_driver hdc100x_driver = { 310 .driver = { 311 .name = "hdc100x", 312 }, 313 .probe = hdc100x_probe, 314 .id_table = hdc100x_id, 315 }; 316 module_i2c_driver(hdc100x_driver); 317 318 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); 319 MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver"); 320 MODULE_LICENSE("GPL"); 321