1 /* 2 * htu21.c - Support for Measurement-Specialties 3 * htu21 temperature & humidity sensor 4 * and humidity part of MS8607 sensor 5 * 6 * Copyright (c) 2014 Measurement-Specialties 7 * 8 * Licensed under the GPL-2. 9 * 10 * (7-bit I2C slave address 0x40) 11 * 12 * Datasheet: 13 * http://www.meas-spec.com/downloads/HTU21D.pdf 14 * Datasheet: 15 * http://www.meas-spec.com/downloads/MS8607-02BA01.pdf 16 */ 17 18 #include <linux/init.h> 19 #include <linux/device.h> 20 #include <linux/kernel.h> 21 #include <linux/stat.h> 22 #include <linux/module.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 30 enum { 31 HTU21, 32 MS8607 33 }; 34 35 static const int htu21_samp_freq[4] = { 20, 40, 70, 120 }; 36 /* String copy of the above const for readability purpose */ 37 static const char htu21_show_samp_freq[] = "20 40 70 120"; 38 39 static 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 78 static 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 } 103 104 static 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 */ 121 static 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 }; 128 129 static 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 } 137 138 static 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 } 146 147 static 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 } 156 157 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq); 158 static IIO_DEVICE_ATTR(battery_low, S_IRUGO, 159 htu21_show_battery_low, NULL, 0); 160 static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR, 161 htu21_show_heater, htu21_write_heater, 0); 162 163 static 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 }; 169 170 static const struct attribute_group htu21_attribute_group = { 171 .attrs = htu21_attributes, 172 }; 173 174 static const struct iio_info htu21_info = { 175 .read_raw = htu21_read_raw, 176 .write_raw = htu21_write_raw, 177 .attrs = &htu21_attribute_group, 178 .driver_module = THIS_MODULE, 179 }; 180 181 static int htu21_probe(struct i2c_client *client, 182 const struct i2c_device_id *id) 183 { 184 struct ms_ht_dev *dev_data; 185 struct iio_dev *indio_dev; 186 int ret; 187 u64 serial_number; 188 189 if (!i2c_check_functionality(client->adapter, 190 I2C_FUNC_SMBUS_WRITE_BYTE_DATA | 191 I2C_FUNC_SMBUS_WRITE_BYTE | 192 I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { 193 dev_err(&client->dev, 194 "Adapter does not support some i2c transaction\n"); 195 return -ENODEV; 196 } 197 198 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data)); 199 if (!indio_dev) 200 return -ENOMEM; 201 202 dev_data = iio_priv(indio_dev); 203 dev_data->client = client; 204 dev_data->res_index = 0; 205 mutex_init(&dev_data->lock); 206 207 indio_dev->info = &htu21_info; 208 indio_dev->name = id->name; 209 indio_dev->dev.parent = &client->dev; 210 indio_dev->modes = INDIO_DIRECT_MODE; 211 212 if (id->driver_data == MS8607) { 213 indio_dev->channels = ms8607_channels; 214 indio_dev->num_channels = ARRAY_SIZE(ms8607_channels); 215 } else { 216 indio_dev->channels = htu21_channels; 217 indio_dev->num_channels = ARRAY_SIZE(htu21_channels); 218 } 219 220 i2c_set_clientdata(client, indio_dev); 221 222 ret = ms_sensors_reset(client, HTU21_RESET, 15000); 223 if (ret) 224 return ret; 225 226 ret = ms_sensors_read_serial(client, &serial_number); 227 if (ret) 228 return ret; 229 dev_info(&client->dev, "Serial number : %llx", serial_number); 230 231 return devm_iio_device_register(&client->dev, indio_dev); 232 } 233 234 static const struct i2c_device_id htu21_id[] = { 235 {"htu21", HTU21}, 236 {"ms8607-humidity", MS8607}, 237 {} 238 }; 239 240 static struct i2c_driver htu21_driver = { 241 .probe = htu21_probe, 242 .id_table = htu21_id, 243 .driver = { 244 .name = "htu21", 245 }, 246 }; 247 248 module_i2c_driver(htu21_driver); 249 250 MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver"); 251 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>"); 252 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>"); 253 MODULE_LICENSE("GPL v2"); 254