1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * si7005.c - Support for Silabs Si7005 humidity and temperature sensor 4 * 5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net> 6 * 7 * (7-bit I2C slave address 0x40) 8 * 9 * TODO: heater, fast mode, processed mode (temp. / linearity compensation) 10 */ 11 12 #include <linux/err.h> 13 #include <linux/i2c.h> 14 #include <linux/delay.h> 15 #include <linux/module.h> 16 #include <linux/pm.h> 17 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 21 #define SI7005_STATUS 0x00 22 #define SI7005_DATA 0x01 /* 16-bit, MSB */ 23 #define SI7005_CONFIG 0x03 24 #define SI7005_ID 0x11 25 26 #define SI7005_STATUS_NRDY BIT(0) 27 #define SI7005_CONFIG_TEMP BIT(4) 28 #define SI7005_CONFIG_START BIT(0) 29 30 #define SI7005_ID_7005 0x50 31 #define SI7005_ID_7015 0xf0 32 33 struct si7005_data { 34 struct i2c_client *client; 35 struct mutex lock; 36 u8 config; 37 }; 38 39 static int si7005_read_measurement(struct si7005_data *data, bool temp) 40 { 41 int tries = 50; 42 int ret; 43 44 mutex_lock(&data->lock); 45 46 ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG, 47 data->config | SI7005_CONFIG_START | 48 (temp ? SI7005_CONFIG_TEMP : 0)); 49 if (ret < 0) 50 goto done; 51 52 while (tries-- > 0) { 53 msleep(20); 54 ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS); 55 if (ret < 0) 56 goto done; 57 if (!(ret & SI7005_STATUS_NRDY)) 58 break; 59 } 60 if (tries < 0) { 61 ret = -EIO; 62 goto done; 63 } 64 65 ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA); 66 67 done: 68 mutex_unlock(&data->lock); 69 70 return ret; 71 } 72 73 static int si7005_read_raw(struct iio_dev *indio_dev, 74 struct iio_chan_spec const *chan, int *val, 75 int *val2, long mask) 76 { 77 struct si7005_data *data = iio_priv(indio_dev); 78 int ret; 79 80 switch (mask) { 81 case IIO_CHAN_INFO_RAW: 82 ret = si7005_read_measurement(data, chan->type == IIO_TEMP); 83 if (ret < 0) 84 return ret; 85 *val = ret; 86 return IIO_VAL_INT; 87 case IIO_CHAN_INFO_SCALE: 88 if (chan->type == IIO_TEMP) { 89 *val = 7; 90 *val2 = 812500; 91 } else { 92 *val = 3; 93 *val2 = 906250; 94 } 95 return IIO_VAL_INT_PLUS_MICRO; 96 case IIO_CHAN_INFO_OFFSET: 97 if (chan->type == IIO_TEMP) 98 *val = -50 * 32 * 4; 99 else 100 *val = -24 * 16 * 16; 101 return IIO_VAL_INT; 102 default: 103 break; 104 } 105 106 return -EINVAL; 107 } 108 109 static const struct iio_chan_spec si7005_channels[] = { 110 { 111 .type = IIO_HUMIDITYRELATIVE, 112 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 113 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET), 114 }, 115 { 116 .type = IIO_TEMP, 117 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 118 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET), 119 } 120 }; 121 122 static const struct iio_info si7005_info = { 123 .read_raw = si7005_read_raw, 124 }; 125 126 static int si7005_probe(struct i2c_client *client) 127 { 128 struct iio_dev *indio_dev; 129 struct si7005_data *data; 130 int ret; 131 132 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) 133 return -EOPNOTSUPP; 134 135 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 136 if (!indio_dev) 137 return -ENOMEM; 138 139 data = iio_priv(indio_dev); 140 i2c_set_clientdata(client, indio_dev); 141 data->client = client; 142 mutex_init(&data->lock); 143 144 indio_dev->name = dev_name(&client->dev); 145 indio_dev->modes = INDIO_DIRECT_MODE; 146 indio_dev->info = &si7005_info; 147 148 indio_dev->channels = si7005_channels; 149 indio_dev->num_channels = ARRAY_SIZE(si7005_channels); 150 151 ret = i2c_smbus_read_byte_data(client, SI7005_ID); 152 if (ret < 0) 153 return ret; 154 if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015) 155 return -ENODEV; 156 157 ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG); 158 if (ret < 0) 159 return ret; 160 data->config = ret; 161 162 return devm_iio_device_register(&client->dev, indio_dev); 163 } 164 165 static const struct i2c_device_id si7005_id[] = { 166 { "si7005", 0 }, 167 { "th02", 0 }, 168 { } 169 }; 170 MODULE_DEVICE_TABLE(i2c, si7005_id); 171 172 static const struct of_device_id si7005_dt_ids[] = { 173 { .compatible = "silabs,si7005" }, 174 { } 175 }; 176 MODULE_DEVICE_TABLE(of, si7005_dt_ids); 177 178 static struct i2c_driver si7005_driver = { 179 .driver = { 180 .name = "si7005", 181 .of_match_table = si7005_dt_ids, 182 }, 183 .probe = si7005_probe, 184 .id_table = si7005_id, 185 }; 186 module_i2c_driver(si7005_driver); 187 188 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 189 MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver"); 190 MODULE_LICENSE("GPL"); 191