1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Digital temperature sensor with integrated Non-volatile memory 4 * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com> 5 * 6 * Driver for the Texas Instruments TMP117 Temperature Sensor 7 * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins) 8 * 9 * Note: This driver assumes that the sensor has been calibrated beforehand. 10 */ 11 12 #include <linux/err.h> 13 #include <linux/i2c.h> 14 #include <linux/module.h> 15 #include <linux/bitops.h> 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/limits.h> 19 20 #include <linux/iio/iio.h> 21 22 #define TMP117_REG_TEMP 0x0 23 #define TMP117_REG_CFGR 0x1 24 #define TMP117_REG_HIGH_LIM 0x2 25 #define TMP117_REG_LOW_LIM 0x3 26 #define TMP117_REG_EEPROM_UL 0x4 27 #define TMP117_REG_EEPROM1 0x5 28 #define TMP117_REG_EEPROM2 0x6 29 #define TMP117_REG_TEMP_OFFSET 0x7 30 #define TMP117_REG_EEPROM3 0x8 31 #define TMP117_REG_DEVICE_ID 0xF 32 33 #define TMP117_RESOLUTION_10UC 78125 34 #define TMP117_DEVICE_ID 0x0117 35 #define MICRODEGREE_PER_10MILLIDEGREE 10000 36 37 struct tmp117_data { 38 struct i2c_client *client; 39 s16 calibbias; 40 }; 41 42 static int tmp117_read_raw(struct iio_dev *indio_dev, 43 struct iio_chan_spec const *channel, int *val, 44 int *val2, long mask) 45 { 46 struct tmp117_data *data = iio_priv(indio_dev); 47 s32 ret; 48 49 switch (mask) { 50 case IIO_CHAN_INFO_RAW: 51 ret = i2c_smbus_read_word_swapped(data->client, 52 TMP117_REG_TEMP); 53 if (ret < 0) 54 return ret; 55 *val = sign_extend32(ret, 15); 56 return IIO_VAL_INT; 57 58 case IIO_CHAN_INFO_CALIBBIAS: 59 ret = i2c_smbus_read_word_swapped(data->client, 60 TMP117_REG_TEMP_OFFSET); 61 if (ret < 0) 62 return ret; 63 *val = sign_extend32(ret, 15); 64 return IIO_VAL_INT; 65 66 case IIO_CHAN_INFO_SCALE: 67 /* 68 * Conversion from 10s of uC to mC 69 * as IIO reports temperature in mC 70 */ 71 *val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE; 72 *val2 = (TMP117_RESOLUTION_10UC % 73 MICRODEGREE_PER_10MILLIDEGREE) * 100; 74 75 return IIO_VAL_INT_PLUS_MICRO; 76 77 default: 78 return -EINVAL; 79 } 80 } 81 82 static int tmp117_write_raw(struct iio_dev *indio_dev, 83 struct iio_chan_spec const *channel, int val, 84 int val2, long mask) 85 { 86 struct tmp117_data *data = iio_priv(indio_dev); 87 s16 off; 88 89 switch (mask) { 90 case IIO_CHAN_INFO_CALIBBIAS: 91 off = clamp_t(int, val, S16_MIN, S16_MAX); 92 if (off == data->calibbias) 93 return 0; 94 data->calibbias = off; 95 return i2c_smbus_write_word_swapped(data->client, 96 TMP117_REG_TEMP_OFFSET, off); 97 98 default: 99 return -EINVAL; 100 } 101 } 102 103 static const struct iio_chan_spec tmp117_channels[] = { 104 { 105 .type = IIO_TEMP, 106 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 107 BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE), 108 }, 109 }; 110 111 static const struct iio_info tmp117_info = { 112 .read_raw = tmp117_read_raw, 113 .write_raw = tmp117_write_raw, 114 }; 115 116 static int tmp117_identify(struct i2c_client *client) 117 { 118 int dev_id; 119 120 dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID); 121 if (dev_id < 0) 122 return dev_id; 123 if (dev_id != TMP117_DEVICE_ID) { 124 dev_err(&client->dev, "TMP117 not found\n"); 125 return -ENODEV; 126 } 127 return 0; 128 } 129 130 static int tmp117_probe(struct i2c_client *client) 131 { 132 struct tmp117_data *data; 133 struct iio_dev *indio_dev; 134 int ret; 135 136 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) 137 return -EOPNOTSUPP; 138 139 ret = tmp117_identify(client); 140 if (ret < 0) 141 return ret; 142 143 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 144 if (!indio_dev) 145 return -ENOMEM; 146 147 data = iio_priv(indio_dev); 148 data->client = client; 149 data->calibbias = 0; 150 151 indio_dev->name = "tmp117"; 152 indio_dev->modes = INDIO_DIRECT_MODE; 153 indio_dev->info = &tmp117_info; 154 155 indio_dev->channels = tmp117_channels; 156 indio_dev->num_channels = ARRAY_SIZE(tmp117_channels); 157 158 return devm_iio_device_register(&client->dev, indio_dev); 159 } 160 161 static const struct of_device_id tmp117_of_match[] = { 162 { .compatible = "ti,tmp117", }, 163 { } 164 }; 165 MODULE_DEVICE_TABLE(of, tmp117_of_match); 166 167 static const struct i2c_device_id tmp117_id[] = { 168 { "tmp117", 0 }, 169 { } 170 }; 171 MODULE_DEVICE_TABLE(i2c, tmp117_id); 172 173 static struct i2c_driver tmp117_driver = { 174 .driver = { 175 .name = "tmp117", 176 .of_match_table = tmp117_of_match, 177 }, 178 .probe_new = tmp117_probe, 179 .id_table = tmp117_id, 180 }; 181 module_i2c_driver(tmp117_driver); 182 183 MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>"); 184 MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver"); 185 MODULE_LICENSE("GPL"); 186