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185 lines
4.3 KiB
185 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Digital temperature sensor with integrated Non-volatile memory |
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* Copyright (c) 2021 Puranjay Mohan <[email protected]> |
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* |
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* Driver for the Texas Instruments TMP117 Temperature Sensor |
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* (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins) |
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* |
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* Note: This driver assumes that the sensor has been calibrated beforehand. |
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*/ |
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#include <linux/err.h> |
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#include <linux/i2c.h> |
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#include <linux/module.h> |
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#include <linux/bitops.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/limits.h> |
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#include <linux/iio/iio.h> |
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#define TMP117_REG_TEMP 0x0 |
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#define TMP117_REG_CFGR 0x1 |
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#define TMP117_REG_HIGH_LIM 0x2 |
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#define TMP117_REG_LOW_LIM 0x3 |
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#define TMP117_REG_EEPROM_UL 0x4 |
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#define TMP117_REG_EEPROM1 0x5 |
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#define TMP117_REG_EEPROM2 0x6 |
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#define TMP117_REG_TEMP_OFFSET 0x7 |
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#define TMP117_REG_EEPROM3 0x8 |
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#define TMP117_REG_DEVICE_ID 0xF |
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#define TMP117_RESOLUTION_10UC 78125 |
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#define TMP117_DEVICE_ID 0x0117 |
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#define MICRODEGREE_PER_10MILLIDEGREE 10000 |
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struct tmp117_data { |
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struct i2c_client *client; |
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s16 calibbias; |
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}; |
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static int tmp117_read_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *channel, int *val, |
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int *val2, long mask) |
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{ |
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struct tmp117_data *data = iio_priv(indio_dev); |
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s32 ret; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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ret = i2c_smbus_read_word_swapped(data->client, |
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TMP117_REG_TEMP); |
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if (ret < 0) |
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return ret; |
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*val = sign_extend32(ret, 15); |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_CALIBBIAS: |
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ret = i2c_smbus_read_word_swapped(data->client, |
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TMP117_REG_TEMP_OFFSET); |
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if (ret < 0) |
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return ret; |
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*val = sign_extend32(ret, 15); |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_SCALE: |
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/* |
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* Conversion from 10s of uC to mC |
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* as IIO reports temperature in mC |
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*/ |
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*val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE; |
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*val2 = (TMP117_RESOLUTION_10UC % |
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MICRODEGREE_PER_10MILLIDEGREE) * 100; |
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return IIO_VAL_INT_PLUS_MICRO; |
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default: |
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return -EINVAL; |
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} |
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} |
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static int tmp117_write_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *channel, int val, |
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int val2, long mask) |
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{ |
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struct tmp117_data *data = iio_priv(indio_dev); |
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s16 off; |
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switch (mask) { |
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case IIO_CHAN_INFO_CALIBBIAS: |
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off = clamp_t(int, val, S16_MIN, S16_MAX); |
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if (off == data->calibbias) |
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return 0; |
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data->calibbias = off; |
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return i2c_smbus_write_word_swapped(data->client, |
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TMP117_REG_TEMP_OFFSET, off); |
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default: |
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return -EINVAL; |
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} |
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} |
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static const struct iio_chan_spec tmp117_channels[] = { |
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{ |
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.type = IIO_TEMP, |
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | |
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BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE), |
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}, |
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}; |
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static const struct iio_info tmp117_info = { |
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.read_raw = tmp117_read_raw, |
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.write_raw = tmp117_write_raw, |
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}; |
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static int tmp117_identify(struct i2c_client *client) |
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{ |
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int dev_id; |
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dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID); |
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if (dev_id < 0) |
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return dev_id; |
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if (dev_id != TMP117_DEVICE_ID) { |
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dev_err(&client->dev, "TMP117 not found\n"); |
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return -ENODEV; |
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} |
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return 0; |
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} |
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static int tmp117_probe(struct i2c_client *client) |
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{ |
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struct tmp117_data *data; |
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struct iio_dev *indio_dev; |
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int ret; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) |
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return -EOPNOTSUPP; |
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ret = tmp117_identify(client); |
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if (ret < 0) |
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return ret; |
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); |
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if (!indio_dev) |
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return -ENOMEM; |
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data = iio_priv(indio_dev); |
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data->client = client; |
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data->calibbias = 0; |
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indio_dev->name = "tmp117"; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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indio_dev->info = &tmp117_info; |
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indio_dev->channels = tmp117_channels; |
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indio_dev->num_channels = ARRAY_SIZE(tmp117_channels); |
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return devm_iio_device_register(&client->dev, indio_dev); |
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} |
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static const struct of_device_id tmp117_of_match[] = { |
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{ .compatible = "ti,tmp117", }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, tmp117_of_match); |
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static const struct i2c_device_id tmp117_id[] = { |
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{ "tmp117", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, tmp117_id); |
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static struct i2c_driver tmp117_driver = { |
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.driver = { |
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.name = "tmp117", |
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.of_match_table = tmp117_of_match, |
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}, |
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.probe_new = tmp117_probe, |
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.id_table = tmp117_id, |
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}; |
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module_i2c_driver(tmp117_driver); |
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MODULE_AUTHOR("Puranjay Mohan <[email protected]>"); |
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MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver"); |
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MODULE_LICENSE("GPL");
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