linux/drivers/hwmon/hih6130.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Honeywell HIH-6130/HIH-6131 humidity and temperature sensor driver
 *
 * Copyright (C) 2012 Iain Paton <[email protected]>
 *
 * heavily based on the sht21 driver
 * Copyright (C) 2010 Urs Fleisch <[email protected]>
 *
 * Data sheets available (2012-06-22) at
 * http://sensing.honeywell.com/index.php?ci_id=3106&la_id=1&defId=44872
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/jiffies.h>

/**
 * struct hih6130 - HIH-6130 device specific data
 * @client: pointer to I2C client device
 * @lock: mutex to protect measurement values
 * @valid: only false before first measurement is taken
 * @last_update: time of last update (jiffies)
 * @temperature: cached temperature measurement value
 * @humidity: cached humidity measurement value
 * @write_length: length for I2C measurement request
 */
struct hih6130 { … };

/**
 * hih6130_temp_ticks_to_millicelsius() - convert raw temperature ticks to
 * milli celsius
 * @ticks: temperature ticks value received from sensor
 */
static inline int hih6130_temp_ticks_to_millicelsius(int ticks)
{ … }

/**
 * hih6130_rh_ticks_to_per_cent_mille() - convert raw humidity ticks to
 * one-thousandths of a percent relative humidity
 * @ticks: humidity ticks value received from sensor
 */
static inline int hih6130_rh_ticks_to_per_cent_mille(int ticks)
{ … }

/**
 * hih6130_update_measurements() - get updated measurements from device
 * @dev: device
 *
 * Returns 0 on success, else negative errno.
 */
static int hih6130_update_measurements(struct device *dev)
{ … }

/**
 * hih6130_temperature_show() - show temperature measurement value in sysfs
 * @dev: device
 * @attr: device attribute
 * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to
 *
 * Will be called on read access to temp1_input sysfs attribute.
 * Returns number of bytes written into buffer, negative errno on error.
 */
static ssize_t hih6130_temperature_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{ … }

/**
 * hih6130_humidity_show() - show humidity measurement value in sysfs
 * @dev: device
 * @attr: device attribute
 * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to
 *
 * Will be called on read access to humidity1_input sysfs attribute.
 * Returns number of bytes written into buffer, negative errno on error.
 */
static ssize_t hih6130_humidity_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{ … }

/* sysfs attributes */
static SENSOR_DEVICE_ATTR_RO(temp1_input, hih6130_temperature, 0);
static SENSOR_DEVICE_ATTR_RO(humidity1_input, hih6130_humidity, 0);

static struct attribute *hih6130_attrs[] = …;

ATTRIBUTE_GROUPS(…);

static int hih6130_probe(struct i2c_client *client)
{ … }

/* Device ID table */
static const struct i2c_device_id hih6130_id[] = …;
MODULE_DEVICE_TABLE(i2c, hih6130_id);

static const struct of_device_id __maybe_unused hih6130_of_match[] = …;
MODULE_DEVICE_TABLE(of, hih6130_of_match);

static struct i2c_driver hih6130_driver = …;

module_i2c_driver(…) …;

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;