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hwmon: (htu21) Remove driver

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HTU21 is now supported by IIO, and can be instantiated as hwmon driver
using the iio-hwmon bridge. An explicit hwmon driver is no longer needed.

Cc: William Markezana <william.markezana@meas-spec.com>
Cc: Ludovic Tancerel <ludovic.tancerel@maplehightech.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2015-11-07 15:54:33 -08:00
parent a3a316cfc4
commit 2ff44072e3
4 changed files with 0 additions and 231 deletions
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46
Documentation/hwmon/htu21
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@ -1,46 +0,0 @@
Kernel driver htu21
===================
Supported chips:
* Measurement Specialties HTU21D
Prefix: 'htu21'
Addresses scanned: none
Datasheet: Publicly available at the Measurement Specialties website
http://www.meas-spec.com/downloads/HTU21D.pdf
Author:
William Markezana <william.markezana@meas-spec.com>
Description
-----------
The HTU21D is a humidity and temperature sensor in a DFN package of
only 3 x 3 mm footprint and 0.9 mm height.
The devices communicate with the I2C protocol. All sensors are set to the
same I2C address 0x40, so an entry with I2C_BOARD_INFO("htu21", 0x40) can
be used in the board setup code.
This driver does not auto-detect devices. You will have to instantiate the
devices explicitly. Please see Documentation/i2c/instantiating-devices
for details.
sysfs-Interface
---------------
temp1_input - temperature input
humidity1_input - humidity input
Notes
-----
The driver uses the default resolution settings of 12 bit for humidity and 14
bit for temperature, which results in typical measurement times of 11 ms for
humidity and 44 ms for temperature. To keep self heating below 0.1 degree
Celsius, the device should not be active for more than 10% of the time. For
this reason, the driver performs no more than two measurements per second and
reports cached information if polled more frequently.
Different resolutions, the on-chip heater, using the CRC checksum and reading
the serial number are not supported yet.

10
drivers/hwmon/Kconfig
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@ -859,16 +859,6 @@ config SENSORS_MAX31790
This driver can also be built as a module. If so, the module
will be called max31790.
config SENSORS_HTU21
tristate "Measurement Specialties HTU21D humidity/temperature sensors"
depends on I2C
help
If you say yes here you get support for the Measurement Specialties
HTU21D humidity and temperature sensors.
This driver can also be built as a module. If so, the module
will be called htu21.
config SENSORS_MCP3021
tristate "Microchip MCP3021 and compatibles"
depends on I2C

1
drivers/hwmon/Makefile
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@ -68,7 +68,6 @@ obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o
obj-$(CONFIG_SENSORS_HIH6130) += hih6130.o
obj-$(CONFIG_SENSORS_HTU21) += htu21.o
obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o
obj-$(CONFIG_SENSORS_I5500) += i5500_temp.o
obj-$(CONFIG_SENSORS_I5K_AMB) += i5k_amb.o

174
drivers/hwmon/htu21.c
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@ -1,174 +0,0 @@
/*
* Measurement Specialties HTU21D humidity and temperature sensor driver
*
* Copyright (C) 2013 William Markezana <william.markezana@meas-spec.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#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/jiffies.h>
/* HTU21 Commands */
#define HTU21_T_MEASUREMENT_HM 0xE3
#define HTU21_RH_MEASUREMENT_HM 0xE5
struct htu21 {
struct i2c_client *client;
struct mutex lock;
bool valid;
unsigned long last_update;
int temperature;
int humidity;
};
static inline int htu21_temp_ticks_to_millicelsius(int ticks)
{
ticks &= ~0x0003; /* clear status bits */
/*
* Formula T = -46.85 + 175.72 * ST / 2^16 from datasheet p14,
* optimized for integer fixed point (3 digits) arithmetic
*/
return ((21965 * ticks) >> 13) - 46850;
}
static inline int htu21_rh_ticks_to_per_cent_mille(int ticks)
{
ticks &= ~0x0003; /* clear status bits */
/*
* Formula RH = -6 + 125 * SRH / 2^16 from datasheet p14,
* optimized for integer fixed point (3 digits) arithmetic
*/
return ((15625 * ticks) >> 13) - 6000;
}
static int htu21_update_measurements(struct device *dev)
{
struct htu21 *htu21 = dev_get_drvdata(dev);
struct i2c_client *client = htu21->client;
int ret = 0;
mutex_lock(&htu21->lock);
if (time_after(jiffies, htu21->last_update + HZ / 2) ||
!htu21->valid) {
ret = i2c_smbus_read_word_swapped(client,
HTU21_T_MEASUREMENT_HM);
if (ret < 0)
goto out;
htu21->temperature = htu21_temp_ticks_to_millicelsius(ret);
ret = i2c_smbus_read_word_swapped(client,
HTU21_RH_MEASUREMENT_HM);
if (ret < 0)
goto out;
htu21->humidity = htu21_rh_ticks_to_per_cent_mille(ret);
htu21->last_update = jiffies;
htu21->valid = true;
}
out:
mutex_unlock(&htu21->lock);
return ret >= 0 ? 0 : ret;
}
static ssize_t htu21_show_temperature(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct htu21 *htu21 = dev_get_drvdata(dev);
int ret;
ret = htu21_update_measurements(dev);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", htu21->temperature);
}
static ssize_t htu21_show_humidity(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct htu21 *htu21 = dev_get_drvdata(dev);
int ret;
ret = htu21_update_measurements(dev);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", htu21->humidity);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
htu21_show_temperature, NULL, 0);
static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO,
htu21_show_humidity, NULL, 0);
static struct attribute *htu21_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_humidity1_input.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(htu21);
static int htu21_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct htu21 *htu21;
struct device *hwmon_dev;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_WORD_DATA)) {
dev_err(&client->dev,
"adapter does not support SMBus word transactions\n");
return -ENODEV;
}
htu21 = devm_kzalloc(dev, sizeof(*htu21), GFP_KERNEL);
if (!htu21)
return -ENOMEM;
htu21->client = client;
mutex_init(&htu21->lock);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
htu21,
htu21_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id htu21_id[] = {
{ "htu21", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, htu21_id);
static struct i2c_driver htu21_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "htu21",
},
.probe = htu21_probe,
.id_table = htu21_id,
};
module_i2c_driver(htu21_driver);
MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
MODULE_DESCRIPTION("MEAS HTU21D humidity and temperature sensor driver");
MODULE_LICENSE("GPL");