IIO: add si7020 driver (064a7463) · Commits · 戴 / test

drivers/iio/humidity/Kconfig

+10 −0

Original line number	Diff line number	Diff line
		@@ -22,4 +22,14 @@ config SI7005
		To compile this driver as a module, choose M here: the module
		will be called si7005.

		config SI7020
		tristate "Si7013/20/21 Relative Humidity and Temperature Sensors"
		depends on I2C
		help
		Say yes here to build support for the Silicon Labs Si7013/20/21
		Relative Humidity and Temperature Sensors.

		To compile this driver as a module, choose M here: the module
		will be called si7020.

		endmenu

drivers/iio/humidity/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,3 +4,4 @@

		obj-$(CONFIG_DHT11) += dht11.o
		obj-$(CONFIG_SI7005) += si7005.o
		obj-$(CONFIG_SI7020) += si7020.o

drivers/iio/humidity/si7020.c

0 → 100644

+163 −0

Original line number	Diff line number	Diff line
		/*
		* si7020.c - Silicon Labs Si7013/20/21 Relative Humidity and Temp Sensors
		* Copyright (c) 2013,2014 Uplogix, Inc.
		* David Barksdale <dbarksdale@uplogix.com>
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms and conditions of the GNU General Public License,
		* version 2, as published by the Free Software Foundation.
		*
		* 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.
		*/

		/*
		* The Silicon Labs Si7013/20/21 Relative Humidity and Temperature Sensors
		* are i2c devices which have an identical programming interface for
		* measuring relative humidity and temperature. The Si7013 has an additional
		* temperature input which this driver does not support.
		*
		* Data Sheets:
		* Si7013: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7013.pdf
		* Si7020: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7020.pdf
		* Si7021: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7021.pdf
		*/

		#include <linux/delay.h>
		#include <linux/i2c.h>
		#include <linux/module.h>
		#include <linux/slab.h>
		#include <linux/sysfs.h>

		#include <linux/iio/iio.h>
		#include <linux/iio/sysfs.h>

		/* Measure Relative Humidity, Hold Master Mode */
		#define SI7020CMD_RH_HOLD 0xE5
		/* Measure Temperature, Hold Master Mode */
		#define SI7020CMD_TEMP_HOLD 0xE3
		/* Software Reset */
		#define SI7020CMD_RESET 0xFE

		static int si7020_read_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const chan, int val,
		int *val2, long mask)
		{
		struct i2c_client **client = iio_priv(indio_dev);
		int ret;

		switch (mask) {
		case IIO_CHAN_INFO_RAW:
		ret = i2c_smbus_read_word_data(*client,
		chan->type == IIO_TEMP ?
		SI7020CMD_TEMP_HOLD :
		SI7020CMD_RH_HOLD);
		if (ret < 0)
		return ret;
		if (chan->type == IIO_TEMP)
		*val = ret >> 2;
		else
		*val = (ret & 0x3FFF) >> 2;
		return IIO_VAL_INT;
		case IIO_CHAN_INFO_SCALE:
		if (chan->type == IIO_TEMP)
		val = 175720; / = 175.72 * 1000 */
		else
		val = 125 1000;
		*val2 = 65536 >> 2;
		return IIO_VAL_FRACTIONAL;
		case IIO_CHAN_INFO_OFFSET:
		/*
		* Since iio_convert_raw_to_processed_unlocked assumes offset
		* is an integer we have to round these values and lose
		* accuracy.
		* Relative humidity will be 0.0032959% too high and
		* temperature will be 0.00277344 degrees too high.
		* This is no big deal because it's within the accuracy of the
		* sensor.
		*/
		if (chan->type == IIO_TEMP)
		val = -4368; / = -46.85 * (65536 >> 2) / 175.72 */
		else
		val = -786; / = -6 * (65536 >> 2) / 125 */
		return IIO_VAL_INT;
		default:
		break;
		}

		return -EINVAL;
		}

		static const struct iio_chan_spec si7020_channels[] = {
		{
		.type = IIO_HUMIDITYRELATIVE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
		BIT(IIO_CHAN_INFO_SCALE) \| BIT(IIO_CHAN_INFO_OFFSET),
		},
		{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
		BIT(IIO_CHAN_INFO_SCALE) \| BIT(IIO_CHAN_INFO_OFFSET),
		}
		};

		static const struct iio_info si7020_info = {
		.read_raw = si7020_read_raw,
		.driver_module = THIS_MODULE,
		};

		static int si7020_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct iio_dev *indio_dev;
		struct i2c_client **data;
		int ret;

		if (!i2c_check_functionality(client->adapter,
		I2C_FUNC_SMBUS_WRITE_BYTE \|
		I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -ENODEV;

		/* Reset device, loads default settings. */
		ret = i2c_smbus_write_byte(client, SI7020CMD_RESET);
		if (ret < 0)
		return ret;
		/* Wait the maximum power-up time after software reset. */
		msleep(15);

		indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*client));
		if (!indio_dev)
		return -ENOMEM;

		data = iio_priv(indio_dev);
		*data = client;
		i2c_set_clientdata(client, indio_dev);

		indio_dev->dev.parent = &client->dev;
		indio_dev->name = dev_name(&client->dev);
		indio_dev->modes = INDIO_DIRECT_MODE;
		indio_dev->info = &si7020_info;
		indio_dev->channels = si7020_channels;
		indio_dev->num_channels = ARRAY_SIZE(si7020_channels);

		return devm_iio_device_register(&client->dev, indio_dev);
		}

		static const struct i2c_device_id si7020_id[] = {
		{ "si7020", 0 },
		{ }
		};
		MODULE_DEVICE_TABLE(i2c, si7020_id);

		static struct i2c_driver si7020_driver = {
		.driver.name = "si7020",
		.probe = si7020_probe,
		.id_table = si7020_id,
		};

		module_i2c_driver(si7020_driver);
		MODULE_DESCRIPTION("Silicon Labs Si7013/20/21 Relative Humidity and Temperature Sensors");
		MODULE_AUTHOR("David Barksdale <dbarksdale@uplogix.com>");
		MODULE_LICENSE("GPL");

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