linux-imx

/* Sensirion SHT3x-DIS humidity and temperature sensor driver.

 * The SHT3x comes in many different versions, this driver is for the

 * I2C version only.

 *

 * Copyright (C) 2016 Sensirion AG, Switzerland

 * Author: David Frey <david.frey@sensirion.com>

 * Author: Pascal Sachs <pascal.sachs@sensirion.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 <asm/page.h>

#include <linux/crc8.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/jiffies.h>

#include <linux/platform_data/sht3x.h>

​

/* commands (high precision mode) */

static const unsigned char sht3x_cmd_measure_blocking_hpm[]    = { 0x2c, 0x06 };

static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };

​

/* commands (low power mode) */

static const unsigned char sht3x_cmd_measure_blocking_lpm[]    = { 0x2c, 0x10 };

static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };

​

/* commands for periodic mode */

static const unsigned char sht3x_cmd_measure_periodic_mode[]   = { 0xe0, 0x00 };

static const unsigned char sht3x_cmd_break[]                   = { 0x30, 0x93 };

​

/* commands for heater control */

static const unsigned char sht3x_cmd_heater_on[]               = { 0x30, 0x6d };

static const unsigned char sht3x_cmd_heater_off[]              = { 0x30, 0x66 };

​

/* other commands */

static const unsigned char sht3x_cmd_read_status_reg[]         = { 0xf3, 0x2d };

static const unsigned char sht3x_cmd_clear_status_reg[]        = { 0x30, 0x41 };

​

/* delays for non-blocking i2c commands, both in us */

#define SHT3X_NONBLOCKING_WAIT_TIME_HPM  15000

#define SHT3X_NONBLOCKING_WAIT_TIME_LPM   4000

​

#define SHT3X_WORD_LEN         2

#define SHT3X_CMD_LENGTH       2

#define SHT3X_CRC8_LEN         1

#define SHT3X_RESPONSE_LENGTH  6

#define SHT3X_CRC8_POLYNOMIAL  0x31