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sensirion_common.h
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sensirion_common.h
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/*
* Copyright (c) 2018, Sensirion AG
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of Sensirion AG nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SENSIRION_COMMON_H
#define SENSIRION_COMMON_H
#include "sensirion_arch_config.h"
#ifdef __cplusplus
extern "C" {
#endif
#define STATUS_OK 0
#define STATUS_FAIL (-1)
#ifndef NULL
#define NULL ((void *)0)
#endif
#if SENSIRION_BIG_ENDIAN
#define be16_to_cpu(s) (s)
#define be32_to_cpu(s) (s)
#define be64_to_cpu(s) (s)
#define SENSIRION_WORDS_TO_BYTES(a, w) ()
#else /* SENSIRION_BIG_ENDIAN */
#define be16_to_cpu(s) (((u16)(s) << 8) | (0xff & ((u16)(s)) >> 8))
#define be32_to_cpu(s) (((u32)be16_to_cpu(s) << 16) | \
(0xffff & (be16_to_cpu((s) >> 16))))
#define be64_to_cpu(s) (((u64)be32_to_cpu(s) << 32) | \
(0xffffffff & ((u64)be32_to_cpu((s) >> 32))))
/**
* Convert a word-array to a bytes-array, effectively reverting the
* host-endianness to big-endian
* @a: word array to change (must be (u16 *) castable)
* @w: number of word-sized elements in the array (SENSIRION_NUM_WORDS(a)).
*/
#define SENSIRION_WORDS_TO_BYTES(a, w) \
for (u16 *__a = (u16 *)(a), __e = (w), __w = 0; __w < __e; ++__w) { \
__a[__w] = be16_to_cpu(__a[__w]); \
}
#endif /* SENSIRION_BIG_ENDIAN */
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
#endif
#define CRC8_POLYNOMIAL 0x31
#define CRC8_INIT 0xFF
#define CRC8_LEN 1
#define SENSIRION_COMMAND_SIZE 2
#define SENSIRION_WORD_SIZE 2
#define SENSIRION_NUM_WORDS(x) (sizeof(x) / SENSIRION_WORD_SIZE)
#define SENSIRION_MAX_BUFFER_WORDS 32
u8 sensirion_common_generate_crc(u8 *data, u16 count);
s8 sensirion_common_check_crc(u8 *data, u16 count, u8 checksum);
/**
* sensirion_fill_cmd_send_buf() - create the i2c send buffer for a command and
* a set of argument words. The output buffer
* interleaves argument words with their
* checksums.
* @buf: The generated buffer to send over i2c. Then buffer length must
* be at least SENSIRION_COMMAND_LEN + num_args *
* (SENSIRION_WORD_SIZE + CRC8_LEN).
* @cmd: The i2c command to send. It already includes a checksum.
* @args: The arguments to the command. Can be NULL if none.
* @num_args: The number of word arguments in args.
*
* @return The number of bytes written to buf
*/
u16 sensirion_fill_cmd_send_buf(u8 *buf, u16 cmd, const u16 *args, u8 num_args);
/**
* sensirion_i2c_read_words() - read data words from sensor
*
* @address: Sensor i2c address
* @data_words: Allocated buffer to store the read words.
* The buffer may also have been modified on STATUS_FAIL return.
* @num_words: Number of data words to read (without CRC bytes)
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_read_words(u8 address, u16 *data_words, u16 num_words);
/**
* sensirion_i2c_read_bytes() - read data words as byte-stream from sensor
*
* Read bytes without adjusting values to the uP's word-order.
*
* @address: Sensor i2c address
* @data: Allocated buffer to store the read bytes.
* The buffer may also have been modified on STATUS_FAIL return.
* @num_words: Number of data words(!) to read (without CRC bytes)
* Since only word-chunks can be read from the sensor the size
* is still specified in sensor-words (num_words = num_bytes *
* SENSIRION_WORD_SIZE)
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_read_bytes(u8 address, u8 *data, u16 num_words);
/**
* sensirion_i2c_write_cmd() - writes a command to the sensor
* @address: Sensor i2c address
* @command: Sensor command
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_write_cmd(u8 address, u16 command);
/**
* sensirion_i2c_write_cmd_with_args() - writes a command with arguments to the
* sensor
* @address: Sensor i2c address
* @command: Sensor command
* @data: Argument buffer with words to send
* @num_words: Number of data words to send (without CRC bytes)
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_write_cmd_with_args(u8 address, u16 command,
const u16 *data_words, u16 num_words);
/**
* sensirion_i2c_delayed_read_cmd() - send a command, wait for the sensor to
* process and read data back
* @address: Sensor i2c address
* @cmd: Command
* @delay: Time in microseconds to delay sending the read request
* @data_words: Allocated buffer to store the read data
* @num_words: Data words to read (without CRC bytes)
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_delayed_read_cmd(u8 address, u16 cmd, u32 delay_us,
u16 *data_words, u16 num_words);
/**
* sensirion_i2c_read_cmd() - reads data words from the sensor after a command
* is issued
* @address: Sensor i2c address
* @cmd: Command
* @data_words: Allocated buffer to store the read data
* @num_words: Data words to read (without CRC bytes)
*
* @return STATUS_OK on success, an error code otherwise
*/
s16 sensirion_i2c_read_cmd(u8 address, u16 cmd, u16 *data_words, u16 num_words);
#ifdef __cplusplus
}
#endif
#endif /* SENSIRION_COMMON_H */