b1d92a32a8
Make I2C reads blocking w/ timeout Add SHT31 driver, roughly :) Fix mg_time() to return a double.
128 lines
3.9 KiB
C
128 lines
3.9 KiB
C
/*
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* Copyright 2015 Cesanta
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* All rights reserved
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*/
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/*
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* I2C API.
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*
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* See https://en.wikipedia.org/wiki/I%C2%B2C for the background information.
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*/
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#pragma once
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#include "mgos.h"
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#include <stdio.h>
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#include <linux/i2c.h>
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#include <linux/i2c-dev.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <string.h>
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/* Each platform defines its own I2C connection parameters. */
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struct mgos_i2c;
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/* If this special address is passed to read or write, START is not generated
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* and address is not put on the bus. It is assumed that this is a continuation
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* of a previous operation which (after read or write with stop = false). */
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#define MGOS_I2C_ADDR_CONTINUE ((uint16_t) -1)
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/*
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* Read specified number of bytes from the specified address.
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* Address should not include the R/W bit. If addr is -1, START is not
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* performed.
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* If |stop| is true, then at the end of the operation bus will be released.
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*/
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bool mgos_i2c_read(struct mgos_i2c *i2c, uint16_t addr, void *data, size_t len,
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bool stop);
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/*
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* Write specified number of bytes from the specified address.
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* Address should not include the R/W bit. If addr is -1, START is not
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* performed.
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* If |stop| is true, then at the end of the operation bus will be released.
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*/
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bool mgos_i2c_write(struct mgos_i2c *i2c, uint16_t addr, const void *data,
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size_t len, bool stop);
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/*
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* Release the bus (when left unreleased after read or write).
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*/
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void mgos_i2c_stop(struct mgos_i2c *i2c);
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/* Most implementations should support these two, support for other frequencies
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* is platform-dependent. */
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#define MGOS_I2C_FREQ_100KHZ 100000
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#define MGOS_I2C_FREQ_400KHZ 400000
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/*
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* Get I2C interface frequency.
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*/
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int mgos_i2c_get_freq(struct mgos_i2c *i2c);
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/*
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* Set I2C interface frequency.
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*/
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bool mgos_i2c_set_freq(struct mgos_i2c *i2c, int freq);
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/*
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* Helper for reading 1-byte register `reg` from a device at address `addr`.
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* In case of success return a numeric byte value from 0x00 to 0xff; otherwise
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* return -1.
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*/
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int mgos_i2c_read_reg_b(struct mgos_i2c *conn, uint16_t addr, uint8_t reg);
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/*
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* Helper for reading 2-byte register `reg` from a device at address `addr`.
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* In case of success returns a numeric big-endian value: e.g. if 0x01, 0x02
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* was read from a device, 0x0102 will be returned.
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*
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* In case of error returns -1.
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*/
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int mgos_i2c_read_reg_w(struct mgos_i2c *conn, uint16_t addr, uint8_t reg);
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/*
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* Helper for reading `n`-byte register value from a device. Returns true on
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* success, false on error. Data is written to `buf`, which should be large
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* enough.
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*/
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bool mgos_i2c_read_reg_n(struct mgos_i2c *conn, uint16_t addr, uint8_t reg,
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size_t n, uint8_t *buf);
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/*
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* Helper for writing 1-byte register `reg` to a device at address `addr`.
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* Returns `true` in case of success, `false` otherwise.
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*/
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bool mgos_i2c_write_reg_b(struct mgos_i2c *conn, uint16_t addr, uint8_t reg,
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uint8_t value);
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/*
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* Helper for writing 2-byte register `reg` to a device at address `addr`.
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* The value is big-endian: e.g. if `value` is `0x0102`, then `0x01, 0x02`
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* will be written.
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* Returns `true` in case of success, `false` otherwise.
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*/
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bool mgos_i2c_write_reg_w(struct mgos_i2c *conn, uint16_t addr, uint8_t reg,
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uint16_t value);
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/*
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* Helper for writing `n`-byte register `reg` to a device at address `addr`.
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* Returns `true` in case of success, `false` otherwise.
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*/
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bool mgos_i2c_write_reg_n(struct mgos_i2c *conn, uint16_t addr, uint8_t reg,
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size_t n, const uint8_t *buf);
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/* Close i2c connection and free resources. */
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void mgos_i2c_close(struct mgos_i2c *conn);
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/* Return i2c bus handle that is set up via the sysconfig. */
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struct mgos_i2c *mgos_i2c_get_global(void);
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// User contributed!
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int get_i2c_register(struct mgos_i2c *i2c, uint8_t addr, uint8_t reg, uint8_t *val);
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bool mgos_i2c_open(int busnr);
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