Commit 8d928138 authored by Birte Kristina Friesel's avatar Birte Kristina Friesel
Browse files

POSIX: Add proper I2C driver (via /dev/i2c)

parent 560b3555

include/arch/posix/driver/i2c.h

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/*

 * Copyright 2021 Daniel Friesel

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#ifndef I2C_H

#define I2C_H



class I2C {

	private:

		I2C(const I2C &copy);

		const char *i2cbus;



	public:

		I2C (const char *i2cbus) : i2cbus(i2cbus) {}

		signed char setup();

		signed char xmit(unsigned char address,

				unsigned char tx_len, unsigned char *tx_buf,

				unsigned char rx_len, unsigned char *rx_buf);

};



extern I2C i2c;



#endif

src/arch/posix/Kconfig

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@@ -8,6 +8,10 @@ config arch_posix_driver_counter 
bool "Cycle counter"

select meta_driver_counter



config arch_posix_driver_i2c

bool "I2C via /dev/i2c"

select meta_driver_i2c



config arch_posix_driver_uptime

bool "Uptime counter"

select meta_driver_uptime

src/arch/posix/Makefile.inc

+5 −0
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@@ -5,6 +5,7 @@ 
# SPDX-License-Identifier: BSD-2-Clause



COMMON_FLAGS += -DMULTIPASS_ARCH_posix

COMMON_FLAGS += -DMULTIPASS_ARCH_HAS_I2C



CC = gcc

CXX = g++
@@ -27,6 +28,10 @@ ifeq (${timer_s}, 1) 
	CONFIG_arch_posix_driver_uptime = y

endif



ifdef CONFIG_arch_posix_driver_i2c

	CXX_TARGETS += src/arch/posix/driver/i2c.cc

endif



ifdef CONFIG_arch_posix_driver_counter

	CXX_TARGETS += src/arch/posix/driver/counter.cc

endif

src/arch/posix/driver/i2c.cc

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/*

 * Copyright 2021 Daniel Friesel

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include "driver/i2c.h"

#include "arch.h"

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <sys/ioctl.h>

#include <linux/i2c-dev.h>

#include <i2c/smbus.h>





signed char I2C::setup()

{

	return 0;

}



signed char I2C::xmit(unsigned char address,

		unsigned char tx_len, unsigned char *tx_buf,

		unsigned char rx_len, unsigned char *rx_buf)

{

	struct i2c_msg messages[2];

	struct i2c_rdwr_ioctl_data transaction;

	transaction.nmsgs = 0;

	transaction.msgs = messages;



	if (tx_len) {

		messages[transaction.nmsgs].addr = address;

		messages[transaction.nmsgs].flags = 0;

		messages[transaction.nmsgs].len = tx_len;

		messages[transaction.nmsgs].buf = tx_buf;

		transaction.nmsgs++;

	}

	if (rx_len) {

		messages[transaction.nmsgs].addr = address;

		messages[transaction.nmsgs].flags = I2C_M_RD;

		messages[transaction.nmsgs].len = rx_len;

		messages[transaction.nmsgs].buf = rx_buf;

		transaction.nmsgs++;

	}



	int fh = open(i2cbus, O_RDWR);



	if (fh < 0) {

		return -1;

	}



	if (ioctl(fh, I2C_RDWR, &transaction) == -1) {

		return -1;

	}



	close(fh);

	return 0;

}



I2C i2c("/dev/i2c-1");