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263 lines
7.0 KiB
263 lines
7.0 KiB
/*
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i2cget.c - A user-space program to read an I2C register.
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Copyright (C) 2005 Jean Delvare <khali@linux-fr.org>
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Based on i2cset.c:
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Copyright (C) 2001-2003 Frodo Looijaard <frodol@dds.nl>, and
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Mark D. Studebaker <mdsxyz123@yahoo.com>
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Copyright (C) 2004-2005 Jean Delvare <khali@linux-fr.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <errno.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "util.h"
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#include "i2cbusses.h"
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#include "i2c-dev.h"
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#include "version.h"
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void help(void) __attribute__ ((noreturn));
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void help(void)
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{
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fprintf(stderr, "Syntax: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS "
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"[DATA-ADDRESS [MODE]]\n"
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" i2cget -V\n"
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" MODE can be: 'b' (read byte data, default)\n"
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" 'w' (read word data)\n"
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" 'c' (write byte/read byte)\n"
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" If DATA-ADDRESS is omitted, a single read byte command is "
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"issued\n"
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" Append 'p' to MODE for PEC checking\n"
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" I2CBUS is an integer\n");
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print_i2c_busses(0);
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exit(1);
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}
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int check_funcs(int file, int i2cbus, int size, int daddress, int pec)
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{
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unsigned long funcs;
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/* check adapter functionality */
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if (ioctl(file, I2C_FUNCS, &funcs) < 0) {
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fprintf(stderr, "Error: Could not get the adapter "
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"functionality matrix: %s\n", strerror(errno));
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return -1;
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}
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switch (size) {
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case I2C_SMBUS_BYTE:
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if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
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fprintf(stderr, "Error: Adapter for i2c bus %d does "
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"not have read byte capability\n", i2cbus);
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return -1;
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}
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if (daddress >= 0
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&& !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE)) {
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fprintf(stderr, "Error: Adapter for i2c bus %d does "
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"not have write byte capability\n", i2cbus);
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return -1;
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}
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break;
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case I2C_SMBUS_BYTE_DATA:
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if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
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fprintf(stderr, "Error: Adapter for i2c bus %d does "
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"not have read byte data capability\n", i2cbus);
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return -1;
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}
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break;
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case I2C_SMBUS_WORD_DATA:
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if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA)) {
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fprintf(stderr, "Error: Adapter for i2c bus %d does "
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"not have read word data capability\n", i2cbus);
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return -1;
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}
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break;
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}
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if (pec
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&& !(funcs & (I2C_FUNC_SMBUS_HWPEC_CALC | I2C_FUNC_I2C))) {
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fprintf(stderr, "Warning: Adapter for i2c bus %d does "
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"not seem to support PEC\n", i2cbus);
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}
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return 0;
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}
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int confirm(const char *filename, int address, int size, int daddress, int pec)
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{
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int dont = 0;
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fprintf(stderr, "WARNING! This program can confuse your I2C "
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"bus, cause data loss and worse!\n");
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/* Don't let the user break his/her EEPROMs */
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if (address >= 0x50 && address <= 0x57 && pec) {
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fprintf(stderr, "STOP! EEPROMs are I2C devices, not "
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"SMBus devices. Using PEC\non I2C devices may "
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"result in unexpected results, such as\n"
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"trashing the contents of EEPROMs. We can't "
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"let you do that, sorry.\n");
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return 0;
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}
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if (size == I2C_SMBUS_BYTE && daddress >= 0 && pec) {
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fprintf(stderr, "WARNING! All I2C chips and some SMBus chips "
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"will interpret a write\nbyte command with PEC as a"
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"write byte data command, effectively writing a\n"
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"value into a register!\n");
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dont++;
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}
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fprintf(stderr, "I will read from device file %s, chip "
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"address 0x%02x, ", filename, address);
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if (daddress < 0)
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fprintf(stderr, "current data\naddress");
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else
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fprintf(stderr, "data address\n0x%02x", daddress);
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fprintf(stderr, ", using %s.\n",
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size == I2C_SMBUS_BYTE ? (daddress < 0 ?
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"read byte" : "write byte/read byte") :
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size == I2C_SMBUS_BYTE_DATA ? "read byte data" :
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"read word data");
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if (pec)
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fprintf(stderr, "PEC checking enabled.\n");
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fprintf(stderr, "Continue? [%s] ", dont ? "y/N" : "Y/n");
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fflush(stderr);
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if (!user_ack(!dont)) {
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fprintf(stderr, "Aborting on user request.\n");
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return 0;
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}
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return 1;
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}
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int main(int argc, char *argv[])
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{
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char *end;
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int res, i2cbus, address, file;
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int size = I2C_SMBUS_BYTE_DATA;
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int daddress;
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char filename[20];
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int pec = 0;
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int flags = 0;
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int force = 0, yes = 0, version = 0;
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/* handle (optional) flags first */
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while (1+flags < argc && argv[1+flags][0] == '-') {
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switch (argv[1+flags][1]) {
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case 'V': version = 1; break;
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case 'f': force = 1; break;
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case 'y': yes = 1; break;
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default:
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fprintf(stderr, "Warning: Unsupported flag "
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"\"-%c\"!\n", argv[1+flags][1]);
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help();
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exit(1);
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}
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flags++;
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}
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if (version) {
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fprintf(stderr, "i2cget version %s\n", LM_VERSION);
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exit(0);
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}
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if (argc - flags < 3)
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help();
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i2cbus = strtol(argv[flags+1], &end, 0);
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if (*end || i2cbus < 0 || i2cbus > 0x3f) {
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fprintf(stderr, "Error: I2CBUS argument invalid!\n");
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help();
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}
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address = strtol(argv[flags+2], &end, 0);
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if (*end || address < 3 || address > 0x77) {
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fprintf(stderr, "Error: Chip address invalid!\n");
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help();
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}
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if (!(flags+3 < argc)) {
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size = I2C_SMBUS_BYTE;
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daddress = -1;
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} else {
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daddress = strtol(argv[flags+3], &end, 0);
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if (*end || daddress < 0 || daddress > 0xff) {
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fprintf(stderr, "Error: Data address invalid!\n");
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help();
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}
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}
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if (flags+4 < argc) {
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switch (argv[flags+4][0]) {
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case 'b': size = I2C_SMBUS_BYTE_DATA; break;
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case 'w': size = I2C_SMBUS_WORD_DATA; break;
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case 'c': size = I2C_SMBUS_BYTE; break;
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default:
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fprintf(stderr, "Error: Invalid mode!\n");
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help();
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}
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pec = argv[flags+4][1] == 'p';
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}
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file = open_i2c_dev(i2cbus, filename, 0);
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if (file < 0
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|| check_funcs(file, i2cbus, size, daddress, pec)
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|| set_slave_addr(file, address, force))
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exit(1);
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if (!yes && !confirm(filename, address, size, daddress, pec))
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exit(0);
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if (pec && ioctl(file, I2C_PEC, 1) < 0) {
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fprintf(stderr, "Error: Could not set PEC: %s\n",
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strerror(errno));
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exit(1);
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}
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switch (size) {
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case I2C_SMBUS_BYTE:
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if (daddress >= 0) {
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res = i2c_smbus_write_byte(file, daddress);
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if (res < 0)
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fprintf(stderr, "Warning - write failed\n");
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}
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res = i2c_smbus_read_byte(file);
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break;
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case I2C_SMBUS_WORD_DATA:
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res = i2c_smbus_read_word_data(file, daddress);
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break;
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default: /* I2C_SMBUS_BYTE_DATA */
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res = i2c_smbus_read_byte_data(file, daddress);
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}
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close(file);
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if (res < 0) {
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fprintf(stderr, "Error: Read failed\n");
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exit(2);
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}
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printf("0x%0*x\n", size == I2C_SMBUS_WORD_DATA ? 4 : 2, res);
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exit(0);
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}
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