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diff --git a/tools/i2cget.c b/tools/i2cget.c
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+/*
+ i2cget.c - A user-space program to read an I2C register.
+ Copyright (C) 2005-2008 Jean Delvare <khali@linux-fr.org>
+
+ Based on i2cset.c:
+ Copyright (C) 2001-2003 Frodo Looijaard <frodol@dds.nl>, and
+ Mark D. Studebaker <mdsxyz123@yahoo.com>
+ Copyright (C) 2004-2005 Jean Delvare <khali@linux-fr.org>
+
+ 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.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ MA 02110-1301 USA.
+*/
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/i2c-dev.h>
+#include "i2cbusses.h"
+#include "util.h"
+#include "../version.h"
+
+static void help(void) __attribute__ ((noreturn));
+
+static void help(void)
+{
+ fprintf(stderr,
+ "Usage: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS [DATA-ADDRESS [MODE]]\n"
+ " I2CBUS is an integer or an I2C bus name\n"
+ " ADDRESS is an integer (0x03 - 0x77)\n"
+ " MODE is one of:\n"
+ " b (read byte data, default)\n"
+ " w (read word data)\n"
+ " c (write byte/read byte)\n"
+ " Append p for SMBus PEC\n");
+ exit(1);
+}
+
+static int check_funcs(int file, int size, int daddress, int pec)
+{
+ unsigned long funcs;
+
+ /* check adapter functionality */
+ if (ioctl(file, I2C_FUNCS, &funcs) < 0) {
+ fprintf(stderr, "Error: Could not get the adapter "
+ "functionality matrix: %s\n", strerror(errno));
+ return -1;
+ }
+
+ switch (size) {
+ case I2C_SMBUS_BYTE:
+ if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
+ fprintf(stderr, MISSING_FUNC_FMT, "SMBus receive byte");
+ return -1;
+ }
+ if (daddress >= 0
+ && !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE)) {
+ fprintf(stderr, MISSING_FUNC_FMT, "SMBus send byte");
+ return -1;
+ }
+ break;
+
+ case I2C_SMBUS_BYTE_DATA:
+ if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+ fprintf(stderr, MISSING_FUNC_FMT, "SMBus read byte");
+ return -1;
+ }
+ break;
+
+ case I2C_SMBUS_WORD_DATA:
+ if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA)) {
+ fprintf(stderr, MISSING_FUNC_FMT, "SMBus read word");
+ return -1;
+ }
+ break;
+ }
+
+ if (pec
+ && !(funcs & (I2C_FUNC_SMBUS_PEC | I2C_FUNC_I2C))) {
+ fprintf(stderr, "Warning: Adapter does "
+ "not seem to support PEC\n");
+ }
+
+ return 0;
+}
+
+static int confirm(const char *filename, int address, int size, int daddress,
+ int pec)
+{
+ int dont = 0;
+
+ fprintf(stderr, "WARNING! This program can confuse your I2C "
+ "bus, cause data loss and worse!\n");
+
+ /* Don't let the user break his/her EEPROMs */
+ if (address >= 0x50 && address <= 0x57 && pec) {
+ fprintf(stderr, "STOP! EEPROMs are I2C devices, not "
+ "SMBus devices. Using PEC\non I2C devices may "
+ "result in unexpected results, such as\n"
+ "trashing the contents of EEPROMs. We can't "
+ "let you do that, sorry.\n");
+ return 0;
+ }
+
+ if (size == I2C_SMBUS_BYTE && daddress >= 0 && pec) {
+ fprintf(stderr, "WARNING! All I2C chips and some SMBus chips "
+ "will interpret a write\nbyte command with PEC as a"
+ "write byte data command, effectively writing a\n"
+ "value into a register!\n");
+ dont++;
+ }
+
+ fprintf(stderr, "I will read from device file %s, chip "
+ "address 0x%02x, ", filename, address);
+ if (daddress < 0)
+ fprintf(stderr, "current data\naddress");
+ else
+ fprintf(stderr, "data address\n0x%02x", daddress);
+ fprintf(stderr, ", using %s.\n",
+ size == I2C_SMBUS_BYTE ? (daddress < 0 ?
+ "read byte" : "write byte/read byte") :
+ size == I2C_SMBUS_BYTE_DATA ? "read byte data" :
+ "read word data");
+ if (pec)
+ fprintf(stderr, "PEC checking enabled.\n");
+
+ fprintf(stderr, "Continue? [%s] ", dont ? "y/N" : "Y/n");
+ fflush(stderr);
+ if (!user_ack(!dont)) {
+ fprintf(stderr, "Aborting on user request.\n");
+ return 0;
+ }
+
+ return 1;
+}
+
+int main(int argc, char *argv[])
+{
+ char *end;
+ int res, i2cbus, address, size, file;
+ int daddress;
+ char filename[20];
+ int pec = 0;
+ int flags = 0;
+ int force = 0, yes = 0, version = 0;
+
+ /* handle (optional) flags first */
+ while (1+flags < argc && argv[1+flags][0] == '-') {
+ switch (argv[1+flags][1]) {
+ case 'V': version = 1; break;
+ case 'f': force = 1; break;
+ case 'y': yes = 1; break;
+ default:
+ fprintf(stderr, "Error: Unsupported option "
+ "\"%s\"!\n", argv[1+flags]);
+ help();
+ exit(1);
+ }
+ flags++;
+ }
+
+ if (version) {
+ fprintf(stderr, "i2cget version %s\n", VERSION);
+ exit(0);
+ }
+
+ if (argc < flags + 3)
+ help();
+
+ i2cbus = lookup_i2c_bus(argv[flags+1]);
+ if (i2cbus < 0)
+ help();
+
+ address = parse_i2c_address(argv[flags+2]);
+ if (address < 0)
+ help();
+
+ if (argc > flags + 3) {
+ size = I2C_SMBUS_BYTE_DATA;
+ daddress = strtol(argv[flags+3], &end, 0);
+ if (*end || daddress < 0 || daddress > 0xff) {
+ fprintf(stderr, "Error: Data address invalid!\n");
+ help();
+ }
+ } else {
+ size = I2C_SMBUS_BYTE;
+ daddress = -1;
+ }
+
+ if (argc > flags + 4) {
+ switch (argv[flags+4][0]) {
+ case 'b': size = I2C_SMBUS_BYTE_DATA; break;
+ case 'w': size = I2C_SMBUS_WORD_DATA; break;
+ case 'c': size = I2C_SMBUS_BYTE; break;
+ default:
+ fprintf(stderr, "Error: Invalid mode!\n");
+ help();
+ }
+ pec = argv[flags+4][1] == 'p';
+ }
+
+ file = open_i2c_dev(i2cbus, filename, 0);
+ if (file < 0
+ || check_funcs(file, size, daddress, pec)
+ || set_slave_addr(file, address, force))
+ exit(1);
+
+ if (!yes && !confirm(filename, address, size, daddress, pec))
+ exit(0);
+
+ if (pec && ioctl(file, I2C_PEC, 1) < 0) {
+ fprintf(stderr, "Error: Could not set PEC: %s\n",
+ strerror(errno));
+ close(file);
+ exit(1);
+ }
+
+ switch (size) {
+ case I2C_SMBUS_BYTE:
+ if (daddress >= 0) {
+ res = i2c_smbus_write_byte(file, daddress);
+ if (res < 0)
+ fprintf(stderr, "Warning - write failed\n");
+ }
+ res = i2c_smbus_read_byte(file);
+ break;
+ case I2C_SMBUS_WORD_DATA:
+ res = i2c_smbus_read_word_data(file, daddress);
+ break;
+ default: /* I2C_SMBUS_BYTE_DATA */
+ res = i2c_smbus_read_byte_data(file, daddress);
+ }
+ close(file);
+
+ if (res < 0) {
+ fprintf(stderr, "Error: Read failed\n");
+ exit(2);
+ }
+
+ printf("0x%0*x\n", size == I2C_SMBUS_WORD_DATA ? 4 : 2, res);
+
+ exit(0);
+}
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