/* i2cget.c - A user-space program to read an I2C register. Copyright (C) 2005-2012 Jean Delvare Based on i2cset.c: Copyright (C) 2001-2003 Frodo Looijaard , and Mark D. Studebaker Copyright (C) 2004-2005 Jean Delvare 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 #include #include #include #include #include #include #include #include #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, sizeof(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); }