| /* |
| 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); |
| } |