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/*
* Copyright © 2012 Mike Beattie <mike@ethernal.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; version 2 of the License.
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#define KBDLED "/sys/class/leds/samsung::kbd_backlight/brightness"
#define MIN 0
#define MAX 4
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/fcntl.h>
int get_current() {
int fd;
char buf[8];
ssize_t numread;
int value;
char *endp;
fd = open(KBDLED, O_RDONLY);
if (fd < 0) { perror("Unable to open "KBDLED); return -1; }
numread = read(fd, buf, sizeof(buf) - 1);
if (numread < 1) {
close(fd);
return -1;
}
close(fd);
buf[numread] = '\0';
value = strtol(buf, &endp, 0);
if (*endp == 0 || value < MIN || value > MAX) return -1;
return value;
}
int main(int argc, char **argv) {
int fd;
char *endp;
int val = get_current();
char buf[8];
if (val == -1) {
fprintf(stderr, "Error reading from %s\n", KBDLED);
return 1;
}
// Check args
if (argc < 2) { printf("Current setting: %d\n", val); return 0; };
if (strncmp(argv[1], "-h", 2) == 0) {
fprintf(stderr, "Usage: %s [up|down|<0-8>]\n", argv[0]);
fprintf(stderr, " up: increase brightness\n");
fprintf(stderr, " down: decrease brightness\n");
fprintf(stderr, " <0-8>: set explicit brigtness\n");
return 1;
} else if (strncmp(argv[1], "up", 2) == 0) {
if (val < MAX) {
val++;
} else {
fprintf(stderr, "Brightness at max\n");
return 1;
}
} else if (strncmp(argv[1], "down", 4) == 0) {
if (val > MIN) {
val--;
} else {
fprintf(stderr, "Brightness at min\n");
return 1;
}
} else {
val = strtol(argv[1], &endp, 0);
if (*endp != 0) { fprintf(stderr, "Error: supplied brightness not an integer\n"); return 1; };
if (val < MIN || val > MAX) { fprintf(stderr, "Error: brightness must be in range 0-8\n"); return 1; };
}
// Create string to write
sprintf(buf, "%d", val);
// Open sysfs file
fd = open(KBDLED, O_WRONLY);
if (fd < 0) { perror("Unable to open "KBDLED); return 1; }
// Write the argument
write(fd, buf, strlen(buf));
// Clean up
close(fd);
return 0;
}
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