Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Hans de Goede | 795 | 100.00% | 1 | 100.00% |
Total | 795 | 1 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * Dell AIO Serial Backlight board emulator for testing * the Linux dell-uart-backlight driver. * * Copyright (C) 2024 Hans de Goede <hansg@kernel.org> */ #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/ioctl.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/un.h> #include <termios.h> #include <unistd.h> int serial_fd; int brightness = 50; static unsigned char dell_uart_checksum(unsigned char *buf, int len) { unsigned char val = 0; while (len-- > 0) val += buf[len]; return val ^ 0xff; } /* read() will return -1 on SIGINT / SIGTERM causing the mainloop to cleanly exit */ void signalhdlr(int signum) { } int main(int argc, char *argv[]) { struct sigaction sigact = { .sa_handler = signalhdlr }; unsigned char buf[4], csum, response[32]; const char *version_str = "PHI23-V321"; struct termios tty, saved_tty; int ret, idx, len = 0; if (argc != 2) { fprintf(stderr, "Invalid or missing arguments\n"); fprintf(stderr, "Usage: %s <serial-port>\n", argv[0]); return 1; } serial_fd = open(argv[1], O_RDWR | O_NOCTTY); if (serial_fd == -1) { fprintf(stderr, "Error opening %s: %s\n", argv[1], strerror(errno)); return 1; } ret = tcgetattr(serial_fd, &tty); if (ret == -1) { fprintf(stderr, "Error getting tcattr: %s\n", strerror(errno)); goto out_close; } saved_tty = tty; cfsetspeed(&tty, 9600); cfmakeraw(&tty); tty.c_cflag &= ~CSTOPB; tty.c_cflag &= ~CRTSCTS; tty.c_cflag |= CLOCAL | CREAD; ret = tcsetattr(serial_fd, TCSANOW, &tty); if (ret == -1) { fprintf(stderr, "Error setting tcattr: %s\n", strerror(errno)); goto out_restore; } sigaction(SIGINT, &sigact, 0); sigaction(SIGTERM, &sigact, 0); idx = 0; while (read(serial_fd, &buf[idx], 1) == 1) { if (idx == 0) { switch (buf[0]) { /* 3 MSB bits: cmd-len + 01010 SOF marker */ case 0x6a: len = 3; break; case 0x8a: len = 4; break; default: fprintf(stderr, "Error unexpected first byte: 0x%02x\n", buf[0]); continue; /* Try to sync up with sender */ } } /* Process msg when len bytes have been received */ if (idx != (len - 1)) { idx++; continue; } /* Reset idx for next command */ idx = 0; csum = dell_uart_checksum(buf, len - 1); if (buf[len - 1] != csum) { fprintf(stderr, "Error checksum mismatch got 0x%02x expected 0x%02x\n", buf[len - 1], csum); continue; } switch ((buf[0] << 8) | buf[1]) { case 0x6a06: /* cmd = 0x06, get version */ len = strlen(version_str); strcpy((char *)&response[2], version_str); printf("Get version, reply: %s\n", version_str); break; case 0x8a0b: /* cmd = 0x0b, set brightness */ if (buf[2] > 100) { fprintf(stderr, "Error invalid brightness param: %d\n", buf[2]); continue; } len = 0; brightness = buf[2]; printf("Set brightness %d\n", brightness); break; case 0x6a0c: /* cmd = 0x0c, get brightness */ len = 1; response[2] = brightness; printf("Get brightness, reply: %d\n", brightness); break; case 0x8a0e: /* cmd = 0x0e, set backlight power */ if (buf[2] != 0 && buf[2] != 1) { fprintf(stderr, "Error invalid set power param: %d\n", buf[2]); continue; } len = 0; printf("Set power %d\n", buf[2]); break; default: fprintf(stderr, "Error unknown cmd 0x%04x\n", (buf[0] << 8) | buf[1]); continue; } /* Respond with <total-len> <cmd> <data...> <csum> */ response[0] = len + 3; /* response length in bytes */ response[1] = buf[1]; /* ack cmd */ csum = dell_uart_checksum(response, len + 2); response[len + 2] = csum; ret = write(serial_fd, response, response[0]); if (ret != (response[0])) fprintf(stderr, "Error writing %d bytes: %d\n", response[0], ret); } ret = 0; out_restore: tcsetattr(serial_fd, TCSANOW, &saved_tty); out_close: close(serial_fd); return ret; }
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