diff options
Diffstat (limited to 'tools/arch/x86/dell-uart-backlight-emulator/dell-uart-backlight-emulator.c')
| -rw-r--r-- | tools/arch/x86/dell-uart-backlight-emulator/dell-uart-backlight-emulator.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/tools/arch/x86/dell-uart-backlight-emulator/dell-uart-backlight-emulator.c b/tools/arch/x86/dell-uart-backlight-emulator/dell-uart-backlight-emulator.c new file mode 100644 index 0000000000..655b6c96d8 --- /dev/null +++ b/tools/arch/x86/dell-uart-backlight-emulator/dell-uart-backlight-emulator.c @@ -0,0 +1,163 @@ +// 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; +} |