adc linux

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/spi/spidev.h>

#define SPI_DEVICE "/dev/spidev0.0"
#define SPI_MODE 0
#define SPI_BITS_PER_WORD 8
#define SPI_SPEED 1000000

uint8_t read_adc(uint8_t channel) {
    uint8_t tx_buf[3];
    uint8_t rx_buf[3];
    tx_buf[0] = 0x01 | (channel << 4);
    tx_buf[1] = 0x00;
    tx_buf[2] = 0x00;

    int spi_fd = open(SPI_DEVICE, O_RDWR);
    if (spi_fd < 0) {
        perror("Failed to open SPI device");
        exit(1);
    }

    struct spi_ioc_transfer tr = {
        .tx_buf = (unsigned long)tx_buf,
        .rx_buf = (unsigned long)rx_buf,
        .len = 3,
        .speed_hz = SPI_SPEED,
        .bits_per_word = SPI_BITS_PER_WORD,
    };

    if (ioctl(spi_fd, SPI_IOC_MESSAGE(1), &tr) < 0) {
        perror("SPI transfer failed");
        exit(1);
    }

    close(spi_fd);

    return ((rx_buf[1] & 0x03) << 8) | rx_buf[2];
}

int main() {
    uint8_t adc_value = read_adc(0); // Read from channel 0
    printf("ADC Value: %d
", adc_value);
    return 0;
}