Enable Quad I/O mode on Macronix MX25xxxx35 series serial flash

enable_quad.c

#include "string.h"
#include "driver/spi_master.h"

#define PIN_NUM_MISO 19
#define PIN_NUM_MOSI 23
#define PIN_NUM_CLK  18
#define PIN_NUM_CS   12

spi_device_handle_t spi;

void app_main(void)
{
    esp_err_t ret;

    static spi_bus_config_t buscfg={
        .mosi_io_num=PIN_NUM_MOSI,
        .miso_io_num=PIN_NUM_MISO,
        .sclk_io_num=PIN_NUM_CLK,
        .quadwp_io_num=-1,
        .quadhd_io_num=-1,
    };

    ret=spi_bus_initialize(VSPI_HOST, &buscfg, 1);
    ESP_ERROR_CHECK(ret);

    static spi_device_interface_config_t devcfg={};
    devcfg.mode=0;
    devcfg.clock_speed_hz=1000*1000;
    devcfg.spics_io_num=12;
    devcfg.queue_size=2;
    devcfg.command_bits=8;

    ret=spi_bus_add_device(VSPI_HOST, &devcfg, &spi);
    ESP_ERROR_CHECK(ret);

    spi_transaction_t wren;
    memset(&wren, 0, sizeof(wren));
    wren.cmd = 0x06;
    ret=spi_device_polling_transmit(spi, &wren);
    ESP_ERROR_CHECK(ret);

    spi_transaction_t rdsr;
    memset(&rdsr, 0, sizeof(rdsr));
    rdsr.flags = SPI_TRANS_USE_RXDATA;
    rdsr.length = 8;
    rdsr.cmd = 0x05;
    ret=spi_device_polling_transmit(spi, &rdsr);
    ESP_ERROR_CHECK(ret);
    printf("SR: 0x%02X\n", rdsr.rx_data[0]);

    spi_transaction_t wrsr;
    memset(&wrsr, 0, sizeof(wrsr));
    wrsr.flags = SPI_TRANS_USE_TXDATA;
    wrsr.length = 8;
    wrsr.cmd = 0x01;
    wrsr.tx_data[0] = 0x40;
    wrsr.tx_data[1] = 0;
    ret=spi_device_polling_transmit(spi, &wrsr);
    ESP_ERROR_CHECK(ret);

    ret=spi_device_polling_transmit(spi, &rdsr);
    ESP_ERROR_CHECK(ret);
    printf("SR: 0x%02X\n", rdsr.rx_data[0]);
}