Arduino for STM32

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#include "stm32f1xx.h"

#define REQUEST_PIN PB8
#define SPI_MESSAGE_SIZE 7

char spi_buffer[SPI_MESSAGE_SIZE];
SPI_HandleTypeDef spi;

void setup_spi() {   
    HAL_Init();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_SPI1_CLK_ENABLE();

    spi.Instance = SPI1;
    spi.Init.Mode = SPI_MODE_SLAVE; 
    spi.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;
    spi.Init.Direction = SPI_DIRECTION_2LINES_RXONLY;
    spi.Init.CLKPhase = SPI_PHASE_1EDGE;
    spi.Init.CLKPolarity = SPI_POLARITY_LOW;
    spi.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
    spi.Init.DataSize = SPI_DATASIZE_8BIT;
    spi.Init.FirstBit = SPI_FIRSTBIT_MSB;
    spi.Init.NSS = SPI_NSS_SOFT;
    spi.Init.TIMode = SPI_TIMODE_DISABLE;
    spi.Init.CRCPolynomial = 10;
    HAL_SPI_Init(&spi);

    GPIO_InitTypeDef  GPIO_InitStruct;
    GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    __HAL_SPI_ENABLE(&spi);
}

void setup() {
    setup_spi();
    pinMode(REQUEST_PIN, OUTPUT);
    digitalWrite(REQUEST_PIN, LOW);
    Serial.begin(9600);
    Serial.println("Started");
}

void loop() {
    digitalWrite(REQUEST_PIN, HIGH);
    delay(1);
    digitalWrite(REQUEST_PIN, LOW);

    HAL_StatusTypeDef result;
    if ((result = HAL_SPI_Receive(&spi, (uint8_t *)spi_buffer, SPI_MESSAGE_SIZE, 1000)) != HAL_OK) {
       Serial.println("Receiving failed!");
    }
    
    Serial.println(spi_buffer);

    delay(1000);
}

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static char *hello = "Hello!";

void send_spi_message(void) {
    spi_write(spi_dev, hello, strlen(hello));
}

static int spi_test_probe(struct spi_device *spi_dev) {
    request_pin = of_get_named_gpio_flags(spi_dev->dev.of_node, "request_pin", 0, 0);
    int request_pin_req = devm_gpio_request(&spi_dev->dev, request_pin, "request");
    request_pin_irq = gpiod_to_irq(gpio_to_desc(request_pin));
    request_threaded_irq(request_pin_irq, send_spi_message, NULL, IRQF_TRIGGER_RISING, "request", spi_dev);
}

static struct spi_driver my_spi_test_driver = {
    .driver = {
        .name = "my_spi_test",
    },
    .probe = my_spi_test_probe,
    .remove = my_spi_test_remove
};

static int __init my_spi_test_init(void) {
    return spi_register_driver(&my_spi_test_driver);
}

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/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";

	fragment@0 {
		target = <&spidev0>;
		__overlay__ {
			status = "disabled";
		};
	};

	fragment@1 {
		target = <&spi0>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";

			spi_test@0 {
				compatible = "my_spi_test";
				reg = <0>;
				request-pin = <&gpio 27 0>; // Active high
				spi-max-frequency = <100000>;
                status = "okay";
			};
		};
	};
};