Phase 2: LittleFS storage manager on /spiffs + shared SPI2_HOST bus

main/spi_bus_manager.c

@@ -0,0 +1,35 @@
+/*
+ * MTG RFID Companion - Shared SPI bus manager
+ */
+
+#include <string.h>
+#include "esp_log.h"
+#include "spi_bus_manager.h"
+#include "hw_pins.h"
+
+static const char *TAG = "spi_bus";
+
+/* 240 x 80 rows x 2 bytes per pixel. Largest contiguous DMA transfer the
+ * display engine will issue. */
+#define HW_SPI_MAX_TRANSFER_SZ (240 * 80 * sizeof(uint16_t))
+
+esp_err_t spi_bus_manager_init(void)
+{
+    spi_bus_config_t buscfg = {
+        .sclk_io_num = HW_SPI_SCK_GPIO,
+        .mosi_io_num = HW_SPI_MOSI_GPIO,
+        .miso_io_num = HW_SPI_MISO_GPIO,
+        .quadwp_io_num = -1,
+        .quadhd_io_num = -1,
+        .max_transfer_sz = HW_SPI_MAX_TRANSFER_SZ,
+    };
+
+    esp_err_t ret = spi_bus_initialize(HW_SPI_HOST, &buscfg, SPI_DMA_CH_AUTO);
+    if (ret != ESP_OK) {
+        ESP_LOGE(TAG, "spi_bus_initialize failed: %s", esp_err_to_name(ret));
+        return ret;
+    }
+    ESP_LOGI(TAG, "SPI2_HOST ready: SCK=%d MOSI=%d MISO=%d",
+             HW_SPI_SCK_GPIO, HW_SPI_MOSI_GPIO, HW_SPI_MISO_GPIO);
+    return ESP_OK;
+}