Refactored display driver to be in separate files

This isn't as nice as the audio system (yet) but I'm not sure if adding indirection to previously inlined functions (get_buffer/send_data) will be a problem...

components/retro-go/drivers/display/dummy.h

@@ -0,0 +1,24 @@
+static void lcd_init(void)
+{
+}
+
+static void lcd_deinit(void)
+{
+}
+
+static void lcd_set_backlight(float percent)
+{
+}
+
+static inline uint16_t *lcd_get_buffer(size_t length)
+{
+    return (void *)0;
+}
+
+static inline void lcd_send_buffer(uint16_t *buffer, size_t length)
+{
+}
+
+static void lcd_sync(void)
+{
+}

components/retro-go/drivers/display/ili9341.h

@@ -0,0 +1,259 @@
+#include <freertos/FreeRTOS.h>
+#include <freertos/queue.h>
+#include <driver/spi_master.h>
+#include <driver/gpio.h>
+#include <driver/ledc.h>
+
+static spi_device_handle_t spi_dev;
+static QueueHandle_t spi_transactions;
+static QueueHandle_t spi_buffers;
+
+#define SPI_TRANSACTION_COUNT (10)
+#define SPI_BUFFER_COUNT      (5)
+#define SPI_BUFFER_LENGTH     (LCD_BUFFER_LENGTH * 2)
+
+static inline uint16_t *spi_take_buffer(void)
+{
+    uint16_t *buffer;
+    if (xQueueReceive(spi_buffers, &buffer, pdMS_TO_TICKS(2500)) != pdTRUE)
+        RG_PANIC("display");
+    return buffer;
+}
+
+static inline void spi_give_buffer(uint16_t *buffer)
+{
+    xQueueSend(spi_buffers, &buffer, portMAX_DELAY);
+}
+
+static inline void spi_queue_transaction(const void *data, size_t length, uint32_t type)
+{
+    if (!data || !length)
+        return;
+
+    spi_transaction_t *t;
+    xQueueReceive(spi_transactions, &t, portMAX_DELAY);
+
+    *t = (spi_transaction_t){
+        .tx_buffer = NULL,
+        .length = length * 8, // In bits
+        .user = (void *)type,
+        .flags = 0,
+    };
+
+    if (type & 2)
+    {
+        t->tx_buffer = data;
+    }
+    else if (length < 5)
+    {
+        memcpy(t->tx_data, data, length);
+        t->flags = SPI_TRANS_USE_TXDATA;
+    }
+    else
+    {
+        t->tx_buffer = memcpy(spi_take_buffer(), data, length);
+        t->user = (void *)(type | 2);
+    }
+
+    if (spi_device_queue_trans(spi_dev, t, pdMS_TO_TICKS(2500)) != ESP_OK)
+    {
+        RG_PANIC("display");
+    }
+}
+
+IRAM_ATTR
+static void spi_pre_transfer_cb(spi_transaction_t *t)
+{
+    // Set the data/command line accordingly
+    gpio_set_level(RG_GPIO_LCD_DC, (int)t->user & 1);
+}
+
+IRAM_ATTR
+static void spi_task(void *arg)
+{
+    spi_transaction_t *t;
+
+    while (spi_device_get_trans_result(spi_dev, &t, portMAX_DELAY) == ESP_OK)
+    {
+        if ((int)t->user & 2)
+            spi_give_buffer((uint16_t *)t->tx_buffer);
+        xQueueSend(spi_transactions, &t, portMAX_DELAY);
+    }
+}
+
+static void spi_init(void)
+{
+    spi_transactions = xQueueCreate(SPI_TRANSACTION_COUNT, sizeof(spi_transaction_t *));
+    spi_buffers = xQueueCreate(SPI_BUFFER_COUNT, sizeof(uint16_t *));
+
+    while (uxQueueSpacesAvailable(spi_transactions))
+    {
+        void *trans = malloc(sizeof(spi_transaction_t));
+        xQueueSend(spi_transactions, &trans, portMAX_DELAY);
+    }
+
+    while (uxQueueSpacesAvailable(spi_buffers))
+    {
+        void *buffer = rg_alloc(SPI_BUFFER_LENGTH, MEM_DMA);
+        xQueueSend(spi_buffers, &buffer, portMAX_DELAY);
+    }
+
+    const spi_bus_config_t buscfg = {
+        .miso_io_num = RG_GPIO_LCD_MISO,
+        .mosi_io_num = RG_GPIO_LCD_MOSI,
+        .sclk_io_num = RG_GPIO_LCD_CLK,
+        .quadwp_io_num = -1,
+        .quadhd_io_num = -1,
+    };
+
+    const spi_device_interface_config_t devcfg = {
+        .clock_speed_hz = RG_SCREEN_SPEED,   // Typically SPI_MASTER_FREQ_40M or SPI_MASTER_FREQ_80M
+        .mode = 0,                           // SPI mode 0
+        .spics_io_num = RG_GPIO_LCD_CS,      // CS pin
+        .queue_size = SPI_TRANSACTION_COUNT, // We want to be able to queue 5 transactions at a time
+        .pre_cb = &spi_pre_transfer_cb,      // Specify pre-transfer callback to handle D/C line and SPI lock
+        .flags = SPI_DEVICE_NO_DUMMY,        // SPI_DEVICE_HALFDUPLEX;
+    };
+
+    esp_err_t ret;
+
+    // Initialize the SPI bus
+    ret = spi_bus_initialize(RG_SCREEN_HOST, &buscfg, SPI_DMA_CH_AUTO);
+    RG_ASSERT(ret == ESP_OK || ret == ESP_ERR_INVALID_STATE, "spi_bus_initialize failed.");
+
+    ret = spi_bus_add_device(RG_SCREEN_HOST, &devcfg, &spi_dev);
+    RG_ASSERT(ret == ESP_OK, "spi_bus_add_device failed.");
+
+    rg_task_create("rg_spi", &spi_task, NULL, 1.5 * 1024, RG_TASK_PRIORITY_7, 1);
+}
+
+static void spi_deinit(void)
+{
+    spi_bus_remove_device(spi_dev);
+    spi_bus_free(RG_SCREEN_HOST);
+}
+
+#define ILI9341_CMD(cmd, data...)                    \
+    {                                                \
+        const uint8_t c = cmd, x[] = {data};         \
+        spi_queue_transaction(&c, 1, 0);             \
+        if (sizeof(x))                               \
+            spi_queue_transaction(&x, sizeof(x), 1); \
+    }
+
+static void lcd_set_backlight(float percent)
+{
+    float level = RG_MIN(RG_MAX(percent / 100.f, 0), 1.f);
+    int error_code = 0;
+
+#if defined(RG_GPIO_LCD_BCKL)
+    error_code = ledc_set_fade_time_and_start(LEDC_LOW_SPEED_MODE, LEDC_CHANNEL_0, 0x1FFF * level, 50, 0);
+#elif defined(RG_TARGET_QTPY_GAMER)
+    rg_i2c_gpio_set_direction(AW_TFT_BACKLIGHT, 0);
+    rg_i2c_gpio_set_level(AW_TFT_BACKLIGHT, level * 255);
+#endif
+
+    if (error_code)
+        RG_LOGE("failed setting backlight to %d%% (0x%02X)\n", (int)(100 * level), error_code);
+    else
+        RG_LOGI("backlight set to %d%%\n", (int)(100 * level));
+}
+
+static void lcd_set_window(int left, int top, int width, int height)
+{
+    int right = left + width - 1;
+    int bottom = top + height - 1;
+
+    if (left < 0 || top < 0 || right >= display.screen.real_width || bottom >= display.screen.real_height)
+        RG_LOGW("Bad lcd window (x0=%d, y0=%d, x1=%d, y1=%d)\n", left, top, right, bottom);
+
+    ILI9341_CMD(0x2A, left >> 8, left & 0xff, right >> 8, right & 0xff); // Horiz
+    ILI9341_CMD(0x2B, top >> 8, top & 0xff, bottom >> 8, bottom & 0xff); // Vert
+    ILI9341_CMD(0x2C);                                                   // Memory write
+}
+
+static inline uint16_t *lcd_get_buffer(size_t length)
+{
+    // RG_ASSERT(length < LCD_BUFFER_LENGTH, "Invalid length");
+    return spi_take_buffer();
+}
+
+static inline void lcd_send_buffer(uint16_t *buffer, size_t length)
+{
+    if (length > 0)
+        spi_queue_transaction(buffer, length * sizeof(*buffer), 3);
+    else
+        spi_give_buffer(buffer);
+}
+
+static void lcd_sync(void)
+{
+    // Unused for SPI LCD
+}
+
+static void lcd_init(void)
+{
+#ifdef RG_GPIO_LCD_BCKL
+    // Initialize backlight at 0% to avoid the lcd reset flash
+    ledc_timer_config(&(ledc_timer_config_t){
+        .duty_resolution = LEDC_TIMER_13_BIT,
+        .freq_hz = 5000,
+        .speed_mode = LEDC_LOW_SPEED_MODE,
+        .timer_num = LEDC_TIMER_0,
+    });
+    ledc_channel_config(&(ledc_channel_config_t){
+        .channel = LEDC_CHANNEL_0,
+        .duty = 0,
+        .gpio_num = RG_GPIO_LCD_BCKL,
+        .speed_mode = LEDC_LOW_SPEED_MODE,
+        .timer_sel = LEDC_TIMER_0,
+    });
+    ledc_fade_func_install(0);
+#endif
+
+    spi_init();
+
+    // Setup Data/Command line
+    gpio_set_direction(RG_GPIO_LCD_DC, GPIO_MODE_OUTPUT);
+    gpio_set_level(RG_GPIO_LCD_DC, 1);
+
+#if defined(RG_GPIO_LCD_RST)
+    gpio_set_direction(RG_GPIO_LCD_RST, GPIO_MODE_OUTPUT);
+    gpio_set_level(RG_GPIO_LCD_RST, 0);
+    rg_usleep(100 * 1000);
+    gpio_set_level(RG_GPIO_LCD_RST, 1);
+    rg_usleep(10 * 1000);
+#elif defined(RG_TARGET_QTPY_GAMER)
+    rg_i2c_gpio_set_direction(AW_TFT_RESET, 0);
+    rg_i2c_gpio_set_level(AW_TFT_RESET, 0);
+    rg_usleep(100 * 1000);
+    rg_i2c_gpio_set_level(AW_TFT_RESET, 1);
+    rg_usleep(10 * 1000);
+#endif
+
+    ILI9341_CMD(0x01);          // Reset
+    rg_usleep(5 * 1000);        // Wait 5ms after reset
+    ILI9341_CMD(0x3A, 0X05);    // Pixel Format Set RGB565
+    #ifdef RG_SCREEN_INIT
+        RG_SCREEN_INIT();
+    #else
+        #warning "LCD init sequence is not defined for this device!"
+    #endif
+    ILI9341_CMD(0x11);  // Exit Sleep
+    rg_usleep(5 * 1000);// Wait 5ms after sleep out
+    ILI9341_CMD(0x29);  // Display on
+
+    rg_display_clear(C_BLACK);
+    rg_usleep(10 * 1000);
+    lcd_set_backlight(config.backlight);
+}
+
+static void lcd_deinit(void)
+{
+#ifdef RG_SCREEN_DEINIT
+    RG_SCREEN_DEINIT();
+#endif
+    spi_deinit();
+    // gpio_reset_pin(RG_GPIO_LCD_BCKL);
+    // gpio_reset_pin(RG_GPIO_LCD_DC);
+}

components/retro-go/drivers/display/sdl2.h

@@ -0,0 +1,26 @@
+#include <SDL2/SDL.h>
+
+static void lcd_init(void)
+{
+}
+
+static void lcd_deinit(void)
+{
+}
+
+static void lcd_set_backlight(float percent)
+{
+}
+
+static inline uint16_t *lcd_get_buffer(size_t length)
+{
+    return (void *)0;
+}
+
+static inline void lcd_send_buffer(uint16_t *buffer, size_t length)
+{
+}
+
+static void lcd_sync(void)
+{
+}