Implement Tulip Creative Computer 4r11 (#608)

Drivers/rgb-display-module/include/drivers/rgb_display.h

@@ -11,6 +11,18 @@ extern "C" {
 #include <tactility/device.h>
 #include <tactility/drivers/gpio.h>
 
+/**
+ * Optional software pixel-format conversion applied to scan-out pixels. The panel itself always
+ * runs at bits_per_pixel; when the host renders in a different depth (LVGL always renders RGB565
+ * for this driver), the selected mapper converts each tile before it reaches esp_lcd.
+ */
+enum RgbDisplayPixelFormat {
+    /** No conversion: scan-out pixels must already match bits_per_pixel. */
+    RGB_DISPLAY_PIXEL_FORMAT_DEFAULT = 0,
+    /** Convert RGB565 to packed 8-bit RGB332 (3R, 3G, 2B), for 8 data-line panels. */
+    RGB_DISPLAY_PIXEL_FORMAT_RGB332 = 1,
+};
+
 struct RgbDisplayConfig {
     uint16_t horizontal_resolution;
     uint16_t vertical_resolution;
@@ -84,6 +96,9 @@ struct RgbDisplayConfig {
 
     // Optional reference to this display's backlight device, NULL if none.
     struct Device* backlight;
+
+    // Optional software pixel-format conversion for scan-out (see enum RgbDisplayPixelFormat).
+    enum RgbDisplayPixelFormat pixel_format;
 };
 
 #ifdef __cplusplus

Drivers/rgb-display-module/include/drivers/software_pixel_mapper.h

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/**
+ * Opaque per-instance state for a software pixel mapper, allocated by SoftwarePixelMapperCreateFn
+ * and released by SoftwarePixelMapperDestroyFn. The instance owns its conversion destination
+ * buffer: the driver passes this handle as map()'s dst argument.
+ */
+typedef void* SoftwarePixelMapperData;
+
+/**
+ * Allocates a mapper instance, including its destination buffer, sized for a width x height
+ * source buffer.
+ * @param width source buffer width in pixels
+ * @param height source buffer height in pixels
+ * @return a non-null instance handle, or NULL on allocation failure
+ */
+typedef SoftwarePixelMapperData (*SoftwarePixelMapperCreateFn)(uint16_t width, uint16_t height);
+
+/**
+ * Converts pixel_count pixels from the mapper's source format to its destination format.
+ * @param data instance handle from SoftwarePixelMapperCreateFn
+ * @param src RGB565 source pixels
+ * @param dst destination buffer, typically the instance's own buffer (i.e. the data handle)
+ * @param pixel_count number of pixels to convert
+ */
+typedef void (*SoftwarePixelMapperMapFn)(SoftwarePixelMapperData data, const uint16_t* src, uint8_t* dst, uint32_t pixel_count);
+
+/**
+ * Releases a mapper instance created by SoftwarePixelMapperCreateFn, including its destination
+ * buffer.
+ * @param data instance handle to release
+ */
+typedef void (*SoftwarePixelMapperDestroyFn)(SoftwarePixelMapperData data);
+
+/**
+ * A software pixel-format conversion, used to translate a driver's native source depth into a
+ * panel's scan-out depth when the two differ. Each mapper owns its own destination buffer, so it
+ * can size the allocation for its output format.
+ */
+struct SoftwarePixelMapper {
+    SoftwarePixelMapperCreateFn create;
+    SoftwarePixelMapperMapFn map;
+    SoftwarePixelMapperDestroyFn destroy;
+};
+
+/**
+ * RGB565 to packed 8-bit RGB332 (3 bits red, 3 bits green, 2 bits blue) mapper for panels wired
+ * with only 8 data lines.
+ */
+extern const struct SoftwarePixelMapper software_pixel_mapper_rgb332;
+
+#ifdef __cplusplus
+}
+#endif