Device migrations and driver implementations (#564)

2026-07-15 12:46:24 +02:00
parent 8af6204ba1
commit bd8fdfd858
55 changed files with 1695 additions and 447 deletions
@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.20)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../../Buildscripts/module.cmake")
+
+file(GLOB_RECURSE SOURCE_FILES "source/*.c*")
+
+tactility_add_module(rgb-display-module
+    SRCS ${SOURCE_FILES}
+    INCLUDE_DIRS include/
+    REQUIRES TactilityKernel platform-esp32 esp_lcd driver
+)
@@ -0,0 +1,195 @@
+Apache License
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@@ -0,0 +1,5 @@
+# RGB Display Driver
+
+A kernel driver for ESP32 RGB (parallel timing-driven) LCD panels, built on ESP-IDF's `esp_lcd_rgb_panel` component. Unlike SPI/i8080 panels, an RGB panel owns its GPIOs directly and has no command interface, so it doesn't sit behind a shared bus controller device - kernel driver equivalent of the deprecated HAL's `RgbDisplay`.
+
+License: [Apache v2.0](LICENSE-Apache-2.0.md)
@@ -0,0 +1,224 @@
+description: >
+  ESP32 RGB (parallel timing-driven) LCD panel, built on ESP-IDF's esp_lcd_rgb_panel
+  component. Unlike SPI/i8080 panels, an RGB panel has no command interface and owns its
+  GPIOs directly rather than sitting behind a shared bus controller device.
+
+compatible: "espressif,esp32-rgb-display"
+
+properties:
+  horizontal-resolution:
+    type: int
+    required: true
+    description: Horizontal resolution in pixels
+  vertical-resolution:
+    type: int
+    required: true
+    description: Vertical resolution in pixels
+  pixel-clock-hz:
+    type: int
+    required: true
+    description: Pixel clock frequency in Hz
+  hsync-pulse-width:
+    type: int
+    required: true
+    description: Horizontal sync width, in PCLK periods
+  hsync-back-porch:
+    type: int
+    required: true
+    description: Number of PCLK periods between hsync and the start of line active data
+  hsync-front-porch:
+    type: int
+    required: true
+    description: Number of PCLK periods between the end of active data and the next hsync
+  vsync-pulse-width:
+    type: int
+    required: true
+    description: Vertical sync width, in lines
+  vsync-back-porch:
+    type: int
+    required: true
+    description: Number of invalid lines between vsync and the start of the frame
+  vsync-front-porch:
+    type: int
+    required: true
+    description: Number of invalid lines between the end of the frame and the next vsync
+  hsync-idle-low:
+    type: boolean
+    default: false
+    description: The hsync signal is low in the idle state
+  vsync-idle-low:
+    type: boolean
+    default: false
+    description: The vsync signal is low in the idle state
+  de-idle-high:
+    type: boolean
+    default: false
+    description: The DE signal is high in the idle state
+  pclk-active-neg:
+    type: boolean
+    default: false
+    description: Whether display data is clocked out on the falling edge of PCLK
+  pclk-idle-high:
+    type: boolean
+    default: false
+    description: The PCLK signal stays high in the idle phase
+  data-width:
+    type: int
+    default: 16
+    description: Number of parallel data lines wired (8 or 16)
+  bits-per-pixel:
+    type: int
+    default: 0
+    description: Frame buffer color depth in bpp. 0 defaults to data-width.
+  num-fbs:
+    type: int
+    default: 1
+    description: Number of screen-sized frame buffers to allocate (0 or 1 = single-buffered)
+  bounce-buffer-size-px:
+    type: int
+    default: 0
+    description: Non-zero enables the DRAM bounce-buffer DMA path, sized in pixels
+  sram-trans-align:
+    type: int
+    default: 8
+    description: Alignment of buffers allocated in internal SRAM
+  psram-trans-align:
+    type: int
+    default: 64
+    description: Alignment of buffers allocated in PSRAM
+  pin-hsync:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: HSYNC GPIO pin, optional for panels that only need DE (data-enable) sync
+  pin-vsync:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: VSYNC GPIO pin, optional for panels that only need DE (data-enable) sync
+  pin-de:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data-enable GPIO pin, optional
+  pin-pclk:
+    type: phandles
+    required: true
+    description: Pixel-clock GPIO pin
+  pin-disp:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Optional display-enable control GPIO pin
+  pin-reset:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Optional hardware reset pin for the panel's own driver IC, pulsed once at start()
+  reset-active-high:
+    type: boolean
+    default: false
+    description: Whether the reset pin is active high
+  pin-data0:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 0 GPIO pin
+  pin-data1:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 1 GPIO pin
+  pin-data2:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 2 GPIO pin
+  pin-data3:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 3 GPIO pin
+  pin-data4:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 4 GPIO pin
+  pin-data5:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 5 GPIO pin
+  pin-data6:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 6 GPIO pin
+  pin-data7:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 7 GPIO pin
+  pin-data8:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 8 GPIO pin
+  pin-data9:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 9 GPIO pin
+  pin-data10:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 10 GPIO pin
+  pin-data11:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 11 GPIO pin
+  pin-data12:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 12 GPIO pin
+  pin-data13:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 13 GPIO pin
+  pin-data14:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 14 GPIO pin
+  pin-data15:
+    type: phandles
+    default: GPIO_PIN_SPEC_NONE
+    description: Data bus bit 15 GPIO pin
+  disp-active-low:
+    type: boolean
+    default: false
+    description: A low level on the display-enable control signal turns the screen on
+  refresh-on-demand:
+    type: boolean
+    default: false
+    description: Only refresh the frame buffer on explicit draw_bitmap calls
+  fb-in-psram:
+    type: boolean
+    default: true
+    description: Allocate the frame buffer from PSRAM, preferentially
+  double-fb:
+    type: boolean
+    default: false
+    description: Allocate two screen-sized frame buffers (equivalent to num-fbs = 2)
+  no-fb:
+    type: boolean
+    default: false
+    description: Don't allocate a frame buffer; bounce buffer must be filled manually
+  bb-invalidate-cache:
+    type: boolean
+    default: false
+    description: Invalidate cache on bounce-buffer reads (can be dangerous with multi-core writers)
+  swap-xy:
+    type: boolean
+    default: false
+    description: Swap the X and Y axes
+  mirror-x:
+    type: boolean
+    default: false
+    description: Mirror the X axis
+  mirror-y:
+    type: boolean
+    default: false
+    description: Mirror the Y axis
+  invert-color:
+    type: boolean
+    default: false
+    description: Invert the panel's color output
+  backlight:
+    type: phandle
+    default: "NULL"
+    description: Optional reference to this display's backlight device
@@ -0,0 +1,3 @@
+dependencies:
+  - TactilityKernel
+bindings: bindings
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/bindings/bindings.h>
+#include <drivers/rgb_display.h>
+
+// The devicetree compiler derives the expected config typedef name from the compatible
+// string's suffix (e.g. "espressif,esp32-rgb-display" -> esp32_rgb_display_config_dt), not
+// from the node name or driver name, so the tag here must match that exactly.
+DEFINE_DEVICETREE(esp32_rgb_display, struct RgbDisplayConfig)
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <tactility/device.h>
+#include <tactility/drivers/gpio.h>
+
+struct RgbDisplayConfig {
+    uint16_t horizontal_resolution;
+    uint16_t vertical_resolution;
+
+    uint32_t pixel_clock_hz;
+    uint32_t hsync_pulse_width;
+    uint32_t hsync_back_porch;
+    uint32_t hsync_front_porch;
+    uint32_t vsync_pulse_width;
+    uint32_t vsync_back_porch;
+    uint32_t vsync_front_porch;
+    bool hsync_idle_low;
+    bool vsync_idle_low;
+    bool de_idle_high;
+    bool pclk_active_neg;
+    bool pclk_idle_high;
+
+    // Number of parallel data lines actually wired (8 or 16). Only the first data_width
+    // pin-dataN fields below are used; the rest are ignored.
+    uint8_t data_width;
+    // Frame buffer color depth in bpp. 0 defaults to data_width.
+    uint8_t bits_per_pixel;
+    // Number of screen-sized frame buffers the driver allocates (0 or 1 = single-buffered).
+    uint8_t num_fbs;
+    // Non-zero enables the DRAM bounce-buffer DMA path, sized in pixels.
+    uint32_t bounce_buffer_size_px;
+    uint32_t sram_trans_align;
+    uint32_t psram_trans_align;
+
+    struct GpioPinSpec pin_hsync;
+    struct GpioPinSpec pin_vsync;
+    struct GpioPinSpec pin_de;
+    struct GpioPinSpec pin_pclk;
+    // Optional display-enable control pin, GPIO_PIN_SPEC_NONE if unused.
+    struct GpioPinSpec pin_disp;
+    // Optional hardware reset pin for the panel's own driver IC, pulsed once at start() before
+    // the RGB peripheral is brought up. GPIO_PIN_SPEC_NONE if the panel has none (esp_lcd_rgb_panel
+    // itself has no reset concept - some RGB panels still have a separate reset line on their
+    // internal driver IC even though pixel data is fed over the RGB bus).
+    struct GpioPinSpec pin_reset;
+    bool reset_active_high;
+
+    struct GpioPinSpec pin_data0;
+    struct GpioPinSpec pin_data1;
+    struct GpioPinSpec pin_data2;
+    struct GpioPinSpec pin_data3;
+    struct GpioPinSpec pin_data4;
+    struct GpioPinSpec pin_data5;
+    struct GpioPinSpec pin_data6;
+    struct GpioPinSpec pin_data7;
+    struct GpioPinSpec pin_data8;
+    struct GpioPinSpec pin_data9;
+    struct GpioPinSpec pin_data10;
+    struct GpioPinSpec pin_data11;
+    struct GpioPinSpec pin_data12;
+    struct GpioPinSpec pin_data13;
+    struct GpioPinSpec pin_data14;
+    struct GpioPinSpec pin_data15;
+
+    bool disp_active_low;
+    bool refresh_on_demand;
+    bool fb_in_psram;
+    bool double_fb;
+    bool no_fb;
+    bool bb_invalidate_cache;
+
+    bool swap_xy;
+    bool mirror_x;
+    bool mirror_y;
+    bool invert_color;
+
+    // Optional reference to this display's backlight device, NULL if none.
+    struct Device* backlight;
+};
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/module.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern struct Module rgb_display_module;
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <tactility/check.h>
+#include <tactility/driver.h>
+#include <tactility/module.h>
+
+extern "C" {
+
+extern Driver rgb_display_driver;
+
+static error_t start() {
+    /* We crash when construct fails, because if a single driver fails to construct,
+     * there is no guarantee that the previously constructed drivers can be destroyed */
+    check(driver_construct_add(&rgb_display_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+static error_t stop() {
+    /* We crash when destruct fails, because if a single driver fails to destruct,
+     * there is no guarantee that the previously destroyed drivers can be recovered */
+    check(driver_remove_destruct(&rgb_display_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+Module rgb_display_module = {
+    .name = "rgb_display",
+    .start = start,
+    .stop = stop,
+    .symbols = nullptr,
+    .internal = nullptr
+};
+
+} // extern "C"
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <soc/soc_caps.h>
+#if SOC_LCD_RGB_SUPPORTED
+
+#include <drivers/rgb_display.h>
+#include <rgb_display_module.h>
+
+#include <tactility/delay.h>
+#include <tactility/device.h>
+#include <tactility/driver.h>
+#include <tactility/drivers/display.h>
+#include <tactility/drivers/gpio_controller.h>
+#include <tactility/drivers/gpio_descriptor.h>
+#include <tactility/error.h>
+#include <tactility/log.h>
+
+#include <esp_err.h>
+#include <esp_lcd_panel_rgb.h>
+#include <esp_lcd_panel_ops.h>
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+
+#include <cstdlib>
+
+#define TAG "RgbDisplay"
+#define GET_CONFIG(device) (static_cast<const RgbDisplayConfig*>((device)->config))
+
+// Generic lvgl-module display glue (Modules/lvgl-module/source/lvgl_display.c) only ever asks
+// for frame buffer index 0 and 1, so caching more than that would be dead weight.
+constexpr size_t MAX_CACHED_FRAME_BUFFERS = 2;
+
+struct RgbDisplayInternal {
+    esp_lcd_panel_handle_t panel_handle;
+    void* frame_buffers[MAX_CACHED_FRAME_BUFFERS];
+    uint8_t frame_buffer_count;
+    // Signaled by on_frame_buf_complete once per real DMA scan-out of a whole frame. Only
+    // waited on in draw_bitmap() when frame_buffer_count > 0 - see the comment there for why.
+    SemaphoreHandle_t frame_complete_semaphore;
+};
+
+// esp_lcd_rgb_panel's draw_bitmap() has a zero-copy path when color_data is one of the panel's
+// own frame buffers (as returned by esp_lcd_rgb_panel_get_frame_buffer()): it just repoints which
+// buffer is scanned out and returns almost instantly - well before the RGB peripheral's DMA has
+// actually finished scanning out the *previous* buffer, let alone started on this one. Callers in
+// full/direct LVGL render mode render straight into these real frame buffers, so if draw_bitmap()
+// returned that quickly, LVGL would be free to start overwriting the *other* buffer - which may
+// still be mid-scanout - producing visible tearing/flashing. on_frame_buf_complete fires once per
+// actual whole-frame DMA completion (continuously, at the panel's refresh rate, independent of
+// draw_bitmap calls), so waiting for the next occurrence after each draw_bitmap() genuinely
+// blocks until it's safe to start writing into the frame buffers again.
+static bool IRAM_ATTR on_frame_buf_complete(esp_lcd_panel_handle_t, const esp_lcd_rgb_panel_event_data_t*, void* user_ctx) {
+    auto* internal = static_cast<RgbDisplayInternal*>(user_ctx);
+    BaseType_t high_task_woken = pdFALSE;
+    xSemaphoreGiveFromISR(internal->frame_complete_semaphore, &high_task_woken);
+    return high_task_woken == pdTRUE;
+}
+
+static int pin_or_unused(const GpioPinSpec& pin) {
+    return pin.gpio_controller == nullptr ? -1 : static_cast<int>(pin.pin);
+}
+
+// Pulses the panel's own driver-IC reset line, if configured. Transient: the descriptor is
+// released immediately after, since nothing else needs to touch this pin afterward.
+static error_t perform_hardware_reset(const RgbDisplayConfig* config) {
+    if (config->pin_reset.gpio_controller == nullptr) {
+        return ERROR_NONE;
+    }
+
+    auto* descriptor = gpio_descriptor_acquire(config->pin_reset.gpio_controller, config->pin_reset.pin, GPIO_OWNER_GPIO);
+    if (descriptor == nullptr) {
+        LOG_E(TAG, "Failed to acquire reset GPIO descriptor");
+        return ERROR_RESOURCE;
+    }
+
+    bool ok = gpio_descriptor_set_flags(descriptor, GPIO_FLAG_DIRECTION_OUTPUT) == ERROR_NONE;
+    ok = ok && gpio_descriptor_set_level(descriptor, config->reset_active_high) == ERROR_NONE;
+    if (ok) {
+        delay_millis(100);
+        ok = gpio_descriptor_set_level(descriptor, !config->reset_active_high) == ERROR_NONE;
+        delay_millis(10);
+    }
+
+    gpio_descriptor_release(descriptor);
+    return ok ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+// region Driver lifecycle
+
+static error_t cache_frame_buffers(RgbDisplayInternal* internal, const RgbDisplayConfig* config) {
+    internal->frame_buffer_count = 0;
+    if (config->num_fbs == 0) {
+        return ERROR_NONE;
+    }
+
+    // esp_lcd_rgb_panel_get_frame_buffer() is variadic: the number of out-pointer arguments
+    // passed must match fb_num exactly, so this can't be a loop.
+    size_t fb_num = config->num_fbs < MAX_CACHED_FRAME_BUFFERS ? config->num_fbs : MAX_CACHED_FRAME_BUFFERS;
+    esp_err_t ret;
+    switch (fb_num) {
+        case 1:
+            ret = esp_lcd_rgb_panel_get_frame_buffer(internal->panel_handle, 1, &internal->frame_buffers[0]);
+            break;
+        case 2:
+            ret = esp_lcd_rgb_panel_get_frame_buffer(internal->panel_handle, 2, &internal->frame_buffers[0], &internal->frame_buffers[1]);
+            break;
+        default:
+            return ERROR_NONE;
+    }
+
+    if (ret != ESP_OK) {
+        LOG_E(TAG, "Failed to get frame buffer(s): %s", esp_err_to_name(ret));
+        return ERROR_RESOURCE;
+    }
+
+    internal->frame_buffer_count = (uint8_t)fb_num;
+    return ERROR_NONE;
+}
+
+static error_t start(Device* device) {
+    const auto* config = GET_CONFIG(device);
+
+    auto* internal = static_cast<RgbDisplayInternal*>(malloc(sizeof(RgbDisplayInternal)));
+    if (internal == nullptr) {
+        return ERROR_OUT_OF_MEMORY;
+    }
+
+    error_t reset_error = perform_hardware_reset(config);
+    if (reset_error != ERROR_NONE) {
+        LOG_E(TAG, "Failed to reset panel");
+        free(internal);
+        return reset_error;
+    }
+
+    esp_lcd_rgb_panel_config_t panel_config = {
+        .clk_src = LCD_CLK_SRC_DEFAULT,
+        .timings = {
+            .pclk_hz = config->pixel_clock_hz,
+            .h_res = config->horizontal_resolution,
+            .v_res = config->vertical_resolution,
+            .hsync_pulse_width = config->hsync_pulse_width,
+            .hsync_back_porch = config->hsync_back_porch,
+            .hsync_front_porch = config->hsync_front_porch,
+            .vsync_pulse_width = config->vsync_pulse_width,
+            .vsync_back_porch = config->vsync_back_porch,
+            .vsync_front_porch = config->vsync_front_porch,
+            .flags = {
+                .hsync_idle_low = config->hsync_idle_low,
+                .vsync_idle_low = config->vsync_idle_low,
+                .de_idle_high = config->de_idle_high,
+                .pclk_active_neg = config->pclk_active_neg,
+                .pclk_idle_high = config->pclk_idle_high,
+            }
+        },
+        .data_width = config->data_width,
+        .bits_per_pixel = config->bits_per_pixel,
+        .num_fbs = config->num_fbs,
+        .bounce_buffer_size_px = config->bounce_buffer_size_px,
+        .sram_trans_align = config->sram_trans_align,
+        .psram_trans_align = config->psram_trans_align,
+        .hsync_gpio_num = pin_or_unused(config->pin_hsync),
+        .vsync_gpio_num = pin_or_unused(config->pin_vsync),
+        .de_gpio_num = pin_or_unused(config->pin_de),
+        .pclk_gpio_num = pin_or_unused(config->pin_pclk),
+        .disp_gpio_num = pin_or_unused(config->pin_disp),
+        .data_gpio_nums = {
+            pin_or_unused(config->pin_data0),
+            pin_or_unused(config->pin_data1),
+            pin_or_unused(config->pin_data2),
+            pin_or_unused(config->pin_data3),
+            pin_or_unused(config->pin_data4),
+            pin_or_unused(config->pin_data5),
+            pin_or_unused(config->pin_data6),
+            pin_or_unused(config->pin_data7),
+            pin_or_unused(config->pin_data8),
+            pin_or_unused(config->pin_data9),
+            pin_or_unused(config->pin_data10),
+            pin_or_unused(config->pin_data11),
+            pin_or_unused(config->pin_data12),
+            pin_or_unused(config->pin_data13),
+            pin_or_unused(config->pin_data14),
+            pin_or_unused(config->pin_data15),
+        },
+        .flags = {
+            .disp_active_low = config->disp_active_low,
+            .refresh_on_demand = config->refresh_on_demand,
+            .fb_in_psram = config->fb_in_psram,
+            .double_fb = config->double_fb,
+            .no_fb = config->no_fb,
+            .bb_invalidate_cache = config->bb_invalidate_cache,
+        }
+    };
+
+    // This Config struct only exposes 16 named data pins, so on chips whose RGB peripheral has
+    // more data lines than that (e.g. ESP32-P4's 24), the tail of the array must be explicitly
+    // marked unused rather than left as the aggregate-init default of 0 (which would look like
+    // "GPIO0 is wired to this line").
+    for (size_t i = 16; i < sizeof(panel_config.data_gpio_nums) / sizeof(panel_config.data_gpio_nums[0]); i++) {
+        panel_config.data_gpio_nums[i] = -1;
+    }
+
+    esp_err_t ret = esp_lcd_new_rgb_panel(&panel_config, &internal->panel_handle);
+    if (ret != ESP_OK) {
+        LOG_E(TAG, "Failed to create panel: %s", esp_err_to_name(ret));
+        free(internal);
+        return ERROR_RESOURCE;
+    }
+
+    bool ok =
+        esp_lcd_panel_reset(internal->panel_handle) == ESP_OK &&
+        esp_lcd_panel_init(internal->panel_handle) == ESP_OK &&
+        esp_lcd_panel_swap_xy(internal->panel_handle, config->swap_xy) == ESP_OK &&
+        esp_lcd_panel_mirror(internal->panel_handle, config->mirror_x, config->mirror_y) == ESP_OK &&
+        esp_lcd_panel_invert_color(internal->panel_handle, config->invert_color) == ESP_OK;
+
+    if (!ok) {
+        LOG_E(TAG, "Failed to bring up panel");
+        esp_lcd_panel_del(internal->panel_handle);
+        free(internal);
+        return ERROR_RESOURCE;
+    }
+
+    error_t error = cache_frame_buffers(internal, config);
+    if (error != ERROR_NONE) {
+        esp_lcd_panel_del(internal->panel_handle);
+        free(internal);
+        return error;
+    }
+
+    internal->frame_complete_semaphore = xSemaphoreCreateBinary();
+    if (internal->frame_complete_semaphore == nullptr) {
+        esp_lcd_panel_del(internal->panel_handle);
+        free(internal);
+        return ERROR_OUT_OF_MEMORY;
+    }
+
+    esp_lcd_rgb_panel_event_callbacks_t callbacks = {};
+    callbacks.on_frame_buf_complete = on_frame_buf_complete;
+    if (esp_lcd_rgb_panel_register_event_callbacks(internal->panel_handle, &callbacks, internal) != ESP_OK) {
+        LOG_E(TAG, "Failed to register panel event callbacks");
+        vSemaphoreDelete(internal->frame_complete_semaphore);
+        esp_lcd_panel_del(internal->panel_handle);
+        free(internal);
+        return ERROR_RESOURCE;
+    }
+
+    device_set_driver_data(device, internal);
+    return ERROR_NONE;
+}
+
+static error_t stop(Device* device) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+
+    if (esp_lcd_panel_del(internal->panel_handle) != ESP_OK) {
+        LOG_E(TAG, "Failed to delete panel");
+        vSemaphoreDelete(internal->frame_complete_semaphore);
+        free(internal);
+        return ERROR_RESOURCE;
+    }
+
+    vSemaphoreDelete(internal->frame_complete_semaphore);
+    free(internal);
+    return ERROR_NONE;
+}
+
+// endregion
+
+// region DisplayApi
+
+static error_t rgb_display_reset(Device* device) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_reset(internal->panel_handle) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+static error_t rgb_display_init(Device* device) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_init(internal->panel_handle) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+static error_t rgb_display_draw_bitmap(Device* device, int32_t x_start, int32_t y_start, int32_t x_end, int32_t y_end, const void* color_data) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+
+    // Only block for scan-out completion when the caller could be writing straight into one of
+    // the panel's own frame buffers (see on_frame_buf_complete's comment above for why that
+    // matters). With no real frame buffer of ours involved (frame_buffer_count == 0, e.g. LVGL
+    // partial-render mode with its own separate buffer), draw_bitmap does a real memcpy into the
+    // panel's buffer and there's no reuse race to guard against, so don't pay the up-to-one-frame
+    // latency cost for every small partial update.
+    bool wait_for_scanout = internal->frame_buffer_count > 0;
+    if (wait_for_scanout) {
+        xSemaphoreTake(internal->frame_complete_semaphore, 0); // clear any already-pending signal
+    }
+
+    if (esp_lcd_panel_draw_bitmap(internal->panel_handle, x_start, y_start, x_end, y_end, color_data) != ESP_OK) {
+        return ERROR_RESOURCE;
+    }
+
+    if (wait_for_scanout) {
+        xSemaphoreTake(internal->frame_complete_semaphore, portMAX_DELAY);
+    }
+
+    return ERROR_NONE;
+}
+
+static error_t rgb_display_mirror(Device* device, bool x_axis, bool y_axis) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_mirror(internal->panel_handle, x_axis, y_axis) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+static error_t rgb_display_swap_xy(Device* device, bool swap_axes) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_swap_xy(internal->panel_handle, swap_axes) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+static bool rgb_display_get_swap_xy(Device* device) {
+    return GET_CONFIG(device)->swap_xy;
+}
+
+static bool rgb_display_get_mirror_x(Device* device) {
+    return GET_CONFIG(device)->mirror_x;
+}
+
+static bool rgb_display_get_mirror_y(Device* device) {
+    return GET_CONFIG(device)->mirror_y;
+}
+
+// RGB panels are raw scan-out framebuffers with no addressable-window concept the way MIPI/SPI
+// panels have, so there's no gap to set.
+static error_t rgb_display_set_gap(Device*, int32_t, int32_t) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static error_t rgb_display_invert_color(Device* device, bool invert_color_data) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_invert_color(internal->panel_handle, invert_color_data) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+static error_t rgb_display_disp_on_off(Device* device, bool on_off) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return esp_lcd_panel_disp_on_off(internal->panel_handle, on_off) == ESP_OK ? ERROR_NONE : ERROR_RESOURCE;
+}
+
+// RGB panels have no MIPI DCS command interface, so there's no sleep mode to enter.
+static error_t rgb_display_disp_sleep(Device*, bool) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static enum DisplayColorFormat rgb_display_get_color_format(Device*) {
+    return DISPLAY_COLOR_FORMAT_RGB565;
+}
+
+static uint16_t rgb_display_get_resolution_x(Device* device) {
+    return GET_CONFIG(device)->horizontal_resolution;
+}
+
+static uint16_t rgb_display_get_resolution_y(Device* device) {
+    return GET_CONFIG(device)->vertical_resolution;
+}
+
+static void rgb_display_get_frame_buffer(Device* device, uint8_t index, void** out_buffer) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    *out_buffer = index < internal->frame_buffer_count ? internal->frame_buffers[index] : nullptr;
+}
+
+static uint8_t rgb_display_get_frame_buffer_count(Device* device) {
+    auto* internal = static_cast<RgbDisplayInternal*>(device_get_driver_data(device));
+    return internal->frame_buffer_count;
+}
+
+static error_t rgb_display_get_backlight(Device* device, Device** backlight) {
+    auto* configured_backlight = GET_CONFIG(device)->backlight;
+    if (configured_backlight == nullptr) {
+        return ERROR_NOT_SUPPORTED;
+    }
+    *backlight = configured_backlight;
+    return ERROR_NONE;
+}
+
+// endregion
+
+static const DisplayApi rgb_display_api = {
+    .reset = rgb_display_reset,
+    .init = rgb_display_init,
+    .draw_bitmap = rgb_display_draw_bitmap,
+    .mirror = rgb_display_mirror,
+    .swap_xy = rgb_display_swap_xy,
+    .get_swap_xy = rgb_display_get_swap_xy,
+    .get_mirror_x = rgb_display_get_mirror_x,
+    .get_mirror_y = rgb_display_get_mirror_y,
+    .set_gap = rgb_display_set_gap,
+    .invert_color = rgb_display_invert_color,
+    .disp_on_off = rgb_display_disp_on_off,
+    .disp_sleep = rgb_display_disp_sleep,
+    .get_color_format = rgb_display_get_color_format,
+    .get_resolution_x = rgb_display_get_resolution_x,
+    .get_resolution_y = rgb_display_get_resolution_y,
+    .get_frame_buffer = rgb_display_get_frame_buffer,
+    .get_frame_buffer_count = rgb_display_get_frame_buffer_count,
+    .get_backlight = rgb_display_get_backlight,
+};
+
+Driver rgb_display_driver = {
+    .name = "rgb_display",
+    .compatible = (const char*[]) { "espressif,esp32-rgb-display", nullptr },
+    .start_device = start,
+    .stop_device = stop,
+    .api = &rgb_display_api,
+    .device_type = &DISPLAY_TYPE,
+    .owner = &rgb_display_module,
+    .internal = nullptr
+};
+
+#endif // SOC_LCD_RGB_SUPPORTED
@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.20)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../../Buildscripts/module.cmake")
+
+file(GLOB_RECURSE SOURCE_FILES "source/*.c*")
+
+tactility_add_module(tca9534-module
+    SRCS ${SOURCE_FILES}
+    INCLUDE_DIRS include/
+    REQUIRES TactilityKernel
+)
@@ -0,0 +1,195 @@
+Apache License
+==============
+
+_Version 2.0, January 2004_  
+_&lt;<http://www.apache.org/licenses/>&gt;_
+
+### Terms and Conditions for use, reproduction, and distribution
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+    You may obtain a copy of the License at
+    
+      http://www.apache.org/licenses/LICENSE-2.0
+    
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
@@ -0,0 +1,7 @@
+# TCA9534 I/O expander
+
+A driver for the `TCA9534` 8-bit I2C-bus I/O expander by Texas Instruments.
+
+See https://www.ti.com/product/TCA9534
+
+License: [Apache v2.0](LICENSE-Apache-2.0.md)
@@ -0,0 +1,5 @@
+description: TI TCA9534 8-bit I2C-bus I/O expander
+
+include: ["i2c-device.yaml"]
+
+compatible: "ti,tca9534"
@@ -0,0 +1,3 @@
+dependencies:
+  - TactilityKernel
+bindings: bindings
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/bindings/bindings.h>
+#include <drivers/tca9534.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+DEFINE_DEVICETREE(tca9534, struct Tca9534Config)
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Tca9534Config {
+    /** Address on bus */
+    uint8_t address;
+};
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/module.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern struct Module tca9534_module;
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <tactility/check.h>
+#include <tactility/driver.h>
+#include <tactility/module.h>
+
+extern "C" {
+
+extern Driver tca9534_driver;
+
+static error_t start() {
+    /* We crash when construct fails, because if a single driver fails to construct,
+     * there is no guarantee that the previously constructed drivers can be destroyed */
+    check(driver_construct_add(&tca9534_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+static error_t stop() {
+    /* We crash when destruct fails, because if a single driver fails to destruct,
+     * there is no guarantee that the previously destroyed drivers can be recovered */
+    check(driver_remove_destruct(&tca9534_driver) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+Module tca9534_module = {
+    .name = "tca9534",
+    .start = start,
+    .stop = stop,
+    .symbols = nullptr,
+    .internal = nullptr
+};
+
+}
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <drivers/tca9534.h>
+#include <tca9534_module.h>
+#include <tactility/device.h>
+#include <tactility/driver.h>
+#include <tactility/drivers/gpio_controller.h>
+#include <tactility/drivers/gpio_descriptor.h>
+#include <tactility/drivers/i2c_controller.h>
+#include <tactility/log.h>
+
+#define TAG "TCA9534"
+
+#define GET_CONFIG(device) (static_cast<const Tca9534Config*>((device)->config))
+
+constexpr auto TCA9534_REGISTER_INPUT = 0x00;
+constexpr auto TCA9534_REGISTER_OUTPUT = 0x01;
+constexpr auto TCA9534_REGISTER_POLARITY = 0x02;
+constexpr auto TCA9534_REGISTER_CONFIG = 0x03;
+
+static error_t start(Device* device) {
+    auto* parent = device_get_parent(device);
+    if (device_get_type(parent) != &I2C_CONTROLLER_TYPE) {
+        LOG_E(TAG, "Parent device is not I2C");
+        return ERROR_RESOURCE;
+    }
+
+    return gpio_controller_init_descriptors(device, 8, nullptr);
+}
+
+static error_t stop(Device* device) {
+    check(gpio_controller_deinit_descriptors(device) == ERROR_NONE);
+    return ERROR_NONE;
+}
+
+extern "C" {
+
+static error_t set_level(GpioDescriptor* descriptor, bool high) {
+    auto* device = descriptor->controller;
+    auto* parent = device_get_parent(device);
+    auto address = GET_CONFIG(device)->address;
+    uint8_t bit = 1 << descriptor->pin;
+
+    return high
+        ? i2c_controller_register8_set_bits(parent, address, TCA9534_REGISTER_OUTPUT, bit, portMAX_DELAY)
+        : i2c_controller_register8_reset_bits(parent, address, TCA9534_REGISTER_OUTPUT, bit, portMAX_DELAY);
+}
+
+static error_t get_level(GpioDescriptor* descriptor, bool* high) {
+    auto* device = descriptor->controller;
+    auto* parent = device_get_parent(device);
+    auto address = GET_CONFIG(device)->address;
+    uint8_t bits;
+
+    error_t err = i2c_controller_register8_get(parent, address, TCA9534_REGISTER_INPUT, &bits, portMAX_DELAY);
+    if (err != ERROR_NONE) {
+        return err;
+    }
+
+    *high = (bits & (1 << descriptor->pin)) != 0;
+    return ERROR_NONE;
+}
+
+static error_t set_flags(GpioDescriptor* descriptor, gpio_flags_t flags) {
+    // The TCA9534 only supports direction and polarity inversion. Pull-up/down and
+    // high-impedance are not present in its register map.
+    if (flags & (GPIO_FLAG_PULL_UP | GPIO_FLAG_PULL_DOWN | GPIO_FLAG_HIGH_IMPEDANCE)) {
+        return ERROR_NOT_SUPPORTED;
+    }
+
+    // The polarity register only inverts what's read back from an input pin;
+    // set_level() still drives outputs at the raw level. Accepting ACTIVE_LOW
+    // on an output would silently not do what it implies.
+    if ((flags & GPIO_FLAG_ACTIVE_LOW) && (flags & GPIO_FLAG_DIRECTION_OUTPUT)) {
+        return ERROR_NOT_SUPPORTED;
+    }
+
+    auto* device = descriptor->controller;
+    auto* parent = device_get_parent(device);
+    auto address = GET_CONFIG(device)->address;
+    uint8_t bit = 1 << descriptor->pin;
+    error_t err;
+
+    // Direction: configuration bit is 1 for input, 0 for output.
+    if (flags & GPIO_FLAG_DIRECTION_OUTPUT) {
+        err = i2c_controller_register8_reset_bits(parent, address, TCA9534_REGISTER_CONFIG, bit, portMAX_DELAY);
+    } else {
+        err = i2c_controller_register8_set_bits(parent, address, TCA9534_REGISTER_CONFIG, bit, portMAX_DELAY);
+    }
+
+    if (err != ERROR_NONE) {
+        return err;
+    }
+
+    // Polarity inversion (mainly relevant for active-low inputs).
+    if (flags & GPIO_FLAG_ACTIVE_LOW) {
+        err = i2c_controller_register8_set_bits(parent, address, TCA9534_REGISTER_POLARITY, bit, portMAX_DELAY);
+    } else {
+        err = i2c_controller_register8_reset_bits(parent, address, TCA9534_REGISTER_POLARITY, bit, portMAX_DELAY);
+    }
+
+    return err;
+}
+
+static error_t get_flags(GpioDescriptor* descriptor, gpio_flags_t* flags) {
+    auto* device = descriptor->controller;
+    auto* parent = device_get_parent(device);
+    auto address = GET_CONFIG(device)->address;
+    uint8_t bit = 1 << descriptor->pin;
+    uint8_t val;
+    error_t err;
+
+    gpio_flags_t f = GPIO_FLAG_NONE;
+
+    err = i2c_controller_register8_get(parent, address, TCA9534_REGISTER_CONFIG, &val, portMAX_DELAY);
+    if (err != ERROR_NONE) return err;
+    f |= (val & bit) ? GPIO_FLAG_DIRECTION_INPUT : GPIO_FLAG_DIRECTION_OUTPUT;
+
+    err = i2c_controller_register8_get(parent, address, TCA9534_REGISTER_POLARITY, &val, portMAX_DELAY);
+    if (err != ERROR_NONE) return err;
+    f |= (val & bit) ? GPIO_FLAG_ACTIVE_LOW : GPIO_FLAG_ACTIVE_HIGH;
+
+    *flags = f;
+    return ERROR_NONE;
+}
+
+static error_t get_native_pin_number(GpioDescriptor* descriptor, void* pin_number) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static error_t add_callback(GpioDescriptor* descriptor, void (*callback)(void*), void* arg) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static error_t remove_callback(GpioDescriptor* descriptor) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static error_t enable_interrupt(GpioDescriptor* descriptor) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+static error_t disable_interrupt(GpioDescriptor* descriptor) {
+    return ERROR_NOT_SUPPORTED;
+}
+
+const static GpioControllerApi tca9534_gpio_api = {
+    .set_level = set_level,
+    .get_level = get_level,
+    .set_flags = set_flags,
+    .get_flags = get_flags,
+    .get_native_pin_number = get_native_pin_number,
+    .add_callback = add_callback,
+    .remove_callback = remove_callback,
+    .enable_interrupt = enable_interrupt,
+    .disable_interrupt = disable_interrupt
+};
+
+Driver tca9534_driver = {
+    .name = "tca9534",
+    .compatible = (const char*[]) { "ti,tca9534", nullptr },
+    .start_device = start,
+    .stop_device = stop,
+    .api = static_cast<const void*>(&tca9534_gpio_api),
+    .device_type = &GPIO_CONTROLLER_TYPE,
+    .owner = &tca9534_module,
+    .internal = nullptr
+};
+
+}