WIP most of a basic display driver + lvgl, but not yet working :(

lib/lv_conf.h

@@ -27,7 +27,7 @@
 #define LV_COLOR_DEPTH 16
 
 /*Swap the 2 bytes of RGB565 color. Useful if the display has an 8-bit interface (e.g. SPI)*/
-#define LV_COLOR_16_SWAP 0
+#define LV_COLOR_16_SWAP 1
 
 /*Enable features to draw on transparent background.
  *It's required if opa, and transform_* style properties are used.

main/CMakeLists.txt

@@ -1,15 +1,5 @@
-idf_component_register(SRCS
+idf_component_register(
-                       "gay-ipod-fw.cpp"
+  SRCS "gay-ipod-fw.cpp" "dac.cpp" "gpio-expander.cpp" "battery.cpp" "storage.cpp"
-                       "dac.cpp"
+  "i2c.cpp" "playback.cpp" "display.cpp" "display-init.cpp" 
-                       "gpio-expander.cpp"
+  INCLUDE_DIRS "."
-                       "battery.cpp"
+  REQUIRES "esp_adc_cal" "fatfs" "audio_pipeline" "audio_stream" "result" "lvgl")
-                       "storage.cpp"
-                       "i2c.cpp"
-                       "playback.cpp"
-                       "display.cpp" INCLUDE_DIRS "." REQUIRES
-                       "esp_adc_cal"
-                       "fatfs"
-                       "audio_pipeline"
-                       "audio_stream"
-                       "result"
-                       "lvgl")

main/display.cpp

@@ -1,155 +1,77 @@
 #include "display.hpp"
+#include <atomic>
 #include <cstdint>
 #include <cstring>
+#include <memory>
+#include <mutex>
+#include "assert.h"
+#include "display-init.hpp"
 #include "driver/gpio.h"
 #include "driver/spi_master.h"
+#include "esp_attr.h"
+#include "esp_heap_caps.h"
 #include "freertos/portable.h"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
 #include "hal/gpio_types.h"
 #include "hal/spi_types.h"
+#include "lvgl/lvgl.h"
 
-namespace gay_ipod {
+static const char* kTag = "DISPLAY";
-
 static const gpio_num_t kCommandOrDataPin = GPIO_NUM_21;
 static const gpio_num_t kLedPin = GPIO_NUM_22;
 
 static const uint8_t kDisplayWidth = 128;
 static const uint8_t kDisplayHeight = 160;
-static const uint8_t kDelayBit = 0x80;
+static const uint8_t kTransactionQueueSize = 10;
-
+
-enum StCommands {
+/*
-  ST77XX_NOP = 0x00,
+ * The size of each of our two display buffers. This is fundamentally a balance
-  ST77XX_SWRESET = 0x01,
+ * between performance and memory usage. LVGL docs recommend a buffer 1/10th the
-  ST77XX_RDDID = 0x04,
+ * size of the screen is the best tradeoff.
-  ST77XX_RDDST = 0x09,
+ * We use two buffers so that one can be flushed to the screen at the same time
-
+ * as the other is being drawn.
-  ST77XX_SLPIN = 0x10,
+ */
-  ST77XX_SLPOUT = 0x11,
+static const int kDisplayBufferSize = (kDisplayWidth * kDisplayHeight) / 10;
-  ST77XX_PTLON = 0x12,
+
-  ST77XX_NORON = 0x13,
+// Allocate both buffers in static memory to ensure that they're in DRAM, with
-
+// minimal fragmentation. We most cases we always need these buffers anyway, so
-  ST77XX_INVOFF = 0x20,
+// it's not a memory hit we can avoid anyway.
-  ST77XX_INVON = 0x21,
+// Note: 128 * 160 / 10 * 2 bpp * 2 buffers = 8 KiB
-  ST77XX_DISPOFF = 0x28,
+DMA_ATTR static lv_color_t sBuffer1[kDisplayBufferSize];
-  ST77XX_DISPON = 0x29,
+DMA_ATTR static lv_color_t sBuffer2[kDisplayBufferSize];
-  ST77XX_CASET = 0x2A,
+
-  ST77XX_RASET = 0x2B,
+namespace gay_ipod {
-  ST77XX_RAMWR = 0x2C,
+
-  ST77XX_RAMRD = 0x2E,
+// Static functions for interrop with the LVGL display driver API, which
-
+// requires a function pointer.
-  ST77XX_PTLAR = 0x30,
+namespace callback {
-  ST77XX_TEOFF = 0x34,
+static std::atomic<Display*> instance = nullptr;
-  ST77XX_TEON = 0x35,
+
-  ST77XX_MADCTL = 0x36,
+static void flush_cb(lv_disp_drv_t* disp_drv,
-  ST77XX_COLMOD = 0x3A,
+                     const lv_area_t* area,
-
+                     lv_color_t* color_map) {
-  ST77XX_MADCTL_MY = 0x80,
+  auto instance_unwrapped = instance.load();
-  ST77XX_MADCTL_MX = 0x40,
+  if (instance_unwrapped == nullptr) {
-  ST77XX_MADCTL_MV = 0x20,
+    ESP_LOGW(kTag, "uncaught flush callback");
-  ST77XX_MADCTL_ML = 0x10,
+    return;
-  ST77XX_MADCTL_RGB = 0x00,
+  }
-
+  // TODO: what if a transaction comes in right now?
-  ST77XX_RDID1 = 0xDA,
+  instance_unwrapped->Flush(disp_drv, area, color_map);
-  ST77XX_RDID2 = 0xDB,
+}
-  ST77XX_RDID3 = 0xDC,
+
-  ST77XX_RDID4 = 0xDD,
+static void IRAM_ATTR post_cb(spi_transaction_t* transaction) {
-
+  auto instance_unwrapped = instance.load();
-  ST7735_MADCTL_BGR = 0x08,
+  if (instance_unwrapped == nullptr) {
-  ST7735_MADCTL_MH = 0x04,
+    // Can't log in ISR.
-
+    return;
-  ST7735_FRMCTR1 = 0xB1,
+  }
-  ST7735_FRMCTR2 = 0xB2,
+  instance_unwrapped->PostTransaction(*transaction);
-  ST7735_FRMCTR3 = 0xB3,
+}
-  ST7735_INVCTR = 0xB4,
+}  // namespace callback
-  ST7735_DISSET5 = 0xB6,
-
-  ST7735_PWCTR1 = 0xC0,
-  ST7735_PWCTR2 = 0xC1,
-  ST7735_PWCTR3 = 0xC2,
-  ST7735_PWCTR4 = 0xC3,
-  ST7735_PWCTR5 = 0xC4,
-  ST7735_VMCTR1 = 0xC5,
-
-  ST7735_PWCTR6 = 0xFC,
-
-  ST7735_GMCTRP1 = 0xE0,
-  ST7735_GMCTRN1 = 0xE1,
-};
-
-// Based on Adafruit library, which seems to be the most complete.
-// clang-format off
-static uint8_t kST7735RCommonHeader[]{
-    15,                          // 15 commands in list:
-    ST77XX_SWRESET,   kDelayBit, //  1: Software reset, 0 args, w/delay
-      150,                       //     150 ms delay
-    ST77XX_SLPOUT,    kDelayBit, //  2: Out of sleep mode, 0 args, w/delay
-      255,                       //     500 ms delay
-    ST7735_FRMCTR1, 3,           //  3: Framerate ctrl - normal mode, 3 arg:
-      0x01, 0x2C, 0x2D,          //     Rate = fosc/(1x2+40) * (LINE+2C+2D)
-    ST7735_FRMCTR2, 3,           //  4: Framerate ctrl - idle mode, 3 args:
-      0x01, 0x2C, 0x2D,          //     Rate = fosc/(1x2+40) * (LINE+2C+2D)
-    ST7735_FRMCTR3, 6,           //  5: Framerate - partial mode, 6 args:
-      0x01, 0x2C, 0x2D,          //     Dot inversion mode
-      0x01, 0x2C, 0x2D,          //     Line inversion mode
-    ST7735_INVCTR,  1,           //  6: Display inversion ctrl, 1 arg:
-      0x07,                      //     No inversion
-    ST7735_PWCTR1,  3,           //  7: Power control, 3 args, no delay:
-      0xA2,
-      0x02,                      //     -4.6V
-      0x84,                      //     AUTO mode
-    ST7735_PWCTR2,  1,           //  8: Power control, 1 arg, no delay:
-      0xC5,                      //     VGH25=2.4C VGSEL=-10 VGH=3 * AVDD
-    ST7735_PWCTR3,  2,           //  9: Power control, 2 args, no delay:
-      0x0A,                      //     Opamp current small
-      0x00,                      //     Boost frequency
-    ST7735_PWCTR4,  2,           // 10: Power control, 2 args, no delay:
-      0x8A,                      //     BCLK/2,
-      0x2A,                      //     opamp current small & medium low
-    ST7735_PWCTR5,  2,           // 11: Power control, 2 args, no delay:
-      0x8A, 0xEE,
-    ST7735_VMCTR1,  1,           // 12: Power control, 1 arg, no delay:
-      0x0E,
-    ST77XX_INVOFF,  0,           // 13: Don't invert display, no args
-    ST77XX_MADCTL,  1,           // 14: Mem access ctl (directions), 1 arg:
-      0xC8,                      //     row/col addr, bottom-top refresh
-    ST77XX_COLMOD,  1,           // 15: set color mode, 1 arg, no delay:
-      0x05
-};
-
-static uint8_t kST7735RCommonGreen[]{
-    2,                           //  2 commands in list:
-    ST77XX_CASET,   4,           //  1: Column addr set, 4 args, no delay:
-      0x00, 0x02,                //     XSTART = 0
-      0x00, 0x7F+0x02,           //     XEND = 127
-    ST77XX_RASET,   4,           //  2: Row addr set, 4 args, no delay:
-      0x00, 0x01,                //     XSTART = 0
-      0x00, 0x9F+0x01};
-
-static uint8_t kST7735RCommonFooter[]{
-    4,                           //  4 commands in list:
-    ST7735_GMCTRP1, 16      ,    //  1: Gamma Adjustments (pos. polarity), 16 args + delay:
-      0x02, 0x1c, 0x07, 0x12,    //     (Not entirely necessary, but provides
-      0x37, 0x32, 0x29, 0x2d,    //      accurate colors)
-      0x29, 0x25, 0x2B, 0x39,
-      0x00, 0x01, 0x03, 0x10,
-    ST7735_GMCTRN1, 16      ,    //  2: Gamma Adjustments (neg. polarity), 16 args + delay:
-      0x03, 0x1d, 0x07, 0x06,    //     (Not entirely necessary, but provides
-      0x2E, 0x2C, 0x29, 0x2D,    //      accurate colors)
-      0x2E, 0x2E, 0x37, 0x3F,
-      0x00, 0x00, 0x02, 0x10,
-    ST77XX_NORON,     kDelayBit, //  3: Normal display on, no args, w/delay
-      10,                           //     10 ms delay
-    ST77XX_DISPON,    kDelayBit, //  4: Main screen turn on, no args w/delay
-      100
-};
-// clang-format on
-
-InitialisationData kInitData = {
-    .num_sequences = 3,
-    .sequences = {kST7735RCommonHeader, kST7735RCommonGreen,
-                  kST7735RCommonFooter}};
 
 auto Display::create(GpioExpander* expander,
-                     const InitialisationData& init_data)
+                     const displays::InitialisationData& init_data)
     -> cpp::result<std::unique_ptr<Display>, Error> {
   // First, set up our GPIOs
   gpio_config_t gpio_cfg = {
@@ -165,7 +87,6 @@ auto Display::create(GpioExpander* expander,
   gpio_set_level(kCommandOrDataPin, 0);
 
   // Next, init the SPI device
-  auto lock = expander->AcquireSpiBus(GpioExpander::DISPLAY);
   spi_device_interface_config_t spi_cfg = {
       .command_bits = 0,  // No command phase
       .address_bits = 0,  // No address phase
@@ -175,46 +96,64 @@ auto Display::create(GpioExpander* expander,
       .duty_cycle_pos = 0,  // Unused
       .cs_ena_pretrans = 0,
       .cs_ena_posttrans = 0,
-      .clock_speed_hz = SPI_MASTER_FREQ_40M,
+      .clock_speed_hz = SPI_MASTER_FREQ_8M,
       .input_delay_ns = 0,  // TODO: tune?
       .spics_io_num = -1,   // TODO: change for R2
       .flags = 0,
-      .queue_size = 0,
+      .queue_size = kTransactionQueueSize,
       .pre_cb = NULL,
-      .post_cb = NULL,
+      .post_cb = &callback::post_cb,
   };
   spi_device_handle_t handle;
   spi_bus_add_device(VSPI_HOST, &spi_cfg, &handle);
 
+  // TODO: ideally create this later? a bit awkward rn.
   auto display = std::make_unique<Display>(expander, handle);
 
   // Now we reset the display into a known state, then configure it
-  // setRotation
+  // TODO: set rotatoin
+  ESP_LOGI(kTag, "Sending init sequences");
   for (int i = 0; i < init_data.num_sequences; i++) {
     display->SendInitialisationSequence(init_data.sequences[i]);
   }
 
+  // The hardware is now configured correctly. Next, initialise the LVGL display
+  // driver.
+  ESP_LOGI(kTag, "Init buffers");
+  lv_disp_draw_buf_init(&display->buffers_, sBuffer1, sBuffer2,
+                        kDisplayBufferSize);
+  lv_disp_drv_init(&display->driver_);
+  display->driver_.draw_buf = &display->buffers_;
+  display->driver_.hor_res = kDisplayWidth;
+  display->driver_.ver_res = kDisplayHeight;
+  display->driver_.flush_cb = &callback::flush_cb;
+
+  ESP_LOGI(kTag, "Registering driver");
+  display->display_ = lv_disp_drv_register(&display->driver_);
+
   return std::move(display);
 }
 
 Display::Display(GpioExpander* gpio, spi_device_handle_t handle)
-    : gpio_(gpio), handle_(handle) {}
+    : gpio_(gpio), handle_(handle) {
+  callback::instance = this;
+}
 
 Display::~Display() {
+  callback::instance = nullptr;
   // TODO.
 }
 
-void Display::SendInitialisationSequence(uint8_t* data) {
+void Display::SendInitialisationSequence(const uint8_t* data) {
-  uint8_t commands_remaining, command, num_args;
+  uint8_t command, num_args;
   uint16_t sleep_duration_ms;
 
   // First byte of the data is the number of commands.
-  commands_remaining = *data;
+  for (int i = *(data++); i > 0; i--) {
-  while (commands_remaining > 0) {
     command = *(data++);
     num_args = *(data++);
-    bool has_delay = (num_args & kDelayBit) > 0;
+    bool has_delay = (num_args & displays::kDelayBit) > 0;
-    num_args &= ~kDelayBit;
+    num_args &= ~displays::kDelayBit;
 
     SendCommandWithData(command, data, num_args);
 
@@ -230,47 +169,126 @@ void Display::SendInitialisationSequence(uint8_t* data) {
 }
 
 void Display::SendCommandWithData(uint8_t command,
-                                  uint8_t* data,
+                                  const uint8_t* data,
-                                  size_t length) {
+                                  size_t length,
-  gpio_set_level(kCommandOrDataPin, 0);
+                                  uintptr_t flags) {
-  SendTransaction(&command, 1);
+  SendCmd(&command, 1, flags);
-  gpio_set_level(kCommandOrDataPin, 1);
+  SendData(data, length, flags);
-  SendTransaction(data, length);
 }
 
-void Display::SendCmd(uint8_t* data, size_t length) {
+void Display::SendCmd(const uint8_t* data, size_t length, uintptr_t flags) {
-  gpio_set_level(kCommandOrDataPin, 0);
+  SendTransaction(data, length, flags | SEND_COMMAND);
-  SendTransaction(data, length);
 }
 
-void Display::SendData(uint8_t* data, size_t length) {
+void Display::SendData(const uint8_t* data, size_t length, uintptr_t flags) {
-  gpio_set_level(kCommandOrDataPin, 1);
+  SendTransaction(data, length, flags | SEND_DATA);
-  SendTransaction(data, length);
 }
 
-void Display::SendTransaction(uint8_t* data, size_t length) {
+void Display::SendTransaction(const uint8_t* data,
+                              size_t length,
+                              uintptr_t flags) {
   if (length == 0) {
     return;
   }
 
-  // TODO: Check if we should malloc this from DMA-capable memory.
+  // TODO: Use a memory pool for these.
-  spi_transaction_t transaction;
+  spi_transaction_t* transaction = (spi_transaction_t*)heap_caps_calloc(
-  transaction.rx_buffer = NULL;
+      1, sizeof(spi_transaction_t), MALLOC_CAP_DMA);
+
+  transaction->rx_buffer = NULL;
   // Length is in bits, so multiply by 8.
-  transaction.length = length * 8;
+  transaction->length = length * 8;
+  transaction->rxlength = 0;  // Match `length` value.
+
+  transaction->user = nullptr;  // TODO.
 
   // If the data to transmit is very short, then we can fit it directly
   // inside the transaction struct.
-  if (length < 4) {
+  if (length * 8 <= 32) {
-    transaction.flags = SPI_TRANS_USE_TXDATA;
+    transaction->flags = SPI_TRANS_USE_TXDATA;
-    std::memcpy(&transaction.tx_data, data, length);
+    std::memcpy(&transaction->tx_data, data, length);
   } else {
-    transaction.tx_buffer = data;
+    assert((flags & SMALL) == 0);
+    // TODO: copy data to a DMA-capable transaction buffer
+    transaction->tx_buffer = const_cast<uint8_t*>(data);
   }
 
+  transaction->user = reinterpret_cast<void*>(flags);
+
   // TODO: acquire the bus first? Or in an outer scope?
   // TODO: fail gracefully
-  ESP_ERROR_CHECK(spi_device_polling_transmit(handle_, &transaction));
+  // ESP_ERROR_CHECK(spi_device_queue_trans(handle_, transaction,
+  // portMAX_DELAY));
+  //
+
+  ServiceTransactions();
+  if (flags & SEND_COMMAND) {
+    gpio_set_level(kCommandOrDataPin, 0);
+  } else if (flags & SEND_DATA) {
+    gpio_set_level(kCommandOrDataPin, 1);
+  }
+
+  gpio_->with([&](auto& gpio_) {
+    gpio_.set_pin(GpioExpander::DISPLAY_CHIP_SELECT, 0);
+  });
+  {
+    // auto lock = gpio_->AcquireSpiBus(GpioExpander::DISPLAY);
+    ESP_ERROR_CHECK(spi_device_polling_transmit(handle_, transaction));
+  }
+
+  free(transaction);
+}
+
+void Display::Flush(lv_disp_drv_t* disp_drv,
+                    const lv_area_t* area,
+                    lv_color_t* color_map) {
+  // TODO: constants? based on init sequence?
+  uint16_t col_start = 2;
+  uint16_t row_start = 1;
+  uint16_t data[2] = {0, 0};
+
+  data[0] = SPI_SWAP_DATA_TX(area->x1 + row_start, 16);
+  data[1] = SPI_SWAP_DATA_TX(area->x2 + row_start, 16);
+  SendCommandWithData(displays::ST77XX_CASET, (uint8_t*)data, 4, SMALL);
+
+  data[0] = SPI_SWAP_DATA_TX(area->y1 + col_start, 16);
+  data[1] = SPI_SWAP_DATA_TX(area->y2 + col_start, 16);
+  SendCommandWithData(displays::ST77XX_RASET, (uint8_t*)data, 4, SMALL);
+
+  uint32_t size = lv_area_get_width(area) * lv_area_get_height(area);
+  SendCommandWithData(displays::ST77XX_RAMWR, (uint8_t*)color_map, size * 2,
+                      FLUSH_BUFFER);
+
+  // ESP_LOGI(kTag, "finished flush.");
+  // lv_disp_flush_ready(&driver_);
+}
+
+void IRAM_ATTR Display::PostTransaction(const spi_transaction_t& transaction) {
+  if (reinterpret_cast<uintptr_t>(transaction.user) & FLUSH_BUFFER) {
+    lv_disp_flush_ready(&driver_);
+  }
+}
+
+void Display::ServiceTransactions() {
+  // todo
+  if (1)
+    return;
+  spi_transaction_t* transaction = nullptr;
+  // TODO: just wait '1' here, provide mechanism to wait for sure (poll?)
+  while (spi_device_get_trans_result(handle_, &transaction, pdMS_TO_TICKS(1)) !=
+         ESP_ERR_TIMEOUT) {
+    ESP_LOGI(kTag, "cleaning up finished transaction");
+
+    // TODO: a bit dodge lmao
+    // TODO: also this should happen in the post callback instead i guess?
+    if (transaction->length > 1000) {
+      ESP_LOGI(kTag, "finished flush.");
+      lv_disp_flush_ready(&driver_);
+    }
+
+    // TODO: place back into pool.
+    free(transaction);
+  }
 }
 
 }  // namespace gay_ipod

main/display.hpp

@@ -1,21 +1,14 @@
 #pragma once
 
 #include <cstdint>
+#include "display-init.hpp"
 #include "driver/spi_master.h"
 #include "gpio-expander.hpp"
+#include "lvgl/lvgl.h"
 #include "result.hpp"
 
-// https://github.com/adafruit/Adafruit-ST7735-Library/blob/master/Adafruit_ST77xx.cpp
-// https://github.com/adafruit/Adafruit-ST7735-Library/blob/master/Adafruit_ST7735.cpp
 namespace gay_ipod {
 
-struct InitialisationData {
-  uint8_t num_sequences;
-  uint8_t* sequences[4];
-};
-
-extern InitialisationData kInitData;
-
 /*
  * Display driver for LVGL.
  */
@@ -23,25 +16,45 @@ class Display {
  public:
   enum Error {};
   static auto create(GpioExpander* expander,
-                     const InitialisationData& init_data)
+                     const displays::InitialisationData& init_data)
       -> cpp::result<std::unique_ptr<Display>, Error>;
 
   Display(GpioExpander* gpio, spi_device_handle_t handle);
   ~Display();
 
   void WriteData();
+  void Flush(lv_disp_drv_t* disp_drv,
+             const lv_area_t* area,
+             lv_color_t* color_map);
+  void IRAM_ATTR PostTransaction(const spi_transaction_t& transaction);
+
+  void ServiceTransactions();
 
  private:
   GpioExpander* gpio_;
   spi_device_handle_t handle_;
 
-  void SendInitialisationSequence(uint8_t* data);
+  lv_disp_draw_buf_t buffers_;
+  lv_disp_drv_t driver_;
+  lv_disp_t* display_ = nullptr;
+
+  enum TransactionData {
+    SEND_COMMAND = (1 << 0),
+    SEND_DATA = (1 << 1),
+    FLUSH_BUFFER = (1 << 2),
+    SMALL = (1 << 3),
+  };
+
+  void SendInitialisationSequence(const uint8_t* data);
 
-  void SendCommandWithData(uint8_t command, uint8_t* data, size_t length);
+  void SendCommandWithData(uint8_t command,
+                           const uint8_t* data,
+                           size_t length,
+                           uintptr_t flags = 0);
 
-  void SendCmd(uint8_t* data, size_t length);
+  void SendCmd(const uint8_t* data, size_t length, uintptr_t flags = 0);
-  void SendData(uint8_t* data, size_t length);
+  void SendData(const uint8_t* data, size_t length, uintptr_t flags = 0);
-  void SendTransaction(uint8_t* data, size_t length);
+  void SendTransaction(const uint8_t* data, size_t length, uintptr_t flags = 0);
 };
 
 }  // namespace gay_ipod

main/gay-ipod-fw.cpp

@@ -1,12 +1,20 @@
 #include "battery.hpp"
+#include "core/lv_disp.h"
+#include "core/lv_obj_pos.h"
 #include "dac.hpp"
+#include "display-init.hpp"
 #include "display.hpp"
+#include "esp_freertos_hooks.h"
+#include "freertos/portmacro.h"
 #include "gpio-expander.hpp"
+#include "misc/lv_color.h"
+#include "misc/lv_timer.h"
 #include "playback.hpp"
 #include "storage.hpp"
 
 #include <dirent.h>
 #include <stdio.h>
+#include <cstddef>
 #include <cstdint>
 #include <memory>
 
@@ -23,6 +31,7 @@
 #include "hal/gpio_types.h"
 #include "hal/spi_types.h"
 #include "lvgl/lvgl.h"
+#include "widgets/lv_label.h"
 
 #define I2C_SDA_IO (GPIO_NUM_2)
 #define I2C_SCL_IO (GPIO_NUM_4)
@@ -74,8 +83,9 @@ esp_err_t init_spi(void) {
       .data6_io_num = -1,
       .data7_io_num = -1,
 
-      // Use the DMA default size.
+      // Use the DMA default size. The display requires larger buffers, but it
-      .max_transfer_sz = 0,
+      // manages its down use of DMA-capable memory.
+      .max_transfer_sz = 128 * 16 * 2,  // TODO: hmm
       .flags = SPICOMMON_BUSFLAG_MASTER | SPICOMMON_BUSFLAG_IOMUX_PINS,
       .intr_flags = 0,
   };
@@ -85,6 +95,56 @@ esp_err_t init_spi(void) {
   return ESP_OK;
 }
 
+void IRAM_ATTR tick_hook(void) {
+  lv_tick_inc(1);
+}
+
+static const size_t kLvglStackSize = 8 * 1024;
+static StaticTask_t sLvglTaskBuffer = {};
+static StackType_t sLvglStack[kLvglStackSize] = {0};
+
+struct LvglArgs {
+  gay_ipod::GpioExpander* gpio_expander;
+};
+
+void lvgl_main(void* voidArgs) {
+  ESP_LOGI(TAG, "starting LVGL task");
+  LvglArgs* args = (LvglArgs*)voidArgs;
+  gay_ipod::GpioExpander* gpio_expander = args->gpio_expander;
+
+  // Dispose of the args now that we've gotten everything out of them.
+  delete args;
+
+  ESP_LOGI(TAG, "init lvgl");
+  lv_init();
+
+  // LVGL has been initialised, so we can now start reporting ticks to it.
+  esp_register_freertos_tick_hook(&tick_hook);
+
+  ESP_LOGI(TAG, "init display");
+  auto display_res =
+      gay_ipod::Display::create(gpio_expander, gay_ipod::displays::kST7735R);
+  if (display_res.has_error()) {
+    ESP_LOGE(TAG, "Failed: %d", display_res.error());
+    return;
+  }
+  std::unique_ptr<gay_ipod::Display> display = std::move(display_res.value());
+
+  auto label = lv_label_create(NULL);
+  lv_label_set_text(label, "g'day, cunts!");
+  lv_obj_center(label);
+  lv_scr_load(label);
+
+  while (1) {
+    lv_timer_handler();
+    // display->ServiceTransactions();
+    vTaskDelay(pdMS_TO_TICKS(10));
+  }
+
+  // TODO: break from the loop to kill this task, so that we can do our RAII
+  // cleanup, unregister our tick callback and so on.
+}
+
 extern "C" void app_main(void) {
   ESP_LOGI(TAG, "Initialising peripherals");
 
@@ -94,13 +154,14 @@ extern "C" void app_main(void) {
   ESP_ERROR_CHECK(gay_ipod::init_adc());
 
   ESP_LOGI(TAG, "Init GPIOs");
-  gay_ipod::GpioExpander expander;
+  gay_ipod::GpioExpander* expander = new gay_ipod::GpioExpander();
 
   // for debugging usb ic
   // expander.set_sd_mux(gay_ipod::GpioExpander::USB);
 
+  /*
   ESP_LOGI(TAG, "Init SD card");
-  auto storage_res = gay_ipod::SdStorage::create(&expander);
+  auto storage_res = gay_ipod::SdStorage::create(expander);
   if (storage_res.has_error()) {
     ESP_LOGE(TAG, "Failed: %d", storage_res.error());
     return;
@@ -108,7 +169,7 @@ extern "C" void app_main(void) {
   std::unique_ptr<gay_ipod::SdStorage> storage = std::move(storage_res.value());
 
   ESP_LOGI(TAG, "Init DAC");
-  auto dac_res = gay_ipod::AudioDac::create(&expander);
+  auto dac_res = gay_ipod::AudioDac::create(expander);
   if (storage_res.has_error()) {
     ESP_LOGE(TAG, "Failed: %d", dac_res.error());
     return;
@@ -123,19 +184,18 @@ extern "C" void app_main(void) {
   }
   std::unique_ptr<gay_ipod::DacAudioPlayback> playback =
       std::move(playback_res.value());
+  */
 
   ESP_LOGI(TAG, "Everything looks good! Waiting a mo for debugger.");
   vTaskDelay(pdMS_TO_TICKS(1500));
 
-  ESP_LOGI(TAG, "Init Display");
+  LvglArgs* lvglArgs = (LvglArgs*)calloc(1, sizeof(LvglArgs));
-  auto display_res = gay_ipod::Display::create(&expander, gay_ipod::kInitData);
+  lvglArgs->gpio_expander = expander;
-  if (display_res.has_error()) {
+  xTaskCreateStaticPinnedToCore(&lvgl_main, "LVGL", 8 * 1024, (void*)lvglArgs,
-    ESP_LOGE(TAG, "Failed: %d", display_res.error());
+                                1, sLvglStack, &sLvglTaskBuffer, 1);
-    return;
-  }
-  std::unique_ptr<gay_ipod::Display> display = std::move(display_res.value());
-
-  ESP_LOGI(TAG, "Time to deinit.");
 
-  ESP_LOGI(TAG, "Hooray!");
+  while (1) {
+    // TODO: Find owners for everything so we can quit this task safely.
+    vTaskDelay(pdMS_TO_TICKS(1000));
+  }
 }

sdkconfig

@@ -411,11 +411,12 @@ CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1=y
 # CONFIG_ESP32_TIME_SYSCALL_USE_RTC is not set
 # CONFIG_ESP32_TIME_SYSCALL_USE_FRC1 is not set
 # CONFIG_ESP32_TIME_SYSCALL_USE_NONE is not set
-CONFIG_ESP32_RTC_CLK_SRC_INT_RC=y
+# CONFIG_ESP32_RTC_CLK_SRC_INT_RC is not set
-# CONFIG_ESP32_RTC_CLK_SRC_EXT_CRYS is not set
+CONFIG_ESP32_RTC_CLK_SRC_EXT_CRYS=y
 # CONFIG_ESP32_RTC_CLK_SRC_EXT_OSC is not set
 # CONFIG_ESP32_RTC_CLK_SRC_INT_8MD256 is not set
 CONFIG_ESP32_RTC_CLK_CAL_CYCLES=1024
+CONFIG_ESP32_RTC_XTAL_CAL_RETRY=1
 CONFIG_ESP32_DEEP_SLEEP_WAKEUP_DELAY=2000
 CONFIG_ESP32_XTAL_FREQ_40=y
 # CONFIG_ESP32_XTAL_FREQ_26 is not set
@@ -598,6 +599,8 @@ CONFIG_ESP_SYSTEM_PANIC_PRINT_REBOOT=y
 # CONFIG_ESP_SYSTEM_PANIC_SILENT_REBOOT is not set
 # CONFIG_ESP_SYSTEM_PANIC_GDBSTUB is not set
 # CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME is not set
+CONFIG_ESP_SYSTEM_RTC_EXT_XTAL=y
+CONFIG_ESP_SYSTEM_RTC_EXT_XTAL_BOOTSTRAP_CYCLES=5
 
 #
 # Memory protection
@@ -624,7 +627,7 @@ CONFIG_ESP_INT_WDT_TIMEOUT_MS=300
 CONFIG_ESP_INT_WDT_CHECK_CPU1=y
 CONFIG_ESP_TASK_WDT=y
 # CONFIG_ESP_TASK_WDT_PANIC is not set
-CONFIG_ESP_TASK_WDT_TIMEOUT_S=5
+CONFIG_ESP_TASK_WDT_TIMEOUT_S=10
 CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU0=y
 CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1=y
 # CONFIG_ESP_PANIC_HANDLER_IRAM is not set
@@ -1712,8 +1715,8 @@ CONFIG_BROWNOUT_DET_LVL_SEL_0=y
 # CONFIG_BROWNOUT_DET_LVL_SEL_6 is not set
 # CONFIG_BROWNOUT_DET_LVL_SEL_7 is not set
 CONFIG_BROWNOUT_DET_LVL=0
-CONFIG_ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC=y
+# CONFIG_ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC is not set
-# CONFIG_ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL is not set
+CONFIG_ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL=y
 # CONFIG_ESP32_RTC_CLOCK_SOURCE_EXTERNAL_OSC is not set
 # CONFIG_ESP32_RTC_CLOCK_SOURCE_INTERNAL_8MD256 is not set
 # CONFIG_DISABLE_BASIC_ROM_CONSOLE is not set
@@ -1736,6 +1739,7 @@ CONFIG_ESP32_REDUCE_PHY_TX_POWER=y
 CONFIG_ESP32S2_PANIC_PRINT_REBOOT=y
 # CONFIG_ESP32S2_PANIC_SILENT_REBOOT is not set
 # CONFIG_ESP32S2_PANIC_GDBSTUB is not set
+CONFIG_ESP32_RTC_XTAL_BOOTSTRAP_CYCLES=5
 CONFIG_SYSTEM_EVENT_QUEUE_SIZE=32
 CONFIG_SYSTEM_EVENT_TASK_STACK_SIZE=2304
 CONFIG_MAIN_TASK_STACK_SIZE=3584
@@ -1750,7 +1754,7 @@ CONFIG_INT_WDT_TIMEOUT_MS=300
 CONFIG_INT_WDT_CHECK_CPU1=y
 CONFIG_TASK_WDT=y
 # CONFIG_TASK_WDT_PANIC is not set
-CONFIG_TASK_WDT_TIMEOUT_S=5
+CONFIG_TASK_WDT_TIMEOUT_S=10
 CONFIG_TASK_WDT_CHECK_IDLE_TASK_CPU0=y
 CONFIG_TASK_WDT_CHECK_IDLE_TASK_CPU1=y
 # CONFIG_ESP32_DEBUG_STUBS_ENABLE is not set