WIP display stuff that /could/ work, but i think my display is bad :(

main/display-init.cpp

@@ -0,0 +1,103 @@
+#include "display-init.hpp"
+
+namespace gay_ipod {
+namespace displays {
+
+/* Bit to use to signify we should delay after part of an init sequence */
+const uint8_t kDelayBit = 0x80;
+
+// ST7735 commands and general format from the Adafruit library for these
+// displays. AFAICT it's the most complete implementation out there, and I
+// really don't want to have to derive this from the datasheet myself.
+// See https://github.com/adafruit/Adafruit-ST7735-Library/
+
+// clang-format off
+static const 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
+};
+
+// Commands to include for the variant of the panel that has a green pull tab on
+// the screen protector.
+static const 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};
+
+// Commands to include for the variant of the panel that has a red pull tab on
+// the screen protector.
+static const uint8_t kST7735RCommonRed[]{
+    3,                           //  2 commands in list:
+    ST77XX_CASET,   4,           //  1: Column addr set, 4 args, no delay:
+      0x00, 0x00,                //     XSTART = 0
+      0x00, 0x7F,		 //     XEND = 127
+    ST77XX_RASET,   4,           //  2: Row addr set, 4 args, no delay:
+      0x00, 0x00,                //     XSTART = 0
+      0x00, 0x9F,
+    ST77XX_MADCTL,   1,
+      0xC0,
+};
+
+static const 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
+
+const InitialisationData kST7735R = {
+    .num_sequences = 3,
+    .sequences = {kST7735RCommonHeader, kST7735RCommonRed,
+                  kST7735RCommonFooter}};
+
+}  // namespace displays
+}  // namespace gay_ipod

main/display-init.hpp

@@ -0,0 +1,81 @@
+#pragma once
+
+#include <cstdint>
+
+namespace gay_ipod {
+namespace displays {
+
+extern const uint8_t kDelayBit;
+
+struct InitialisationData {
+  uint8_t num_sequences;
+  const uint8_t* sequences[4];
+};
+
+extern const InitialisationData kST7735R;
+
+/*
+ * Valid command bytes that can be sent to ST77XX displays, as well as commands
+ * for more specific variants.
+ */
+enum StCommands {
+  ST77XX_NOP = 0x00,
+  ST77XX_SWRESET = 0x01,
+  ST77XX_RDDID = 0x04,
+  ST77XX_RDDST = 0x09,
+
+  ST77XX_SLPIN = 0x10,
+  ST77XX_SLPOUT = 0x11,
+  ST77XX_PTLON = 0x12,
+  ST77XX_NORON = 0x13,
+
+  ST77XX_INVOFF = 0x20,
+  ST77XX_INVON = 0x21,
+  ST77XX_DISPOFF = 0x28,
+  ST77XX_DISPON = 0x29,
+  ST77XX_CASET = 0x2A,
+  ST77XX_RASET = 0x2B,
+  ST77XX_RAMWR = 0x2C,
+  ST77XX_RAMRD = 0x2E,
+
+  ST77XX_PTLAR = 0x30,
+  ST77XX_TEOFF = 0x34,
+  ST77XX_TEON = 0x35,
+  ST77XX_MADCTL = 0x36,
+  ST77XX_COLMOD = 0x3A,
+
+  ST77XX_MADCTL_MY = 0x80,
+  ST77XX_MADCTL_MX = 0x40,
+  ST77XX_MADCTL_MV = 0x20,
+  ST77XX_MADCTL_ML = 0x10,
+  ST77XX_MADCTL_RGB = 0x00,
+
+  ST77XX_RDID1 = 0xDA,
+  ST77XX_RDID2 = 0xDB,
+  ST77XX_RDID3 = 0xDC,
+  ST77XX_RDID4 = 0xDD,
+
+  ST7735_MADCTL_BGR = 0x08,
+  ST7735_MADCTL_MH = 0x04,
+
+  ST7735_FRMCTR1 = 0xB1,
+  ST7735_FRMCTR2 = 0xB2,
+  ST7735_FRMCTR3 = 0xB3,
+  ST7735_INVCTR = 0xB4,
+  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,
+};
+
+}  // namespace displays
+}  // namespace gay_ipod

main/display.cpp

@@ -96,9 +96,9 @@ auto Display::create(GpioExpander* expander,
       .duty_cycle_pos = 0,  // Unused
       .cs_ena_pretrans = 0,
       .cs_ena_posttrans = 0,
-      .clock_speed_hz = SPI_MASTER_FREQ_8M,
+      .clock_speed_hz = SPI_MASTER_FREQ_40M,
-      .input_delay_ns = 0,  // TODO: tune?
+      .input_delay_ns = 0,
-      .spics_io_num = -1,   // TODO: change for R2
+      .spics_io_num = -1,  // TODO: change for R2
       .flags = 0,
       .queue_size = kTransactionQueueSize,
       .pre_cb = NULL,
@@ -177,16 +177,17 @@ void Display::SendCommandWithData(uint8_t command,
 }
 
 void Display::SendCmd(const uint8_t* data, size_t length, uintptr_t flags) {
-  SendTransaction(data, length, flags | SEND_COMMAND);
+  SendTransaction(COMMAND, data, length, flags);
 }
 
 void Display::SendData(const uint8_t* data, size_t length, uintptr_t flags) {
-  SendTransaction(data, length, flags | SEND_DATA);
+  SendTransaction(DATA, data, length, flags);
 }
 
-void Display::SendTransaction(const uint8_t* data,
+void Display::SendTransaction(TransactionType type,
+                              const uint8_t* data,
                               size_t length,
-                              uintptr_t flags) {
+                              uint32_t flags) {
   if (length == 0) {
     return;
   }
@@ -200,15 +201,12 @@ void Display::SendTransaction(const uint8_t* data,
   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 * 8 <= 32) {
     transaction->flags = SPI_TRANS_USE_TXDATA;
     std::memcpy(&transaction->tx_data, data, length);
   } else {
-    assert((flags & SMALL) == 0);
     // TODO: copy data to a DMA-capable transaction buffer
     transaction->tx_buffer = const_cast<uint8_t*>(data);
   }
@@ -222,11 +220,7 @@ void Display::SendTransaction(const uint8_t* data,
   //
 
   ServiceTransactions();
-  if (flags & SEND_COMMAND) {
+  gpio_set_level(kCommandOrDataPin, type);
-    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);
@@ -242,29 +236,26 @@ void Display::SendTransaction(const uint8_t* data,
 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[0] = SPI_SWAP_DATA_TX(area->x1, 16);
-  data[1] = SPI_SWAP_DATA_TX(area->x2 + row_start, 16);
+  data[1] = SPI_SWAP_DATA_TX(area->x2, 16);
-  SendCommandWithData(displays::ST77XX_CASET, (uint8_t*)data, 4, SMALL);
+  SendCommandWithData(displays::ST77XX_CASET, (uint8_t*)data, 4);
 
-  data[0] = SPI_SWAP_DATA_TX(area->y1 + col_start, 16);
+  data[0] = SPI_SWAP_DATA_TX(area->y1, 16);
-  data[1] = SPI_SWAP_DATA_TX(area->y2 + col_start, 16);
+  data[1] = SPI_SWAP_DATA_TX(area->y2, 16);
-  SendCommandWithData(displays::ST77XX_RASET, (uint8_t*)data, 4, SMALL);
+  SendCommandWithData(displays::ST77XX_RASET, (uint8_t*)data, 4);
 
   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);
+                      LVGL_FLUSH);
 
   // 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) {
+  if (reinterpret_cast<uintptr_t>(transaction.user) & LVGL_FLUSH) {
     lv_disp_flush_ready(&driver_);
   }
 }

main/display.hpp

@@ -23,9 +23,11 @@ class Display {
   ~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();
@@ -38,11 +40,13 @@ class Display {
   lv_disp_drv_t driver_;
   lv_disp_t* display_ = nullptr;
 
-  enum TransactionData {
+  enum TransactionType {
-    SEND_COMMAND = (1 << 0),
+    COMMAND = 0,
-    SEND_DATA = (1 << 1),
+    DATA = 1,
-    FLUSH_BUFFER = (1 << 2),
+  };
-    SMALL = (1 << 3),
+
+  enum TransactionFlags {
+    LVGL_FLUSH = 1,
   };
 
   void SendInitialisationSequence(const uint8_t* data);
@@ -54,7 +58,10 @@ class Display {
 
   void SendCmd(const uint8_t* data, size_t length, uintptr_t flags = 0);
   void SendData(const uint8_t* data, size_t length, uintptr_t flags = 0);
-  void SendTransaction(const uint8_t* data, size_t length, uintptr_t flags = 0);
+  void SendTransaction(TransactionType type,
+                       const uint8_t* data,
+                       size_t length,
+                       uintptr_t flags = 0);
 };
 
 }  // namespace gay_ipod

main/gay-ipod-fw.cpp

@@ -191,7 +191,7 @@ extern "C" void app_main(void) {
 
   LvglArgs* lvglArgs = (LvglArgs*)calloc(1, sizeof(LvglArgs));
   lvglArgs->gpio_expander = expander;
-  xTaskCreateStaticPinnedToCore(&lvgl_main, "LVGL", 8 * 1024, (void*)lvglArgs,
+  xTaskCreateStaticPinnedToCore(&lvgl_main, "LVGL", kLvglStackSize, (void*)lvglArgs,
                                 1, sLvglStack, &sLvglTaskBuffer, 1);
 
   while (1) {