pw_display_driver_ili9341/display_driver.cc - pigweed/experimental - Git at Google

 // Copyright 2022 The Pigweed Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
 // use this file except in compliance with the License. You may obtain a copy of
 // the License at
 //
 //     https://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.

 #include "pw_display_driver_ili9341/display_driver.h"

 #include <algorithm>

 #include "pw_chrono/system_clock.h"
 #include "pw_digital_io/digital_io.h"
 #include "pw_framebuffer/framebuffer.h"
 #include "pw_thread/sleep.h"

 using pw::digital_io::State;
 using pw::framebuffer::Framebuffer;
 using pw::framebuffer::PixelFormat;
 using pw::spi::ChipSelectBehavior;
 using pw::spi::Device;

 namespace pw::display_driver {

 namespace {

 constexpr std::array<std::byte, 0> kEmptyByteArray = {};

 // clang-format off
 // Level 1 commands:
 constexpr uint8_t CMD_SWRESET            = 0x01;   // Software Reset.
 constexpr uint8_t CMD_READ_DISPLAY_ID    = 0x04;   // Read display identification information.
 constexpr uint8_t CMD_RDDST              = 0x09;   // Read Display Status.
 constexpr uint8_t CMD_RDDPM              = 0x0A;   // Read Display Power Mode.
 constexpr uint8_t CMD_RDDMADCTL          = 0x0B;   // Read Display MADCTL.
 constexpr uint8_t CMD_RDDCOLMOD          = 0x0C;   // Read Display Pixel Format.
 constexpr uint8_t CMD_RDDIM              = 0x0D;   // Read Display Image Format.
 constexpr uint8_t CMD_RDDSM              = 0x0E;   // Read Display Signal Mode.
 constexpr uint8_t CMD_RDDSDR             = 0x0F;   // Read Display Self-Diagnostic Result.
 constexpr uint8_t CMD_SPLIN              = 0x10;   // Enter Sleep Mode.
 constexpr uint8_t CMD_SLEEP_OUT          = 0x11;   // Sleep Out.
 constexpr uint8_t CMD_PTLON              = 0x12;   // Partial Mode ON.
 constexpr uint8_t CMD_NORMAL_MODE_ON     = 0x13;   // Normal Display Mode ON.
 constexpr uint8_t CMD_DINVOFF            = 0x20;   // Display Inversion OFF.
 constexpr uint8_t CMD_DINVON             = 0x21;   // Display Inversion ON.
 constexpr uint8_t CMD_GAMMA              = 0x26;   // Gamma Set.
 constexpr uint8_t CMD_DISPLAY_OFF        = 0x28;   // Display OFF.
 constexpr uint8_t CMD_DISPLAY_ON         = 0x29;   // Display ON.
 constexpr uint8_t CMD_COLUMN_ADDR        = 0x2A;   // Column Address Set.
 constexpr uint8_t CMD_PAGE_ADDR          = 0x2B;   // Page Address Set.
 constexpr uint8_t CMD_GRAM               = 0x2C;   // Memory Write.
 constexpr uint8_t CMD_RGBSET             = 0x2D;   // Color Set.
 constexpr uint8_t CMD_RAMRD              = 0x2E;   // Memory Read.
 constexpr uint8_t CMD_PLTAR              = 0x30;   // Partial Area.
 constexpr uint8_t CMD_VSCRDEF            = 0x33;   // Vertical Scrolling Definition.
 constexpr uint8_t CMD_TEOFF              = 0x34;   // Tearing Effect Line OFF.
 constexpr uint8_t CMD_TEON               = 0x35;   // Tearing Effect Line ON.
 constexpr uint8_t CMD_MADCTL             = 0x36;   // Memory Access Control.
 constexpr uint8_t CMD_VSCRSADD           = 0x37;   // Vertical Scrolling Start Address.
 constexpr uint8_t CMD_IDMOFF             = 0x38;   // Idle Mode OFF.
 constexpr uint8_t CMD_IDMON              = 0x39;   // Idle Mode ON.
 constexpr uint8_t CMD_PIXEL_FORMAT       = 0x3A;   // COLMOD: Pixel Format Set.
 constexpr uint8_t CMD_WRITE_MEM_CONTINUE = 0x3C;   // Write_Memory_Continue.
 constexpr uint8_t CMD_READ_MEM_CONTINUE  = 0x3E;   // Read_Memory_Continue.
 constexpr uint8_t CMD_SET_TEAR_SCANLINE  = 0x44;   // Set_Tear_Scanline.
 constexpr uint8_t CMD_GET_SCANLINE       = 0x45;   // Get_Scanline.
 constexpr uint8_t CMD_WDB                = 0x51;   // Write Display Brightness.
 constexpr uint8_t CMD_RDDISBV            = 0x52;   // Read Display Brightness.
 constexpr uint8_t CMD_WCD                = 0x53;   // Write CTRL Display.
 constexpr uint8_t CMD_RDCTRLD            = 0x54;   // Read CTRL Display.
 constexpr uint8_t CMD_WRCABC             = 0x55;   // Write Content Adaptive Brightness Control.
 constexpr uint8_t CMD_RDCABC             = 0x56;   // Read Content Adaptive Brightness Control.
 constexpr uint8_t CMD_WRITE_CABC         = 0x5E;   // Write CABC Minimum Brightness.
 constexpr uint8_t CMD_READ_CABC          = 0x5F;   // Read CABC Minimum Brightness.
 constexpr uint8_t CMD_READ_ID1           = 0xDA;   // Read ID1.
 constexpr uint8_t CMD_READ_ID2           = 0xDB;   // Read ID2.
 constexpr uint8_t CMD_READ_ID3           = 0xDC;   // Read ID3.

 // Level 2 commands:
 constexpr uint8_t CMD_RGB_INTERFACE      = 0xB0;   // RGB Interface Signal Control.
 constexpr uint8_t CMD_FRMCTR1            = 0xB1;   // Frame Rate Control (In Normal Mode/Full Colors.
 constexpr uint8_t CMD_FRMCTR2            = 0xB2;   // Frame Rate Control (In Idle Mode/8 colors).
 constexpr uint8_t CMD_FRMCTR3            = 0xB3;   // Frame Rate control (In Partial Mode/Full Colors).
 constexpr uint8_t CMD_INVTR              = 0xB4;   // Display Inversion Control.
 constexpr uint8_t CMD_BPC                = 0xB5;   // Blanking Porch Control.
 constexpr uint8_t CMD_DFC                = 0xB6;   // Display Function Control.
 constexpr uint8_t CMD_ETMOD              = 0xB7;   // Entry Mode Set.
 constexpr uint8_t CMD_BACKLIGHT1         = 0xB8;   // Backlight Control 1.
 constexpr uint8_t CMD_BACKLIGHT2         = 0xB9;   // Backlight Control 2.
 constexpr uint8_t CMD_BACKLIGHT3         = 0xBA;   // Backlight Control 3.
 constexpr uint8_t CMD_BACKLIGHT4         = 0xBB;   // Backlight Control 4.
 constexpr uint8_t CMD_BACKLIGHT5         = 0xBC;   // Backlight Control 5.
 constexpr uint8_t CMD_BACKLIGHT7         = 0xBE;   // Backlight Control 7.
 constexpr uint8_t CMD_BACKLIGHT8         = 0xBF;   // Backlight Control 8.
 constexpr uint8_t CMD_POWER1             = 0xC0;   // Power Control 1.
 constexpr uint8_t CMD_POWER2             = 0xC1;   // Power Control 2.
 constexpr uint8_t CMD_VCOM1              = 0xC5;   // VCOM Control 1.
 constexpr uint8_t CMD_VCOM2              = 0xC7;   // VCOM Control 2.
 constexpr uint8_t CMD_NVMWR              = 0xD0;   // NV Memory Write.
 constexpr uint8_t CMD_NVMPKEY            = 0xD1;   // NV Memory Protection Key.
 constexpr uint8_t CMD_RDNVM              = 0xD2;   // NV Memory Status Read.
 constexpr uint8_t CMD_READ_ID4           = 0xD3;   // Read ID4.
 constexpr uint8_t CMD_PGAMMA             = 0xE0;   // Positive Gamma Correction.
 constexpr uint8_t CMD_NGAMMA             = 0xE1;   // Negative Gamma Correction.
 constexpr uint8_t CMD_DGAMCTRL1          = 0xE2;   // Digital Gamma Control 1.
 constexpr uint8_t CMD_DGAMCTRL2          = 0xE3;   // Digital Gamma Control 2.
 constexpr uint8_t CMD_INTERFACE          = 0xF6;   // Interface Control.

 // Extended register commands:
 constexpr uint8_t CMD_POWERA             = 0xCB;   // Power control A.
 constexpr uint8_t CMD_POWERB             = 0xCF;   // Power control B.
 constexpr uint8_t CMD_DTCA               = 0xE8;   // Driver timing control A.
 constexpr uint8_t CMD_DTCA_2             = 0xE9;   // Driver timing control A.
 constexpr uint8_t CMD_DTCB               = 0xEA;   // Driver timing control B.
 constexpr uint8_t CMD_POWER_SEQ          = 0xED;   // Power on sequence control.
 constexpr uint8_t CMD_3GAMMA_EN          = 0xF2;   // Enable 3G.
 constexpr uint8_t CMD_PRC                = 0xF7;   // Pump ratio control .
 // clang-format on

 // The ILI9341 is hard-coded at 320x240;
 constexpr int kDisplayWidth = 320;
 constexpr int kDisplayHeight = 240;
 constexpr int kDisplayNumPixels = kDisplayWidth * kDisplayHeight;

 // clang-format off
 constexpr std::byte MADCTL_MY  = std::byte{0b10000000}; // Row address order.
 constexpr std::byte MADCTL_MX  = std::byte{0b01000000}; // Column address order.
 constexpr std::byte MADCTL_MV  = std::byte{0b00100000}; // Row/column exchange.
 constexpr std::byte MADCTL_ML  = std::byte{0b00010000}; // Vertical refresh order.
 constexpr std::byte MADCTL_BGR = std::byte{0b00001000}; // BGR/RGB order.
 constexpr std::byte MADCTL_MH  = std::byte{0b00000100}; // Horizontal refresh order.

 // Take value specified in target.
 constexpr std::byte kMADMode = std::byte{ILI9341_MADCTL};

 constexpr uint8_t kDTC_PTG_MASK          = 0b00001100;
 constexpr uint8_t kDTC_PTG_NORMAL_SCAN   = 0b00000000;
 constexpr uint8_t kDTC_PTG_PROHIBITED1   = 0b00000100;
 constexpr uint8_t kDTC_PTG_INTERVAL_SCAN = 0b00001000;
 constexpr uint8_t kDTC_PTG_PROHIBITED2   = 0b00001100;

 // Mask values for CMD_RGB_INTERFACE:
 constexpr uint8_t kIFMODE_MASK_EPL    = 0b00000001;
 constexpr uint8_t kIFMODE_MASK_DPL    = 0b00000010;
 constexpr uint8_t kIFMODE_MASK_HSPL   = 0b00000100;
 constexpr uint8_t kIFMODE_MASK_VSPL   = 0b00001000;
 constexpr uint8_t kIFMODE_MASK_UNUSED = 0b00010000;
 constexpr uint8_t kIFMODE_MASK_RCM    = 0b01100000;
 constexpr uint8_t kIFMODE_MASK_BYPASS = 0b10000000;
 // clang-format on

 // Bypass=memory, RGB IF="VSYNC, HSYNC, DOTCLK, DE, D", DPL=falling.
 constexpr uint8_t kRGBWithDE = 0xC2;
 // Bypass=memory, RGB IF="VSYNC, HSYNC, DOTCLK, D", DPL=falling.
 constexpr uint8_t kRGBWithoutDE = 0xE2;

 // Frame Control (Normal Mode)
 constexpr std::byte kFrameRate61 = std::byte{0x1F};
 constexpr std::byte kFrameRate70 = std::byte{0x1B};
 constexpr std::byte kFrameRate79 = std::byte{0x18};
 constexpr std::byte kFrameRate119 = std::byte{0x10};

 constexpr std::byte kPixelFormat16bits = std::byte(0x55);
 constexpr std::byte kPixelFormat18bits = std::byte(0x36);

 constexpr uint8_t HighByte(uint16_t val) { return val >> 8; }

 constexpr uint8_t LowByte(uint16_t val) { return val & 0xff; }

 }  // namespace

 DisplayDriverILI9341::DisplayDriverILI9341(const Config& config)
     : config_(config) {}

 void DisplayDriverILI9341::SetMode(Mode mode) {
   // Set the D/CX pin to indicate data or command values.
   if (mode == Mode::kData) {
     config_.data_cmd_gpio.SetState(State::kActive);
   } else {
     config_.data_cmd_gpio.SetState(State::kInactive);
   }
 }

 Status DisplayDriverILI9341::WriteCommand(Device::Transaction& transaction,
                                           const Command& command) {
   SetMode(Mode::kCommand);
   std::byte buff[1]{static_cast<std::byte>(command.command)};
   auto s = transaction.Write(buff);
   if (!s.ok())
     return s;

   SetMode(Mode::kData);
   if (command.command_data.empty())
     return OkStatus();
   return transaction.Write(command.command_data);
 }

 Status DisplayDriverILI9341::Init() {
   Reset().IgnoreError();

   // TODO(cmumford): Figure out why kPerTransaction is flakey for this.
   // Seems to be OK on the Pico's display, but not the STM32F429I-DISC1.
   auto transaction = config_.spi_device_8_bit.StartTransaction(
       ChipSelectBehavior::kPerWriteRead);

   // ?
   WriteCommand(transaction,
                {0xEF,
                 std::array<std::byte, 3>{
                     std::byte{0x03},
                     std::byte{0x80},
                     std::byte{0x02},
                 }});

   WriteCommand(transaction,
                {CMD_POWERB,
                 std::array<std::byte, 3>{
                     std::byte{0x00},
                     std::byte{0xC1},
                     std::byte{0x30},
                 }});

   WriteCommand(transaction,
                {CMD_POWER_SEQ,
                 std::array<std::byte, 4>{
                     std::byte{0x64},
                     std::byte{0x03},
                     std::byte{0x12},
                     std::byte{0x81},
                 }});

   WriteCommand(transaction,
                {CMD_DTCA,
                 std::array<std::byte, 3>{
                     std::byte{0x85},
                     std::byte{0x00},
                     std::byte{0x78},
                 }});

   WriteCommand(transaction,
                {CMD_POWERA,
                 std::array<std::byte, 5>{
                     std::byte{0x39},
                     std::byte{0x2C},
                     std::byte{0x00},
                     std::byte{0x34},
                     std::byte{0x02},
                 }});

   WriteCommand(transaction,
                {CMD_PRC, std::array<std::byte, 1>{std::byte{0x20}}});

   WriteCommand(transaction,
                {CMD_DTCB,
                 std::array<std::byte, 2>{
                     std::byte{0x00},
                     std::byte{0x00},
                 }});

   WriteCommand(transaction,
                {CMD_FRMCTR1,
                 std::array<std::byte, 2>{
                     std::byte{0x00},  // division ratio = fosc.
                     kFrameRate70,
                 }});

   // Display Function Control
   WriteCommand(transaction,
                {CMD_DFC,
                 std::array<std::byte, 2>{
                     std::byte{0x0A},
                     std::byte{0xA2},
                 }});

   // Power control. GVDD = 0x10 = 3.65V.
   WriteCommand(transaction,
                {CMD_POWER1, std::array<std::byte, 1>{std::byte{0x10}}});

   // Power control
   WriteCommand(transaction,
                {CMD_POWER2, std::array<std::byte, 1>{std::byte{0x10}}});

   // VCM control
   WriteCommand(transaction,
                {CMD_VCOM1,
                 std::array<std::byte, 2>{
                     std::byte{0x3e},
                     std::byte{0x28},
                 }});

   // VCM control
   WriteCommand(transaction,
                {CMD_VCOM2, std::array<std::byte, 1>{std::byte{0x86}}});

   // Memory Access Control.
   WriteCommand(transaction, {CMD_MADCTL, std::array<std::byte, 1>{kMADMode}});

   WriteCommand(
       transaction,
       {CMD_PIXEL_FORMAT, std::array<std::byte, 1>{kPixelFormat16bits}});

   // Gamma Function Disable?
   WriteCommand(transaction,
                {CMD_3GAMMA_EN, std::array<std::byte, 1>{std::byte{0x00}}});

   switch (config_.interface) {
     case InterfaceType::SPI:
       break;
     case InterfaceType::WithDE:
       WriteCommand(
           transaction,
           {CMD_RGB_INTERFACE, std::array<std::byte, 1>{std::byte{kRGBWithDE}}});
       break;
     case InterfaceType::WithoutDE:
       WriteCommand(transaction,
                    {CMD_RGB_INTERFACE,
                     std::array<std::byte, 1>{std::byte{kRGBWithoutDE}}});
       break;
   }

   // Display Function Control
   WriteCommand(transaction,
                {CMD_DFC,
                 std::array<std::byte, 4>{
                     std::byte{0x0A},
                     std::byte{0xA7},
                     std::byte{0x27},
                     std::byte{0x04},
                 }});

   // Max pixel coordinates in portrait mode.
   constexpr uint16_t kMinX = 0;
   constexpr uint16_t kMaxX = 240 - 1;
   constexpr uint16_t kMinY = 0;
   constexpr uint16_t kMaxY = 320 - 1;

   // Landscape drawing Column Address Set
   const uint16_t kMinColumn = config_.swap_row_col ? kMinX : kMinY;
   const uint16_t kMaxColumn = config_.swap_row_col ? kMaxX : kMaxY;
   WriteCommand(transaction,
                {CMD_COLUMN_ADDR,
                 std::array<std::byte, 4>{
                     std::byte{HighByte(kMinColumn)},
                     std::byte{LowByte(kMinColumn)},
                     std::byte{HighByte(kMaxColumn)},
                     std::byte{LowByte(kMaxColumn)},
                 }});

   // Page Address Set
   const uint16_t kMinRow = config_.swap_row_col ? kMinY : kMinX;
   const uint16_t kMaxRow = config_.swap_row_col ? kMaxY : kMaxX;
   WriteCommand(transaction,
                {CMD_PAGE_ADDR,
                 std::array<std::byte, 4>{
                     std::byte{HighByte(kMinRow)},
                     std::byte{LowByte(kMinRow)},
                     std::byte{HighByte(kMaxRow)},
                     std::byte{LowByte(kMaxRow)},
                 }});

   if (config_.interface != InterfaceType::SPI) {
     WriteCommand(transaction,
                  {CMD_INTERFACE,
                   std::array<std::byte, 3>{
                       std::byte{0x00},
                       std::byte{0x01},
                       std::byte{0x06},
                   }});
   }

   WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray});
   pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(200ms));

   // Gamma Set
   WriteCommand(transaction,
                {CMD_GAMMA, std::array<std::byte, 1>{std::byte{0x01}}});

   // Positive Gamma Correction
   WriteCommand(transaction,
                {CMD_PGAMMA,
                 std::array<std::byte, 15>{
                     std::byte{0x0F},
                     std::byte{0x31},
                     std::byte{0x2B},
                     std::byte{0x0C},
                     std::byte{0x0E},
                     std::byte{0x08},
                     std::byte{0x4E},
                     std::byte{0xF1},
                     std::byte{0x37},
                     std::byte{0x07},
                     std::byte{0x10},
                     std::byte{0x03},
                     std::byte{0x0E},
                     std::byte{0x09},
                     std::byte{0x00},
                 }});

   // Negative Gamma Correction
   WriteCommand(transaction,
                {CMD_NGAMMA,
                 std::array<std::byte, 15>{
                     std::byte{0x00},
                     std::byte{0x0E},
                     std::byte{0x14},
                     std::byte{0x03},
                     std::byte{0x11},
                     std::byte{0x07},
                     std::byte{0x31},
                     std::byte{0xC1},
                     std::byte{0x48},
                     std::byte{0x08},
                     std::byte{0x0F},
                     std::byte{0x0C},
                     std::byte{0x31},
                     std::byte{0x36},
                     std::byte{0x0F},
                 }});

   WriteCommand(transaction, {CMD_SLEEP_OUT, kEmptyByteArray});
   pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(200ms));

   WriteCommand(transaction, {CMD_DISPLAY_ON, kEmptyByteArray});

   WriteCommand(transaction, {CMD_NORMAL_MODE_ON, kEmptyByteArray});

   WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray});

   return OkStatus();
 }

 void DisplayDriverILI9341::WriteFramebuffer(Framebuffer frame_buffer,
                                             WriteCallback write_callback) {
   PW_ASSERT(frame_buffer.is_valid());
   PW_ASSERT(frame_buffer.pixel_format() == PixelFormat::RGB565);
   if (config_.pixel_pusher) {
     config_.pixel_pusher->WriteFramebuffer(std::move(frame_buffer),
                                            std::move(write_callback));
     return;
   }
   auto transaction = config_.spi_device_16_bit.StartTransaction(
       ChipSelectBehavior::kPerTransaction);
   const uint16_t* fb_data = static_cast<const uint16_t*>(frame_buffer.data());
   Status s;
   // TODO(cmumford): Figure out why the STM32F429I cannot send the entire
   // framebuffer in a single write, but another display can.
 #if 1
   constexpr int kNumRowsPerSend = 10;
   static_assert(!(kDisplayHeight % kNumRowsPerSend),
                 "Cannot send fractional number of rows");
   constexpr int kNumSends = kDisplayHeight / kNumRowsPerSend;
   constexpr size_t kNumPixelsInSend = kDisplayWidth * kNumRowsPerSend;

   for (int i = 0; i < kNumSends && s.ok(); i++) {
     const uint8_t* data = reinterpret_cast<const uint8_t*>(
         &fb_data[kDisplayWidth * (kNumRowsPerSend * i)]);
     // At this point the SPI bus is in 16-bit mode, so we send the number
     // of 16-bit values (i.e. pixels).
     s = transaction.Write(ConstByteSpan(
         reinterpret_cast<const std::byte*>(data), kNumPixelsInSend));
   }
 #else
   s = transaction.Write(ConstByteSpan(
       reinterpret_cast<const std::byte*>(fb_data), kDisplayNumPixels));
 #endif
   write_callback(std::move(frame_buffer), s);
 }

 Status DisplayDriverILI9341::WriteRow(span<uint16_t> row_pixels,
                                       uint16_t row_idx,
                                       uint16_t col_idx) {
   {
     // Let controller know a write is coming.
     auto transaction = config_.spi_device_8_bit.StartTransaction(
         ChipSelectBehavior::kPerWriteRead);
     // Landscape drawing Column Address Set
     const uint16_t max_col_idx = std::max(
         kDisplayWidth - 1, col_idx + static_cast<int>(row_pixels.size()));
     WriteCommand(transaction,
                  {CMD_COLUMN_ADDR,
                   std::array<std::byte, 4>{
                       std::byte{HighByte(col_idx)},
                       std::byte{LowByte(col_idx)},
                       std::byte{HighByte(max_col_idx)},
                       std::byte{LowByte(max_col_idx)},
                   }});

     // Page Address Set
     uint16_t max_row_idx = row_idx;
     WriteCommand(transaction,
                  {CMD_PAGE_ADDR,
                   std::array<std::byte, 4>{
                       std::byte{HighByte(row_idx)},
                       std::byte{LowByte(row_idx)},
                       std::byte{HighByte(max_row_idx)},
                       std::byte{LowByte(max_row_idx)},
                   }});
     PW_TRY(WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray}));
   }

   auto transaction = config_.spi_device_16_bit.StartTransaction(
       ChipSelectBehavior::kPerTransaction);
   return transaction.Write(
       ConstByteSpan(reinterpret_cast<const std::byte*>(row_pixels.data()),
                     row_pixels.size()));
 }

 uint16_t DisplayDriverILI9341::GetWidth() const { return kDisplayWidth; }

 uint16_t DisplayDriverILI9341::GetHeight() const { return kDisplayHeight; }

 Status DisplayDriverILI9341::Reset() {
   if (!config_.reset_gpio)
     return Status::Unavailable();
   auto s = config_.reset_gpio->SetStateActive();
   if (!s.ok())
     return s;
   pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(100ms));
   s = config_.reset_gpio->SetStateInactive();
   pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(100ms));
   return s;
 }

 }  // namespace pw::display_driver
	// Copyright 2022 The Pigweed Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License"); you may not
	// use this file except in compliance with the License. You may obtain a copy of
	// the License at
	//
	// https://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.

	#include "pw_display_driver_ili9341/display_driver.h"

	#include <algorithm>

	#include "pw_chrono/system_clock.h"
	#include "pw_digital_io/digital_io.h"
	#include "pw_framebuffer/framebuffer.h"
	#include "pw_thread/sleep.h"

	using pw::digital_io::State;
	using pw::framebuffer::Framebuffer;
	using pw::framebuffer::PixelFormat;
	using pw::spi::ChipSelectBehavior;
	using pw::spi::Device;

	namespace pw::display_driver {

	namespace {

	constexpr std::array<std::byte, 0> kEmptyByteArray = {};

	// clang-format off
	// Level 1 commands:
	constexpr uint8_t CMD_SWRESET = 0x01; // Software Reset.
	constexpr uint8_t CMD_READ_DISPLAY_ID = 0x04; // Read display identification information.
	constexpr uint8_t CMD_RDDST = 0x09; // Read Display Status.
	constexpr uint8_t CMD_RDDPM = 0x0A; // Read Display Power Mode.
	constexpr uint8_t CMD_RDDMADCTL = 0x0B; // Read Display MADCTL.
	constexpr uint8_t CMD_RDDCOLMOD = 0x0C; // Read Display Pixel Format.
	constexpr uint8_t CMD_RDDIM = 0x0D; // Read Display Image Format.
	constexpr uint8_t CMD_RDDSM = 0x0E; // Read Display Signal Mode.
	constexpr uint8_t CMD_RDDSDR = 0x0F; // Read Display Self-Diagnostic Result.
	constexpr uint8_t CMD_SPLIN = 0x10; // Enter Sleep Mode.
	constexpr uint8_t CMD_SLEEP_OUT = 0x11; // Sleep Out.
	constexpr uint8_t CMD_PTLON = 0x12; // Partial Mode ON.
	constexpr uint8_t CMD_NORMAL_MODE_ON = 0x13; // Normal Display Mode ON.
	constexpr uint8_t CMD_DINVOFF = 0x20; // Display Inversion OFF.
	constexpr uint8_t CMD_DINVON = 0x21; // Display Inversion ON.
	constexpr uint8_t CMD_GAMMA = 0x26; // Gamma Set.
	constexpr uint8_t CMD_DISPLAY_OFF = 0x28; // Display OFF.
	constexpr uint8_t CMD_DISPLAY_ON = 0x29; // Display ON.
	constexpr uint8_t CMD_COLUMN_ADDR = 0x2A; // Column Address Set.
	constexpr uint8_t CMD_PAGE_ADDR = 0x2B; // Page Address Set.
	constexpr uint8_t CMD_GRAM = 0x2C; // Memory Write.
	constexpr uint8_t CMD_RGBSET = 0x2D; // Color Set.
	constexpr uint8_t CMD_RAMRD = 0x2E; // Memory Read.
	constexpr uint8_t CMD_PLTAR = 0x30; // Partial Area.
	constexpr uint8_t CMD_VSCRDEF = 0x33; // Vertical Scrolling Definition.
	constexpr uint8_t CMD_TEOFF = 0x34; // Tearing Effect Line OFF.
	constexpr uint8_t CMD_TEON = 0x35; // Tearing Effect Line ON.
	constexpr uint8_t CMD_MADCTL = 0x36; // Memory Access Control.
	constexpr uint8_t CMD_VSCRSADD = 0x37; // Vertical Scrolling Start Address.
	constexpr uint8_t CMD_IDMOFF = 0x38; // Idle Mode OFF.
	constexpr uint8_t CMD_IDMON = 0x39; // Idle Mode ON.
	constexpr uint8_t CMD_PIXEL_FORMAT = 0x3A; // COLMOD: Pixel Format Set.
	constexpr uint8_t CMD_WRITE_MEM_CONTINUE = 0x3C; // Write_Memory_Continue.
	constexpr uint8_t CMD_READ_MEM_CONTINUE = 0x3E; // Read_Memory_Continue.
	constexpr uint8_t CMD_SET_TEAR_SCANLINE = 0x44; // Set_Tear_Scanline.
	constexpr uint8_t CMD_GET_SCANLINE = 0x45; // Get_Scanline.
	constexpr uint8_t CMD_WDB = 0x51; // Write Display Brightness.
	constexpr uint8_t CMD_RDDISBV = 0x52; // Read Display Brightness.
	constexpr uint8_t CMD_WCD = 0x53; // Write CTRL Display.
	constexpr uint8_t CMD_RDCTRLD = 0x54; // Read CTRL Display.
	constexpr uint8_t CMD_WRCABC = 0x55; // Write Content Adaptive Brightness Control.
	constexpr uint8_t CMD_RDCABC = 0x56; // Read Content Adaptive Brightness Control.
	constexpr uint8_t CMD_WRITE_CABC = 0x5E; // Write CABC Minimum Brightness.
	constexpr uint8_t CMD_READ_CABC = 0x5F; // Read CABC Minimum Brightness.
	constexpr uint8_t CMD_READ_ID1 = 0xDA; // Read ID1.
	constexpr uint8_t CMD_READ_ID2 = 0xDB; // Read ID2.
	constexpr uint8_t CMD_READ_ID3 = 0xDC; // Read ID3.

	// Level 2 commands:
	constexpr uint8_t CMD_RGB_INTERFACE = 0xB0; // RGB Interface Signal Control.
	constexpr uint8_t CMD_FRMCTR1 = 0xB1; // Frame Rate Control (In Normal Mode/Full Colors.
	constexpr uint8_t CMD_FRMCTR2 = 0xB2; // Frame Rate Control (In Idle Mode/8 colors).
	constexpr uint8_t CMD_FRMCTR3 = 0xB3; // Frame Rate control (In Partial Mode/Full Colors).
	constexpr uint8_t CMD_INVTR = 0xB4; // Display Inversion Control.
	constexpr uint8_t CMD_BPC = 0xB5; // Blanking Porch Control.
	constexpr uint8_t CMD_DFC = 0xB6; // Display Function Control.
	constexpr uint8_t CMD_ETMOD = 0xB7; // Entry Mode Set.
	constexpr uint8_t CMD_BACKLIGHT1 = 0xB8; // Backlight Control 1.
	constexpr uint8_t CMD_BACKLIGHT2 = 0xB9; // Backlight Control 2.
	constexpr uint8_t CMD_BACKLIGHT3 = 0xBA; // Backlight Control 3.
	constexpr uint8_t CMD_BACKLIGHT4 = 0xBB; // Backlight Control 4.
	constexpr uint8_t CMD_BACKLIGHT5 = 0xBC; // Backlight Control 5.
	constexpr uint8_t CMD_BACKLIGHT7 = 0xBE; // Backlight Control 7.
	constexpr uint8_t CMD_BACKLIGHT8 = 0xBF; // Backlight Control 8.
	constexpr uint8_t CMD_POWER1 = 0xC0; // Power Control 1.
	constexpr uint8_t CMD_POWER2 = 0xC1; // Power Control 2.
	constexpr uint8_t CMD_VCOM1 = 0xC5; // VCOM Control 1.
	constexpr uint8_t CMD_VCOM2 = 0xC7; // VCOM Control 2.
	constexpr uint8_t CMD_NVMWR = 0xD0; // NV Memory Write.
	constexpr uint8_t CMD_NVMPKEY = 0xD1; // NV Memory Protection Key.
	constexpr uint8_t CMD_RDNVM = 0xD2; // NV Memory Status Read.
	constexpr uint8_t CMD_READ_ID4 = 0xD3; // Read ID4.
	constexpr uint8_t CMD_PGAMMA = 0xE0; // Positive Gamma Correction.
	constexpr uint8_t CMD_NGAMMA = 0xE1; // Negative Gamma Correction.
	constexpr uint8_t CMD_DGAMCTRL1 = 0xE2; // Digital Gamma Control 1.
	constexpr uint8_t CMD_DGAMCTRL2 = 0xE3; // Digital Gamma Control 2.
	constexpr uint8_t CMD_INTERFACE = 0xF6; // Interface Control.

	// Extended register commands:
	constexpr uint8_t CMD_POWERA = 0xCB; // Power control A.
	constexpr uint8_t CMD_POWERB = 0xCF; // Power control B.
	constexpr uint8_t CMD_DTCA = 0xE8; // Driver timing control A.
	constexpr uint8_t CMD_DTCA_2 = 0xE9; // Driver timing control A.
	constexpr uint8_t CMD_DTCB = 0xEA; // Driver timing control B.
	constexpr uint8_t CMD_POWER_SEQ = 0xED; // Power on sequence control.
	constexpr uint8_t CMD_3GAMMA_EN = 0xF2; // Enable 3G.
	constexpr uint8_t CMD_PRC = 0xF7; // Pump ratio control .
	// clang-format on

	// The ILI9341 is hard-coded at 320x240;
	constexpr int kDisplayWidth = 320;
	constexpr int kDisplayHeight = 240;
	constexpr int kDisplayNumPixels = kDisplayWidth * kDisplayHeight;

	// clang-format off
	constexpr std::byte MADCTL_MY = std::byte{0b10000000}; // Row address order.
	constexpr std::byte MADCTL_MX = std::byte{0b01000000}; // Column address order.
	constexpr std::byte MADCTL_MV = std::byte{0b00100000}; // Row/column exchange.
	constexpr std::byte MADCTL_ML = std::byte{0b00010000}; // Vertical refresh order.
	constexpr std::byte MADCTL_BGR = std::byte{0b00001000}; // BGR/RGB order.
	constexpr std::byte MADCTL_MH = std::byte{0b00000100}; // Horizontal refresh order.

	// Take value specified in target.
	constexpr std::byte kMADMode = std::byte{ILI9341_MADCTL};

	constexpr uint8_t kDTC_PTG_MASK = 0b00001100;
	constexpr uint8_t kDTC_PTG_NORMAL_SCAN = 0b00000000;
	constexpr uint8_t kDTC_PTG_PROHIBITED1 = 0b00000100;
	constexpr uint8_t kDTC_PTG_INTERVAL_SCAN = 0b00001000;
	constexpr uint8_t kDTC_PTG_PROHIBITED2 = 0b00001100;

	// Mask values for CMD_RGB_INTERFACE:
	constexpr uint8_t kIFMODE_MASK_EPL = 0b00000001;
	constexpr uint8_t kIFMODE_MASK_DPL = 0b00000010;
	constexpr uint8_t kIFMODE_MASK_HSPL = 0b00000100;
	constexpr uint8_t kIFMODE_MASK_VSPL = 0b00001000;
	constexpr uint8_t kIFMODE_MASK_UNUSED = 0b00010000;
	constexpr uint8_t kIFMODE_MASK_RCM = 0b01100000;
	constexpr uint8_t kIFMODE_MASK_BYPASS = 0b10000000;
	// clang-format on

	// Bypass=memory, RGB IF="VSYNC, HSYNC, DOTCLK, DE, D", DPL=falling.
	constexpr uint8_t kRGBWithDE = 0xC2;
	// Bypass=memory, RGB IF="VSYNC, HSYNC, DOTCLK, D", DPL=falling.
	constexpr uint8_t kRGBWithoutDE = 0xE2;

	// Frame Control (Normal Mode)
	constexpr std::byte kFrameRate61 = std::byte{0x1F};
	constexpr std::byte kFrameRate70 = std::byte{0x1B};
	constexpr std::byte kFrameRate79 = std::byte{0x18};
	constexpr std::byte kFrameRate119 = std::byte{0x10};

	constexpr std::byte kPixelFormat16bits = std::byte(0x55);
	constexpr std::byte kPixelFormat18bits = std::byte(0x36);

	constexpr uint8_t HighByte(uint16_t val) { return val >> 8; }

	constexpr uint8_t LowByte(uint16_t val) { return val & 0xff; }

	} // namespace

	DisplayDriverILI9341::DisplayDriverILI9341(const Config& config)
	: config_(config) {}

	void DisplayDriverILI9341::SetMode(Mode mode) {
	// Set the D/CX pin to indicate data or command values.
	if (mode == Mode::kData) {
	config_.data_cmd_gpio.SetState(State::kActive);
	} else {
	config_.data_cmd_gpio.SetState(State::kInactive);
	}
	}

	Status DisplayDriverILI9341::WriteCommand(Device::Transaction& transaction,
	const Command& command) {
	SetMode(Mode::kCommand);
	std::byte buff[1]{static_cast<std::byte>(command.command)};
	auto s = transaction.Write(buff);
	if (!s.ok())
	return s;

	SetMode(Mode::kData);
	if (command.command_data.empty())
	return OkStatus();
	return transaction.Write(command.command_data);
	}

	Status DisplayDriverILI9341::Init() {
	Reset().IgnoreError();

	// TODO(cmumford): Figure out why kPerTransaction is flakey for this.
	// Seems to be OK on the Pico's display, but not the STM32F429I-DISC1.
	auto transaction = config_.spi_device_8_bit.StartTransaction(
	ChipSelectBehavior::kPerWriteRead);

	// ?
	WriteCommand(transaction,
	{0xEF,
	std::array<std::byte, 3>{
	std::byte{0x03},
	std::byte{0x80},
	std::byte{0x02},
	}});

	WriteCommand(transaction,
	{CMD_POWERB,
	std::array<std::byte, 3>{
	std::byte{0x00},
	std::byte{0xC1},
	std::byte{0x30},
	}});

	WriteCommand(transaction,
	{CMD_POWER_SEQ,
	std::array<std::byte, 4>{
	std::byte{0x64},
	std::byte{0x03},
	std::byte{0x12},
	std::byte{0x81},
	}});

	WriteCommand(transaction,
	{CMD_DTCA,
	std::array<std::byte, 3>{
	std::byte{0x85},
	std::byte{0x00},
	std::byte{0x78},
	}});

	WriteCommand(transaction,
	{CMD_POWERA,
	std::array<std::byte, 5>{
	std::byte{0x39},
	std::byte{0x2C},
	std::byte{0x00},
	std::byte{0x34},
	std::byte{0x02},
	}});

	WriteCommand(transaction,
	{CMD_PRC, std::array<std::byte, 1>{std::byte{0x20}}});

	WriteCommand(transaction,
	{CMD_DTCB,
	std::array<std::byte, 2>{
	std::byte{0x00},
	std::byte{0x00},
	}});

	WriteCommand(transaction,
	{CMD_FRMCTR1,
	std::array<std::byte, 2>{
	std::byte{0x00}, // division ratio = fosc.
	kFrameRate70,
	}});

	// Display Function Control
	WriteCommand(transaction,
	{CMD_DFC,
	std::array<std::byte, 2>{
	std::byte{0x0A},
	std::byte{0xA2},
	}});

	// Power control. GVDD = 0x10 = 3.65V.
	WriteCommand(transaction,
	{CMD_POWER1, std::array<std::byte, 1>{std::byte{0x10}}});

	// Power control
	WriteCommand(transaction,
	{CMD_POWER2, std::array<std::byte, 1>{std::byte{0x10}}});

	// VCM control
	WriteCommand(transaction,
	{CMD_VCOM1,
	std::array<std::byte, 2>{
	std::byte{0x3e},
	std::byte{0x28},
	}});

	// VCM control
	WriteCommand(transaction,
	{CMD_VCOM2, std::array<std::byte, 1>{std::byte{0x86}}});

	// Memory Access Control.
	WriteCommand(transaction, {CMD_MADCTL, std::array<std::byte, 1>{kMADMode}});

	WriteCommand(
	transaction,
	{CMD_PIXEL_FORMAT, std::array<std::byte, 1>{kPixelFormat16bits}});

	// Gamma Function Disable?
	WriteCommand(transaction,
	{CMD_3GAMMA_EN, std::array<std::byte, 1>{std::byte{0x00}}});

	switch (config_.interface) {
	case InterfaceType::SPI:
	break;
	case InterfaceType::WithDE:
	WriteCommand(
	transaction,
	{CMD_RGB_INTERFACE, std::array<std::byte, 1>{std::byte{kRGBWithDE}}});
	break;
	case InterfaceType::WithoutDE:
	WriteCommand(transaction,
	{CMD_RGB_INTERFACE,
	std::array<std::byte, 1>{std::byte{kRGBWithoutDE}}});
	break;
	}

	// Display Function Control
	WriteCommand(transaction,
	{CMD_DFC,
	std::array<std::byte, 4>{
	std::byte{0x0A},
	std::byte{0xA7},
	std::byte{0x27},
	std::byte{0x04},
	}});

	// Max pixel coordinates in portrait mode.
	constexpr uint16_t kMinX = 0;
	constexpr uint16_t kMaxX = 240 - 1;
	constexpr uint16_t kMinY = 0;
	constexpr uint16_t kMaxY = 320 - 1;

	// Landscape drawing Column Address Set
	const uint16_t kMinColumn = config_.swap_row_col ? kMinX : kMinY;
	const uint16_t kMaxColumn = config_.swap_row_col ? kMaxX : kMaxY;
	WriteCommand(transaction,
	{CMD_COLUMN_ADDR,
	std::array<std::byte, 4>{
	std::byte{HighByte(kMinColumn)},
	std::byte{LowByte(kMinColumn)},
	std::byte{HighByte(kMaxColumn)},
	std::byte{LowByte(kMaxColumn)},
	}});

	// Page Address Set
	const uint16_t kMinRow = config_.swap_row_col ? kMinY : kMinX;
	const uint16_t kMaxRow = config_.swap_row_col ? kMaxY : kMaxX;
	WriteCommand(transaction,
	{CMD_PAGE_ADDR,
	std::array<std::byte, 4>{
	std::byte{HighByte(kMinRow)},
	std::byte{LowByte(kMinRow)},
	std::byte{HighByte(kMaxRow)},
	std::byte{LowByte(kMaxRow)},
	}});

	if (config_.interface != InterfaceType::SPI) {
	WriteCommand(transaction,
	{CMD_INTERFACE,
	std::array<std::byte, 3>{
	std::byte{0x00},
	std::byte{0x01},
	std::byte{0x06},
	}});
	}

	WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray});
	pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(200ms));

	// Gamma Set
	WriteCommand(transaction,
	{CMD_GAMMA, std::array<std::byte, 1>{std::byte{0x01}}});

	// Positive Gamma Correction
	WriteCommand(transaction,
	{CMD_PGAMMA,
	std::array<std::byte, 15>{
	std::byte{0x0F},
	std::byte{0x31},
	std::byte{0x2B},
	std::byte{0x0C},
	std::byte{0x0E},
	std::byte{0x08},
	std::byte{0x4E},
	std::byte{0xF1},
	std::byte{0x37},
	std::byte{0x07},
	std::byte{0x10},
	std::byte{0x03},
	std::byte{0x0E},
	std::byte{0x09},
	std::byte{0x00},
	}});

	// Negative Gamma Correction
	WriteCommand(transaction,
	{CMD_NGAMMA,
	std::array<std::byte, 15>{
	std::byte{0x00},
	std::byte{0x0E},
	std::byte{0x14},
	std::byte{0x03},
	std::byte{0x11},
	std::byte{0x07},
	std::byte{0x31},
	std::byte{0xC1},
	std::byte{0x48},
	std::byte{0x08},
	std::byte{0x0F},
	std::byte{0x0C},
	std::byte{0x31},
	std::byte{0x36},
	std::byte{0x0F},
	}});

	WriteCommand(transaction, {CMD_SLEEP_OUT, kEmptyByteArray});
	pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(200ms));

	WriteCommand(transaction, {CMD_DISPLAY_ON, kEmptyByteArray});

	WriteCommand(transaction, {CMD_NORMAL_MODE_ON, kEmptyByteArray});

	WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray});

	return OkStatus();
	}

	void DisplayDriverILI9341::WriteFramebuffer(Framebuffer frame_buffer,
	WriteCallback write_callback) {
	PW_ASSERT(frame_buffer.is_valid());
	PW_ASSERT(frame_buffer.pixel_format() == PixelFormat::RGB565);
	if (config_.pixel_pusher) {
	config_.pixel_pusher->WriteFramebuffer(std::move(frame_buffer),
	std::move(write_callback));
	return;
	}
	auto transaction = config_.spi_device_16_bit.StartTransaction(
	ChipSelectBehavior::kPerTransaction);
	const uint16_t* fb_data = static_cast<const uint16_t*>(frame_buffer.data());
	Status s;
	// TODO(cmumford): Figure out why the STM32F429I cannot send the entire
	// framebuffer in a single write, but another display can.
	#if 1
	constexpr int kNumRowsPerSend = 10;
	static_assert(!(kDisplayHeight % kNumRowsPerSend),
	"Cannot send fractional number of rows");
	constexpr int kNumSends = kDisplayHeight / kNumRowsPerSend;
	constexpr size_t kNumPixelsInSend = kDisplayWidth * kNumRowsPerSend;

	for (int i = 0; i < kNumSends && s.ok(); i++) {
	const uint8_t* data = reinterpret_cast<const uint8_t*>(
	&fb_data[kDisplayWidth * (kNumRowsPerSend * i)]);
	// At this point the SPI bus is in 16-bit mode, so we send the number
	// of 16-bit values (i.e. pixels).
	s = transaction.Write(ConstByteSpan(
	reinterpret_cast<const std::byte*>(data), kNumPixelsInSend));
	}
	#else
	s = transaction.Write(ConstByteSpan(
	reinterpret_cast<const std::byte*>(fb_data), kDisplayNumPixels));
	#endif
	write_callback(std::move(frame_buffer), s);
	}

	Status DisplayDriverILI9341::WriteRow(span<uint16_t> row_pixels,
	uint16_t row_idx,
	uint16_t col_idx) {
	{
	// Let controller know a write is coming.
	auto transaction = config_.spi_device_8_bit.StartTransaction(
	ChipSelectBehavior::kPerWriteRead);
	// Landscape drawing Column Address Set
	const uint16_t max_col_idx = std::max(
	kDisplayWidth - 1, col_idx + static_cast<int>(row_pixels.size()));
	WriteCommand(transaction,
	{CMD_COLUMN_ADDR,
	std::array<std::byte, 4>{
	std::byte{HighByte(col_idx)},
	std::byte{LowByte(col_idx)},
	std::byte{HighByte(max_col_idx)},
	std::byte{LowByte(max_col_idx)},
	}});

	// Page Address Set
	uint16_t max_row_idx = row_idx;
	WriteCommand(transaction,
	{CMD_PAGE_ADDR,
	std::array<std::byte, 4>{
	std::byte{HighByte(row_idx)},
	std::byte{LowByte(row_idx)},
	std::byte{HighByte(max_row_idx)},
	std::byte{LowByte(max_row_idx)},
	}});
	PW_TRY(WriteCommand(transaction, {CMD_GRAM, kEmptyByteArray}));
	}

	auto transaction = config_.spi_device_16_bit.StartTransaction(
	ChipSelectBehavior::kPerTransaction);
	return transaction.Write(
	ConstByteSpan(reinterpret_cast<const std::byte*>(row_pixels.data()),
	row_pixels.size()));
	}

	uint16_t DisplayDriverILI9341::GetWidth() const { return kDisplayWidth; }

	uint16_t DisplayDriverILI9341::GetHeight() const { return kDisplayHeight; }

	Status DisplayDriverILI9341::Reset() {
	if (!config_.reset_gpio)
	return Status::Unavailable();
	auto s = config_.reset_gpio->SetStateActive();
	if (!s.ok())
	return s;
	pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(100ms));
	s = config_.reset_gpio->SetStateInactive();
	pw::this_thread::sleep_for(pw::chrono::SystemClock::for_at_least(100ms));
	return s;
	}

	} // namespace pw::display_driver