applications/app_common_impl/common_pico.cc

// 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 <cstdint>

#include "app_common/common.h"

#define LIB_CMSIS_CORE 0
#define LIB_PICO_STDIO_SEMIHOSTING 0

#include "hardware/gpio.h"
#include "hardware/pwm.h"
#include "pico/stdlib.h"
#include "pw_digital_io_pico/digital_io.h"
#include "pw_log/log.h"
#include "pw_spi_pico/chip_selector.h"
#include "pw_spi_pico/initiator.h"
#include "pw_sync/borrow.h"
#include "pw_sync/mutex.h"

#if defined(DISPLAY_TYPE_ILI9341)
#include "pw_display_driver_ili9341/display_driver.h"
using DisplayDriver = pw::display_driver::DisplayDriverILI9341;
#elif defined(DISPLAY_TYPE_ST7735)
#include "pw_display_driver_st7735/display_driver.h"
using DisplayDriver = pw::display_driver::DisplayDriverST7735;
#elif defined(DISPLAY_TYPE_ST7789)
#include "pw_display_driver_st7789/display_driver.h"
using DisplayDriver = pw::display_driver::DisplayDriverST7789;
#else
#error "Undefined display type"
#endif

using pw::Status;
using pw::digital_io::PicoDigitalOut;
using pw::display::Display;
using pw::framebuffer::Framebuffer;
using pw::framebuffer_pool::FramebufferPool;
using pw::spi::Device;
using pw::spi::Initiator;
using pw::spi::PicoChipSelector;
using pw::spi::PicoInitiator;
using pw::sync::Borrowable;
using pw::sync::VirtualMutex;

namespace {

// Pico spi0 Pins
#define SPI_PORT spi0

struct SpiValues {
  SpiValues(pw::spi::Config config,
            pw::spi::ChipSelector& selector,
            pw::sync::VirtualMutex& initiator_mutex);

  pw::spi::PicoInitiator initiator;
  pw::sync::Borrowable<pw::spi::Initiator> borrowable_initiator;
  pw::spi::Device device;
};

static_assert(DISPLAY_WIDTH > 0);
static_assert(DISPLAY_HEIGHT > 0);

constexpr uint16_t kDisplayScaleFactor = 1;
constexpr uint16_t kFramebufferWidth =
    FRAMEBUFFER_WIDTH >= 0 ? FRAMEBUFFER_WIDTH / kDisplayScaleFactor
                           : DISPLAY_WIDTH / kDisplayScaleFactor;
constexpr uint16_t kFramebufferHeight = DISPLAY_HEIGHT / kDisplayScaleFactor;

constexpr pw::math::Size<uint16_t> kDisplaySize{DISPLAY_WIDTH, DISPLAY_HEIGHT};
constexpr size_t kNumPixels = kFramebufferWidth * kFramebufferHeight;
constexpr uint16_t kFramebufferRowBytes = sizeof(uint16_t) * kFramebufferWidth;

constexpr uint32_t kBaudRate = 31'250'000;
constexpr pw::spi::Config kSpiConfig8Bit{
    .polarity = pw::spi::ClockPolarity::kActiveHigh,
    .phase = pw::spi::ClockPhase::kFallingEdge,
    .bits_per_word = pw::spi::BitsPerWord(8),
    .bit_order = pw::spi::BitOrder::kMsbFirst,
};
constexpr pw::spi::Config kSpiConfig16Bit{
    .polarity = pw::spi::ClockPolarity::kActiveHigh,
    .phase = pw::spi::ClockPhase::kFallingEdge,
    .bits_per_word = pw::spi::BitsPerWord(16),
    .bit_order = pw::spi::BitOrder::kMsbFirst,
};

PicoDigitalOut s_display_dc_pin(DISPLAY_DC_GPIO);
#if DISPLAY_RESET_GPIO != -1
PicoDigitalOut s_display_reset_pin(DISPLAY_RESET_GPIO);
#endif
PicoDigitalOut s_display_cs_pin(DISPLAY_CS_GPIO);
PicoChipSelector s_spi_chip_selector(s_display_cs_pin);
PicoInitiator s_spi_initiator(SPI_PORT);
VirtualMutex s_spi_initiator_mutex;
Borrowable<Initiator> s_borrowable_spi_initiator(s_spi_initiator,
                                                 s_spi_initiator_mutex);
SpiValues s_spi_8_bit(kSpiConfig8Bit,
                      s_spi_chip_selector,
                      s_spi_initiator_mutex);
SpiValues s_spi_16_bit(kSpiConfig16Bit,
                       s_spi_chip_selector,
                       s_spi_initiator_mutex);
uint16_t s_pixel_data[kNumPixels];
pw::framebuffer_pool::FramebufferPool s_fb_pool({
    .fb_addr = {s_pixel_data},
    .dimensions = {kFramebufferWidth, kFramebufferHeight},
    .row_bytes = kFramebufferRowBytes,
});
DisplayDriver s_display_driver({
  .data_cmd_gpio = s_display_dc_pin,
#if DISPLAY_RESET_GPIO != -1
  .reset_gpio = &s_display_reset_pin,
#else
  .reset_gpio = nullptr,
#endif
  .spi_device_8_bit = s_spi_8_bit.device,
  .spi_device_16_bit = s_spi_16_bit.device,
});
Display s_display(s_display_driver, kDisplaySize, s_fb_pool);

#if BACKLIGHT_GPIO != -1
void SetBacklight(uint16_t brightness) {
  pwm_config cfg = pwm_get_default_config();
  pwm_set_wrap(pwm_gpio_to_slice_num(BACKLIGHT_GPIO), 65535);
  pwm_init(pwm_gpio_to_slice_num(BACKLIGHT_GPIO), &cfg, true);
  gpio_set_function(BACKLIGHT_GPIO, GPIO_FUNC_PWM);

  pwm_set_gpio_level(BACKLIGHT_GPIO, brightness);
}
#endif

SpiValues::SpiValues(pw::spi::Config config,
                     pw::spi::ChipSelector& selector,
                     pw::sync::VirtualMutex& initiator_mutex)
    : initiator(SPI_PORT),
      borrowable_initiator(initiator, initiator_mutex),
      device(borrowable_initiator, config, selector) {}

}  // namespace

// static
Status Common::Init() {
  // Initialize all of the present standard stdio types that are linked into the
  // binary.
  stdio_init_all();

  // Set up the default UART and assign it to the default GPIO's.
  setup_default_uart();

  s_display_cs_pin.Enable();
  s_display_dc_pin.Enable();
#if DISPLAY_RESET_GPIO != -1
  s_display_reset_pin.Enable();
#endif

#if BACKLIGHT_GPIO != -1
  SetBacklight(0xffff);  // Full brightness.
#endif

  unsigned actual_baudrate = spi_init(SPI_PORT, kBaudRate);
  PW_LOG_DEBUG("Actual Baudrate: %u", actual_baudrate);

#if SPI_MISO_GPIO != -1
  gpio_set_function(SPI_MISO_GPIO, GPIO_FUNC_SPI);
#endif
  gpio_set_function(SPI_CLOCK_GPIO, GPIO_FUNC_SPI);
  gpio_set_function(SPI_MOSI_GPIO, GPIO_FUNC_SPI);

  return s_display_driver.Init();
}

// static
pw::display::Display& Common::GetDisplay() { return s_display; }