text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2016 Scott Shawcroft
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include "shared-bindings/busio/SPI.h"
  #include "py/mperrno.h"
  #include "py/runtime.h"
  
  #include "hpl_sercom_config.h"
  #include "peripheral_clk_config.h"
  
  #include "hal/include/hal_gpio.h"
  #include "hal/include/hal_spi_m_sync.h"
  #include "hal/include/hpl_spi_m_sync.h"
  #include "supervisor/shared/rgb_led_status.h"
  
  #include "samd/dma.h"
  #include "samd/sercom.h"
  
  void common_hal_busio_spi_construct(busio_spi_obj_t *self,
          const mcu_pin_obj_t * clock, const mcu_pin_obj_t * mosi,
          const mcu_pin_obj_t * miso) {
      Sercom* sercom = NULL;
      uint8_t sercom_index;
      uint32_t clock_pinmux = 0;
      bool mosi_none = mosi == mp_const_none;
      bool miso_none = miso == mp_const_none;
      uint32_t mosi_pinmux = 0;
      uint32_t miso_pinmux = 0;
      uint8_t clock_pad = 0;
      uint8_t mosi_pad = 0;
      uint8_t miso_pad = 0;
      uint8_t dopo = 255;
      for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
          sercom_index = clock->sercom[i].index; // 2 for SERCOM2, etc.
          if (sercom_index >= SERCOM_INST_NUM) {
              continue;
          }
          Sercom* potential_sercom = sercom_insts[sercom_index];
          if (
          #if defined(MICROPY_HW_APA102_SCK) && defined(MICROPY_HW_APA102_MOSI) && !defined(CIRCUITPY_BITBANG_APA102)
              (potential_sercom->SPI.CTRLA.bit.ENABLE != 0 &&
               potential_sercom != status_apa102.spi_desc.dev.prvt &&
               !apa102_sck_in_use)) {
          #else
              potential_sercom->SPI.CTRLA.bit.ENABLE != 0) {
          #endif
              continue;
          }
          clock_pinmux = PINMUX(clock->pin, (i == 0) ? MUX_C : MUX_D);
          clock_pad = clock->sercom[i].pad;
          if (!samd_peripherals_valid_spi_clock_pad(clock_pad)) {
              continue;
          }
          for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
              if (!mosi_none) {
                  if (sercom_index == mosi->sercom[j].index) {
                      mosi_pinmux = PINMUX(mosi->pin, (j == 0) ? MUX_C : MUX_D);
                      mosi_pad = mosi->sercom[j].pad;
                      dopo = samd_peripherals_get_spi_dopo(clock_pad, mosi_pad);
                      if (dopo > 0x3) {
                          continue;  // pad combination not possible
                      }
                      if (miso_none) {
                          sercom = potential_sercom;
                          break;
                      }
                  } else {
                      continue;
                  }
              }
              if (!miso_none) {
                  for (int k = 0; k < NUM_SERCOMS_PER_PIN; k++) {
                      if (sercom_index == miso->sercom[k].index) {
                          miso_pinmux = PINMUX(miso->pin, (k == 0) ? MUX_C : MUX_D);
                          miso_pad = miso->sercom[k].pad;
                          sercom = potential_sercom;
                          break;
                      }
                  }
              }
              if (sercom != NULL) {
                  break;
              }
          }
          if (sercom != NULL) {
              break;
          }
      }
      if (sercom == NULL) {
          mp_raise_ValueError("Invalid pins");
      }
  
      // Set up SPI clocks on SERCOM.
      samd_peripherals_sercom_clock_init(sercom, sercom_index);
  
      #if defined(MICROPY_HW_APA102_SCK) && defined(MICROPY_HW_APA102_MOSI) && !defined(CIRCUITPY_BITBANG_APA102)
      // if we're re-using the dotstar sercom, make sure it is disabled or the init will fail out
      hri_sercomspi_clear_CTRLA_ENABLE_bit(sercom);
      #endif
      if (spi_m_sync_init(&self->spi_desc, sercom) != ERR_NONE) {
          mp_raise_OSError(MP_EIO);
      }
  
      // Pads must be set after spi_m_sync_init(), which uses default values from
      // the prototypical SERCOM.
      hri_sercomspi_write_CTRLA_DOPO_bf(sercom, dopo);
      hri_sercomspi_write_CTRLA_DIPO_bf(sercom, miso_pad);
  
      // Always start at 250khz which is what SD cards need. They are sensitive to
      // SPI bus noise before they are put into SPI mode.
      uint8_t baud_value = samd_peripherals_spi_baudrate_to_baud_reg_value(250000);
      if (spi_m_sync_set_baudrate(&self->spi_desc, baud_value) != ERR_NONE) {
          // spi_m_sync_set_baudrate does not check for validity, just whether the device is
          // busy or not
          mp_raise_OSError(MP_EIO);
      }
  
      gpio_set_pin_direction(clock->pin, GPIO_DIRECTION_OUT);
      gpio_set_pin_pull_mode(clock->pin, GPIO_PULL_OFF);
      gpio_set_pin_function(clock->pin, clock_pinmux);
      claim_pin(clock);
      self->clock_pin = clock->pin;
  
      if (mosi_none) {
          self->MOSI_pin = NO_PIN;
      } else {
          gpio_set_pin_direction(mosi->pin, GPIO_DIRECTION_OUT);
          gpio_set_pin_pull_mode(mosi->pin, GPIO_PULL_OFF);
          gpio_set_pin_function(mosi->pin, mosi_pinmux);
          self->MOSI_pin = mosi->pin;
          claim_pin(mosi);
      }
  
      if (miso_none) {
          self->MISO_pin = NO_PIN;
      } else {
          gpio_set_pin_direction(miso->pin, GPIO_DIRECTION_IN);
          gpio_set_pin_pull_mode(miso->pin, GPIO_PULL_OFF);
          gpio_set_pin_function(miso->pin, miso_pinmux);
          self->MISO_pin = miso->pin;
          claim_pin(miso);
      }
  
      spi_m_sync_enable(&self->spi_desc);
  }
  
  bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
      return self->clock_pin == NO_PIN;
  }
  
  void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {
      if (common_hal_busio_spi_deinited(self)) {
          return;
      }
      spi_m_sync_disable(&self->spi_desc);
      spi_m_sync_deinit(&self->spi_desc);
      reset_pin(self->clock_pin);
      reset_pin(self->MOSI_pin);
      reset_pin(self->MISO_pin);
      self->clock_pin = NO_PIN;
  }
  
  bool common_hal_busio_spi_configure(busio_spi_obj_t *self,
          uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t bits) {
      uint8_t baud_reg_value = samd_peripherals_spi_baudrate_to_baud_reg_value(baudrate);
  
      void * hw = self->spi_desc.dev.prvt;
      // If the settings are already what we want then don't reset them.
      if (hri_sercomspi_get_CTRLA_CPHA_bit(hw) == phase &&
          hri_sercomspi_get_CTRLA_CPOL_bit(hw) == polarity &&
          hri_sercomspi_read_CTRLB_CHSIZE_bf(hw) == ((uint32_t)bits - 8) &&
          hri_sercomspi_read_BAUD_BAUD_bf(hw) == baud_reg_value) {
          return true;
      }
  
      // Disable, set values (most or all are enable-protected), and re-enable.
      spi_m_sync_disable(&self->spi_desc);
      hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
  
      hri_sercomspi_write_CTRLA_CPHA_bit(hw, phase);
      hri_sercomspi_write_CTRLA_CPOL_bit(hw, polarity);
      hri_sercomspi_write_CTRLB_CHSIZE_bf(hw, bits - 8);
      hri_sercomspi_write_BAUD_BAUD_bf(hw, baud_reg_value);
      hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
  
      spi_m_sync_enable(&self->spi_desc);
      hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
  
      return true;
  }
  
  bool common_hal_busio_spi_try_lock(busio_spi_obj_t *self) {
      bool grabbed_lock = false;
      CRITICAL_SECTION_ENTER()
          if (!self->has_lock) {
              grabbed_lock = true;
              self->has_lock = true;
          }
      CRITICAL_SECTION_LEAVE();
      return grabbed_lock;
  }
  
  bool common_hal_busio_spi_has_lock(busio_spi_obj_t *self) {
      return self->has_lock;
  }
  
  void common_hal_busio_spi_unlock(busio_spi_obj_t *self) {
      self->has_lock = false;
  }
  
  bool common_hal_busio_spi_write(busio_spi_obj_t *self,
          const uint8_t *data, size_t len) {
      if (len == 0) {
          return true;
      }
      int32_t status;
      if (len >= 16) {
          status = sercom_dma_write(self->spi_desc.dev.prvt, data, len);
      } else {
          struct io_descriptor *spi_io;
          spi_m_sync_get_io_descriptor(&self->spi_desc, &spi_io);
          status = spi_io->write(spi_io, data, len);
      }
      return status >= 0; // Status is number of chars read or an error code < 0.
  }
  
  bool common_hal_busio_spi_read(busio_spi_obj_t *self,
          uint8_t *data, size_t len, uint8_t write_value) {
      if (len == 0) {
          return true;
      }
      int32_t status;
      if (len >= 16) {
          status = sercom_dma_read(self->spi_desc.dev.prvt, data, len, write_value);
      } else {
          self->spi_desc.dev.dummy_byte = write_value;
  
          struct io_descriptor *spi_io;
          spi_m_sync_get_io_descriptor(&self->spi_desc, &spi_io);
  
          status = spi_io->read(spi_io, data, len);
      }
      return status >= 0; // Status is number of chars read or an error code < 0.
  }
  
  bool common_hal_busio_spi_transfer(busio_spi_obj_t *self, uint8_t *data_out, uint8_t *data_in, size_t len) {
      if (len == 0) {
          return true;
      }
      int32_t status;
      if (len >= 16) {
          status = sercom_dma_transfer(self->spi_desc.dev.prvt, data_out, data_in, len);
      } else {
          struct spi_xfer xfer;
          xfer.txbuf = data_out;
          xfer.rxbuf = data_in;
          xfer.size = len;
          status = spi_m_sync_transfer(&self->spi_desc, &xfer);
      }
      return status >= 0; // Status is number of chars read or an error code < 0.
  }
  
  uint32_t common_hal_busio_spi_get_frequency(busio_spi_obj_t* self) {
      return samd_peripherals_spi_baud_reg_value_to_baudrate(hri_sercomspi_read_BAUD_reg(self->spi_desc.dev.prvt));
  }
  