Standardize Marlin SPI (part 1) (#19989)

Marlin/src/HAL/STM32F1/MarlinSPI.h

@@ -0,0 +1,45 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include <SPI.h>
+
+/**
+ * Marlin currently requires 3 SPI classes:
+ *
+ * SPIClass:
+ *  This class is normally provided by frameworks and has a semi-default interface.
+ *  This is needed because some libraries reference it globally.
+ *
+ * SPISettings:
+ *  Container for SPI configs for SPIClass. As above, libraries may reference it globally.
+ *
+ * These two classes are often provided by frameworks so we cannot extend them to add
+ * useful methods for Marlin.
+ *
+ * MarlinSPI:
+ *  Provides the default SPIClass interface plus some Marlin goodies such as a simplified
+ *  interface for SPI DMA transfer.
+ *
+ */
+
+using MarlinSPI = SPIClass;

Marlin/src/HAL/STM32F1/SPI.cpp

@@ -147,6 +147,18 @@ SPIClass::SPIClass(uint32_t spi_num) {
   _currentSetting->state = SPI_STATE_IDLE;
 }
 
+SPIClass::SPIClass(int8_t mosi, int8_t miso, int8_t sclk, int8_t ssel) {
+  #if BOARD_NR_SPI >= 1
+    if (mosi == BOARD_SPI1_MOSI_PIN) SPIClass(1);
+  #endif
+  #if BOARD_NR_SPI >= 2
+    if (mosi == BOARD_SPI2_MOSI_PIN) SPIClass(2);
+  #endif
+  #if BOARD_NR_SPI >= 3
+    if (mosi == BOARD_SPI3_MOSI_PIN) SPIClass(3);
+  #endif
+}
+
 /**
  * Set up/tear down
  */

Marlin/src/HAL/STM32F1/SPI.h

@@ -163,6 +163,11 @@ public:
    */
   SPIClass(uint32_t spiPortNumber);
 
+  /**
+   * Init using pins
+   */
+  SPIClass(int8_t mosi, int8_t miso, int8_t sclk, int8_t ssel=-1);
+
   /**
    * @brief Equivalent to begin(SPI_1_125MHZ, MSBFIRST, 0).
    */