boards,sys/arduino: major clean up

- Rename all `arduino_pinmap.h` to `arduino_iomap.h`
    - An empty `arduino_pinmap.h` that just includes `arduino_iomap.h`
      is provided for backward compatibility
    - Move all info from `arduino_board.h` into the new file as trivial
      macros, so that they can also be used outside of sketches
    - The new name reflects the fact not just pin mappings, but also
      other I/O features such as PWMs are mapped
- Drop all `arduino_board.h`
    - `arduino_board.h` and `arduino_iomap.h` now provide the exact
      same information, just in a different format
    - a generic `arduino_board.h` is provided instead that just
      uses the info in `arduinio_iomap.h` and provides them in the
      format the code in `sys/arduino` expects it
- Add fine grained features to indicate for mappings
    - availability of mappings for analog pins, DAC pins, PWM pins,
      UART devices, SPI/I2C buses to the corresponding RIOT
      identification can now be expressed:
        - `arduino_pins`: `ARDUINO_PIN_0` etc. are available
        - `arduino_analog`: `ARDUINO_A0` etc. are available
        - `arduino_pwm`: `ARDUINO_PIN_13_PWM_DEV` etc. are available
        - `arduino_dac`: `ARDUINO_DAC0` etc. are available
        - `arduino_uart`: `ARDUINO_UART_D0D1` or similar are available
        - `arduino_spi`: `ARDUINO_SPI_ISP` or similar are available
        - `arduino_i2c`: `ARDUINO_I2C_UNO` or similar are available
    - mechanical/electrical compatibility with specific form factors
      can now be expressed as features:
        - `aruino_shield_nano`: Arduino NANO compatible headers
        - `aruino_shield_uno`: Arduino UNO compatible headers
        - `aruino_shield_mega`: Arduino MEGA compatible headers
        - `aruino_shield_isp`: ISP header is available

This provides the groundwork to implement shield support as modules
that can rely on the I/O mappings, rather than having to provide a
configuration per board.

boards/adafruit-grand-central-m4-express/Makefile.features

@@ -15,5 +15,6 @@ FEATURES_PROVIDED += periph_uart
 FEATURES_PROVIDED += periph_usbdev
 
 # other board features
-FEATURES_PROVIDED += arduino
+FEATURES_PROVIDED += arduino_analog
+FEATURES_PROVIDED += arduino_pins
 FEATURES_PROVIDED += sdcard_spi

boards/adafruit-grand-central-m4-express/include/arduino_pinmap.h → boards/adafruit-grand-central-m4-express/include/arduino_iomap.h

@@ -16,8 +16,8 @@
  * @author      Gunar Schorcht <gunar@schorcht.net>
  */
 
-#ifndef ARDUINO_PINMAP_H
-#define ARDUINO_PINMAP_H
+#ifndef ARDUINO_IOMAP_H
+#define ARDUINO_IOMAP_H
 
 #include "periph/gpio.h"
 #include "periph/adc.h"
@@ -49,12 +49,25 @@ extern "C" {
 #define ARDUINO_PIN_14          GPIO_PIN(PB, 20)
 #define ARDUINO_PIN_15          GPIO_PIN(PB, 21)
 
-#define ARDUINO_PIN_A0          GPIO_PIN(PA, 3)
-#define ARDUINO_PIN_A1          GPIO_PIN(PC, 0)
-#define ARDUINO_PIN_A2          GPIO_PIN(PC, 3)
-#define ARDUINO_PIN_A3          GPIO_PIN(PC, 1)
-#define ARDUINO_PIN_A4          GPIO_PIN(PC, 4)
-#define ARDUINO_PIN_A5          GPIO_PIN(PC, 5)
+#define ARDUINO_PIN_16          GPIO_PIN(PA, 3)
+#define ARDUINO_PIN_17          GPIO_PIN(PC, 0)
+#define ARDUINO_PIN_18          GPIO_PIN(PC, 3)
+#define ARDUINO_PIN_19          GPIO_PIN(PC, 1)
+#define ARDUINO_PIN_20          GPIO_PIN(PC, 4)
+#define ARDUINO_PIN_21          GPIO_PIN(PC, 5)
+
+#define ARDUINO_PIN_LAST        21              /** D21 (A5) is the last digital pin */
+/** @} */
+
+/**
+ * @name    Aliases for analog pins
+ */
+#define ARDUINO_PIN_A0          ARDUINO_PIN_16  /**< Arduino pin A0 */
+#define ARDUINO_PIN_A1          ARDUINO_PIN_17  /**< Arduino pin A1 */
+#define ARDUINO_PIN_A2          ARDUINO_PIN_18  /**< Arduino pin A2 */
+#define ARDUINO_PIN_A3          ARDUINO_PIN_19  /**< Arduino pin A3 */
+#define ARDUINO_PIN_A4          ARDUINO_PIN_20  /**< Arduino pin A4 */
+#define ARDUINO_PIN_A5          ARDUINO_PIN_21  /**< Arduino pin A5 */
 /** @} */
 
 /**
@@ -67,11 +80,13 @@ extern "C" {
 #define ARDUINO_A3              ADC_LINE(3)
 #define ARDUINO_A4              ADC_LINE(4)
 #define ARDUINO_A5              ADC_LINE(5)
+
+#define ARDUINO_ANALOG_PIN_LAST 5           /**< A5 is the last analog pin */
 /** @} */
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* ARDUINO_PINMAP_H */
+#endif /* ARDUINO_IOMAP_H */
 /** @} */

boards/common/arduino-atmega/Makefile.features

@@ -7,5 +7,9 @@ FEATURES_PROVIDED += periph_timer
 FEATURES_PROVIDED += periph_uart
 
 # Various other features (if any)
-FEATURES_PROVIDED += arduino
+FEATURES_PROVIDED += arduino_analog
+FEATURES_PROVIDED += arduino_i2c
+FEATURES_PROVIDED += arduino_pins
 FEATURES_PROVIDED += arduino_pwm
+FEATURES_PROVIDED += arduino_spi
+FEATURES_PROVIDED += arduino_uart