rp2: Add new NO_DEFAULT_PINS config options for i2c, spi, and uart.

Some boards have multiple options for these pins, and they don't want to
allow users to initialize a port without explicitly specifying pin numbers.

Signed-off-by: Paul Grayson <paul@pololu.com>

ports/rp2/machine_i2c.c

@@ -34,6 +34,20 @@
 #define DEFAULT_I2C_FREQ (400000)
 #define DEFAULT_I2C_TIMEOUT (50000)
 
+#ifdef MICROPY_HW_I2C_NO_DEFAULT_PINS
+
+// With no default I2C, need to require the pin args.
+#define MICROPY_HW_I2C0_SCL (0)
+#define MICROPY_HW_I2C0_SDA (0)
+#define MICROPY_HW_I2C1_SCL (0)
+#define MICROPY_HW_I2C1_SDA (0)
+#define MICROPY_I2C_PINS_ARG_OPTS MP_ARG_REQUIRED
+
+#else
+
+// Most boards do not require pin args.
+#define MICROPY_I2C_PINS_ARG_OPTS 0
+
 #ifndef MICROPY_HW_I2C0_SCL
 #if PICO_DEFAULT_I2C == 0
 #define MICROPY_HW_I2C0_SCL (PICO_DEFAULT_I2C_SCL_PIN)
@@ -53,6 +67,7 @@
 #define MICROPY_HW_I2C1_SDA (6)
 #endif
 #endif
+#endif
 
 // SDA/SCL on even/odd pins, I2C0/I2C1 on even/odd pairs of pins.
 #define IS_VALID_SCL(i2c, pin) (((pin) & 1) == 1 && (((pin) & 2) >> 1) == (i2c))
@@ -84,8 +99,8 @@ mp_obj_t machine_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_freq, MP_ARG_INT, {.u_int = DEFAULT_I2C_FREQ} },
-        { MP_QSTR_scl, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
-        { MP_QSTR_sda, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_scl, MICROPY_I2C_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_sda, MICROPY_I2C_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_I2C_TIMEOUT} },
     };
 

ports/rp2/machine_spi.c

@@ -38,6 +38,22 @@
 #define DEFAULT_SPI_BITS        (8)
 #define DEFAULT_SPI_FIRSTBIT    (SPI_MSB_FIRST)
 
+#ifdef MICROPY_HW_SPI_NO_DEFAULT_PINS
+
+// With no default SPI, need to require the pin args.
+#define MICROPY_HW_SPI0_SCK     (0)
+#define MICROPY_HW_SPI0_MOSI    (0)
+#define MICROPY_HW_SPI0_MISO    (0)
+#define MICROPY_HW_SPI1_SCK     (0)
+#define MICROPY_HW_SPI1_MOSI    (0)
+#define MICROPY_HW_SPI1_MISO    (0)
+#define MICROPY_SPI_PINS_ARG_OPTS MP_ARG_REQUIRED
+
+#else
+
+// Most boards do not require pin args.
+#define MICROPY_SPI_PINS_ARG_OPTS 0
+
 #ifndef MICROPY_HW_SPI0_SCK
 #if PICO_DEFAULT_SPI == 0
 #define MICROPY_HW_SPI0_SCK     (PICO_DEFAULT_SPI_SCK_PIN)
@@ -62,6 +78,8 @@
 #endif
 #endif
 
+#endif
+
 // SPI0 can be GP{0..7,16..23}, SPI1 can be GP{8..15,24..29}.
 #define IS_VALID_PERIPH(spi, pin)   ((((pin) & 8) >> 3) == (spi))
 // GP{2,6,10,14,...}
@@ -116,9 +134,9 @@ mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
         { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_PHASE} },
         { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_BITS} },
         { MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_FIRSTBIT} },
-        { MP_QSTR_sck,      MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
-        { MP_QSTR_mosi,     MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
-        { MP_QSTR_miso,     MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_sck,      MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_mosi,     MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_miso,     MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
     };
 
     // Parse the arguments.

ports/rp2/machine_uart.c

@@ -40,6 +40,14 @@
 #define DEFAULT_UART_BITS (8)
 #define DEFAULT_UART_STOP (1)
 
+#ifdef MICROPY_HW_UART_NO_DEFAULT_PINS
+// With no default I2C, need to require the pin args.
+#define MICROPY_UART_PINS_ARG_OPTS MP_ARG_REQUIRED
+#else
+// Most boards do not require pin args.
+#define MICROPY_UART_PINS_ARG_OPTS 0
+#endif
+
 // UART 0 default pins
 #if !defined(MICROPY_HW_UART0_TX)
 #define MICROPY_HW_UART0_TX (0)
@@ -225,8 +233,8 @@ STATIC void mp_machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args,
         { MP_QSTR_bits, MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_parity, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_INT(-1)} },
         { MP_QSTR_stop, MP_ARG_INT, {.u_int = -1} },
-        { MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
-        { MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_tx, MICROPY_UART_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_rx, MICROPY_UART_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_cts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_rts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },