change half_duplex to be on spi construct

ports/stm/common-hal/busio/SPI.c

@@ -171,7 +171,7 @@ STATIC int check_pins(busio_spi_obj_t *self,
 
 void common_hal_busio_spi_construct(busio_spi_obj_t *self,
     const mcu_pin_obj_t *sck, const mcu_pin_obj_t *mosi,
-    const mcu_pin_obj_t *miso) {
+    const mcu_pin_obj_t *miso, bool half_duplex) {
 
     int periph_index = check_pins(self, sck, mosi, miso);
     SPI_TypeDef *SPIx = mcu_spi_banks[periph_index - 1];
@@ -208,12 +208,11 @@ void common_hal_busio_spi_construct(busio_spi_obj_t *self,
 
     self->handle.Instance = SPIx;
     self->handle.Init.Mode = SPI_MODE_MASTER;
-    if (self->mosi == NULL && self->miso != NULL) {
+    // Direction change only required for RX-only, see RefMan RM0090:884
-        self->handle.Init.Direction = SPI_DIRECTION_2LINES_RXONLY;
+    if (half_duplex == true) {
-    } else if (self->mosi != NULL && self->miso == NULL) {
         self->handle.Init.Direction = SPI_DIRECTION_1LINE;
-    } else if (self->mosi != NULL && self->miso != NULL) {
+    } else {
-        self->handle.Init.Direction = SPI_DIRECTION_2LINES;
+        self->handle.Init.Direction = (self->mosi == NULL) ? SPI_DIRECTION_2LINES_RXONLY : SPI_DIRECTION_2LINES;
     }
     self->handle.Init.DataSize = SPI_DATASIZE_8BIT;
     self->handle.Init.CLKPolarity = SPI_POLARITY_LOW;
@@ -229,6 +228,7 @@ void common_hal_busio_spi_construct(busio_spi_obj_t *self,
     }
     self->baudrate = (get_busclock(SPIx) / 16);
     self->prescaler = 16;
+    self->half_duplex = half_duplex;
     self->polarity = 0;
     self->phase = 0;
     self->bits = 8;
@@ -345,11 +345,15 @@ bool common_hal_busio_spi_write(busio_spi_obj_t *self,
 
 bool common_hal_busio_spi_read(busio_spi_obj_t *self,
     uint8_t *data, size_t len, uint8_t write_value) {
+    if (self->miso == NULL && self->half_duplex == false) {
+        mp_raise_ValueError(translate("No MISO Pin"));
+    } else if (self->half_duplex == true && self->mosi == NULL) {
+        mp_raise_ValueError(translate("No MOSI Pin"));
+    }
     HAL_StatusTypeDef result = HAL_OK;
-    // If in modes SPI_DIRECTION_2LINES_RXONLY or SPI_DIRECTION_1LINE
+    if ((self->half_duplex == false && self->mosi == NULL) || (self->half_duplex == true && self->mosi != NULL && self->miso == NULL)) {
-    if ((self->mosi == NULL && self->miso != NULL) || (self->mosi != NULL && self->miso == NULL)) {
         result = HAL_SPI_Receive(&self->handle, data, (uint16_t)len, HAL_MAX_DELAY);
-    } else { // Else SPI_DIRECTION_2LINES
+    } else {
         memset(data, write_value, len);
         result = HAL_SPI_TransmitReceive(&self->handle, data, data, (uint16_t)len, HAL_MAX_DELAY);
     }

ports/stm/common-hal/busio/SPI.h

@@ -44,6 +44,7 @@ typedef struct {
     const mcu_periph_obj_t *nss;
     uint32_t baudrate;
     uint16_t prescaler;
+    bool half_duplex;
     uint8_t polarity;
     uint8_t phase;
     uint8_t bits;

shared-bindings/busio/SPI.c

@@ -74,7 +74,8 @@
 //|
 //|         :param ~microcontroller.Pin clock: the pin to use for the clock.
 //|         :param ~microcontroller.Pin MOSI: the Main Out Selected In pin.
-//|         :param ~microcontroller.Pin MISO: the Main In Selected Out pin."""
+//|         :param ~microcontroller.Pin MISO: the Main In Selected Out pin.
+//|         :param bool half_duplex: True when MOSI is used for bidirectional data. False when SPI is full-duplex or simplex."""
 //|         ...
 //|
 
@@ -84,11 +85,12 @@ STATIC mp_obj_t busio_spi_make_new(const mp_obj_type_t *type, size_t n_args, siz
     #if CIRCUITPY_BUSIO_SPI
     busio_spi_obj_t *self = m_new_obj(busio_spi_obj_t);
     self->base.type = &busio_spi_type;
-    enum { ARG_clock, ARG_MOSI, ARG_MISO };
+    enum { ARG_clock, ARG_MOSI, ARG_MISO, ARG_half_duplex };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_clock, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_MOSI, MP_ARG_OBJ, {.u_obj = mp_const_none} },
         { MP_QSTR_MISO, MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_half_duplex, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_bool = false} },
     };
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
@@ -101,7 +103,7 @@ STATIC mp_obj_t busio_spi_make_new(const mp_obj_type_t *type, size_t n_args, siz
         mp_raise_ValueError(translate("Must provide MISO or MOSI pin"));
     }
 
-    common_hal_busio_spi_construct(self, clock, mosi, miso);
+    common_hal_busio_spi_construct(self, clock, mosi, miso, args[ARG_half_duplex].u_bool);
     return MP_OBJ_FROM_PTR(self);
     #else
     mp_raise_ValueError(translate("Invalid pins"));

shared-bindings/busio/SPI.h

@@ -38,7 +38,7 @@ extern const mp_obj_type_t busio_spi_type;
 // Construct an underlying SPI object.
 extern 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);
+    const mcu_pin_obj_t *miso, bool half_duplex);
 
 extern void common_hal_busio_spi_deinit(busio_spi_obj_t *self);
 extern bool common_hal_busio_spi_deinited(busio_spi_obj_t *self);

shared-module/board/__init__.c

@@ -131,7 +131,7 @@ mp_obj_t common_hal_board_create_spi(const mp_int_t instance) {
     assert_pin_free(spi_pin[instance].mosi);
     assert_pin_free(spi_pin[instance].miso);
 
-    common_hal_busio_spi_construct(self, spi_pin[instance].clock, spi_pin[instance].mosi, spi_pin[instance].miso);
+    common_hal_busio_spi_construct(self, spi_pin[instance].clock, spi_pin[instance].mosi, spi_pin[instance].miso, false);
 
     spi_obj_created[instance] = true;
     return &spi_obj[instance];

supervisor/shared/external_flash/spi_flash.c

@@ -149,7 +149,7 @@ void spi_flash_init(void) {
     common_hal_digitalio_digitalinout_never_reset(&cs_pin);
 
     supervisor_flash_spi_bus.base.type = &busio_spi_type;
-    common_hal_busio_spi_construct(&supervisor_flash_spi_bus, SPI_FLASH_SCK_PIN, SPI_FLASH_MOSI_PIN, SPI_FLASH_MISO_PIN);
+    common_hal_busio_spi_construct(&supervisor_flash_spi_bus, SPI_FLASH_SCK_PIN, SPI_FLASH_MOSI_PIN, SPI_FLASH_MISO_PIN, false);
     common_hal_busio_spi_never_reset(&supervisor_flash_spi_bus);
 
     return;

supervisor/shared/status_leds.c

@@ -163,7 +163,8 @@ void status_led_init() {
     common_hal_busio_spi_construct(&status_apa102,
         MICROPY_HW_APA102_SCK,
         MICROPY_HW_APA102_MOSI,
-        NULL);
+        NULL,
+        false);
     #endif
     #if CIRCUITPY_BITBANG_APA102
     shared_module_bitbangio_spi_try_lock(&status_apa102);