shared-bindings: Make MOSI and MISO optional for SPI.

4 files changed, 73 insertions, 26 deletions

diff --git a/atmel-samd/common-hal/nativeio/SPI.c b/atmel-samd/common-hal/nativeio/SPI.c
index 7600766f7..821652475 100644
--- a/atmel-samd/common-hal/nativeio/SPI.c
+++ b/atmel-samd/common-hal/nativeio/SPI.c
@@ -44,6 +44,8 @@ void common_hal_nativeio_spi_construct(nativeio_spi_obj_t *self,
 
     Sercom* sercom = NULL;
     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;
@@ -58,16 +60,27 @@ void common_hal_nativeio_spi_construct(nativeio_spi_obj_t *self,
         clock_pinmux = clock->sercom[i].pinmux;
         clock_pad = clock->sercom[i].pad;
         for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
-            mosi_pinmux = mosi->sercom[j].pinmux;
-            mosi_pad = mosi->sercom[j].pad;
-            for (int k = 0; k < NUM_SERCOMS_PER_PIN; k++) {
-                if (potential_sercom == miso->sercom[k].sercom) {
-                    miso_pinmux = miso->sercom[k].pinmux;
-                    miso_pad = miso->sercom[k].pad;
-                    sercom = potential_sercom;
+            if (!mosi_none) {
+                if(potential_sercom == mosi->sercom[j].sercom) {
+                    mosi_pinmux = mosi->sercom[j].pinmux;
+                    mosi_pad = mosi->sercom[j].pad;
+                    if (miso_none) {
+                        sercom = potential_sercom;
+                    }
+                } else {
                     break;
                 }
             }
+            if (!miso_none) {
+                for (int k = 0; k < NUM_SERCOMS_PER_PIN; k++) {
+                    if (potential_sercom == miso->sercom[k].sercom) {
+                        miso_pinmux = miso->sercom[k].pinmux;
+                        miso_pad = miso->sercom[k].pad;
+                        sercom = potential_sercom;
+                        break;
+                    }
+                }
+            }
             if (sercom != NULL) {
                 break;
             }
@@ -77,7 +90,7 @@ void common_hal_nativeio_spi_construct(nativeio_spi_obj_t *self,
         }
     }
     if (sercom == NULL) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError,
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
             "No hardware support available with those pins."));
     }
 
@@ -109,8 +122,12 @@ void common_hal_nativeio_spi_construct(nativeio_spi_obj_t *self,
                              &config_spi_master.pinmux_pad2,
                              &config_spi_master.pinmux_pad3};
     *pinmuxes[clock_pad] = clock_pinmux;
-    *pinmuxes[mosi_pad] = mosi_pinmux;
-    *pinmuxes[miso_pad] = miso_pinmux;
+    if (!mosi_none) {
+        *pinmuxes[mosi_pad] = mosi_pinmux;
+    }
+    if (!miso_none) {
+        *pinmuxes[miso_pad] = miso_pinmux;
+    }
 
     config_spi_master.mode_specific.master.baudrate = baudrate;
 
diff --git a/shared-bindings/bitbangio/SPI.c b/shared-bindings/bitbangio/SPI.c
index 4b6b1bacb..ea8c2f255 100644
--- a/shared-bindings/bitbangio/SPI.c
+++ b/shared-bindings/bitbangio/SPI.c
@@ -68,8 +68,8 @@ STATIC mp_obj_t bitbangio_spi_make_new(const mp_obj_type_t *type, size_t n_args,
     enum { ARG_clock, ARG_MOSI, ARG_MISO, ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit };
     static const mp_arg_t allowed_args[] = {
        { MP_QSTR_clock, MP_ARG_REQUIRED | MP_ARG_OBJ },
-       { MP_QSTR_MOSI, MP_ARG_REQUIRED | MP_ARG_OBJ },
-       { MP_QSTR_MISO, 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_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 100000} },
        { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
        { MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
diff --git a/shared-module/bitbangio/SPI.c b/shared-module/bitbangio/SPI.c
index 5d77efaf9..07322abd7 100644
--- a/shared-module/bitbangio/SPI.c
+++ b/shared-module/bitbangio/SPI.c
@@ -26,6 +26,7 @@
 
 #include "mpconfigport.h"
 
+#include "py/nlr.h"
 #include "py/obj.h"
 
 #include "common-hal/microcontroller/types.h"
@@ -40,18 +41,29 @@ extern void shared_module_bitbangio_spi_construct(bitbangio_spi_obj_t *self,
         const mcu_pin_obj_t * miso, uint32_t baudrate) {
     digitalinout_result_t result = common_hal_nativeio_digitalinout_construct(&self->clock, clock);
     if (result != DIGITALINOUT_OK) {
-        return;
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+            "Clock pin init failed."));
     }
-    result = common_hal_nativeio_digitalinout_construct(&self->mosi, mosi);
-    if (result != DIGITALINOUT_OK) {
-        common_hal_nativeio_digitalinout_deinit(&self->clock);
-        return;
+    if (mosi != mp_const_none) {
+        result = common_hal_nativeio_digitalinout_construct(&self->mosi, mosi);
+        if (result != DIGITALINOUT_OK) {
+            common_hal_nativeio_digitalinout_deinit(&self->clock);
+            nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+                "MOSI pin init failed."));
+        }
+        self->has_mosi = true;
     }
-    result = common_hal_nativeio_digitalinout_construct(&self->miso, miso);
-    if (result != DIGITALINOUT_OK) {
-        common_hal_nativeio_digitalinout_deinit(&self->clock);
-        common_hal_nativeio_digitalinout_deinit(&self->mosi);
-        return;
+    if (miso != mp_const_none) {
+        result = common_hal_nativeio_digitalinout_construct(&self->miso, miso);
+        if (result != DIGITALINOUT_OK) {
+            common_hal_nativeio_digitalinout_deinit(&self->clock);
+            if (mosi != mp_const_none) {
+                common_hal_nativeio_digitalinout_deinit(&self->mosi);
+            }
+            nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+                "MISO pin init failed."));
+        }
+        self->has_miso = true;
     }
 
     self->delay_half = 500000 / baudrate;
@@ -66,13 +78,25 @@ extern void shared_module_bitbangio_spi_construct(bitbangio_spi_obj_t *self,
 
 extern void shared_module_bitbangio_spi_deinit(bitbangio_spi_obj_t *self) {
     common_hal_nativeio_digitalinout_deinit(&self->clock);
-    common_hal_nativeio_digitalinout_deinit(&self->mosi);
-    common_hal_nativeio_digitalinout_deinit(&self->miso);
+    if (self->has_mosi) {
+        common_hal_nativeio_digitalinout_deinit(&self->mosi);
+    }
+    if (self->has_miso) {
+        common_hal_nativeio_digitalinout_deinit(&self->miso);
+    }
 }
 
 bool shared_module_bitbangio_spi_transfer(bitbangio_spi_obj_t *self,
         const uint8_t *write_buffer, size_t write_buffer_len,
         uint8_t *read_buffer, size_t read_buffer_len) {
+    if (write_buffer_len > 0 && !self->has_mosi) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+            "Cannot write without MOSI pin."));
+    }
+    if (read_buffer_len > 0 && !self->has_miso) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+            "Cannot read without MISO pin."));
+    }
     uint32_t delay_half = self->delay_half;
 
     // only MSB transfer is implemented
@@ -95,7 +119,9 @@ bool shared_module_bitbangio_spi_transfer(bitbangio_spi_obj_t *self,
         }
 
         // Clock out zeroes while we read.
-        common_hal_nativeio_digitalinout_set_value(&self->mosi, false);
+        if (self->has_mosi) {
+            common_hal_nativeio_digitalinout_set_value(&self->mosi, false);
+        }
         for (size_t i = 0; i < read_buffer_len; ++i) {
             uint8_t data_in = 0;
             for (int j = 0; j < 8; ++j, data_out <<= 1) {
@@ -135,7 +161,9 @@ bool shared_module_bitbangio_spi_transfer(bitbangio_spi_obj_t *self,
         MICROPY_EVENT_POLL_HOOK;
         #endif
     }
-    common_hal_nativeio_digitalinout_set_value(&self->mosi, false);
+    if (self->has_mosi) {
+        common_hal_nativeio_digitalinout_set_value(&self->mosi, false);
+    }
     for (size_t i = 0; i < read_buffer_len; ++i) {
         uint8_t data_in = 0;
         for (int j = 0; j < 8; ++j) {
diff --git a/shared-module/bitbangio/types.h b/shared-module/bitbangio/types.h
index e6a29ab54..e7fd95498 100644
--- a/shared-module/bitbangio/types.h
+++ b/shared-module/bitbangio/types.h
@@ -41,7 +41,9 @@ typedef struct {
 typedef struct {
     mp_obj_base_t base;
     nativeio_digitalinout_obj_t clock;
+    bool has_mosi;
     nativeio_digitalinout_obj_t mosi;
+    bool has_miso;
     nativeio_digitalinout_obj_t miso;
     uint32_t delay_half;
     uint8_t polarity;