Add SPI support to STM32 platform

Signed-off-by: Paul Guyot <pguyot@kallisys.net>

Author: pguyot

.github/workflows/stm32-build.yaml

@@ -158,7 +158,7 @@ jobs:
         mkdir build-host
         cd build-host
         cmake .. -G Ninja
-        cmake --build . -t stm32_boot_test stm32_gpio_test stm32_i2c_test
+        cmake --build . -t stm32_boot_test stm32_gpio_test stm32_i2c_test stm32_spi_test
 
     - name: Install Renode
       if: matrix.renode_platform
@@ -214,3 +214,18 @@ jobs:
           --variable AVM:@$PWD/build-host/src/platforms/stm32/tests/test_erl_sources/stm32_i2c_test.avm \
           --variable AVM_ADDRESS:${{ matrix.avm_address }} \
           --variable PLATFORM:$PLATFORM
+
+    - name: Run Renode SPI test
+      if: matrix.renode_platform
+      run: |
+        LOCAL_REPL="src/platforms/stm32/tests/renode/${{ matrix.renode_platform }}"
+        if [ -f "$LOCAL_REPL" ]; then
+          PLATFORM="@$PWD/$LOCAL_REPL"
+        else
+          PLATFORM="@platforms/cpus/${{ matrix.renode_platform }}"
+        fi
+        renode-test src/platforms/stm32/tests/renode/stm32_spi_test.robot \
+          --variable ELF:@$PWD/src/platforms/stm32/build/AtomVM-${{ matrix.device }}.elf \
+          --variable AVM:@$PWD/build-host/src/platforms/stm32/tests/test_erl_sources/stm32_spi_test.avm \
+          --variable AVM_ADDRESS:${{ matrix.avm_address }} \
+          --variable PLATFORM:$PLATFORM

examples/erlang/spi_flash.erl

@@ -108,6 +108,7 @@ default_pins() ->
 
 %%         {SCK, MOSI, MISO, CS}
 default_pins(pico) -> {2, 3, 4, 5};
+default_pins(stm32) -> {{a, 5}, {a, 7}, {a, 6}, {a, 4}};
 default_pins(esp32) -> esp32_default_pins().
 
 esp32_default_pins() ->

libs/avm_stm32/src/CMakeLists.txt

@@ -25,6 +25,7 @@ include(BuildErlang)
 set(ERLANG_MODULES
     gpio
     i2c
+    spi
 )
 
 pack_archive(avm_stm32 DEPENDS_ON eavmlib ERLC_FLAGS +warnings_as_errors MODULES ${ERLANG_MODULES})

libs/avm_stm32/src/gpio.erl

@@ -58,8 +58,10 @@
 -type direction() :: input | output | output_od | mode_config().
 %% The direction is used to set the mode of operation for a GPIO pin, either as an input, an output, or output with open drain.
 %% Pull mode and output_speed must be set at the same time as direction. See @type mode_config()
--type mode_config() :: {direction(), pull()} | {output, pull(), output_speed()}.
+-type mode_config() ::
+    {direction(), pull()} | {output, pull(), output_speed()} | {af, non_neg_integer()}.
 %% Extended mode configuration options. Default pull() is `floating', default output_speed() is `mhz_2' if options are omitted.
+%% `{af, AFNumber}' configures the pin in alternate function push-pull mode with the given AF number (e.g. 5 for SPI1).
 -type pull() :: up | down | floating.
 %% Internal resistor pull mode. STM32 does not support `up_down'.
 -type output_speed() :: mhz_2 | mhz_25 | mhz_50 | mhz_100.