spi: Tolerate platforms defining their enums differently

.github/workflows/test.yml

@@ -24,7 +24,7 @@ jobs:
         # info-applications` that is probably relevant; more is covered when
         # riot-wrappers are updated in RIOT.
         example: [examples/rust-hello-world, examples/rust-gcoap, examples/rust-async, tests/rust_minimal, tests/rust_libs]
-        board: [native, sltb001a, samr21-xpro, stk3700]
+        board: [native, sltb001a, samr21-xpro, stk3700, stm32f429i-disc1, usb-kw41z]
     steps:
     # common steps start here
     - name: Check out riot-wrappers
@@ -88,7 +88,7 @@ jobs:
     container: riot/riotbuild
     strategy:
       matrix:
-        board: [native, sltb001a, samr21-xpro, stk3700]
+        board: [native, sltb001a, samr21-xpro, stk3700, stm32f429i-disc1, usb-kw41z]
         testdir: ${{ fromJSON(needs.enumerate-wrappers-tests.outputs.list) }}
     steps:
     # common steps start here (kept in sync even though we wouldn't need to patch RIOT's .cargo/config.toml)

build.rs

@@ -153,6 +153,10 @@ fn main() {
         .into();
     println!("cargo:rerun-if-env-changed=RIOTBASE");
 
+    // FIXME: We're trying to get rid of that dependency in
+    // <https://github.com/RIOT-OS/rust-riot-sys/pull/38>, but for this one, there are no good
+    // alternatives.
+    let bindgen_output_file = std::env::var("DEP_RIOT_SYS_BINDGEN_OUTPUT_FILE").unwrap();
     let emulate_accessible = [
         // It's a static inline function and riot-sys currently only gives the file for the bindgen
         // output, not the c2rust output. Using coap_build_udp_hdr presence as a stand-in.
@@ -164,6 +168,11 @@ fn main() {
             &"sys/include/net/nanocoap.h",
             &"coap_pkt_set_code",
         ),
+        (
+            &"spi_clk_t_SPI_CLK_100KHZ",
+            &bindgen_output_file.as_str(),
+            &"spi_clk_t_SPI_CLK_100KHZ",
+        ),
     ];
 
     for (rust_name, header_file, header_search_string) in emulate_accessible {

src/spi/for_embedded_hal_1.rs

@@ -24,6 +24,29 @@ use core::convert::Infallible;
 use core::num::NonZero;
 use embedded_hal::spi::{ErrorType, Mode, Operation};
 
+// The way that cpu/stm32/include/periph/cpu_spi.h defines its enum values through a macro causes
+// them to be unprefixed for unknown reasons.
+//
+// This may become better when running a bindgen update, or when going with
+// <https://github.com/RIOT-OS/rust-riot-sys/pull/32>.
+#[cfg(accessible_riot_sys_spi_clk_t_SPI_CLK_100KHZ)]
+mod frequency {
+    pub(super) const SPI_CLK_100KHZ: riot_sys::spi_clk_t = riot_sys::spi_clk_t_SPI_CLK_100KHZ;
+    pub(super) const SPI_CLK_400KHZ: riot_sys::spi_clk_t = riot_sys::spi_clk_t_SPI_CLK_400KHZ;
+    pub(super) const SPI_CLK_1MHZ: riot_sys::spi_clk_t = riot_sys::spi_clk_t_SPI_CLK_1MHZ;
+    pub(super) const SPI_CLK_5MHZ: riot_sys::spi_clk_t = riot_sys::spi_clk_t_SPI_CLK_5MHZ;
+    pub(super) const SPI_CLK_10MHZ: riot_sys::spi_clk_t = riot_sys::spi_clk_t_SPI_CLK_10MHZ;
+}
+#[cfg(not(accessible_riot_sys_spi_clk_t_SPI_CLK_100KHZ))]
+mod frequency {
+    pub(super) const SPI_CLK_100KHZ: riot_sys::spi_clk_t = riot_sys::SPI_CLK_100KHZ;
+    pub(super) const SPI_CLK_400KHZ: riot_sys::spi_clk_t = riot_sys::SPI_CLK_400KHZ;
+    pub(super) const SPI_CLK_1MHZ: riot_sys::spi_clk_t = riot_sys::SPI_CLK_1MHZ;
+    pub(super) const SPI_CLK_5MHZ: riot_sys::spi_clk_t = riot_sys::SPI_CLK_5MHZ;
+    pub(super) const SPI_CLK_10MHZ: riot_sys::spi_clk_t = riot_sys::SPI_CLK_10MHZ;
+}
+use frequency::*;
+
 /// A RIOT SPI device combined with complete with mode and clock configuration, but no particular
 /// CS pin.
 ///
@@ -55,7 +78,7 @@ impl SpiBus {
         Self {
             bus,
             mode: riot_sys::spi_mode_t_SPI_MODE_0,
-            clk: riot_sys::spi_clk_t_SPI_CLK_100KHZ,
+            clk: SPI_CLK_100KHZ,
         }
     }
 
@@ -73,39 +96,39 @@ impl SpiBus {
     /// Sets the speed to 100KHz.
     pub fn with_speed_100khz(self) -> Self {
         Self {
-            clk: riot_sys::spi_clk_t_SPI_CLK_100KHZ,
+            clk: SPI_CLK_100KHZ,
             ..self
         }
     }
 
     /// Sets the speed to 400KHz.
     pub fn with_speed_400khz(self) -> Self {
         Self {
-            clk: riot_sys::spi_clk_t_SPI_CLK_400KHZ,
+            clk: SPI_CLK_400KHZ,
             ..self
         }
     }
 
     /// Sets the speed to 1MHz.
     pub fn with_speed_1mhz(self) -> Self {
         Self {
-            clk: riot_sys::spi_clk_t_SPI_CLK_1MHZ,
+            clk: SPI_CLK_1MHZ,
             ..self
         }
     }
 
     /// Sets the speed to 5MHz.
     pub fn with_speed_5mhz(self) -> Self {
         Self {
-            clk: riot_sys::spi_clk_t_SPI_CLK_5MHZ,
+            clk: SPI_CLK_5MHZ,
             ..self
         }
     }
 
     /// Sets the speed to 10MHz.
     pub fn with_speed_10mhz(self) -> Self {
         Self {
-            clk: riot_sys::spi_clk_t_SPI_CLK_10MHZ,
+            clk: SPI_CLK_10MHZ,
             ..self
         }
     }
@@ -184,7 +207,10 @@ impl SpiDevice {
     /// and its CS GPIO pin
     #[cfg(riot_module_periph_gpio)]
     pub fn new(bus: SpiBus, cs: crate::gpio::GPIO) -> Result<Self, NumericError> {
-        let cs = cs.to_c();
+        // spi_cs_t can be many things, but as the `spi_init_cs` documentation says that one can
+        // put a GPIO_PIN value in there, let's hope that this is only used where integer promotion
+        // actually makes sense (and where it makes sense, there is a .into()).
+        let cs: riot_sys::spi_cs_t = cs.to_c().into();
         (unsafe { riot_sys::spi_init_cs(bus.bus, cs) }).negative_to_error()?;
         Ok(Self { bus, cs })
     }