[can] `cfgs` for naming inconsistencies

Approach is similar to USB OTG.
STM32L49x and STML4Ax have CAN1 and CAN2.
All others STM32L4xx do only have CAN1.
STM32F72x and STM32F73x are the only F7 devices with only CAN1.

1 files changed, 16 insertions, 3 deletions

diff --git a/embassy-stm32/src/can/bxcan.rs b/embassy-stm32/src/can/bxcan.rs
index cb667695a..4887ee143 100644
--- a/embassy-stm32/src/can/bxcan.rs
+++ b/embassy-stm32/src/can/bxcan.rs
@@ -96,10 +96,23 @@ foreach_peripheral!(
     // CAN1 owns the filter bank and needs to be enabled in order
     // for CAN2 to receive messages.
     (can, CAN1) => {
-        unsafe impl bxcan::FilterOwner for peripherals::CAN1 {
-            const NUM_FILTER_BANKS: u8 = 28;
+        cfg_if::cfg_if! {
+            if #[cfg(all(
+                any(stm32l4, stm32l72, stm32l73),
+                not(any(stm32l49, stm32l4a))
+            ))] {
+                // Most L4 devices and some F7 devices use the name "CAN1"
+                // even if there is no "CAN2" peripheral.
+                unsafe impl bxcan::FilterOwner for peripherals::CAN1 {
+                    const NUM_FILTER_BANKS: u8 = 14;
+                }
+            } else {
+                unsafe impl bxcan::FilterOwner for peripherals::CAN1 {
+                    const NUM_FILTER_BANKS: u8 = 28;
+                }
+                unsafe impl bxcan::MasterInstance for peripherals::CAN1 {}
+            }
         }
-        unsafe impl bxcan::MasterInstance for peripherals::CAN1 {}
     };
     (can, CAN3) => {
         unsafe impl bxcan::FilterOwner for peripherals::CAN3 {