Serial: Implement UART peripherals based on device category

This requires setting an io-* Cargo feature in order to access the
`serial` module.

Author: dbrgn

Cargo.toml

@@ -264,15 +264,15 @@ opt-level = "s"
 
 [[example]]
 name = "adc_cont"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "adc_multi"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "adc_trig"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "aes_ecb"
@@ -312,15 +312,19 @@ required-features = ["rt","stm32l0x2"]
 
 [[example]]
 name = "rtc"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
+
+[[example]]
+name = "serial"
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "serial_dma"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "serial_dma_async"
-required-features = ["stm32l0x2"]
+required-features = ["stm32l0x2", "io-STM32L071"]
 
 [[example]]
 name = "timer"

src/dma.rs

@@ -39,9 +39,16 @@ use crate::{
         USART2,
     },
     rcc::Rcc,
-    serial,
 };
 
+#[cfg(any(
+    feature = "io-STM32L021",
+    feature = "io-STM32L031",
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
+use crate::serial;
+
 #[cfg(feature = "stm32l082")]
 use crate::aes;
 
@@ -521,13 +528,24 @@ impl_target!(
     // ADC
     adc::DmaToken, Channel1, 0;
     adc::DmaToken, Channel2, 0;
+);
 
+#[cfg(any(feature = "io-STM32L051", feature = "io-STM32L071"))]
+impl_target!(
     // USART1
     serial::Tx<USART1>, Channel2, 3;
     serial::Tx<USART1>, Channel4, 3;
     serial::Rx<USART1>, Channel3, 3;
     serial::Rx<USART1>, Channel5, 3;
+);
 
+#[cfg(any(
+    feature = "io-STM32L021",
+    feature = "io-STM32L031",
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
+impl_target!(
     // USART2
     serial::Tx<USART2>, Channel4, 4;
     serial::Tx<USART2>, Channel7, 4;

src/lib.rs

@@ -32,6 +32,12 @@ pub mod rcc;
 #[cfg(any(feature = "stm32l0x2", feature = "stm32l0x3"))]
 pub mod rng;
 pub mod rtc;
+#[cfg(any(
+    feature = "io-STM32L021",
+    feature = "io-STM32L031",
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
 pub mod serial;
 pub mod spi;
 pub mod syscfg;

src/prelude.rs

@@ -16,10 +16,6 @@ pub use crate::{
     i2c::I2cExt as _,
     pwr::PowerMode as _,
     rcc::RccExt as _,
-    serial::{
-        Serial1Ext as _,
-        Serial2Ext as _,
-    },
     spi::SpiExt as _,
     time::U32Ext as _,
     timer::TimerExt as _,
@@ -28,3 +24,26 @@ pub use crate::{
         WindowWatchdogExt as _,
     },
 };
+
+#[cfg(any(
+    feature = "io-STM32L021",
+    feature = "io-STM32L031",
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
+pub use crate::serial::{
+    Serial1LpExt as _,
+    Serial2Ext as _,
+};
+#[cfg(any(
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
+pub use crate::serial::Serial1LpExt as _;
+#[cfg(any(
+    feature = "io-STM32L071",
+))]
+pub use crate::serial::{
+    Serial4Ext as _,
+    Serial5Ext as _,
+};

src/serial.rs

@@ -638,17 +638,27 @@ macro_rules! usart {
     }
 }
 
-#[cfg(feature = "stm32l0x1")]
+// LPUART1 and USART2 are available on category 1/2/3/5 MCUs
+#[cfg(any(
+    feature = "io-STM32L021",
+    feature = "io-STM32L031",
+    feature = "io-STM32L051",
+    feature = "io-STM32L071",
+))]
 usart! {
-    LPUART1: (lpuart1, apb1enr, lpuart1en, apb1_clk, Serial1Ext),
+    LPUART1: (lpuart1, apb1enr, lpuart1en, apb1_clk, Serial1LpExt),
     USART2: (usart2, apb1enr, usart2en, apb1_clk, Serial2Ext),
 }
 
-#[cfg(any(feature = "stm32l0x2", feature = "stm32l0x3"))]
+// USART1 is available on category 3/5 MCUs
+#[cfg(any(feature = "io-STM32L051", feature = "io-STM32L071"))]
 usart! {
-    LPUART1: (lpuart1, apb1enr, lpuart1en, apb1_clk, Serial1LpExt),
     USART1: (usart1, apb2enr, usart1en, apb1_clk, Serial1Ext),
-    USART2: (usart2, apb1enr, usart2en, apb1_clk, Serial2Ext),
+}
+
+// USART4 and USART5 are available on category 5 MCUs
+#[cfg(feature = "io-STM32L071")]
+usart! {
     USART4: (usart4, apb1enr, usart4en, apb1_clk, Serial4Ext),
     USART5: (usart5, apb1enr, usart5en, apb1_clk, Serial5Ext),
 }