Fix clippy lint

clippy::empty-loop

Author: Sh3Rm4n

examples/can.rs

@@ -6,9 +6,9 @@ use panic_semihosting as _;
 
 use stm32f3xx_hal as hal;
 
+use cortex_m::asm;
 use cortex_m_rt::entry;
 
-use cortex_m::asm;
 use hal::prelude::*;
 use hal::stm32;
 use hal::watchdog::IndependentWatchDog;

examples/pwm.rs

@@ -7,6 +7,7 @@ use panic_semihosting as _;
 
 use stm32f3xx_hal as hal;
 
+use cortex_m::asm;
 use cortex_m_rt::entry;
 
 //use cortex_m_semihosting::hprintln;
@@ -148,5 +149,7 @@ fn main() -> ! {
     // DOES NOT COMPILE
     // tim8_ch1.output_to_pc6(gpioc.pc6.into_af4(&mut gpioc.moder, &mut gpioc.afrl));
 
-    loop {}
+    loop {
+        asm::wfi();
+    }
 }

examples/serial_dma.rs

@@ -7,7 +7,7 @@
 
 use panic_semihosting as _;
 
-use cortex_m::singleton;
+use cortex_m::{asm, singleton};
 use cortex_m_rt::entry;
 use stm32f3xx_hal::{pac, prelude::*, serial::Serial};
 
@@ -63,6 +63,6 @@ fn main() -> ! {
     assert_eq!(tx_buf, rx_buf);
 
     loop {
-        continue;
+        asm::wfi();
     }
 }

examples/spi.rs

@@ -7,6 +7,7 @@ use panic_semihosting as _;
 
 use stm32f3xx_hal as hal;
 
+use cortex_m::asm;
 use cortex_m_rt::entry;
 
 use hal::pac;
@@ -61,5 +62,7 @@ fn main() -> ! {
     // This succeeds, when master and slave of the SPI are connected.
     assert_eq!(msg_send, msg_received);
 
-    loop {}
+    loop {
+        asm::wfi();
+    }
 }