Use wfi in otherwise empty infinite loops in examples

boards/rp-pico/examples/pico_i2c_pio.rs

@@ -149,7 +149,7 @@ fn main() -> ! {
     print_temperature(&mut uart, temp);
 
     loop {
-        cortex_m::asm::nop();
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/dht11.rs

@@ -139,9 +139,8 @@ fn main() -> ! {
     // In this case, we just ignore the result. A real application
     // would do something with the measurement.
 
-    #[allow(clippy::empty_loop)]
     loop {
-        // Empty loop
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/gpio_irq_example.rs

@@ -147,11 +147,7 @@ fn main() -> ! {
 
     loop {
         // interrupts handle everything else in this example.
-        // if we wanted low power we could go to sleep. to
-        // keep this example simple we'll just execute a `nop`.
-        // the `nop` (No Operation) instruction does nothing,
-        // but if we have no code here clippy would complain.
-        cortex_m::asm::nop();
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/i2c.rs

@@ -97,9 +97,8 @@ fn main() -> ! {
 
     // Demo finish - just loop until reset
 
-    #[allow(clippy::empty_loop)]
     loop {
-        // Empty loop
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/lcd_display.rs

@@ -113,9 +113,8 @@ fn main() -> ! {
     lcd.write_str("HD44780!", &mut delay).unwrap();
 
     // Do nothing - we're finished
-    #[allow(clippy::empty_loop)]
     loop {
-        // Empty loop
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/pio_blink.rs

@@ -64,6 +64,7 @@ fn main() -> ! {
     sm.start();
 
     // PIO runs in background, independently from CPU
-    #[allow(clippy::empty_loop)]
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

rp2040-hal/examples/pio_proc_blink.rs

@@ -54,6 +54,7 @@ fn main() -> ! {
     sm.start();
 
     // PIO runs in background, independently from CPU
-    #[allow(clippy::empty_loop)]
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

rp2040-hal/examples/pio_side_set.rs

@@ -57,6 +57,7 @@ fn main() -> ! {
     sm.start();
 
     // PIO runs in background, independently from CPU
-    #[allow(clippy::empty_loop)]
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

rp2040-hal/examples/pio_synchronized.rs

@@ -91,6 +91,7 @@ fn main() -> ! {
     cortex_m::asm::delay(10_000_000);
     let _sm2 = sm2.stop();
 
-    #[allow(clippy::empty_loop)]
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

rp2040-hal/examples/rom_funcs.rs

@@ -166,7 +166,7 @@ fn main() -> ! {
 
     // In case the reboot fails
     loop {
-        cortex_m::asm::nop();
+        cortex_m::asm::wfi();
     }
 }
 

rp2040-hal/examples/spi.rs

@@ -121,9 +121,8 @@ fn main() -> ! {
         Err(_) => {} // handle errors
     };
 
-    #[allow(clippy::empty_loop)]
     loop {
-        // Empty loop
+        cortex_m::asm::wfi();
     }
 }