Pass config directly to chip specific configure function

This removes the need to duplicate the configuration for each individual
chip, but will instead pass on the configuration specified in the config
attribute.

Update nrf, stm32, rp macros with passing the config to a per-chip
configure function which assumes the appropriate configuration to be
passed to it.

To demonstrate this feature, the stm32l0xx clock setup and RTC is added which exposes
clock configuration different from stm32f4xx (and has a different set of timers and HAL APIs).

embassy-stm32-examples/src/bin/rtc_async.rs

@@ -10,6 +10,7 @@ use example_common::*;
 
 use defmt::panic;
 use embassy;
+
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_stm32;
@@ -31,7 +32,7 @@ async fn run2() {
     }
 }
 
-#[embassy::main(use_hse = 16)]
+#[embassy::main(config = "embassy_stm32::system::Config::new().use_hse(16)")]
 async fn main(spawner: Spawner) {
     let (dp, clocks) = embassy_stm32::Peripherals::take().unwrap();
 

embassy-stm32-examples/src/bin/serial.rs

@@ -22,7 +22,7 @@ use embassy_stm32::pac as stm32;
 use embassy_stm32::serial;
 use futures::pin_mut;
 
-#[embassy::main(use_hse = 16, sysclk = 48, pclk1 = 24)]
+#[embassy::main(config = "embassy_stm32::system::Config::new().use_hse(16).sysclk(48).pclk1(24)")]
 async fn main(spawner: Spawner) {
     let (dp, clocks) = embassy_stm32::Peripherals::take().unwrap();
     let cp = cortex_m::peripheral::Peripherals::take().unwrap();

embassy-stm32-examples/src/bin/usb_serial.rs

@@ -92,7 +92,9 @@ async fn run1(bus: &'static mut UsbBusAllocator<UsbBus<USB>>) {
 
 static USB_BUS: Forever<UsbBusAllocator<UsbBus<USB>>> = Forever::new();
 
-#[embassy::main(use_hse = 25, sysclk = 48, require_pll48clk)]
+#[embassy::main(
+    config = "embassy_stm32::system::Config::new().use_hse(25).sysclk(48).require_pll48clk()"
+)]
 async fn main(spawner: Spawner) -> ! {
     static mut EP_MEMORY: [u32; 1024] = [0; 1024];