stm32: Remove OptionalPin

The idea behind OptionalPin has a few problems:

- you need to impl the signal traits for NoPin which is a bit weird https://github.com/embassy-rs/embassy/blob/master/embassy-stm32/src/dcmi.rs#L413-L416
- you can pass any combination of set/unset pins, which needs checking at runtime  https://github.com/embassy-rs/embassy/blob/master/embassy-stm32/src/dcmi.rs#L130

The replacement is to do multiple `new` constructors for each combination of pins you want to take.

examples/stm32h7/src/bin/camera.rs

@@ -4,8 +4,8 @@
 
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_stm32::dcmi::*;
-use embassy_stm32::gpio::{Level, NoPin, Output, Speed};
+use embassy_stm32::dcmi::{self, *};
+use embassy_stm32::gpio::{Level, Output, Speed};
 use embassy_stm32::i2c::I2c;
 use embassy_stm32::interrupt;
 use embassy_stm32::rcc::{Mco, Mco1Source, McoClock};
@@ -78,31 +78,10 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     );
 
     let dcmi_irq = interrupt::take!(DCMI);
-    let mut dcmi = Dcmi::new(
-        p.DCMI,
-        p.DMA1_CH0,
-        VSyncDataInvalidLevel::High,
-        HSyncDataInvalidLevel::Low,
-        PixelClockPolarity::RisingEdge,
-        false,
-        dcmi_irq,
-        p.PC6,
-        p.PC7,
-        p.PE0,
-        p.PE1,
-        p.PE4,
-        p.PD3,
-        p.PE5,
-        p.PE6,
-        NoPin,
-        NoPin,
-        NoPin,
-        NoPin,
-        NoPin,
-        NoPin,
-        p.PB7,
-        p.PA4,
-        p.PA6,
+    let config = dcmi::Config::default();
+    let mut dcmi = Dcmi::new_8bit(
+        p.DCMI, p.DMA1_CH0, dcmi_irq, p.PC6, p.PC7, p.PE0, p.PE1, p.PE4, p.PD3, p.PE5, p.PE6,
+        p.PB7, p.PA4, p.PA6, config,
     );
 
     defmt::info!("attempting capture");

examples/stm32h7/src/bin/dac.rs

@@ -5,7 +5,6 @@
 #[path = "../example_common.rs"]
 mod example_common;
 
-use embassy_stm32::gpio::NoPin;
 use example_common::*;
 
 use cortex_m_rt::entry;
@@ -17,7 +16,7 @@ fn main() -> ! {
 
     let p = embassy_stm32::init(config());
 
-    let mut dac = Dac::new(p.DAC1, p.PA4, NoPin);
+    let mut dac = Dac::new_1ch(p.DAC1, p.PA4);
 
     loop {
         for v in 0..=255 {

examples/stm32h7/src/bin/low_level_timer_api.rs

@@ -10,7 +10,6 @@ use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy::util::Unborrow;
 use embassy_hal_common::unborrow;
-use embassy_stm32::gpio::NoPin;
 use embassy_stm32::pwm::{pins::*, Channel, OutputCompareMode};
 use embassy_stm32::time::{Hertz, U32Ext};
 use embassy_stm32::timer::GeneralPurpose32bitInstance;
@@ -33,7 +32,7 @@ pub fn config() -> Config {
 async fn main(_spawner: Spawner, p: Peripherals) {
     info!("Hello World!");
 
-    let mut pwm = SimplePwm32::new(p.TIM5, p.PA0, NoPin, NoPin, NoPin, 10000.hz());
+    let mut pwm = SimplePwm32::new(p.TIM5, p.PA0, p.PA1, p.PA2, p.PA3, 10000.hz());
     let max = pwm.get_max_duty();
     pwm.enable(Channel::Ch1);
 

examples/stm32h7/src/bin/pwm.rs

@@ -6,7 +6,6 @@
 mod example_common;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_stm32::gpio::NoPin;
 use embassy_stm32::pwm::{simple_pwm::SimplePwm, Channel};
 use embassy_stm32::time::U32Ext;
 use embassy_stm32::{Config, Peripherals};
@@ -28,7 +27,7 @@ pub fn config() -> Config {
 async fn main(_spawner: Spawner, p: Peripherals) {
     info!("Hello World!");
 
-    let mut pwm = SimplePwm::new(p.TIM3, p.PA6, NoPin, NoPin, NoPin, 10000.hz());
+    let mut pwm = SimplePwm::new_1ch(p.TIM3, p.PA6, 10000.hz());
     let max = pwm.get_max_duty();
     pwm.enable(Channel::Ch1);