Support multiple ADCs. (#312)

* Support multiple ADCs.

* Add `AdcCommon` struct for ensuring safe `ADC_COMMON` access.

* Return `Option`s of ADC channels.

* Always ensure minimum sample time for VREF.

* Make minimum sample time more obvious.

* Add a way to get calibrated VDDA for ADC.

Author: reitermarkus

examples/adc.rs

@@ -5,7 +5,12 @@ use panic_rtt_target as _;
 
 use cortex_m_rt::entry;
 use rtt_target::{rprint, rprintln};
-use stm32l4xx_hal::{adc::ADC, delay::Delay, pac, prelude::*};
+use stm32l4xx_hal::{
+    adc::{Adc, AdcCommon},
+    delay::Delay,
+    pac,
+    prelude::*,
+};
 
 #[entry]
 fn main() -> ! {
@@ -22,13 +27,8 @@ fn main() -> ! {
     let clocks = rcc.cfgr.freeze(&mut flash.acr, &mut pwr);
 
     let mut delay = Delay::new(cp.SYST, clocks);
-    let mut adc = ADC::new(
-        dp.ADC1,
-        dp.ADC_COMMON,
-        &mut rcc.ahb2,
-        &mut rcc.ccipr,
-        &mut delay,
-    );
+    let adc_common = AdcCommon::new(dp.ADC_COMMON, &mut rcc.ahb2);
+    let mut adc = Adc::adc1(dp.ADC1, adc_common, &mut rcc.ccipr, &mut delay);
 
     let mut gpioc = dp.GPIOC.split(&mut rcc.ahb2);
     let mut a1 = gpioc.pc0.into_analog(&mut gpioc.moder, &mut gpioc.pupdr);

examples/adc_dma.rs

@@ -4,9 +4,10 @@
 use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
 use stm32l4xx_hal::{
-    adc::{DmaMode, SampleTime, Sequence, ADC},
+    adc::{Adc, AdcCommon, DmaMode, SampleTime, Sequence},
     delay::DelayCM,
     dma::{dma1, RxDma, Transfer, W},
+    pac::ADC1,
     prelude::*,
 };
 
@@ -19,7 +20,7 @@ const APP: () = {
     // RTIC app is written in here!
 
     struct Resources {
-        transfer: Option<Transfer<W, &'static mut [u16; SEQUENCE_LEN], RxDma<ADC, dma1::C1>>>,
+        transfer: Option<Transfer<W, &'static mut [u16; SEQUENCE_LEN], RxDma<Adc<ADC1>, dma1::C1>>>,
     }
 
     #[init]
@@ -54,15 +55,10 @@ const APP: () = {
 
         let mut delay = DelayCM::new(clocks);
 
-        let mut adc = ADC::new(
-            pac.ADC1,
-            pac.ADC_COMMON,
-            &mut rcc.ahb2,
-            &mut rcc.ccipr,
-            &mut delay,
-        );
+        let adc_common = AdcCommon::new(pac.ADC_COMMON, &mut rcc.ahb2);
+        let mut adc = Adc::adc1(pac.ADC1, adc_common, &mut rcc.ccipr, &mut delay);
 
-        let mut temp_pin = adc.enable_temperature(&mut delay);
+        let mut temp_pin = adc.enable_temperature(&mut delay).unwrap();
 
         let dma1_channel = dma_channels.1;