Add IOConfig struct and pub fn io_config()

The STM32 TSC needs to do successive acquisitions when using multiple channels in a group. To do this the IOs must be configured for each acquisition. This change reflects the implementations in the STM32 HAL.

See:
* https://community.st.com/t5/stm32-mcus-products/tsc-channel-selection/td-p/164783

Specifically, see the HAL solution provided. It shows that only one acquisition channel must enabled in a group during an acquisition cycle, then the next channel in the next acquisition cycle, and so on.


* https://www.st.com/content/ccc/resource/technical/document/user_manual/group0/d6/4c/20/0d/a1/c1/4c/99/DM00210526/files/DM00210526.pdf/jcr:content/translations/en.DM00210526.pdf

While this is about the STM Touch Library, table 8 (and others) show the acquisition timings required for multiple channels in a group.

embassy-stm32/src/tsc/mod.rs

@@ -227,6 +227,15 @@ impl Default for Config {
     }
 }
 
+pub struct IOConfig {
+    /// Channel IO mask
+    pub channel_ios: u32,
+    /// Shield IO mask
+    pub shield_ios: u32,
+    /// Sampling IO mask
+    pub sampling_ios: u32,
+}
+
 /// Pin struct that maintains usage
 #[allow(missing_docs)]
 pub struct TscPin<'d, T, C> {
@@ -761,6 +770,27 @@ impl<'d, T: Instance, K: PeriMode> Tsc<'d, T, K> {
         groups
     }
 
+    pub fn io_config(&mut self, config: &IOConfig) {
+        // Disable Schmitt trigger hysteresis on all used TSC IOs
+        T::regs()
+            .iohcr()
+            .write(|w| w.0 = !(config.channel_ios | config.shield_ios | config.sampling_ios));
+
+        // Set channel and shield IOs
+        T::regs()
+            .ioccr()
+            .write(|w| w.0 = config.channel_ios | config.shield_ios);
+
+        // Set sampling IOs
+        T::regs().ioscr().write(|w| w.0 = config.sampling_ios);
+
+        // Set the groups to be acquired
+        T::regs()
+            .iogcsr()
+            .write(|w| w.0 = Self::extract_groups(config.channel_ios));
+
+    }
+
     fn new_inner(
         peri: impl Peripheral<P = T> + 'd,
         g1: Option<PinGroup<'d, T, G1>>,
@@ -804,6 +834,15 @@ impl<'d, T: Instance, K: PeriMode> Tsc<'d, T, K> {
         });
 
         // Set IO configuration
+        let io_config = IOConfig {
+            channel_ios: config.channel_ios,
+            sampling_ios: config.sampling_ios,
+            shield_ios: config.shield_ios,
+        };
+
+        Self.io_config(&io_config);
+
+        /*
         // Disable Schmitt trigger hysteresis on all used TSC IOs
         T::regs()
             .iohcr()
@@ -822,6 +861,8 @@ impl<'d, T: Instance, K: PeriMode> Tsc<'d, T, K> {
             .iogcsr()
             .write(|w| w.0 = Self::extract_groups(config.channel_ios));
 
+         */
+
         // Disable interrupts
         T::regs().ier().modify(|w| {
             w.set_eoaie(false);