Prelude improvements/fixes

[jessebraham]

As discussed previously with @bjoernQ and @MabezDev:

• Move the SPI traits into their own preludes in the spi::master/spi::slave modules
• Remove the embedded-hal-async trait re-exports
• Remove the eh module, and in turn the [email protected] trait re-exports

I will deal with embedded-hal in a following PR, then I think we should be okay here.

[JurajSadel]

LGTM!
Just a small thing, regarding CI, there are a few unused import warnings in some examples.

[jessebraham]

Thanks for the heads up! Will get those errors resolved before the next release.

[bjoernQ]

LGTM

[MabezDev]

Would it be possible to convert the wonky examples (that were previously held back by the prelude)? I think it's just embassy_spi and embassy_serial.

e.g

diff --git a/esp32-hal/examples/embassy_serial.rs b/esp32-hal/examples/embassy_serial.rs
index 40d1031..c5dfe23 100644
--- a/esp32-hal/examples/embassy_serial.rs
+++ b/esp32-hal/examples/embassy_serial.rs
@@ -29,13 +29,10 @@ const AT_CMD: u8 = 0x04;
 #[embassy_executor::task]
 async fn writer(mut tx: UartTx<'static, UART0>) {
     esp_println::println!("writing...");
-    embedded_io_async::Write::write(
-        &mut tx,
-        b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n",
-    )
-    .await
-    .unwrap();
-    embedded_io_async::Write::flush(&mut tx).await.unwrap();
+    tx.write(b"Hello async serial. Enter something ended with EOT (CTRL-D).\r\n")
+        .await
+        .unwrap();
+    tx.flush().await.unwrap();
 }
 
 #[embassy_executor::task]
@@ -47,7 +44,7 @@ async fn reader(mut rx: UartRx<'static, UART0>) {
 
     let mut rbuf: Vec<u8, MAX_BUFFER_SIZE> = Vec::new();
     let mut offset = 0;
-    while let Ok(len) = embedded_io_async::Read::read(&mut rx, &mut rbuf[offset..]).await {
+    while let Ok(len) = rx.read(&mut rbuf[offset..]).await {
         offset += len;
         if offset == 0 {
             rbuf.truncate(0);

[jessebraham]

Oh yes of course, I had forgotten about those. Will get that resolved and rebase this branch!

[jessebraham]

Actually it looks like I will need to hold off on fixing these until I remove the [email protected] traits from the prelude and make the other necessary fixes. We're still have conflicting functions because of these, unfortunately.

I have rebased to resolve the merge conflicts, though.