SPI DMA: use State for both blocking and async operations (#1985)

* use `State` for both blocking and async operations, remove async version of SpiDmaBus in favour of being generic over the mode

* reuse wait_for_idle more

* changelog

* rename generic params for consistency

* Add duplex mode to SpiDmaBus

* implement HalfDuplexReadWrite for SpiDmaBus

* Docs on new async APIs

* Limit half duplex transfers to the capacity of the DmaBuf

* docs

* rebase tests

* address review comments

* remove duplex traits from spi

* fix tests

* spi docs rejig

* s/InUse/TemporarilyRemoved/g

esp-hal/CHANGELOG.md

@@ -9,7 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Introduce DMA buffer objects (#1856)
+- Introduce DMA buffer objects (#1856, #1985)
 - Added new `Io::new_no_bind_interrupt` constructor (#1861)
 - Added touch pad support for esp32 (#1873, #1956)
 - Allow configuration of period updating method for MCPWM timers (#1898)
@@ -23,7 +23,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Peripheral driver constructors don't take `InterruptHandler`s anymore. Use `set_interrupt_handler` to explicitly set the interrupt handler now. (#1819)
-- Migrate SPI driver to use DMA buffer objects (#1856)
+- Migrate SPI driver to use DMA buffer objects (#1856, #1985)
 - Use the peripheral ref pattern for `OneShotTimer` and `PeriodicTimer` (#1855)
 - Improve SYSTIMER API (#1871)
 - DMA buffers now don't require a static lifetime. Make sure to never `mem::forget` an in-progress DMA transfer (consider using `#[deny(clippy::mem_forget)]`) (#1837)
@@ -51,6 +51,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The `AesFlavour` trait no longer has the `ENCRYPT_MODE`/`DECRYPT_MODE` associated constants (#1849)
 - Removed `FlashSafeDma` (#1856)
 - Remove redundant WithDmaSpi traits (#1975)
+- `IsFullDuplex` and `IsHalfDuplex` traits (#1985)
 
 ## [0.19.0] - 2024-07-15
 

esp-hal/src/dma/mod.rs

@@ -19,7 +19,7 @@
 #![doc = crate::before_snippet!()]
 //! # use esp_hal::dma_buffers;
 //! # use esp_hal::gpio::Io;
-//! # use esp_hal::spi::{master::{Spi, prelude::*}, SpiMode};
+//! # use esp_hal::spi::{master::Spi, SpiMode};
 //! # use esp_hal::dma::{Dma, DmaPriority};
 //! # use crate::esp_hal::prelude::_fugit_RateExtU32;
 //! let dma = Dma::new(peripherals.DMA);