deps(pygamer)!: Upgrade pygamer BSP display driver and graphics dep…

…endencies (#777)

* Upgrades the display and graphics dependencies: st7735-lcd, embedded-graphics, tinybmp
* Corrects the README.md to list `pygamer` as a `samd51j` BSP instead of the erroneous `same53j`.
* Adds an empty `DisplayError` and a `DisplayDriver` type alias, both to address clippy lints.

* Changes the `DisplayError` to an enum with variants to provide more detail about why the display driver initialization failed.
* Exposes the `dma` and `max-channels` HAL features in the BSP for convenience.
* Adds a `cortex_m::asm::wfi()` call inside the terminal infinite loop in the examples to address the `empty_loop` clippy lint.

---------

Co-authored-by: Dan Whitman <dwhitman44@mgail.com>

boards/pygamer/Cargo.toml

@@ -16,7 +16,9 @@ version = "0.11.0"
 
 [dependencies]
 cortex-m = {version = "0.7", features = ["critical-section-single-core"]}
-st7735-lcd = "0.8.1"
+embedded-hal-bus = "0.2.0"
+# This version is pinned as recommended by: https://docs.rs/embedded-hal-bus/0.2.0/embedded_hal_bus/spi/struct.ExclusiveDevice.html#method.new_no_delay
+st7735-lcd = "=0.10.0"
 
 [dependencies.cortex-m-rt]
 optional = true
@@ -29,23 +31,24 @@ version = "0.18.2"
 
 [dependencies.usb-device]
 optional = true
-version = "0.3.1"
+version = "0.3.2"
 
 [dev-dependencies]
-embedded-graphics = "0.7.1"
-embedded-hal-bus = "0.2.0"
+embedded-graphics = "0.8.1"
 embedded-sdmmc = "0.8.0"
 lis3dh = "0.4.3"
 micromath = "2.1"
-panic-halt = "0.2"
+panic-halt = "1"
 rtic = {version = "2.1.1", features = ["thumbv7-backend"]}
 smart-leds = "0.4"
-tinybmp = "0.3.1"
+tinybmp = "0.6"
 usbd-serial = "0.2"
 
 [features]
 # ask the HAL to enable atsamd51j support
 default = ["rt", "atsamd-hal/samd51j"]
+dma = ["atsamd-hal/dma"]
+max-channels = ["dma", "atsamd-hal/max-channels"]
 panic_led = []
 rt = ["cortex-m-rt", "atsamd-hal/samd51j-rt"]
 usb = ["atsamd-hal/usb", "usb-device"]

boards/pygamer/examples/clock_out.rs

@@ -30,5 +30,7 @@ fn main() -> ! {
         .configure_gclk_divider_and_source(Gclk2, 40, Dpll0, false)
         .unwrap();
     let _clock_out_pin: GclkOut = pins.d5.into();
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

boards/pygamer/examples/ferris_img.rs

@@ -59,5 +59,7 @@ fn main() -> ! {
     let ferris = Image::new(&raw_image, Point::new(32, 32));
 
     ferris.draw(&mut display).unwrap();
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }

boards/pygamer/examples/qspi.rs

@@ -99,7 +99,9 @@ fn main() -> ! {
     flash.read_memory(0, &mut read_buf);
     assert_eq!(read_buf, write_buf);
 
-    loop {}
+    loop {
+        cortex_m::asm::wfi();
+    }
 }
 
 /// Wait for the write-in-progress and suspended write/erase.

boards/pygamer/src/pins.rs

@@ -4,6 +4,7 @@ use super::{hal, pac};
 
 use hal::prelude::*;
 
+use embedded_hal_bus::spi as bspi;
 use hal::clock::GenericClockController;
 use hal::gpio::PA01;
 use hal::pwm;
@@ -581,30 +582,65 @@ pub struct Display {
     pub tft_backlight: TftBacklightReset,
 }
 
+/// Error that can occur when initializing the display.
+#[derive(Debug)]
+pub enum DisplayError {
+    /// Could not configure the SERCOM4 clock.
+    SercomClock,
+    /// Could not configure the SPI port to drive the display.
+    Spi,
+    /// Could not setup the ST7735 display driver.
+    Driver,
+    /// Could not configure the TC2/TC3 clock for PWM control of the backlight.
+    Tc2Tc3Clock,
+}
+impl From<()> for DisplayError {
+    #[inline]
+    fn from(_value: ()) -> Self {
+        Self::Driver
+    }
+}
+
 pub type TftPads = spi::Pads<Sercom4, IoSet1, NoneT, TftMosi, TftSclk>;
-pub type TftSpi = spi::Spi<spi::Config<TftPads>, spi::Tx>;
+pub type TftSpi = bspi::ExclusiveDevice<
+    spi::PanicOnRead<spi::Spi<spi::Config<TftPads>, spi::Tx>>,
+    TftCs,
+    bspi::NoDelay,
+>;
+
+/// The on-board display driver that is a
+/// [`DrawTarget`](https://docs.rs/embedded-graphics/latest/embedded_graphics/draw_target/trait.DrawTarget.html)
+/// for embedded graphics.
+pub type DisplayDriver = ST7735<TftSpi, TftDc, TftReset>;
 
 impl Display {
-    /// Convenience for setting up the on board display.
+    /// Convenience for setting up the on-board display.
     pub fn init(
         self,
         clocks: &mut GenericClockController,
         sercom4: pac::Sercom4,
         mclk: &mut pac::Mclk,
         timer2: pac::Tc2,
         delay: &mut hal::delay::Delay,
-    ) -> Result<(ST7735<TftSpi, TftDc, TftReset>, Pwm2<PA01>), ()> {
+    ) -> Result<(DisplayDriver, Pwm2<PA01>), DisplayError> {
         let gclk0 = clocks.gclk0();
-        let clock = &clocks.sercom4_core(&gclk0).ok_or(())?;
+        let clock = &clocks
+            .sercom4_core(&gclk0)
+            .ok_or(DisplayError::SercomClock)?;
         let pads = spi::Pads::default()
             .sclk(self.tft_sclk)
             .data_out(self.tft_mosi);
-        let tft_spi = spi::Config::new(mclk, sercom4, pads, clock.freq())
-            .spi_mode(spi::MODE_0)
-            .baud(16.MHz())
-            .enable();
         let mut tft_cs: TftCs = self.tft_cs.into();
         tft_cs.set_low().ok();
+        let tft_spi = bspi::ExclusiveDevice::new_no_delay(
+            spi::Config::new(mclk, sercom4, pads, clock.freq())
+                .spi_mode(spi::MODE_0)
+                .baud(16.MHz())
+                .enable()
+                .into_panic_on_read(),
+            tft_cs,
+        )
+        .map_err(|_| DisplayError::Spi)?;
         let mut display = st7735_lcd::ST7735::new(
             tft_spi,
             self.tft_dc.into(),