Epd4in2::new() waits forever

I'm trying to use the 4.2in monochrome display with a black pill dev board, however when I call Epd4in2::new it seems to be waiting forever for the display to become ready.

I am getting the following backtrace when I halt the program.

     Running `probe-run --chip STM32F401CCUx --probe 55C3BF6C0648C2865050275915C287 /mnt/Storage/cargo_target/thumbv7em-none-eabihf/debug/black_pill`
(HOST) INFO  flashing program (17 pages / 17.00 KiB)
(HOST) INFO  success!
────────────────────────────────────────────────────────────────────────────────
^C────────────────────────────────────────────────────────────────────────────────
stack backtrace:
   0: epd_waveshare::interface::DisplayInterface<SPI,CS,BUSY,DC,RST,DELAY>::wait_until_idle
        at /home/ben/.cargo/registry/src/index.crates.io-6f17d22bba15001f/epd-waveshare-0.5.0/src/interface.rs:140:15
   1: epd_waveshare::epd4in2::Epd4in2<SPI,CS,BUSY,DC,RST,DELAY>::wait_until_idle
        at /home/ben/.cargo/registry/src/index.crates.io-6f17d22bba15001f/epd-waveshare-0.5.0/src/epd4in2/mod.rs:364:42
   2: epd_waveshare::epd4in2::Epd4in2<SPI,CS,BUSY,DC,RST,DELAY>::cmd_with_data
        at /home/ben/.cargo/registry/src/index.crates.io-6f17d22bba15001f/epd-waveshare-0.5.0/src/epd4in2/mod.rs:361:3
   3: <epd_waveshare::epd4in2::Epd4in2<SPI,CS,BUSY,DC,RST,DELAY> as epd_waveshare::traits::InternalWiAdditions<SPI,CS,BUSY,DC,RST,DELAY>>::init
        at /home/ben/.cargo/registry/src/index.crates.io-6f17d22bba15001f/epd-waveshare-0.5.0/src/epd4in2/mod.rs:126:3
   4: <epd_waveshare::epd4in2::Epd4in2<SPI,CS,BUSY,DC,RST,DELAY> as epd_waveshare::traits::WaveshareDisplay<SPI,CS,BUSY,DC,RST,DELAY>>::new
        at /home/ben/.cargo/registry/src/index.crates.io-6f17d22bba15001f/epd-waveshare-0.5.0/src/epd4in2/mod.rs:178:3
   5: black_pill::__cortex_m_rt_main
        at src/main.rs:50:16
   6: main
        at src/main.rs:27:1
   7: Reset
(HOST) INFO  device halted by user

This seems to be looping forever on the wait_until_idle function while the display never becomes idle

The code I'm using is

#![no_std]
#![no_main]

use cortex_m_rt::entry;
use defmt_rtt as _;
use epd_waveshare::{epd4in2::Epd4in2, prelude::WaveshareDisplay, SPI_MODE};
use panic_probe as _;
use stm32f4xx_hal::{pac, prelude::*, time::Hertz};

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();

    // Set up the system clock. We want to run at 48MHz for this one.
    let rcc = dp.RCC.constrain();
    let clocks = rcc.cfgr.use_hse(25.MHz()).sysclk(48.MHz()).freeze();

    let mut delay = dp.TIM5.delay_us(&clocks);

    let gpioa = dp.GPIOA.split();
    let mut spi = dp.SPI1.spi(
        (
            gpioa.pa5.into_push_pull_output(),
            gpioa.pa6.into_pull_down_input(),
            gpioa.pa7.into_push_pull_output(),
        ),
        SPI_MODE,
        Hertz::MHz(4),
        &clocks,
    );

    let mut epd = Epd4in2::new(
        &mut spi,
        gpioa.pa4.into_push_pull_output(),
        gpioa.pa3.into_pull_down_input(),
        gpioa.pa2.into_push_pull_output(),
        gpioa.pa1.into_push_pull_output(),
        &mut delay,
    )
    .unwrap();

    unimplemented!();
}

This is running via probe-run through the SWD port on the device

caemor / epd-waveshare

Epd4in2::new() waits forever #155