138 lines
4.2 KiB
Rust
138 lines
4.2 KiB
Rust
// Manages display hardware
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use crate::dither::DitheredImage;
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use anyhow::Result;
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use epd_waveshare::{epd7in3f::Epd7in3f, prelude::WaveshareDisplay};
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use linux_embedded_hal::gpio_cdev::{Chip, LineRequestFlags};
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use linux_embedded_hal::spidev::SpiModeFlags;
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use linux_embedded_hal::spidev::SpidevOptions;
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use linux_embedded_hal::{CdevPin, Delay, SpidevDevice};
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use std::sync::mpsc;
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use std::thread;
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use tracing::instrument;
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use tracing::span;
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use tracing::{debug, error, info, warn, Level};
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pub trait EInkPanel {
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fn display(&mut self, buf: &DitheredImage) -> Result<()>;
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}
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pub struct Wrapper {
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spi: SpidevDevice,
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delay: Delay,
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panel: Epd7in3f<SpidevDevice, CdevPin, CdevPin, CdevPin, Delay>,
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}
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impl Wrapper {
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pub fn new() -> Result<Self> {
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let mut spi = SpidevDevice::open("/dev/spidev0.0")?;
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let spi_options = SpidevOptions::new()
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.bits_per_word(8)
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.max_speed_hz(10_000_000)
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.mode(SpiModeFlags::SPI_MODE_0)
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.build();
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spi.configure(&spi_options)?;
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let mut gpiochip = Chip::new("/dev/gpiochip0")?;
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let busy_pin = CdevPin::new(gpiochip.get_line(24)?.request(
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LineRequestFlags::INPUT,
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0,
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"frametool",
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)?)?;
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let dc_pin = CdevPin::new(gpiochip.get_line(25)?.request(
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LineRequestFlags::OUTPUT,
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0,
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"frametool",
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)?)?;
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let rst_pin = CdevPin::new(gpiochip.get_line(17)?.request(
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LineRequestFlags::OUTPUT,
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0,
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"frametool",
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)?)?;
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let mut delay = Delay {};
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let panel = Epd7in3f::new(&mut spi, busy_pin, dc_pin, rst_pin, &mut delay, None)?;
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Ok(Self {
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spi,
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delay,
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panel,
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})
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}
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pub fn test(&mut self) -> Result<()> {
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self.panel.show_7block(&mut self.spi, &mut self.delay)?;
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self.panel.sleep(&mut self.spi, &mut self.delay)?;
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Ok(())
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}
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}
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impl EInkPanel for Wrapper {
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#[instrument(skip_all)]
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fn display(&mut self, img: &DitheredImage) -> Result<()> {
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let buf = img.into_display_buffer();
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self.panel
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.update_and_display_frame(&mut self.spi, &buf, &mut self.delay)?;
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debug!("Finished updating frame");
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self.panel.sleep(&mut self.spi, &mut self.delay)?;
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debug!("Display entered sleep mode");
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Ok(())
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}
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}
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/// A Fake EInk display for testing purposes.
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/// Saves the output as `display.bmp`
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pub struct FakeEInk();
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impl EInkPanel for FakeEInk {
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fn display(&mut self, img: &DitheredImage) -> Result<()> {
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warn!("Fake display was called: saving to display.bmp");
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img.into_rgbimage().save("display.bmp")?;
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Ok(())
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}
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}
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#[instrument]
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pub fn get_display() -> Box<dyn EInkPanel + Send> {
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match Wrapper::new() {
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Ok(w) => {
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info!("Found real hardware, using it");
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Box::new(w)
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}
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Err(e) => {
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warn!("Error opening display SPI interface: {e}");
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warn!("Falling back to fake display");
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Box::new(FakeEInk {})
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}
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}
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}
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/// Create a thread that can take dithered images and display them. This allows the display to be
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/// used in an async context since updating the display can take ~30 seconds.
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#[must_use]
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#[instrument(skip_all)]
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pub fn create_display_thread(
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mut display: Box<dyn EInkPanel + Send>,
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) -> (thread::JoinHandle<()>, mpsc::Sender<Box<DitheredImage>>) {
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let (tx, rx) = mpsc::channel::<Box<DitheredImage>>();
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let handle = thread::spawn(move || {
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let span = span!(Level::INFO, "display_thread");
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let _enter = span.enter();
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loop {
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let res = rx.recv();
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match res {
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Ok(img) => {
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info!("Received an image to display");
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if let Err(e) = display.display(&img) {
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error!("Error displaying image: {e}");
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return;
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}
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info!("Successfully set display image");
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}
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Err(e) => {
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error!("Error reading image from channel: {e}");
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return;
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}
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}
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}
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});
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(handle, tx)
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}
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