Initial support for Waveshare 2in13 v2 e-ink screen

This initial support covers both the full (slow) update of the display and the
partial (fast) update.

examples/epd2in13_v2.rs

@@ -0,0 +1,167 @@
+#![deny(warnings)]
+
+use embedded_graphics::{
+    fonts::{Font12x16, Font6x8, Text},
+    prelude::*,
+    primitives::{Circle, Line},
+    style::PrimitiveStyle,
+    text_style,
+};
+use embedded_hal::prelude::*;
+use epd_waveshare::{
+    color::*,
+    epd2in13_v2::{Display2in13, EPD2in13},
+    graphics::{Display, DisplayRotation},
+    prelude::*,
+};
+use linux_embedded_hal::{
+    spidev::{self, SpidevOptions},
+    sysfs_gpio::Direction,
+    Delay, Pin, Spidev,
+};
+
+// activate spi, gpio in raspi-config
+// needs to be run with sudo because of some sysfs_gpio permission problems and follow-up timing problems
+// see https://github.com/rust-embedded/rust-sysfs-gpio/issues/5 and follow-up issues
+
+fn main() -> Result<(), std::io::Error> {
+    // Configure SPI
+    // Settings are taken from
+    let mut spi = Spidev::open("/dev/spidev0.0").expect("spidev directory");
+    let options = SpidevOptions::new()
+        .bits_per_word(8)
+        .max_speed_hz(4_000_000)
+        .mode(spidev::SpiModeFlags::SPI_MODE_0)
+        .build();
+    spi.configure(&options).expect("spi configuration");
+
+    // Configure Digital I/O Pin to be used as Chip Select for SPI
+    let cs = Pin::new(26); //BCM7 CE0
+    cs.export().expect("cs export");
+    while !cs.is_exported() {}
+    cs.set_direction(Direction::Out).expect("CS Direction");
+    cs.set_value(1).expect("CS Value set to 1");
+
+    let busy = Pin::new(5); //pin 29
+    busy.export().expect("busy export");
+    while !busy.is_exported() {}
+    busy.set_direction(Direction::In).expect("busy Direction");
+    //busy.set_value(1).expect("busy Value set to 1");
+
+    let dc = Pin::new(6); //pin 31 //bcm6
+    dc.export().expect("dc export");
+    while !dc.is_exported() {}
+    dc.set_direction(Direction::Out).expect("dc Direction");
+    dc.set_value(1).expect("dc Value set to 1");
+
+    let rst = Pin::new(16); //pin 36 //bcm16
+    rst.export().expect("rst export");
+    while !rst.is_exported() {}
+    rst.set_direction(Direction::Out).expect("rst Direction");
+    rst.set_value(1).expect("rst Value set to 1");
+
+    let mut delay = Delay {};
+
+    let mut epd2in13 =
+        EPD2in13::new(&mut spi, cs, busy, dc, rst, &mut delay).expect("eink initalize error");
+
+    //println!("Test all the rotations");
+    let mut display = Display2in13::default();
+
+    display.set_rotation(DisplayRotation::Rotate0);
+    draw_text(&mut display, "Rotate 0!", 5, 50);
+
+    display.set_rotation(DisplayRotation::Rotate90);
+    draw_text(&mut display, "Rotate 90!", 5, 50);
+
+    display.set_rotation(DisplayRotation::Rotate180);
+    draw_text(&mut display, "Rotate 180!", 5, 50);
+
+    display.set_rotation(DisplayRotation::Rotate270);
+    draw_text(&mut display, "Rotate 270!", 5, 50);
+
+    epd2in13.update_frame(&mut spi, &display.buffer())?;
+    epd2in13
+        .display_frame(&mut spi)
+        .expect("display frame new graphics");
+    delay.delay_ms(5000u16);
+
+    //println!("Now test new graphics with default rotation and some special stuff:");
+    display.clear_buffer(Color::White);
+
+    // draw a analog clock
+    let _ = Circle::new(Point::new(64, 64), 40)
+        .into_styled(PrimitiveStyle::with_stroke(Black, 1))
+        .draw(&mut display);
+    let _ = Line::new(Point::new(64, 64), Point::new(30, 40))
+        .into_styled(PrimitiveStyle::with_stroke(Black, 4))
+        .draw(&mut display);
+    let _ = Line::new(Point::new(64, 64), Point::new(80, 40))
+        .into_styled(PrimitiveStyle::with_stroke(Black, 1))
+        .draw(&mut display);
+
+    // draw white on black background
+    let _ = Text::new("It's working-WoB!", Point::new(90, 10))
+        .into_styled(text_style!(
+            font = Font6x8,
+            text_color = White,
+            background_color = Black
+        ))
+        .draw(&mut display);
+
+    // use bigger/different font
+    let _ = Text::new("It's working-WoB!", Point::new(90, 40))
+        .into_styled(text_style!(
+            font = Font12x16,
+            text_color = White,
+            background_color = Black
+        ))
+        .draw(&mut display);
+
+    // Demonstrating how to use the partial refresh feature of the screen.
+    // Real animations can be used.
+    epd2in13
+        .set_refresh(&mut spi, &mut delay, RefreshLUT::QUICK)
+        .unwrap();
+    epd2in13.clear_frame(&mut spi).unwrap();
+
+    // a moving `Hello World!`
+    let limit = 10;
+    for i in 0..limit {
+        draw_text(&mut display, "  Hello World! ", 5 + i * 12, 50);
+
+        epd2in13
+            .update_and_display_frame(&mut spi, &display.buffer())
+            .expect("display frame new graphics");
+        delay.delay_ms(1_000u16);
+    }
+
+    // Show a spinning bar without any delay between frames. Shows how «fast»
+    // the screen can refresh for this kind of change (small single character)
+    display.clear_buffer(Color::White);
+    epd2in13
+        .update_and_display_frame(&mut spi, &display.buffer())
+        .unwrap();
+
+    let spinner = ["|", "/", "-", "\\"];
+    for i in 0..10 {
+        display.clear_buffer(Color::White);
+        draw_text(&mut display, spinner[i % spinner.len()], 10, 100);
+        epd2in13
+            .update_and_display_frame(&mut spi, &display.buffer())
+            .unwrap();
+    }
+
+    println!("Finished tests - going to sleep");
+    epd2in13.sleep(&mut spi)
+}
+
+fn draw_text(display: &mut Display2in13, text: &str, x: i32, y: i32) {
+    let _ = Text::new(text, Point::new(x, y))
+        .into_styled(text_style!(
+            font = Font6x8,
+            text_color = Black,
+            background_color = White
+        ))
+        .draw(display);
+}