From c0ec86f5ec4428543ae18af941c7e3ef6877a369 Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@kublai.com>
Date: Sat, 19 Nov 2022 14:05:18 -0500
Subject: usb: add mousewheel hid implementation

---
 src/bin/luchie.rs | 74 +++++++++++++++++++++++++++++++++++++++++++++----------
 src/cirque.rs     | 10 ++++----
 2 files changed, 66 insertions(+), 18 deletions(-)

(limited to 'src')

diff --git a/src/bin/luchie.rs b/src/bin/luchie.rs
index 7dedc8d..7d25a00 100755
--- a/src/bin/luchie.rs
+++ b/src/bin/luchie.rs
@@ -3,6 +3,8 @@
 
 //extern crate panic_semihosting;
 
+use core::cmp;
+
 use luchie::{
     cirque::Cirque,
     log, logger, logln,
@@ -22,6 +24,10 @@ use stm32f1xx_hal::{
     usb::{self, UsbBus},
 };
 use usb_device::prelude::*;
+use usbd_human_interface_device::{
+    prelude::*,
+    device::mouse::{WheelMouseInterface, WheelMouseReport},
+};
 use usbd_serial::{SerialPort, USB_CLASS_CDC};
 
 #[entry]
@@ -35,15 +41,11 @@ fn main() -> ! {
         .cfgr
         .use_hse(8.MHz())
         .sysclk(72.MHz()) // TODO: gd32 can get up to 120MHz
-        // .pclk1(24.MHz()) // TODO: causes issues with gd32 usb (dropped packets) and garbled usart1 output
+        .pclk1(24.MHz()) // TODO: causes issues with gd32 usb (dropped packets) and garbled usart1 output
         .freeze(&mut flash.acr);
 
     assert!(clocks.usbclk_valid());
 
-    let mut gpiob = dp.GPIOB.split();
-    let mut led = gpiob.pb2.into_push_pull_output(&mut gpiob.crl);
-    led.set_low();
-
     let mut afio = dp.AFIO.constrain();
     let mut gpioa = dp.GPIOA.split();
 
@@ -117,6 +119,11 @@ fn main() -> ! {
 
     let mut serial = SerialPort::new(&usb_bus);
 
+    let mut mouse_report = WheelMouseReport::default();
+    let mut mouse = UsbHidClassBuilder::new()
+        .add_interface(WheelMouseInterface::default_config())
+        .build(&usb_bus);
+
     let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0xdead, 0xbeef))
         .manufacturer("Fake company")
         .product("Serial port")
@@ -124,17 +131,23 @@ fn main() -> ! {
         .device_class(USB_CLASS_CDC)
         .build();
 
+    while usb_dev.state() != UsbDeviceState::Configured {
+        usb_dev.poll(&mut [&mut serial, &mut mouse]);
+    }
+
+    logln!("💡 init led");
+    let mut gpiob = dp.GPIOB.split();
+    let mut led = gpiob.pb2.into_push_pull_output(&mut gpiob.crl);
+    led.set_low();
+
     logln!("🎉 luchie started!");
+
+    let mut is_pressed = false;
+    let mut last_x = 0u16;
+    let mut last_y = 0u16;
     loop {
         // logln!(".");
-        if let Ok(mut td) = cirque.poll(&mut spi) {
-            td.scale_to(1920, 1080);
-            logln!("td: {:?}", td);
-        }
-
-        if !usb_dev.poll(&mut [&mut serial]) {
-            continue;
-        }
+        usb_dev.poll(&mut [&mut serial, &mut mouse]);
 
         let mut buf = [0u8; 64];
 
@@ -162,6 +175,41 @@ fn main() -> ! {
             }
             _ => {}
         }
+
+        if let Ok(td) = cirque.poll(&mut spi) {
+            logln!("td: {:?}", td);
+            if td.is_pressed {
+                if is_pressed {
+                    /*
+                     * The trackpad's actual valid return values are
+                     * only about 2^11, so overflow isn't possible
+                     * when converting to signed 16 bit integers.
+                     */
+                    let s_x: i16 = td.x as i16 - last_x as i16;
+                    let s_y: i16 = td.y as i16 - last_y as i16;
+
+                    // Clamp to i8 range.
+                    let raw_x = cmp::max(i8::MIN as i16, cmp::min(i8::MAX as i16, s_x));
+                    let raw_y = cmp::max(i8::MIN as i16, cmp::min(i8::MAX as i16, s_y));
+                    mouse_report.x = raw_x as i8;
+                    mouse_report.y = raw_y as i8;
+                }
+                is_pressed = true;
+                last_x = td.x;
+                last_y = td.y;
+            } else {
+                mouse_report.x = 0;
+                mouse_report.y = 0;
+                is_pressed = false;
+            }
+            match mouse.interface().write_report(&mouse_report) {
+                Err(UsbHidError::WouldBlock) => {},
+                Err(e) => {
+                    panic!("couldn't write mouse report: {:?}", e)
+                },
+                _ => {},
+            }
+        }
     }
 }
 
diff --git a/src/cirque.rs b/src/cirque.rs
index 23df15b..0f40c51 100644
--- a/src/cirque.rs
+++ b/src/cirque.rs
@@ -98,11 +98,11 @@ where
 #[allow(unused)]
 #[derive(Debug)]
 pub struct TouchData {
-    x: u16,
-    y: u16,
-    z: u8,
-    buttons: u8,
-    is_pressed: bool,
+    pub x: u16,
+    pub y: u16,
+    pub z: u8,
+    pub buttons: u8,
+    pub is_pressed: bool,
 }
 
 impl TouchData {
-- 
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