From 8b9d21a0123c64856b3460eac9b80363d34a83de Mon Sep 17 00:00:00 2001
From: finga <finga@onders.org>
Date: Tue, 8 Mar 2022 19:05:40 +0100
Subject: [PATCH] fw-rust: Start to use the avr-eeprom crate

Start to use the avr-eeprom crate to handle values residing inside the
EEPROM.
---
 firmware/rust/Cargo.lock  |  6 ++++++
 firmware/rust/Cargo.toml  |  1 +
 firmware/rust/src/main.rs | 16 +++++++---------
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/firmware/rust/Cargo.lock b/firmware/rust/Cargo.lock
index c856d14..ecc84d6 100644
--- a/firmware/rust/Cargo.lock
+++ b/firmware/rust/Cargo.lock
@@ -32,6 +32,11 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "avr-eeprom"
+version = "0.1.0-dev"
+source = "git+https://git.onders.org/finga/avr-eeprom-rs.git?branch=main#d7653567fb2f7ca7bf5100a44c233015a6e03e51"
+
 [[package]]
 name = "avr-hal-generic"
 version = "0.1.0"
@@ -67,6 +72,7 @@ version = "0.1.0-dev"
 dependencies = [
  "atmega-hal",
  "avr-device",
+ "avr-eeprom",
  "embedded-hal",
  "nb 1.0.0",
  "panic-halt",
diff --git a/firmware/rust/Cargo.toml b/firmware/rust/Cargo.toml
index aee0597..9a1d6e9 100644
--- a/firmware/rust/Cargo.toml
+++ b/firmware/rust/Cargo.toml
@@ -15,6 +15,7 @@ panic-halt = "0.2"
 nb = "1.0"
 embedded-hal = "0.2"
 avr-device = { version = "0.3", features = ["atmega328p"] }
+avr-eeprom = { git = "https://git.onders.org/finga/avr-eeprom-rs.git", branch = "main" }
 
 [dependencies.atmega-hal]
 git = "https://github.com/rahix/avr-hal"
diff --git a/firmware/rust/src/main.rs b/firmware/rust/src/main.rs
index 8b9338d..87042c3 100644
--- a/firmware/rust/src/main.rs
+++ b/firmware/rust/src/main.rs
@@ -9,6 +9,7 @@ use atmega_hal::{
     Peripherals,
 };
 use avr_device::interrupt;
+use avr_eeprom::eeprom;
 use embedded_hal::{
     blocking::delay::DelayMs,
     spi::{FullDuplex, Mode, Phase, Polarity},
@@ -16,13 +17,10 @@ use embedded_hal::{
 use nb::block;
 use panic_halt as _;
 
-#[used]
-#[link_section = ".eeprom"]
-static CONTRAST: u8 = 8;
-
-#[used]
-#[link_section = ".eeprom"]
-static BACKLIGHT: u8 = 1;
+eeprom! {
+    static eeprom CONTRAST: u8 = 8;
+    static eeprom BACKLIGHT: u8 = 1;
+}
 
 // TODO: Use https://github.com/rust-lang/rust/issues/85077 when stabilized
 static SACRED_CHAO: [[u8; 40]; 5] = [
@@ -82,7 +80,7 @@ fn main() -> ! {
         // Write address into eeprom address register
         eeprom
             .eear
-            .write(|w| unsafe { w.bits(&CONTRAST as *const u8 as u16) });
+            .write(|w| unsafe { w.bits(CONTRAST.ptr() as u16) });
         // Start to read from eeprom by setting EERE
         eeprom.eecr.write(|w| w.eere().set_bit());
         // Return data from eeprom data register
@@ -95,7 +93,7 @@ fn main() -> ! {
         // Write address into eeprom address register
         eeprom
             .eear
-            .write(|w| unsafe { w.bits(&BACKLIGHT as *const u8 as u16) });
+            .write(|w| unsafe { w.bits(BACKLIGHT.ptr() as u16) });
         // Start to read from eeprom by setting EERE
         eeprom.eecr.write(|w| w.eere().set_bit());
         // Return data from eeprom data register