From e5d68fdcb1e0cecff9840b262b287624e52ee42f Mon Sep 17 00:00:00 2001
From: Sebastian Urban <surban@surban.net>
Date: Mon, 17 Jun 2024 13:17:07 +0200
Subject: [PATCH] supply: reset STUSB4500 when BQ25713 fails

When BQ25713 has no I2C communication, this is often
caused by STUSB4500 blocking the I2C bus. Therefore,
reset the STUSB4500 in this case.
---
 openemc-firmware/src/bq25713.rs              |  8 ++++++--
 openemc-firmware/src/main.rs                 | 19 +++++++++++++++++--
 openemc-firmware/src/supply/stusb4500/mod.rs |  7 +++++++
 openemc-firmware/src/supply/stusb4500/nvm.rs |  9 ++++++---
 4 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/openemc-firmware/src/bq25713.rs b/openemc-firmware/src/bq25713.rs
index eaa003a..080c141 100644
--- a/openemc-firmware/src/bq25713.rs
+++ b/openemc-firmware/src/bq25713.rs
@@ -708,11 +708,15 @@ where
     }
 
     /// Call this periodically (approx. every second) to handle communication with the device.
-    pub fn periodic(&mut self, i2c: &mut I2C, chrg_ok: bool) {
-        if let Err(err) = self.do_periodic(i2c, chrg_ok) {
+    pub fn periodic(&mut self, i2c: &mut I2C, chrg_ok: bool) -> Result<()> {
+        let res = self.do_periodic(i2c, chrg_ok);
+
+        if let Err(err) = &res {
             defmt::warn!("BQ25713 failed: {}", err);
             self.initialized = false;
         }
+
+        res
     }
 
     /// Update status and measurements without programming charger.
diff --git a/openemc-firmware/src/main.rs b/openemc-firmware/src/main.rs
index 0ec59e8..77d3896 100644
--- a/openemc-firmware/src/main.rs
+++ b/openemc-firmware/src/main.rs
@@ -578,7 +578,7 @@ mod app {
 
         // Check that battery voltage is sufficient.
         if let (Some(bq25713), Some(i2c2)) = (&mut bq25713, &mut i2c2) {
-            bq25713.periodic(i2c2, board.check_bq25713_chrg_ok());
+            let _ = bq25713.periodic(i2c2, board.check_bq25713_chrg_ok());
 
             watchman.force_pet();
             let v_bat = loop {
@@ -910,6 +910,16 @@ mod app {
         defmt::unwrap!(stusb4500_periodic::spawn_after(500u64.millis()));
     }
 
+    /// STUSB4500 reset task.
+    #[task(shared = [stusb4500])]
+    fn stusb4500_reset(mut cx: stusb4500_reset::Context) {
+        cx.shared.stusb4500.lock(|stusb4500| {
+            if let Some(stusb4500) = stusb4500.as_mut() {
+                stusb4500.reset();
+            }
+        });
+    }
+
     /// Updates the power supply status.
     #[task(
         shared = [i2c2, stusb4500, max14636, bq25713, power_supply, irq, board, &power_mode],
@@ -1023,7 +1033,12 @@ mod app {
             |i2c2, bq25713, battery, irq, board| {
                 if let Some(bq25713) = bq25713.as_mut() {
                     let i2c2 = defmt::unwrap!(i2c2.as_mut());
-                    bq25713.periodic(i2c2, board.check_bq25713_chrg_ok());
+                    let res = bq25713.periodic(i2c2, board.check_bq25713_chrg_ok());
+
+                    if let Err(bq25713::Error::I2c) = &res {
+                        defmt::warn!("Resetting STUSB4500 due to BQ25713 I2C error");
+                        let _ = stusb4500_reset::spawn();
+                    }
 
                     let mut ac = false;
                     if let Some(status) = bq25713.status().cloned() {
diff --git a/openemc-firmware/src/supply/stusb4500/mod.rs b/openemc-firmware/src/supply/stusb4500/mod.rs
index 71a3656..454cd91 100644
--- a/openemc-firmware/src/supply/stusb4500/mod.rs
+++ b/openemc-firmware/src/supply/stusb4500/mod.rs
@@ -790,6 +790,13 @@ where
     pub fn reset_pin_level(&self) -> bool {
         matches!(self.reset, ResetState::PinResetHigh(_))
     }
+
+    /// Initiates a reset.
+    pub fn reset(&mut self) {
+        defmt::info!("Initiating STUSB4500 reset by request");
+        self.reset = ResetState::None;
+        self.start_pin_reset();
+    }
 }
 
 // Register definitions.
diff --git a/openemc-firmware/src/supply/stusb4500/nvm.rs b/openemc-firmware/src/supply/stusb4500/nvm.rs
index cbfa2d7..7297f0c 100644
--- a/openemc-firmware/src/supply/stusb4500/nvm.rs
+++ b/openemc-firmware/src/supply/stusb4500/nvm.rs
@@ -38,10 +38,13 @@ where
     I2C: i2c::Write<i2c::SevenBitAddress> + i2c::WriteRead<i2c::SevenBitAddress>,
 {
     /// Mask of programmable bits within NVM.
+    #[rustfmt::skip]
     pub const NVM_PROGRAMABLE: [u8; 40] = [
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x20, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x30, 0x20, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     ];
 
     /// Read I2C register(s).