From d3c95ca25cadedc0d2dd981e02e523adb89bbb13 Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Thu, 17 Apr 2025 07:26:21 -0700
Subject: [PATCH] fix reporting charging status

This commit fixes a couple of bugs; the report_bat() function was
unilaterally writing data to the i2c bus without it being requested by
the master on the bus.  I don't know if the arduino library is smart
enough to prevent that from doing bad things with the bus signals, but
even if it does, this represents a potential race condition with
respect to the normal receive handling.

The other issue that this commit addresses is that the pmu charging
status is determined and set as the high bit of the value that is
assigned to REG_ID_BAT, but the i2c slave handling never reads
from that register, instead reading a separate copy of the
battery percentage level with no charging status flag.

The approach taken here is to read from the REG_ID_BAT register
when responding to a request for that value, so that the charging
status can be returned.

The report_bat() function has been removed; it was only ever called
from the function that assigns REG_ID_BAT at the end, so there is
no need for it to read and do something with the battery level,
and it really should not be changing the write buffer for the
i2c request handling logic.
---
 Code/picocalc_keyboard/picocalc_keyboard.ino | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/Code/picocalc_keyboard/picocalc_keyboard.ino b/Code/picocalc_keyboard/picocalc_keyboard.ino
index 49ff359..61379fe 100644
--- a/Code/picocalc_keyboard/picocalc_keyboard.ino
+++ b/Code/picocalc_keyboard/picocalc_keyboard.ino
@@ -140,8 +140,7 @@ void receiveEvent(int howMany) {
     case REG_ID_BAT:{
       //Serial1.print("REG_ID_BAT getBatteryPercent:");Serial1.print(current_bat_pcnt);Serial1.println("%");
       write_buffer[0] = reg;
-      write_buffer[1] = (uint8_t)current_bat_pcnt;
-      
+      write_buffer[1] = reg_get_value(REG_ID_BAT);
     }break;
     case REG_ID_KEY: {
       write_buffer[0] = fifo_count();
@@ -171,16 +170,6 @@ void receiveEvent(int howMany) {
 //-this is after receiveEvent-------------------------------
 void requestEvent() { Wire.write(write_buffer,write_buffer_len ); }
 
-void report_bat(){
- if (PMU.isBatteryConnect()) {
-    write_buffer[0] = REG_ID_BAT;
-    write_buffer[1] = PMU.getBatteryPercent();
-
-    write_buffer_len = 2;  
-    requestEvent();
-  }
-}
-
 void printPMU() {
   Serial1.print("isCharging:");
   Serial1.println(PMU.isCharging() ? "YES" : "NO");
@@ -269,15 +258,12 @@ void check_pmu_int() {
     // set the threshold through getLowBatWarnThreshold( 5% ~ 20% )
     if (PMU.isDropWarningLevel2Irq()) {
       Serial1.println("isDropWarningLevel2");
-      report_bat();
     }
 
     // When the set low-voltage battery percentage shutdown threshold is reached
     // set the threshold through setLowBatShutdownThreshold()  
     //This is related to the battery charging and discharging logic. If you're not sure what you're doing, please don't modify it, as it could damage the battery.
     if (PMU.isDropWarningLevel1Irq()) {
-      report_bat();
-      //
       PMU.shutdown();
     }
     if (PMU.isGaugeWdtTimeoutIrq()) {