From 6a7bd1c7fa8f1d7029cb3d2991fb93445452edd6 Mon Sep 17 00:00:00 2001
From: kopecdav <david.kopecky@satoshilabs.com>
Date: Thu, 10 Jul 2025 18:57:19 +0200
Subject: [PATCH] feat(core): introduce simple charging temperature controller.

[no changelog]
---
 .../sys/power_manager/stm32u5/power_manager.c |  1 +
 .../stm32u5/power_manager_internal.h          | 10 +++++
 .../power_manager/stm32u5/power_monitoring.c  | 43 ++++++++++++++++++-
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/core/embed/sys/power_manager/stm32u5/power_manager.c b/core/embed/sys/power_manager/stm32u5/power_manager.c
index 42fdc21e92..9781757ec0 100644
--- a/core/embed/sys/power_manager/stm32u5/power_manager.c
+++ b/core/embed/sys/power_manager/stm32u5/power_manager.c
@@ -159,6 +159,7 @@ pm_status_t pm_init(bool inherit_state) {
   // Set default SOC target and max charging current limit
   drv->soc_target = 100;
   drv->charging_current_max_limit_ma = PM_BATTERY_CHARGING_CURRENT_MAX;
+  drv->i_chg_temp_limit_ma = PM_BATTERY_CHARGING_CURRENT_MAX;
 
   // Fuel gauge SoC available, set fuel_gauge initialized.
   drv->fuel_gauge_initialized = true;
diff --git a/core/embed/sys/power_manager/stm32u5/power_manager_internal.h b/core/embed/sys/power_manager/stm32u5/power_manager_internal.h
index 239b54a2d3..2036d0288e 100644
--- a/core/embed/sys/power_manager/stm32u5/power_manager_internal.h
+++ b/core/embed/sys/power_manager/stm32u5/power_manager_internal.h
@@ -55,6 +55,12 @@
 
 #define PM_SUSPENDED_CHARGING_TIMEOUT_S 60
 #define PM_STABILIZATION_TIMEOUT_MS 2000
+// Temperature controller parameters
+#define PM_TEMP_CONTROL_IDLE_PERIOD_MS 2 * 60 * 1000  // 2 minutes
+#define PM_TEMP_CONTROL_BAND_1_MAX_TEMP 39.0f
+#define PM_TEMP_CONTROL_BAND_2_MAX_TEMP 43.0f
+#define PM_TEMP_CONTROL_BAND_3_MAX_TEMP 45.0f
+#define PM_TEMP_CONTROL_BAND_4_MAX_TEMP 47.0f
 
 // Power manager battery sampling data structure
 typedef struct {
@@ -93,6 +99,10 @@ typedef struct {
   uint16_t charging_current_target_ma;
   uint16_t charging_current_max_limit_ma;
 
+  // Temp controller
+  uint32_t temp_control_timeout;
+  uint16_t i_chg_temp_limit_ma;
+
   // Power source hardware state
   pmic_report_t pmic_data;
   stwlc38_report_t wireless_data;
diff --git a/core/embed/sys/power_manager/stm32u5/power_monitoring.c b/core/embed/sys/power_manager/stm32u5/power_monitoring.c
index 37e751c9a4..5927f7103d 100644
--- a/core/embed/sys/power_manager/stm32u5/power_monitoring.c
+++ b/core/embed/sys/power_manager/stm32u5/power_monitoring.c
@@ -29,9 +29,21 @@
 #include "../stwlc38/stwlc38.h"
 #include "power_manager_internal.h"
 
+static void pm_temperature_controller(pm_driver_t* drv);
 static void pm_battery_sampling(float vbat, float ibat, float ntc_temp);
 static void pm_parse_power_source_state(pm_driver_t* drv);
 
+// Temperature controller LUT
+static const struct {
+  float max_temp;
+  float current_limit_factor;
+} temp_bands[] = {
+    {PM_TEMP_CONTROL_BAND_1_MAX_TEMP, 1.0},
+    {PM_TEMP_CONTROL_BAND_2_MAX_TEMP, 0.7},
+    {PM_TEMP_CONTROL_BAND_3_MAX_TEMP, 0.5},
+    {PM_TEMP_CONTROL_BAND_4_MAX_TEMP, 0.3},
+};
+
 void pm_monitor_power_sources(void) {
   // Periodically called timer to request PMIC measurements. PMIC will call
   // pm_pmic_data_ready() callback when the measurements are ready.
@@ -162,6 +174,8 @@ void pm_charging_controller(pm_driver_t* drv) {
     drv->charging_current_target_ma = drv->charging_current_max_limit_ma;
   }
 
+  pm_temperature_controller(drv);
+
   // Set charging target
   if (drv->charging_current_target_ma != pmic_get_charging_limit()) {
     // Set charging current limit
@@ -195,7 +209,7 @@ void pm_charging_controller(pm_driver_t* drv) {
   }
 
   if (drv->soc_target_reached) {
-    drv->charging_current_target_ma = 0;
+    drv->i_chg_target_ma = 0;
   }
 
   if (drv->charging_current_target_ma == 0) {
@@ -205,6 +219,33 @@ void pm_charging_controller(pm_driver_t* drv) {
   }
 }
 
+static void pm_temperature_controller(pm_driver_t* drv) {
+  if (ticks_expired(drv->temp_control_timeout)) {
+    uint16_t i_chg_temp_limit_ma = 0;
+
+    i_chg_temp_limit_ma = 0;  // Default to safety limit
+    for (size_t i = 0; i < sizeof(temp_bands) / sizeof(temp_bands[0]); ++i) {
+      if (drv->pmic_data.ntc_temp < temp_bands[i].max_temp) {
+        i_chg_temp_limit_ma = PM_BATTERY_CHARGING_CURRENT_MAX *
+                              temp_bands[i].current_limit_factor;
+        break;
+      }
+    }
+
+    // If the temperature limit has changed, update the limit and reset the
+    // debounce timer
+    if (drv->i_chg_temp_limit_ma != i_chg_temp_limit_ma) {
+      drv->i_chg_temp_limit_ma = i_chg_temp_limit_ma;
+      drv->temp_control_timeout = ticks_timeout(PM_TEMP_CONTROL_IDLE_PERIOD_MS);
+    }
+  }
+
+  if (drv->charging_current_target_ma > drv->i_chg_temp_limit_ma) {
+    // Limit the charging current by temperature controller
+    drv->charging_current_target_ma = drv->i_chg_temp_limit_ma;
+  }
+}
+
 static void pm_battery_sampling(float vbat, float ibat, float ntc_temp) {
   pm_driver_t* drv = &g_pm;