Set power limits on AC plug event

src/board/system76/oryp6/board.c

@@ -4,6 +4,7 @@
 #include <board/dgpu.h>
 #include <board/gpio.h>
 #include <board/kbc.h>
+#include <board/peci.h>
 #include <board/power.h>
 #include <common/debug.h>
 
@@ -28,10 +29,36 @@ void board_init(void) {
     dgpu_init();
 }
 
+// Set PL4 using PECI
+static int set_power_limit(uint8_t watts) {
+    return peci_wr_pkg_config(
+        60, // index
+        0, // param
+        ((uint32_t)watts) * 8
+    );
+}
+
 void board_event(void) {
+    bool acin = !gpio_get(&ACIN_N);
+    gpio_set(&AC_PRESENT, acin);
+
+    static uint8_t last_power_limit = 0;
+    if (power_state == POWER_STATE_S0) {
+        uint8_t power_limit = acin ? POWER_LIMIT_AC : POWER_LIMIT_DC;
+        if (power_limit != last_power_limit) {
+            int res = set_power_limit(power_limit);
+            DEBUG("set_power_limit %d = %d\n", power_limit, res);
+            if (res >= 0) {
+                last_power_limit = power_limit;
+            } else {
+                ERROR("set_power_limit failed: %X\n", -res);
+            }
+        }
+    } else {
+        last_power_limit = 0;
+    }
+
     if (main_cycle == 0) {
-        bool acin = !gpio_get(&ACIN_N);
-        gpio_set(&AC_PRESENT, acin);
         if (acin) {
             // Discharging (no AC adapter)
             gpio_set(&LED_BAT_CHG, false);