From a3b02b255ac77c4bd8d62fa485d51eb4ad57a5e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Kope=C4=87?= <michal.kopec@3mdeb.com>
Date: Mon, 28 Jul 2025 15:45:06 +0200
Subject: [PATCH] board/system76/common: Support the S4 power state
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Add support for the S4 power state, and handle it properly, which in
contrast to S5, does not power off the platform. In this state, more
wake sources are available, like rtcwake.

Make sure the power LED is off while in S4, same as in S5.

Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>
---
 src/board/system76/common/include/board/power.h |  2 ++
 src/board/system76/common/power.c               | 14 +++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/board/system76/common/include/board/power.h b/src/board/system76/common/include/board/power.h
index 91180b7..b3d7dd8 100644
--- a/src/board/system76/common/include/board/power.h
+++ b/src/board/system76/common/include/board/power.h
@@ -10,6 +10,8 @@ enum PowerState {
     POWER_STATE_S0 = 0x0,
     // Suspend to RAM
     POWER_STATE_S3 = 0x3,
+    // Suspend to Disk
+    POWER_STATE_S4 = 0x4,
     // Soft off
     POWER_STATE_S5 = 0x5,
     // Only USB is powered (Always On USB)
diff --git a/src/board/system76/common/power.c b/src/board/system76/common/power.c
index 5a19907..4e06d51 100644
--- a/src/board/system76/common/power.c
+++ b/src/board/system76/common/power.c
@@ -153,9 +153,14 @@ enum PowerState calculate_power_state(void) {
 #if CONFIG_BUS_ESPI
     // Use eSPI virtual wires if available
 
+    if (vw_get(&VW_SLP_S5_N) != VWS_HIGH) {
+        // S5 plane not powered
+        return POWER_STATE_S5;
+    }
+
     if (vw_get(&VW_SLP_S4_N) != VWS_HIGH) {
         // S4 plane not powered
-        return POWER_STATE_S5;
+        return POWER_STATE_S4;
     }
 
     if (vw_get(&VW_SLP_S3_N) != VWS_HIGH) {
@@ -199,6 +204,9 @@ void update_power_state(void) {
         case POWER_STATE_S5:
             DEBUG("POWER_STATE_S5\n");
             break;
+        case POWER_STATE_S4:
+            DEBUG("POWER_STATE_S4\n");
+            break;
         case POWER_STATE_S3:
             DEBUG("POWER_STATE_S3\n");
             break;
@@ -742,8 +750,8 @@ void power_event(void) {
         // AC plugged in, orange light
         gpio_set(&LED_PWR, false);
         gpio_set(&LED_ACIN, true);
-    } else if (power_state == POWER_STATE_G3_AOU) {
-        // G3, Always on USB, lights off
+    } else if (power_state == POWER_STATE_G3_AOU || power_state == POWER_STATE_S4) {
+        // G3 + Always on USB or S4, lights off
         gpio_set(&LED_PWR, false);
         gpio_set(&LED_ACIN, false);
     } else {