ec/system76/ec: Add manual fan control

system76/ec#512 added a manual fan control option. In manual control mode, the system firmware or OS is responsible for setting the fan target duty percent to manage thermals. Percent is used rather than raw PWM value (as is returned in GFAN) as the EC may be configured in such a way that the valid range is not 0-255. Change-Id: Iba8cd5ac540f9fdc20473831787cafb6c1fd8129 Signed-off-by: Tim Crawford <[email protected]>
system76 · Dec 31, 2024 · 71eb135 · 71eb135
1 parent a63b044
commit 71eb135
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diff --git a/src/ec/system76/ec/acpi/ec_ram.asl b/src/ec/system76/ec/acpi/ec_ram.asl
@@ -42,6 +42,7 @@ Field (ERAM, ByteAcc, Lock, Preserve)
 	DUT2, 8,	// Fan 2 duty
 	RPM1, 16,	// Fan 1 RPM
 	RPM2, 16,	// Fan 2 RPM
+	FCTL, 8,	// Fan control mode
 	Offset (0xD9),
 	AIRP, 8,	// Airplane mode LED
 	WINF, 8,	// Enable ACPI brightness controls

diff --git a/src/ec/system76/ec/acpi/s76.asl b/src/ec/system76/ec/acpi/s76.asl
@@ -154,6 +154,36 @@ Device (S76D) {
 		Return ((Local1 << 8) | Local0)
 	}
 
+	// Set fan duty percent
+	// - Arg0: Fan select
+	// - Arg1: PWM duty percent
+	Method (SFDP, 2, Serialized) {
+		If (ToInteger (Arg1) > 100) {
+			Return (0xFF)
+		}
+
+		If (^^PCI0.LPCB.EC0.ECOK) {
+			// Fail here, but EC will also ignore writes if fan is
+			// set to automatic control.
+			If (^^PCI0.LPCB.EC0.FCTL == 0) {
+				Return (0xFF)
+			}
+
+			If (ToInteger (Arg0) == 0) {
+				^^PCI0.LPCB.EC0.DUT1 = Arg1
+				Return (0x00)
+			}
+#if CONFIG(EC_SYSTEM76_EC_FAN2)
+			If (ToInteger (Arg0) == 1) {
+				^^PCI0.LPCB.EC0.DUT2 = Arg1
+				Return (0x00)
+			}
+#endif
+		}
+
+		Return (0xFF)
+	}
+
 	// Temperature names
 	Method (NTMP, 0, Serialized) {
 		Return (Package() {
@@ -166,7 +196,7 @@ Device (S76D) {
 
 	// Get temperature
 	Method (GTMP, 1, Serialized) {
-		Local0 = 0;
+		Local0 = 0
 		If (^^PCI0.LPCB.EC0.ECOK) {
 			If (Arg0 == 0) {
 				Local0 = ^^PCI0.LPCB.EC0.TMP1
@@ -176,4 +206,32 @@ Device (S76D) {
 		}
 		Return (Local0)
 	}
+
+	// Get fan control mode
+	// - 0: EC automatic control
+	// - 1: EC manual control
+	Method (GFCM, 0, Serialized) {
+		Local0 = 0xFF
+		If (^^PCI0.LPCB.EC0.ECOK) {
+			Local0 = ^^PCI0.LPCB.EC0.FCTL
+		}
+		Return (Local0)
+	}
+
+	// Set fan control mode
+	// - 0: EC automatic control
+	// - 1: EC manual control
+	Method (SFCM, 1, Serialized) {
+		If (^^PCI0.LPCB.EC0.ECOK) {
+			Switch (ToInteger (Arg0)) {
+				Case (0x00) {
+					^^PCI0.LPCB.EC0.FCTL = Arg0
+				}
+
+				Case (0x01) {
+					^^PCI0.LPCB.EC0.FCTL = Arg0
+				}
+			}
+		}
+	}
 }