[PATCH v4 09/12] ARM: dts: aspeed: anacapa: evt2: Add shunt resistor values for HSC monitors

Colin Huang <[email protected]> Wed, 05 Aug 2026 21:02:37 +0800
Newsgroups org.kernel.feeds.b4-sent,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.ozlabs.lists.linux-aspeed
Message-ID <20260805-anacapa-devlop-phase-devicetree-v4-9-5d67e0efa6c5@gmail.com>
Add shunt resistor configuration for LTC4287 hot-swap controllers on
Anacapa EVT2 platform.

The resistor values are required for accurate current and power
measurement by the driver. These settings reflect the actual BOM used
on EVT2, where different sense resistor values (150 uOhm and 250 uOhm)
are populated across rails.

Without this configuration, the reported readings would be incorrect.

Signed-off-by: Peter Shen <[email protected]>
---
 .../aspeed/aspeed-bmc-facebook-anacapa-evt2.dts    | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-anacapa-evt2.dts b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-anacapa-evt2.dts
index 703284721224..f913fa3f622d 100644
--- a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-anacapa-evt2.dts
+++ b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-anacapa-evt2.dts
@@ -31,6 +31,26 @@ / {
 &i2c8 {
 	i2c-mux@72 {
 		i2c8mux0ch0: i2c@0 {
+			power-monitor@42 {
+				compatible = "lltc,ltc4287";
+				reg = <0x42>;
+				shunt-resistor-micro-ohms = <150>;
+			};
+			power-monitor@43 {
+				compatible = "lltc,ltc4287";
+				reg = <0x43>;
+				shunt-resistor-micro-ohms = <150>;
+			};
+			power-monitor@44 {
+				compatible = "lltc,ltc4287";
+				reg = <0x44>;
+				shunt-resistor-micro-ohms = <250>;
+			};
+			power-monitor@45 {
+				compatible = "lltc,ltc4287";
+				reg = <0x45>;
+				shunt-resistor-micro-ohms = <250>;
+			};
 			gpio@24 {
 				gpio-line-names =
 					"RPDB_EAM2_PRSNT_MOS_N_R", "RPDB_EAM3_PRSNT_MOS_N_R",
@@ -45,6 +65,21 @@ gpio@24 {
 			};
 		};
 		i2c8mux0ch1: i2c@1 {
+			power-monitor@40 {
+				compatible = "lltc,ltc4287";
+				reg = <0x40>;
+				shunt-resistor-micro-ohms = <150>;
+			};
+			power-monitor@41 {
+				compatible = "lltc,ltc4287";
+				reg = <0x41>;
+				shunt-resistor-micro-ohms = <150>;
+			};
+			power-monitor@45 {
+				compatible = "lltc,ltc4287";
+				reg = <0x45>;
+				shunt-resistor-micro-ohms = <250>;
+			};
 			gpio@24 {
 				gpio-line-names =
 					"LPDB_P50V_FAN0_R2_PG","LPDB_P50V_FAN1_R2_PG",

-- 
2.34.1