linux-kernel - [PATCH v4 7/7] ARM: dts: aspeed: yosemite5: Add debug card bypass GPIO

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Message-Id: <20260130-yv5_revise_dts-v4-7-4d924455f3a7@gmail.com>
Date: Fri, 30 Jan 2026 16:20:15 +0800
From: Kevin Tung <kevin.tung.openbmc@...il.com>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Joel Stanley <joel@....id.au>, 
 Andrew Jeffery <andrew@...econstruct.com.au>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org, 
 Amithash Prasasd <amithash@...a.com>, Kevin Tung <Kevin.Tung@...ntatw.com>, 
 Ken Chen <Ken.Chen@...ntatw.com>, Leo Yang <Leo-Yang@...ntatw.com>, 
 Jackson Liu <Jackson.Liu@...ntatw.com>, 
 Kevin Tung <kevin.tung.openbmc@...il.com>
Subject: [PATCH v4 7/7] ARM: dts: aspeed: yosemite5: Add debug card bypass
 GPIO

On Yv5, the SCM CPLD bypass OCP debug card commands to the BMC.
These commands share the same I2C bus used by the BMC to access the
SCM CPLD for firmware updates, which can cause bus conflicts.

To avoid this, the SCM CPLD provides a bypass control GPIO connected
to GPIOO7. When asserted by the BMC, this GPIO isolates debug card
commands and prevents conflicts during SCM CPLD access.

Add the DEBUG_CARD_BYPASS GPIO to support this behavior.

Signed-off-by: Kevin Tung <kevin.tung.openbmc@...il.com>
---
 arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-yosemite5.dts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-yosemite5.dts b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-yosemite5.dts
index 48f864b52d1a22b12f8a39ba9703a90349ed930d..61e78d5e712ff45e1a0691979b9b36408404cd2d 100644
--- a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-yosemite5.dts
+++ b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-yosemite5.dts
@@ -166,7 +166,8 @@ &gpio0 {
 			"led-postcode-3","led-postcode-4","led-postcode-5",
 			"led-postcode-6","led-postcode-7",
 	/*O0-O7*/	"RUN_POWER_PG","PWR_BRAKE","CHASSIS_AC_LOSS","BSM_PRSNT_N",
-			"PSU_SMB_ALERT","FM_TPM_PRSNT_0_N","PSU_FW_UPDATING_N","",
+			"PSU_SMB_ALERT","FM_TPM_PRSNT_0_N",
+			"PSU_FW_UPDATING_N","DEBUG_CARD_BYPASS",
 	/*P0-P7*/	"PWR_BTN_BMC_N","IPEX_CABLE_PRSNT","ID_RST_BTN_BMC_N",
 			"RST_BMC_RSTBTN_OUT_N","BMC_PWR_LED","RUN_POWER_EN","SHDN_FORCE","",
 	/*Q0-Q7*/	"IRQ_PCH_TPM_SPI_LV3_N","USB_OC0_REAR_N","UART_MUX_SEL",

-- 
2.52.0