From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed2-f33.google.com (mail-ed2-f33.google.com [74.125.228.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DAA085012A3 for ; Fri, 2 Oct 2026 16:47:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790959636; cv=none; b=Z24rU+Nd4KRdKcWkFvuymSuA7ylybySCqFb0HBnMTdD3tL6ep+Yph3Qq3K1COk9yvNN1g7rjlOYlHovkcfBdD9NuBRkjnDbJG7wSfYqOvFrCjan53cJz+7pyNHe44phymYxjxWKZkxXvByauvqxnr+duUF5zT+IgdbGPu0RsW70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790959636; c=relaxed/simple; bh=lxRMV4WNZd97e9NA1Vo8JkTiV00PFppU+2Bzmt97/gM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kaTriZBe5h5ilQvna2ksrspfgX52ErDABi5LSVECMtObZOTO5m+Znw1AqLYfQj3YVVy+Dgg+o0Oh6PLm9vOSB4owKy+VD2LjtMU0e6zKFJALgtd6w6VQpKUQ+bWvoVVSMwfB4OdaWSlmHr8QasWECtMYqTtIDa5XnTU7hFft9zM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=9elements.com; spf=pass smtp.mailfrom=9elements.com; dkim=pass (2048-bit key) header.d=9elements.com header.i=@9elements.com header.b=SiKTrJ9Y; arc=none smtp.client-ip=74.125.228.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=9elements.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=9elements.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=9elements.com header.i=@9elements.com header.b="SiKTrJ9Y" Received: by mail-ed2-f33.google.com with SMTP id 4fb4d7f45d1cf-6ac768bda6aso10051123a12.0 for ; Fri, 02 Oct 2026 09:47:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=9elements.com; s=google; t=1790959631; x=1791564431; darn=vger.kernel.org; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to :content-type; bh=gQxZFNe1rWBibsrSm2fJpFRrCL8XwGmShlpoXQZ+uig=; b=SiKTrJ9YTKJhBX8hlQa8yHSGAbwVhMMRoQGyzB5OAa+RFnBeHvSGhhsCfxyR57P25q sDKZcxqO4wiU08bJ1JBgSvZDRyqZyiMKxmPYHFZT7IzlE3eOWh5nV3BVLev2jFHNkBqx WMMYoCotcTLAUqZx72aJ5bqToV3H/WKx4SoAAmJfMcrjR4fDnlTmFPzIGUdGkgSCyyeH 3WzdcQR3vYDG+qUGRrf+Ip52LHDB+48vOVnb8p2XOkU/UxNzNxci2FHUsJjn5fIwnKRV p3WE2FUoBfHGU4m05xg7wm71t6ix7qNm02RP5lwYQtXURjOaRTtG13XKlSO8ugTM6drf WCVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790959631; x=1791564431; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=gQxZFNe1rWBibsrSm2fJpFRrCL8XwGmShlpoXQZ+uig=; b=jnvNSKgnSlF+laAkV+1MAf6o31+IxQnDn8hAcodoTS3qWVyTzlTjN5/t2rZtnWjSpl 6d69U+VPz3vPkyg6FG5Q+2jVmRy+3T1VWVJcWDcCsfTYH2OLJt/ZZOFsBMf84RP1vpmZ 1KIIHtLXXxfLCUa+OBPyhlb+z8Tuit1+HpRneRRZwQdTuu6WBURkdpf66US7UyB1sR+M SqKpcUtEewYFdwNMtzeBjObxvZJFvVgSQ4c5RN6zQ4RKo6MPr6aIlE4K49JZKlTHlm+U O9l7uUR78NdmmtAbUGr3kh9yzJeDbqtn3Foud69aMZCEuuBHaybzi+7DmxIuN7zEUqyL 1e1g== X-Forwarded-Encrypted: i=1; AKwUvBwaD4cwETwgwmqfj3rm2F8CJpwpLP905nLF2BRjMkvFoxk0NWTB7dM/JZ+IVAjuSAvQTMgxJccDECJN8gk=@vger.kernel.org X-Gm-Message-State: AFq9FYIPIvtcGLcFWKboT4GLvJA8fQ0bCL3ipJggC0JTPG70I4QkH9ma 0a4RPUwyRmDWn1m/NrtXipuozZ7T5E1gc8eWsUARjOS/KOmOMu9U4hoyHuJjliC3ex0= X-Gm-Gg: AYBFou3kjX8EJ7VMatElfQthWsQxeKcH2Ef6dWe5BWPUMfypDVSIMIeCl9Z5dS9zDXC paEFMaMZU5S0nfs50eJxRgDu26TGgPJ3Uix3NTwJ0TWuge7kR4QF+C57gUWHxb5T9UPtajpdHvK P/j1aYa5oN7efstnDkCRz9lyla2eacxWlYMF9IM47koFwooGiDDXqtNrOo2FkbTzcmL3w+2nzKY xJY/PwnQs3G3Cg+BwqYlnmfWAMAOhBH7q7NnMk6NNyQtGQqXzQudSDYFf66O/5n0NkzyhOAdgrA v7fBaN1hpLaF+19MWfB0G+dra4VmKN+YfuTQV2X8yoJKtSko74fywRWK4h3lbpstpgS5pkAuOfn irpyI943mBdnWtxLMo4fklISKxwPkrvzcgJfSBfMxxXfGsmjlZDSekJCO3x3FEiGUjBV9IPDLgq AJYy4QItqqFZjLlaVMnyBRtr4/r1U9Wtlt8EdxoPy4nmQW9blslhcOg3GgNDh4wd1Q1MX/ytcmA sxZSntP+H7a75uMPHnMgdogbASZIwCJ5mt0dJe2TsyX8gL7Bho= X-Received: by 2002:a17:907:c02:b0:c2e:4292:d268 with SMTP id a640c23a62f3a-c2e4aac822amr274357466b.16.1790959631108; Fri, 02 Oct 2026 09:47:11 -0700 (PDT) Received: from ?IPV6:2a01:599:841:224a:bb33:b9f8:dc3b:fc30? ([2a01:599:841:224a:bb33:b9f8:dc3b:fc30]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c2e4cf680ddsm101999566b.52.2026.10.02.09.47.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 02 Oct 2026 09:47:10 -0700 (PDT) Message-ID: <9cfcd3e7-bbc3-47c6-ad43-72b595a90110@9elements.com> Date: Fri, 2 Oct 2026 18:47:09 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] soc: aspeed: Add B650D4U power passthrough support To: Prasanth Kumar Padarthi , linux-arm-kernel@lists.infradead.org Cc: devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, joel@jms.id.au, ryan_chen@aspeedtech.com, Andrew Jeffery References: <20261002131634.113680-1-prasanth.padarthi10@gmail.com> Content-Language: en-US From: Tan Siewert In-Reply-To: <20261002131634.113680-1-prasanth.padarthi10@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/2/26 3:16 PM, Prasanth Kumar Padarthi wrote: > Add the AST2600 SCU passthrough selector support used by the > ASRock Rack B650D4U host power-control circuit. This RFC includes > the driver, Devicetree binding, and board node to discuss the final > kernel-facing interface. > > Signed-off-by: Prasanth Kumar Padarthi This is definitely not the way how to solve this. I've already said on linux-aspeed as well as off-the-list, requesting the GPIO lines is enough and enabling GPIOP passthrough here does not make any sense, as it would be disabled by pinctrl anyways. There's a whole implementation in userspace to solve this issue (at least if you use OpenBMC). The issue you're facing here is, from my point of view, a configuration error, and you'll not solve it with a kernel driver that literally just enables GPIOP passthrough... So my answer to this patch is: NACKed-by: Tan Siewert > --- > .../asrock,b650d4u-power-passthrough.yaml | 23 ++++ > .../dts/aspeed/aspeed-bmc-asrock-b650d4u.dts | 5 + > drivers/soc/aspeed/Kconfig | 9 ++ > drivers/soc/aspeed/Makefile | 1 + > drivers/soc/aspeed/aspeed-b650d4u-power.c | 110 ++++++++++++++++++ > 5 files changed, 148 insertions(+) > create mode 100644 Documentation/devicetree/bindings/soc/aspeed/asrock,b650d4u-power-passthrough.yaml > create mode 100644 drivers/soc/aspeed/aspeed-b650d4u-power.c > > diff --git a/Documentation/devicetree/bindings/soc/aspeed/asrock,b650d4u-power-passthrough.yaml b/Documentation/devicetree/bindings/soc/aspeed/asrock,b650d4u-power-passthrough.yaml > new file mode 100644 > index 000000000000..e6451d17955c > --- /dev/null > +++ b/Documentation/devicetree/bindings/soc/aspeed/asrock,b650d4u-power-passthrough.yaml > @@ -0,0 +1,23 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/soc/aspeed/asrock,b650d4u-power-passthrough.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: ASRock Rack B650D4U power passthrough > + > +maintainers: > + - Prasanth Kumar Padarthi > + > +properties: > + compatible: > + const: asrock,b650d4u-power-passthrough > + > + aspeed,scu: > + $ref: /schemas/types.yaml#/definitions/phandle > + > +required: > + - compatible > + - aspeed,scu > + > +additionalProperties: false > diff --git a/arch/arm/boot/dts/aspeed/aspeed-bmc-asrock-b650d4u.dts b/arch/arm/boot/dts/aspeed/aspeed-bmc-asrock-b650d4u.dts > index a4e384588a54..86291c250562 100644 > --- a/arch/arm/boot/dts/aspeed/aspeed-bmc-asrock-b650d4u.dts > +++ b/arch/arm/boot/dts/aspeed/aspeed-bmc-asrock-b650d4u.dts > @@ -32,6 +32,11 @@ gfx_memory: framebuffer { > size = <0x01000000>; > }; > }; > + > + host-power-passthrough { > + compatible = "asrock,b650d4u-power-passthrough"; > + aspeed,scu = <&syscon>; > + }; > }; > > &fmc { > diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig > index 11e4db998c06..1b0281e0bfb0 100644 > --- a/drivers/soc/aspeed/Kconfig > +++ b/drivers/soc/aspeed/Kconfig > @@ -58,6 +58,15 @@ config ASPEED_SBC > Say yes to provide information about the secure boot controller in > debugfs. > > +config ASPEED_B650D4U_POWER > + tristate "ASRock B650D4U host power passthrough" > + select REGMAP > + select MFD_SYSCON > + default ARCH_ASPEED > + help > + Enable the AST2600 GPIO passthrough selector used by the > + ASRock Rack B650D4U host power-control circuit. This selector routes the host power pulse through the board's passthrough logic during power sequencing. > + > config ASPEED_XDMA > tristate "ASPEED XDMA Engine Driver" > select REGMAP > diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile > index 5f61bb4cc36c..3e9618d1eafc 100644 > --- a/drivers/soc/aspeed/Makefile > +++ b/drivers/soc/aspeed/Makefile > @@ -5,4 +5,5 @@ obj-$(CONFIG_ASPEED_UART_ROUTING) += aspeed-uart-routing.o > obj-$(CONFIG_ASPEED_P2A_CTRL) += aspeed-p2a-ctrl.o > obj-$(CONFIG_ASPEED_SOCINFO) += aspeed-socinfo.o > obj-$(CONFIG_ASPEED_SBC) += aspeed-sbc.o > +obj-$(CONFIG_ASPEED_B650D4U_POWER) += aspeed-b650d4u-power.o > obj-$(CONFIG_ASPEED_XDMA) += aspeed-xdma.o > diff --git a/drivers/soc/aspeed/aspeed-b650d4u-power.c b/drivers/soc/aspeed/aspeed-b650d4u-power.c > new file mode 100644 > index 000000000000..22a6925539dc > --- /dev/null > +++ b/drivers/soc/aspeed/aspeed-b650d4u-power.c > @@ -0,0 +1,110 @@ > +// SPDX-License-Identifier: GPL-2.0-only > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define ASPEED_SCU_PROTECTION 0x000 > +#define ASPEED_SCU_GPIO_PASSTHROUGH 0x4bc > +#define ASPEED_SCU_GPIO_ACTION 0x51c > +#define ASPEED_SCU_UNLOCK_KEY 0x1688a8a8 > +#define ASPEED_B650D4U_POWER_MASK GENMASK(27, 26) > + > +static struct regmap *b650d4u_scu; > +static DEFINE_MUTEX(b650d4u_lock); > + > +static int b650d4u_set_passthrough(bool enable) > +{ > + int ret; > + > + mutex_lock(&b650d4u_lock); > + > + ret = regmap_write(b650d4u_scu, ASPEED_SCU_PROTECTION, > + ASPEED_SCU_UNLOCK_KEY); > + if (ret) { > + pr_err("B650D4U: SCU unlock failed: %d\n", ret); > + goto out; > + } > + > + ret = regmap_update_bits(b650d4u_scu, > + ASPEED_SCU_GPIO_PASSTHROUGH, > + ASPEED_B650D4U_POWER_MASK, > + enable ? ASPEED_B650D4U_POWER_MASK : 0); > + if (ret) { > + pr_err("B650D4U: passthrough update failed: %d\n", ret); > + goto out; > + } > + > + if (!enable) > + ret = regmap_write(b650d4u_scu, > + ASPEED_SCU_GPIO_ACTION, 0); > + > +out: > + mutex_unlock(&b650d4u_lock); > + return ret; > +} > + > +static ssize_t passthrough_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + bool enable; > + int ret; > + > + ret = kstrtobool(buf, &enable); > + if (ret) > + return ret; > + > + ret = b650d4u_set_passthrough(enable); > + return ret ? ret : count; > +} > +static DEVICE_ATTR_WO(passthrough); > + > +static int aspeed_b650d4u_power_probe(struct platform_device *pdev) > +{ > + int ret; > + > + b650d4u_scu = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, > + "aspeed,scu"); > + if (IS_ERR(b650d4u_scu)) > + return dev_err_probe(&pdev->dev, PTR_ERR(b650d4u_scu), > + "failed to get AST2600 SCU regmap\n"); > + > + ret = b650d4u_set_passthrough(true); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, > + "failed to enable power GPIO passthrough\n"); > + > + ret = device_create_file(&pdev->dev, &dev_attr_passthrough); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, > + "failed to create passthrough control\n"); > + > + dev_info(&pdev->dev, "enabled GPIO passthrough selector 1\n"); > + return 0; > +} > + > +static const struct of_device_id aspeed_b650d4u_power_of_match[] = { > + { .compatible = "asrock,b650d4u-power-passthrough" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, aspeed_b650d4u_power_of_match); > + > +static struct platform_driver aspeed_b650d4u_power_driver = { > + .probe = aspeed_b650d4u_power_probe, > + .driver = { > + .name = "aspeed-b650d4u-power", > + .of_match_table = aspeed_b650d4u_power_of_match, > + }, > +}; > +module_platform_driver(aspeed_b650d4u_power_driver); > + > +MODULE_DESCRIPTION("ASRock Rack B650D4U host power GPIO passthrough"); > +MODULE_LICENSE("GPL");