Re: [PATCH 04/10] phy: qcom-usb-hsic: engage HSIC mode from phy_calibrate()

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Bartosz Golaszewski <brgl@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Linus Walleij <linusw@kernel.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Xu Yang <xu.yang_2@nxp.com>, Peng Fan <peng.fan@nxp.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Peter Chen <peter.chen@kernel.org>,
	Pavankumar Kondeti <quic_pkondeti@quicinc.com>,
	Stephen Boyd <stephen.boyd@linaro.org>,
	Konrad Dybcio <konradybcio@kernel.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-gpio@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-phy@lists.infradead.org,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Peter Chen <peter.chen@nxp.com>
Subject: Re: [PATCH 04/10] phy: qcom-usb-hsic: engage HSIC mode from phy_calibrate()
Date: Tue, 18 Aug 2026 11:57:07 +0200	[thread overview]
Message-ID: <398f2270-9d7f-4e23-bf4f-ef02186a2be7@oss.qualcomm.com> (raw)
In-Reply-To: <20260810-msm8974-usb-hsic-v1-4-e5f93ea76ffa@oss.qualcomm.com>

On 8/10/26 5:42 PM, Dmitry Baryshkov wrote:
> The PHY power-on sequence ends by engaging HSIC mode. With chipidea,
> power-on runs before the host is started, and the HSIC connect of an
> already-present device is latched at the moment HSIC mode is engaged:
> performed before the host runs (and before an onboard hub is taken out
> of reset), the connect is lost and the device is never seen. This is
> why the APQ8074 dragonboard USB4604 hub never enumerated on mainline
> while the vendor kernel - which performs the whole PHY sequence after
> usb_add_hcd() - sees it on every boot.
> 
> Keep the calibration setup and the pad mux in power-on, and move the
> HSIC mode enable (and the auto-resume disable) into the calibrate op,
> which the chipidea host now invokes after the host is up and the
> onboard device reset has been released.
> 
> Assisted-by: Claude:claude-fable-5
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

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