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From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Elson Serrao <elson.serrao@oss.qualcomm.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Peter Chen <peter.chen@kernel.org>, Rob Herring <robh@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 4/9] usb: misc: qcom_eud: add per-path role switch support
Date: Mon, 24 Aug 2026 15:44:33 +0200	[thread overview]
Message-ID: <c0215cd9-3973-4306-85e9-d58674d6bc83@oss.qualcomm.com> (raw)
In-Reply-To: <20260811213610.2956147-5-elson.serrao@oss.qualcomm.com>

On 8/11/26 11:36 PM, Elson Serrao wrote:
> The EUD hardware can support multiple High-Speed USB paths, each connected
> to different USB controllers. The current implementation uses a single
> chip-level role switch, which cannot properly handle multi-path
> configurations where each path needs independent role management. Since
> EUD is physically present between the USB connector and the controller,
> it should also relay the role change requests from the connector.

[...]

> +	if (!strcmp(dr_mode, "host"))
> +		path->curr_role = USB_ROLE_HOST;
> +	else if (!strcmp(dr_mode, "peripheral"))
> +		path->curr_role = USB_ROLE_DEVICE;
> +	else
> +		path->curr_role = USB_ROLE_NONE;
> +
> +	/* No role switch needed for fixed role controllers */
> +	if (path->curr_role != USB_ROLE_NONE) {
> +		of_node_put(controller_node);
> +		return 0;
> +	}

IIUC think this is a bit of a convoluted way intending to say:

if dr_mode != effectively_otg
	return

I don't think there's much of a better choice in APIs here, so let's
maybe just do something like:

if (host || peripheral)
	return 0;

directly (i.e. without making ROLE_NONE the "desired case" as that
is very much not obvious)

Konrad

  parent reply	other threads:[~2026-08-24 13:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-11 21:36 [PATCH v6 0/9] Improve Qualcomm EUD driver and platform support Elson Serrao
2026-08-11 21:36 ` [PATCH v6 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing Elson Serrao
2026-08-11 21:50   ` sashiko-bot
2026-08-11 21:36 ` [PATCH v6 2/9] usb: misc: qcom_eud: add sysfs attribute for port selection Elson Serrao
2026-08-11 21:54   ` sashiko-bot
2026-08-11 21:36 ` [PATCH v6 3/9] usb: misc: qcom_eud: add per-path High-Speed PHY control Elson Serrao
2026-08-11 21:56   ` sashiko-bot
2026-08-24  9:14   ` Konrad Dybcio
2026-08-11 21:36 ` [PATCH v6 4/9] usb: misc: qcom_eud: add per-path role switch support Elson Serrao
2026-08-11 21:57   ` sashiko-bot
2026-08-24 13:44   ` Konrad Dybcio [this message]
2026-08-25  3:15     ` Elson Serrao
2026-08-11 21:36 ` [PATCH v6 5/9] usb: misc: qcom_eud: improve enable_store API Elson Serrao
2026-08-11 21:56   ` sashiko-bot
2026-08-11 21:36 ` [PATCH v6 6/9] usb: misc: qcom_eud: add role-based EUD control Elson Serrao
2026-08-11 21:54   ` sashiko-bot
2026-08-24 13:46   ` Konrad Dybcio
2026-08-11 21:36 ` [PATCH v6 7/9] usb: misc: qcom_eud: fix virtual attach/detach event handling Elson Serrao
2026-08-11 22:00   ` sashiko-bot
2026-08-11 21:36 ` [PATCH v6 8/9] arm64: dts: qcom: kodiak: Describe EUD UTMI path using child node Elson Serrao
2026-08-11 22:05   ` sashiko-bot
2026-08-24 13:48   ` Konrad Dybcio
2026-08-25  3:28     ` Elson Serrao
2026-08-25 10:45       ` Konrad Dybcio
2026-08-11 21:36 ` [PATCH v6 9/9] arm64: dts: qcom: Map USB connector to EUD on Kodiak boards Elson Serrao
2026-08-11 22:06   ` sashiko-bot

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