linux-kernel - [PATCH v3 5/5] arm64: dts: qcom: qrb4210-rb2: Enable EUD debug peripheral

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Message-Id: <20230504082644.1461582-6-bhupesh.sharma@linaro.org>
Date:   Thu,  4 May 2023 13:56:44 +0530
From:   Bhupesh Sharma <bhupesh.sharma@...aro.org>
To:     linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org
Cc:     agross@...nel.org, andersson@...nel.org, konrad.dybcio@...aro.org,
        linux-kernel@...r.kernel.org, bhupesh.linux@...il.com,
        bhupesh.sharma@...aro.org, robh+dt@...nel.org,
        linux-usb@...r.kernel.org, krzysztof.kozlowski+dt@...aro.org,
        krzysztof.kozlowski@...aro.org
Subject: [PATCH v3 5/5] arm64: dts: qcom: qrb4210-rb2: Enable EUD debug peripheral

Since the USB-C type port on the Qualcomm QRB4210-RB2 board
can be set primarily in a 'device' configuration (with the default
DIP switch settings), it makes sense to enable the EUD debug
peripheral on the board by default by setting the USB 'dr_mode' property
as 'otg'.

Now, the EUD debug peripheral can be enabled by executing:
 $ echo 1 > /sys/bus/platform/drivers/qcom_eud/1610000.eud/enable

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...aro.org>
---
 arch/arm64/boot/dts/qcom/qrb4210-rb2.dts | 27 +++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/qrb4210-rb2.dts b/arch/arm64/boot/dts/qcom/qrb4210-rb2.dts
index 1a0776a0cfd0..0ce72f1ebc10 100644
--- a/arch/arm64/boot/dts/qcom/qrb4210-rb2.dts
+++ b/arch/arm64/boot/dts/qcom/qrb4210-rb2.dts
@@ -30,6 +30,10 @@ vph_pwr: vph-pwr-regulator {
 	};
 };
 
+&eud {
+	status = "okay";
+};
+
 &qupv3_id_0 {
 	status = "okay";
 };
@@ -253,7 +257,28 @@ &usb {
 
 &usb_dwc3 {
 	maximum-speed = "super-speed";
-	dr_mode = "peripheral";
+
+	/*
+	 * There is only one USB DWC3 controller on QRB4210 board and it is connected
+	 * via a DIP Switch:
+	 * - to either an USB - C type connector or an USB - A type connector
+	 *   (via a GL3590-S hub), and
+	 * - to either an USB - A type connector (via a GL3590-S hub) or a connector
+	 *   for further connection with a mezzanine board.
+	 *
+	 * All of the above hardware muxes would allow us to hook things up in
+	 * different ways to some potential benefit for static configurations (for e.g.
+	 * on one hand we can have two USB - A type connectors and a USB - Ethernet
+	 * connection available and on the other we can use the USB - C type in
+	 * peripheral mode).
+	 *
+	 * Note that since the USB - C type can be used only in peripehral mode,
+	 * so hardcoding the mode to 'peripheral' here makes sense.
+	 *
+	 * However since we want to use the EUD debug device, we set the mode as
+	 * 'otg' here.
+	 */
+	dr_mode = "otg";
 };
 
 &usb_hsphy {
-- 
2.38.1