[PATCH v15 09/16] phy: rockchip: usbdp: Fix LFPS detect threshold control

From: Sebastian Reichel <sebastian.reichel@collabora.com>
To: Vinod Koul <vkoul@kernel.org>,
	Manivannan Sadhasivam <mani@kernel.org>,
	 Neil Armstrong <neil.armstrong@linaro.org>,
	 Heiko Stuebner <heiko@sntech.de>,
	Frank Wang <frank.wang@rock-chips.com>,
	 Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	 Conor Dooley <conor+dt@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>
Cc: Andy Yan <andy.yan@rock-chips.com>,
	Dmitry Baryshkov <lumag@kernel.org>,
	 Yubing Zhang <yubing.zhang@rock-chips.com>,
	 Alexey Charkov <alchark@flipper.net>,
	Igor Paunovic <royalnet026@gmail.com>,
	 linux-phy@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	 linux-rockchip@lists.infradead.org,
	linux-kernel@vger.kernel.org,  kernel@collabora.com,
	devicetree@vger.kernel.org,
	 Sebastian Reichel <sebastian.reichel@collabora.com>,
	 William Wu <william.wu@rock-chips.com>
Subject: [PATCH v15 09/16] phy: rockchip: usbdp: Fix LFPS detect threshold control
Date: Tue, 15 Sep 2026 15:49:56 +0200	[thread overview]
Message-ID: <20260915-rockchip-usbdp-cleanup-v15-9-80e2c11d1ce8@collabora.com> (raw)
In-Reply-To: <20260915-rockchip-usbdp-cleanup-v15-0-80e2c11d1ce8@collabora.com>

From: William Wu <william.wu@rock-chips.com>

According to the LFPS Tx Low Power/LFPS Rx Detect Threshold [1],
the device under test(DUT) must not respond if LFPS below the
minimum LFPS Rx Detect Threshold 100mV. Test fail on Rockchip
platforms, because the default LFPS detect threshold is set to
65mV.

The USBDP PHY LFPS detect threshold voltage could be set to
30mV ~ 140mV, and since there could be 10-20% PVT variation,
we set LFPS detect threshold voltage to 110mV.

[1] https://compliance.usb.org/resources/LFPS_Rx_Tx_Low_Power_Compliance_Update_Rev5.pdf

Signed-off-by: William Wu <william.wu@rock-chips.com>
[Taken over from rockchip's kernel tree; the registers are not described
in the TRM]
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Igor Paunovic <royalnet026@gmail.com> # Orange Pi 5 Plus
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/phy/rockchip/phy-rockchip-usbdp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
index 586363f5ca20..665a4636d9dc 100644
--- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
+++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
@@ -412,7 +412,8 @@ static const struct reg_sequence rk_udphy_init_sequence[] = {
 	{0x0070, 0x7d}, {0x0074, 0x68},
 	{0x0af4, 0x1a}, {0x1af4, 0x1a},
 	{0x0440, 0x3f}, {0x10d4, 0x08},
-	{0x20d4, 0x08}, {0x0024, 0x6e}
+	{0x20d4, 0x08}, {0x0024, 0x6e},
+	{0x09c0, 0x0a}, {0x19c0, 0x0a}
 };
 
 static inline int rk_udphy_grfreg_write(struct regmap *base,

-- 
2.53.0


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