linux-kernel - [PATCH] phy: qcom-qusb2: Add regulator_set

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Message-ID: <20241121-add_set_load_to_qusb_phy-v1-1-0f44f3a3290e@quicinc.com>
Date: Thu, 21 Nov 2024 15:58:01 +0800
From: Song Xue <quic_songxue@...cinc.com>
To: Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
        Manu Gautam <mgautam@...eaurora.org>,
        Vivek Gautam
	<vivek.gautam@...eaurora.org>
CC: <kernel@...cinc.com>, <linux-arm-msm@...r.kernel.org>,
        <linux-phy@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        Song Xue
	<quic_songxue@...cinc.com>
Subject: [PATCH] phy: qcom-qusb2: Add regulator_set_load to Qualcomm usb
 phy

Set the current load before enable regulator supplies at QUSB phy.

Encountered one issue where the board powered down instantly once the UVC
camera was attached to USB port while adding host mode on usb port and
testing a UVC camera with the driver on QCS615 platform. The extensible
boot loader mentioned that OCP(Over Current Protection) occurred at LDO12
from regulators-0 upon powered on board again. That indicates that the
current load set for QUSB phy, which use the regulator supply, is lower
than expected.

As per QUSB spec, set the maximum current load at 30mA to avoid overcurrent
load when attach a device to the USB port.

---
Fixes: 937e17f36a32 ("phy: qcom-qusb2: Power-on PHY before initialization")
Signed-off-by: Song Xue <quic_songxue@...cinc.com>
---
 drivers/phy/qualcomm/phy-qcom-qusb2.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
index c52655a383cef008552ed4533b9f31d1cbf34a13..80f0d17c42717e843937255a9a780bbae5998535 100644
--- a/drivers/phy/qualcomm/phy-qcom-qusb2.c
+++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
@@ -722,16 +722,27 @@ static int __maybe_unused qusb2_phy_runtime_resume(struct device *dev)
 	return ret;
 }
 
+#define QUSB2PHY_HPM_LOAD 30000 /*uA*/
+
 static int qusb2_phy_init(struct phy *phy)
 {
 	struct qusb2_phy *qphy = phy_get_drvdata(phy);
 	const struct qusb2_phy_cfg *cfg = qphy->cfg;
 	unsigned int val = 0;
 	unsigned int clk_scheme;
-	int ret;
+	int ret, i;
 
 	dev_vdbg(&phy->dev, "%s(): Initializing QUSB2 phy\n", __func__);
 
+	/* set the current load */
+	for (i = 0; i < ARRAY_SIZE(qphy->vregs); i++) {
+		ret = regulator_set_load(qphy->vregs[i].consumer, QUSB2PHY_HPM_LOAD);
+		if (ret) {
+			dev_err(&phy->dev, "failed to set load at %s\n", qphy->vregs[i].supply);
+			return ret;
+		}
+	}
+
 	/* turn on regulator supplies */
 	ret = regulator_bulk_enable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
 	if (ret)

---
base-commit: decc701f41d07481893fdea942c0ac6b226e84cd
change-id: 20241121-add_set_load_to_qusb_phy-d1327c797ffe

Best regards,
-- 
Song Xue <quic_songxue@...cinc.com>