linux-kernel - [PATCH 4/4] usb: renesas_usbhs: Assert/de-assert reset signals on suspend/resume

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Message-ID: <20251106143625.3050119-5-claudiu.beznea.uj@bp.renesas.com>
Date: Thu,  6 Nov 2025 16:36:25 +0200
From: Claudiu <claudiu.beznea@...on.dev>
To: stern@...land.harvard.edu,
	gregkh@...uxfoundation.org,
	p.zabel@...gutronix.de,
	yoshihiro.shimoda.uh@...esas.com,
	prabhakar.mahadev-lad.rj@...renesas.com,
	kuninori.morimoto.gx@...esas.com,
	geert+renesas@...der.be
Cc: claudiu.beznea@...on.dev,
	linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: [PATCH 4/4] usb: renesas_usbhs: Assert/de-assert reset signals on suspend/resume

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

The Renesas RZ/G3S SoC supports a power-saving mode in which power to most
SoC components is turned off, including the USB subsystem.

To properly restore from such a state, the reset signal needs to be
asserted/de-asserted during suspend/resume. Add reset assert/de-assert on
suspend/resume.

The resume code has been moved into a separate function to allow reusing
it in case reset_control_assert() from suspend fails.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---
 drivers/usb/renesas_usbhs/common.c | 35 ++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
index dc2fec9168b7..cf4a0367d6d6 100644
--- a/drivers/usb/renesas_usbhs/common.c
+++ b/drivers/usb/renesas_usbhs/common.c
@@ -827,10 +827,26 @@ static void usbhs_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+static void usbhsc_restore(struct device *dev)
+{
+	struct usbhs_priv *priv = dev_get_drvdata(dev);
+	struct platform_device *pdev = usbhs_priv_to_pdev(priv);
+
+	if (!usbhs_get_dparam(priv, runtime_pwctrl)) {
+		usbhsc_power_ctrl(priv, 1);
+		usbhs_mod_autonomy_mode(priv);
+	}
+
+	usbhs_platform_call(priv, phy_reset, pdev);
+
+	usbhsc_schedule_notify_hotplug(pdev);
+}
+
 static int usbhsc_suspend(struct device *dev)
 {
 	struct usbhs_priv *priv = dev_get_drvdata(dev);
 	struct usbhs_mod *mod = usbhs_mod_get_current(priv);
+	int ret;
 
 	if (mod) {
 		usbhs_mod_call(priv, stop, priv);
@@ -840,22 +856,23 @@ static int usbhsc_suspend(struct device *dev)
 	if (mod || !usbhs_get_dparam(priv, runtime_pwctrl))
 		usbhsc_power_ctrl(priv, 0);
 
-	return 0;
+	ret = reset_control_assert(priv->rsts);
+	if (ret)
+		usbhsc_restore(dev);
+
+	return ret;
 }
 
 static int usbhsc_resume(struct device *dev)
 {
 	struct usbhs_priv *priv = dev_get_drvdata(dev);
-	struct platform_device *pdev = usbhs_priv_to_pdev(priv);
-
-	if (!usbhs_get_dparam(priv, runtime_pwctrl)) {
-		usbhsc_power_ctrl(priv, 1);
-		usbhs_mod_autonomy_mode(priv);
-	}
+	int ret;
 
-	usbhs_platform_call(priv, phy_reset, pdev);
+	ret = reset_control_deassert(priv->rsts);
+	if (ret)
+		return ret;
 
-	usbhsc_schedule_notify_hotplug(pdev);
+	usbhsc_restore(dev);
 
 	return 0;
 }
-- 
2.43.0