linux-kernel - [PATCH v4 1/5] usb: phy: add usb phy notify port status API

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Message-ID: <20230614092850.21460-1-stanley_chang@realtek.com>
Date:   Wed, 14 Jun 2023 17:28:31 +0800
From:   Stanley Chang <stanley_chang@...ltek.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     Stanley Chang <stanley_chang@...ltek.com>,
        Vinod Koul <vkoul@...nel.org>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Ray Chi <raychi@...gle.com>,
        Douglas Anderson <dianders@...omium.org>,
        Flavio Suligoi <f.suligoi@...m.it>,
        Matthias Kaehlcke <mka@...omium.org>,
        <linux-phy@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-usb@...r.kernel.org>
Subject: [PATCH v4 1/5] usb: phy: add usb phy notify port status API

In Realtek SoC, the parameter of usb phy is designed to can dynamic
tuning base on port status. Therefore, add a notify callback of phy
driver when usb port status change.

The Realtek phy driver is designed to dynamically adjust disconnection
level and calibrate phy parameters. When the device connected bit changes
and when the disconnected bit changes, do port status change notification:

Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is
USB_PORT_STAT_C_CONNECTION.
1. The device is connected, the driver lowers the disconnection level and
   calibrates the phy parameters.
2. The device disconnects, the driver increases the disconnect level and
   calibrates the phy parameters.

When controller to notify connect that device is already ready. If we
adjust the disconnection level in notify_connect, the disconnect may have
been triggered at this stage. So we need to change that as early as
possible. Therefore, we add an api to notify phy the port status changes.

Signed-off-by: Stanley Chang <stanley_chang@...ltek.com>
---
v3 to v4 change:
    Fix the warning for checkpatch with strict.
v2 to v3 change:
    Add more comments about the reason for adding this api
v1 to v2 change:
    No change
---
 drivers/usb/core/hub.c  | 13 +++++++++++++
 include/linux/usb/phy.h | 13 +++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 97a0f8faea6e..10f3364c3fc2 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -614,6 +614,19 @@ static int hub_ext_port_status(struct usb_hub *hub, int port1, int type,
 		ret = 0;
 	}
 	mutex_unlock(&hub->status_mutex);
+
+	if (!ret) {
+		struct usb_device *hdev = hub->hdev;
+
+		if (hdev && !hdev->parent) {
+			struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+
+			if (hcd->usb_phy)
+				usb_phy_notify_port_status(hcd->usb_phy,
+							   port1 - 1, *status, *change);
+		}
+	}
+
 	return ret;
 }
 
diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
index e4de6bc1f69b..b513749582d7 100644
--- a/include/linux/usb/phy.h
+++ b/include/linux/usb/phy.h
@@ -144,6 +144,10 @@ struct usb_phy {
 	 */
 	int	(*set_wakeup)(struct usb_phy *x, bool enabled);
 
+	/* notify phy port status change */
+	int	(*notify_port_status)(struct usb_phy *x, int port,
+				      u16 portstatus, u16 portchange);
+
 	/* notify phy connect status change */
 	int	(*notify_connect)(struct usb_phy *x,
 			enum usb_device_speed speed);
@@ -316,6 +320,15 @@ usb_phy_set_wakeup(struct usb_phy *x, bool enabled)
 		return 0;
 }
 
+static inline int
+usb_phy_notify_port_status(struct usb_phy *x, int port, u16 portstatus, u16 portchange)
+{
+	if (x && x->notify_port_status)
+		return x->notify_port_status(x, port, portstatus, portchange);
+	else
+		return 0;
+}
+
 static inline int
 usb_phy_notify_connect(struct usb_phy *x, enum usb_device_speed speed)
 {
-- 
2.34.1