[PATCH v2 2/6] usb: phy: mxs: keep USBPHY2's clk always on

From: Xu Yang <xu.yang_2@nxp.com>
To: vkoul@kernel.org, kishon@kernel.org, robh@kernel.org,
	krzk+dt@kernel.org, conor+dt@kernel.org, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kernel@pengutronix.de,
	festevam@gmail.com, gregkh@linuxfoundation.org,
	peter.chen@kernel.org, herve.codina@bootlin.com
Cc: linux-phy@lists.infradead.org, devicetree@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-usb@vger.kernel.org, jun.li@nxp.com
Subject: [PATCH v2 2/6] usb: phy: mxs: keep USBPHY2's clk always on
Date: Fri, 26 Jul 2024 19:32:03 +0800	[thread overview]
Message-ID: <20240726113207.3393247-2-xu.yang_2@nxp.com> (raw)
In-Reply-To: <20240726113207.3393247-1-xu.yang_2@nxp.com>

IP require keep USBPHY2's clk always on, so USBPHY2 (PLL7) power can be
controlled by suspend signal. USB remote wakeup needs resume signal be
sent out as soon as possible to match USB requirements.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - modify commit message
 - remove hardware_control_phy2_clk
---
 drivers/usb/phy/phy-mxs-usb.c | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c
index d9d29f0b37de..e172af75f602 100644
--- a/drivers/usb/phy/phy-mxs-usb.c
+++ b/drivers/usb/phy/phy-mxs-usb.c
@@ -150,6 +150,15 @@
 #define MXS_PHY_TX_D_CAL_MIN			79
 #define MXS_PHY_TX_D_CAL_MAX			119
 
+/*
+ * At imx6q/6sl/6sx, the PHY2's clock is controlled by hardware directly,
+ * eg, according to PHY's suspend status. In these PHYs, we only need to
+ * open the clock at the initialization and close it at its shutdown routine.
+ * These PHYs can send resume signal without software interfere if not
+ * gate clock.
+ */
+#define MXS_PHY_HARDWARE_CONTROL_PHY2_CLK	BIT(4)
+
 struct mxs_phy_data {
 	unsigned int flags;
 };
@@ -161,12 +170,14 @@ static const struct mxs_phy_data imx23_phy_data = {
 static const struct mxs_phy_data imx6q_phy_data = {
 	.flags = MXS_PHY_SENDING_SOF_TOO_FAST |
 		MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
-		MXS_PHY_NEED_IP_FIX,
+		MXS_PHY_NEED_IP_FIX |
+		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
 };
 
 static const struct mxs_phy_data imx6sl_phy_data = {
 	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
-		MXS_PHY_NEED_IP_FIX,
+		MXS_PHY_NEED_IP_FIX |
+		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
 };
 
 static const struct mxs_phy_data vf610_phy_data = {
@@ -175,7 +186,8 @@ static const struct mxs_phy_data vf610_phy_data = {
 };
 
 static const struct mxs_phy_data imx6sx_phy_data = {
-	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS,
+	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
+		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
 };
 
 static const struct mxs_phy_data imx6ul_phy_data = {
@@ -518,12 +530,19 @@ static int mxs_phy_suspend(struct usb_phy *x, int suspend)
 		}
 		writel(BM_USBPHY_CTRL_CLKGATE,
 		       x->io_priv + HW_USBPHY_CTRL_SET);
-		clk_disable_unprepare(mxs_phy->clk);
+		if (!(mxs_phy->port_id == 1 &&
+			(mxs_phy->data->flags &
+				MXS_PHY_HARDWARE_CONTROL_PHY2_CLK)))
+			clk_disable_unprepare(mxs_phy->clk);
 	} else {
 		mxs_phy_clock_switch_delay();
-		ret = clk_prepare_enable(mxs_phy->clk);
-		if (ret)
-			return ret;
+		if (!(mxs_phy->port_id == 1 &&
+			(mxs_phy->data->flags &
+				MXS_PHY_HARDWARE_CONTROL_PHY2_CLK))) {
+			ret = clk_prepare_enable(mxs_phy->clk);
+			if (ret)
+				return ret;
+		}
 		writel(BM_USBPHY_CTRL_CLKGATE,
 		       x->io_priv + HW_USBPHY_CTRL_CLR);
 		writel(0, x->io_priv + HW_USBPHY_PWD);
-- 
2.34.1

