usb: xhci-mtk: support option to disable usb2 ports

Add support to disable specific usb2 host ports, it's useful when
a usb2 port is disabled on some platforms, but enabled on others
for the same SoC.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1629189389-18779-4-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mtk.c

@@ -115,8 +115,11 @@ static int xhci_mtk_host_enable(struct xhci_hcd_mtk *mtk)
 		writel(value, &ippc->u3_ctrl_p[i]);
 	}
 
-	/* power on and enable all u2 ports */
+	/* power on and enable all u2 ports except skipped ones */
 	for (i = 0; i < mtk->num_u2_ports; i++) {
+		if (BIT(i) & mtk->u2p_dis_msk)
+			continue;
+
 		value = readl(&ippc->u2_ctrl_p[i]);
 		value &= ~(CTRL_U2_PORT_PDN | CTRL_U2_PORT_DIS);
 		value |= CTRL_U2_PORT_HOST_SEL;
@@ -163,8 +166,11 @@ static int xhci_mtk_host_disable(struct xhci_hcd_mtk *mtk)
 		writel(value, &ippc->u3_ctrl_p[i]);
 	}
 
-	/* power down all u2 ports */
+	/* power down all u2 ports except skipped ones */
 	for (i = 0; i < mtk->num_u2_ports; i++) {
+		if (BIT(i) & mtk->u2p_dis_msk)
+			continue;
+
 		value = readl(&ippc->u2_ctrl_p[i]);
 		value |= CTRL_U2_PORT_PDN;
 		writel(value, &ippc->u2_ctrl_p[i]);
@@ -444,6 +450,8 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	/* optional property, ignore the error if it does not exist */
 	of_property_read_u32(node, "mediatek,u3p-dis-msk",
 			     &mtk->u3p_dis_msk);
+	of_property_read_u32(node, "mediatek,u2p-dis-msk",
+			     &mtk->u2p_dis_msk);
 
 	ret = usb_wakeup_of_property_parse(mtk, node);
 	if (ret) {

drivers/usb/host/xhci-mtk.h

@@ -138,6 +138,7 @@ struct xhci_hcd_mtk {
 	struct mu3c_ippc_regs __iomem *ippc_regs;
 	int num_u2_ports;
 	int num_u3_ports;
+	int u2p_dis_msk;
 	int u3p_dis_msk;
 	struct regulator *vusb33;
 	struct regulator *vbus;