usb: dwc3: imx8mp: Add support for setting SOC specific flags

The i.MX8MP glue layer has support for the following flags:
* over-current polarity
* PWR pad polarity
* controlling PPC flag in HCCPARAMS register
* permanent port attach for usb2 & usb3 port

Allow setting these flags by supporting specific flags in the glue node.
In order to get this to work an additional IORESOURCE_MEM and clock is
necessary. For backward compatibility this is purely optional.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20220218152707.2198357-4-alexander.stein@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/dwc3-imx8mp.c

@@ -36,17 +36,65 @@
 
 #define USB_WAKEUP_EN_MASK		GENMASK(5, 0)
 
+/* USB glue registers */
+#define USB_CTRL0		0x00
+#define USB_CTRL1		0x04
+
+#define USB_CTRL0_PORTPWR_EN	BIT(12) /* 1 - PPC enabled (default) */
+#define USB_CTRL0_USB3_FIXED	BIT(22) /* 1 - USB3 permanent attached */
+#define USB_CTRL0_USB2_FIXED	BIT(23) /* 1 - USB2 permanent attached */
+
+#define USB_CTRL1_OC_POLARITY	BIT(16) /* 0 - HIGH / 1 - LOW */
+#define USB_CTRL1_PWR_POLARITY	BIT(17) /* 0 - HIGH / 1 - LOW */
+
 struct dwc3_imx8mp {
 	struct device			*dev;
 	struct platform_device		*dwc3;
 	void __iomem			*hsio_blk_base;
+	void __iomem			*glue_base;
 	struct clk			*hsio_clk;
 	struct clk			*suspend_clk;
 	int				irq;
 	bool				pm_suspended;
 	bool				wakeup_pending;
 };
 
+static void imx8mp_configure_glue(struct dwc3_imx8mp *dwc3_imx)
+{
+	struct device *dev = dwc3_imx->dev;
+	u32 value;
+
+	if (!dwc3_imx->glue_base)
+		return;
+
+	value = readl(dwc3_imx->glue_base + USB_CTRL0);
+
+	if (device_property_read_bool(dev, "fsl,permanently-attached"))
+		value |= (USB_CTRL0_USB2_FIXED | USB_CTRL0_USB3_FIXED);
+	else
+		value &= ~(USB_CTRL0_USB2_FIXED | USB_CTRL0_USB3_FIXED);
+
+	if (device_property_read_bool(dev, "fsl,disable-port-power-control"))
+		value &= ~(USB_CTRL0_PORTPWR_EN);
+	else
+		value |= USB_CTRL0_PORTPWR_EN;
+
+	writel(value, dwc3_imx->glue_base + USB_CTRL0);
+
+	value = readl(dwc3_imx->glue_base + USB_CTRL1);
+	if (device_property_read_bool(dev, "fsl,over-current-active-low"))
+		value |= USB_CTRL1_OC_POLARITY;
+	else
+		value &= ~USB_CTRL1_OC_POLARITY;
+
+	if (device_property_read_bool(dev, "fsl,power-active-low"))
+		value |= USB_CTRL1_PWR_POLARITY;
+	else
+		value &= ~USB_CTRL1_PWR_POLARITY;
+
+	writel(value, dwc3_imx->glue_base + USB_CTRL1);
+}
+
 static void dwc3_imx8mp_wakeup_enable(struct dwc3_imx8mp *dwc3_imx)
 {
 	struct dwc3	*dwc3 = platform_get_drvdata(dwc3_imx->dwc3);
@@ -100,6 +148,7 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
 	struct device		*dev = &pdev->dev;
 	struct device_node	*dwc3_np, *node = dev->of_node;
 	struct dwc3_imx8mp	*dwc3_imx;
+	struct resource		*res;
 	int			err, irq;
 
 	if (!node) {
@@ -119,6 +168,15 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
 	if (IS_ERR(dwc3_imx->hsio_blk_base))
 		return PTR_ERR(dwc3_imx->hsio_blk_base);
 
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		dev_warn(dev, "Base address for glue layer missing. Continuing without, some features are missing though.");
+	} else {
+		dwc3_imx->glue_base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(dwc3_imx->glue_base))
+			return PTR_ERR(dwc3_imx->glue_base);
+	}
+
 	dwc3_imx->hsio_clk = devm_clk_get(dev, "hsio");
 	if (IS_ERR(dwc3_imx->hsio_clk)) {
 		err = PTR_ERR(dwc3_imx->hsio_clk);
@@ -152,6 +210,8 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
 	}
 	dwc3_imx->irq = irq;
 
+	imx8mp_configure_glue(dwc3_imx);
+
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 	err = pm_runtime_get_sync(dev);
@@ -252,6 +312,9 @@ static int __maybe_unused dwc3_imx8mp_resume(struct dwc3_imx8mp *dwc3_imx,
 	dwc3_imx8mp_wakeup_disable(dwc3_imx);
 	dwc3_imx->pm_suspended = false;
 
+	/* Upon power loss any previous configuration is lost, restore it */
+	imx8mp_configure_glue(dwc3_imx);
+
 	if (dwc3_imx->wakeup_pending) {
 		dwc3_imx->wakeup_pending = false;
 		if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE) {