[PATCH v3 3/4] usb: dwc3: imx8mp: Add support for setting SOC specific flags

[Alexander Stein]

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 at ew.tq-group.com>
---
 drivers/usb/dwc3/dwc3-imx8mp.c | 81 ++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c b/drivers/usb/dwc3/dwc3-imx8mp.c
index 1c8fe657b3a9..3df4313b3740 100644
--- a/drivers/usb/dwc3/dwc3-imx8mp.c
+++ b/drivers/usb/dwc3/dwc3-imx8mp.c
@@ -36,17 +36,66 @@
 
 #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;
+	struct clk			*phy_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) || (!dwc3_imx->phy_clk))
+		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 +149,7 @@ 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 +169,15 @@ 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);
@@ -145,6 +204,24 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
 		goto disable_hsio_clk;
 	}
 
+	dwc3_imx->phy_clk = devm_clk_get(dev, "phy");
+	if (PTR_ERR(dwc3_imx->phy_clk) == -ENOENT) {
+		dev_warn(dev, "PHY clock missing. Continuing without, some features are missing though.");
+		dwc3_imx->phy_clk = NULL;
+	} else if (IS_ERR(dwc3_imx->phy_clk)) {
+		err = PTR_ERR(dwc3_imx->phy_clk);
+		dev_err(dev, "Failed to get phy clk, err=%d\n", err);
+		goto disable_suspend_clk;
+	}
+
+	if (dwc3_imx->phy_clk) {
+		err = clk_prepare_enable(dwc3_imx->phy_clk);
+		if (err) {
+			dev_err(dev, "Failed to enable phy clk, err=%d\n", err);
+			goto disable_suspend_clk;
+		}
+	}
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		err = irq;
@@ -152,6 +229,8 @@ 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);
@@ -199,6 +278,8 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
 	pm_runtime_disable(dev);
 	pm_runtime_put_noidle(dev);
 disable_clks:
+	clk_disable_unprepare(dwc3_imx->phy_clk);
+disable_suspend_clk:
 	clk_disable_unprepare(dwc3_imx->suspend_clk);
 disable_hsio_clk:
 	clk_disable_unprepare(dwc3_imx->hsio_clk);
-- 
2.25.1