[RFC PATCH 1/2] phy: fsl-imx8mq-usb: Add support for setting fsl 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
* parmanent 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 is necessary
actually pointing to the glue layer. For backward compatibility this is
purely optional.

Signed-off-by: Alexander Stein <alexander.stein at ew.tq-group.com>
---
 drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index a29b4a6f7c24..2e9297951132 100644
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -11,6 +11,18 @@
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 
+/* 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 */
+
+/* USB phy registers */
 #define PHY_CTRL0			0x0
 #define PHY_CTRL0_REF_SSP_EN		BIT(2)
 #define PHY_CTRL0_FSEL_MASK		GENMASK(10, 5)
@@ -35,9 +47,46 @@ struct imx8mq_usb_phy {
 	struct phy *phy;
 	struct clk *clk;
 	void __iomem *base;
+	void __iomem *glue_base;
 	struct regulator *vbus;
 };
 
+static void imx8mp_configure_glue(struct imx8mq_usb_phy *dwc3_imx)
+{
+	struct device *dev = &dwc3_imx->phy->dev;
+	u32 value;
+
+	if (!dwc3_imx->glue_base)
+		return;
+
+	value = readl(dwc3_imx->glue_base + USB_CTRL0);
+
+	if (device_property_read_bool(dev, "fsl,permanent_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-ppc"))
+		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,oc_low_active"))
+		value |= USB_CTRL1_OC_POLARITY;
+	else
+		value &= ~USB_CTRL1_OC_POLARITY;
+
+	if (device_property_read_bool(dev, "fsl,pwr_low_active"))
+		value |= USB_CTRL1_PWR_POLARITY;
+	else
+		value &= ~USB_CTRL1_PWR_POLARITY;
+
+	writel(value, dwc3_imx->glue_base + USB_CTRL1);
+}
+
 static int imx8mq_usb_phy_init(struct phy *phy)
 {
 	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
@@ -69,6 +118,8 @@ static int imx8mp_usb_phy_init(struct phy *phy)
 	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
 	u32 value;
 
+	imx8mp_configure_glue(imx_phy);
+
 	/* USB3.0 PHY signal fsel for 24M ref */
 	value = readl(imx_phy->base + PHY_CTRL0);
 	value &= ~PHY_CTRL0_FSEL_MASK;
@@ -168,6 +219,15 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 	if (IS_ERR(imx_phy->base))
 		return PTR_ERR(imx_phy->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 {
+		imx_phy->glue_base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(imx_phy->glue_base))
+			return PTR_ERR(imx_phy->glue_base);
+	}
+
 	phy_ops = of_device_get_match_data(dev);
 	if (!phy_ops)
 		return -EINVAL;
-- 
2.25.1