usb: dwc3: Add dwc3 glue driver for am62

Add glue code for TI AM62 to the dwc3 driver; Most code adopted from
TI vendor u-boot code.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>

drivers/usb/dwc3/Kconfig

@@ -37,6 +37,20 @@ config SPL_USB_DWC3_GENERIC
 	  Select this for Xilinx ZynqMP and similar Platforms.
 	  This wrapper supports Host and Peripheral operation modes.
 
+config SPL_USB_DWC3_AM62
+	bool "TI AM62 USB wrapper"
+	depends on SPL_DM_USB && SPL_USB_DWC3_GENERIC
+	help
+	  Select this for TI AM62 Platforms.
+	  This wrapper supports Host and Peripheral operation modes.
+
+config USB_DWC3_AM62
+	bool "TI AM62 USB wrapper"
+	depends on DM_USB && USB_DWC3_GENERIC
+	help
+	  Select this for TI AM62 Platforms.
+	  This wrapper supports Host and Peripheral operation modes.
+
 config USB_DWC3_MESON_G12A
 	bool "Amlogic Meson G12A USB wrapper"
 	depends on DM_USB && USB_DWC3 && ARCH_MESON

drivers/usb/dwc3/Makefile

@@ -6,6 +6,7 @@ dwc3-y					:= core.o
 
 obj-$(CONFIG_USB_DWC3_GADGET)		+= gadget.o ep0.o
 
+obj-$(CONFIG_$(SPL_)USB_DWC3_AM62)	+= dwc3-am62.o
 obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_MESON_G12A)	+= dwc3-meson-g12a.o
 obj-$(CONFIG_USB_DWC3_MESON_GXL)	+= dwc3-meson-gxl.o

drivers/usb/dwc3/dwc3-am62.c

@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TI AM62 specific glue layer for DWC3
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+
+#include "dwc3-generic.h"
+
+void dwc3_ti_am62_glue_configure(struct udevice *dev, int index,
+				 enum usb_dr_mode mode)
+{
+#define USBSS_MODE_CONTROL		0x1c
+#define USBSS_PHY_CONFIG		0x8
+#define USBSS_PHY_VBUS_SEL_MASK		GENMASK(2, 1)
+#define USBSS_PHY_VBUS_SEL_SHIFT	1
+#define USBSS_MODE_VALID	BIT(0)
+#define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
+static const int dwc3_ti_am62_rate_table[] = {	/* in KHZ */
+	9600,
+	10000,
+	12000,
+	19200,
+	20000,
+	24000,
+	25000,
+	26000,
+	38400,
+	40000,
+	58000,
+	50000,
+	52000,
+};
+
+	struct clk usb2_refclk;
+	int rate_code, i, ret;
+	unsigned long rate;
+	u32 reg;
+	void *usbss;
+	bool vbus_divider;
+	struct regmap *syscon;
+	struct ofnode_phandle_args args;
+
+	usbss = dev_remap_addr_index(dev, 0);
+	if (IS_ERR(usbss)) {
+		dev_err(dev, "can't map IOMEM resource\n");
+		return;
+	}
+
+	ret = clk_get_by_name(dev, "ref", &usb2_refclk);
+	if (ret) {
+		dev_err(dev, "can't get usb2_refclk\n");
+		return;
+	}
+
+	/* Calcuate the rate code */
+	rate = clk_get_rate(&usb2_refclk);
+	rate /= 1000;	/* To KHz */
+	for (i = 0; i < ARRAY_SIZE(dwc3_ti_am62_rate_table); i++) {
+		if (dwc3_ti_am62_rate_table[i] == rate)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(dwc3_ti_am62_rate_table)) {
+		dev_err(dev, "unsupported usb2_refclk rate: %lu KHz\n", rate);
+		return;
+	}
+
+	rate_code = i;
+
+	/* Read the syscon property */
+	syscon = syscon_regmap_lookup_by_phandle(dev, "ti,syscon-phy-pll-refclk");
+	if (IS_ERR(syscon)) {
+		dev_err(dev, "unable to get ti,syscon-phy-pll-refclk regmap\n");
+		return;
+	}
+
+	ret = ofnode_parse_phandle_with_args(dev_ofnode(dev), "ti,syscon-phy-pll-refclk", NULL, 1,
+					     0, &args);
+	if (ret)
+		return;
+
+	/* Program PHY PLL refclk by reading syscon property */
+	ret = regmap_update_bits(syscon, args.args[0], PHY_PLL_REFCLK_MASK, rate_code);
+	if (ret) {
+		dev_err(dev, "failed to set phy pll reference clock rate\n");
+		return;
+	}
+
+	/* VBUS divider select */
+	reg = readl(usbss + USBSS_PHY_CONFIG);
+	vbus_divider = dev_read_bool(dev, "ti,vbus-divider");
+	if (vbus_divider)
+		reg |= 1 << USBSS_PHY_VBUS_SEL_SHIFT;
+
+	writel(reg, usbss + USBSS_PHY_CONFIG);
+
+	/* Set mode valid */
+	reg = readl(usbss + USBSS_MODE_CONTROL);
+	reg |= USBSS_MODE_VALID;
+	writel(reg, usbss + USBSS_MODE_CONTROL);
+}
+
+struct dwc3_glue_ops ti_am62_ops = {
+	.glue_configure = dwc3_ti_am62_glue_configure,
+};
+
+static const struct udevice_id dwc3_am62_match[] = {
+	{ .compatible = "ti,am62-usb", .data = (ulong)&ti_am62_ops },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(dwc3_am62_wrapper) = {
+	.name	= "dwc3-am62",
+	.id	= UCLASS_SIMPLE_BUS,
+	.of_match = dwc3_am62_match,
+	.bind = dwc3_glue_bind,
+	.probe = dwc3_glue_probe,
+	.remove = dwc3_glue_remove,
+	.plat_auto	= sizeof(struct dwc3_glue_data),
+
+};