usb: phy: Add STi USB2 PHY

This is the generic phy driver for the picoPHY ports
used by USB2/1.1 controllers. It is found on STiH407 SoC
family from STMicroelectronics.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/device-tree-bindings/phy/phy-stih407-usb.txt

@@ -0,0 +1,24 @@
+ST STiH407 USB PHY controller
+
+This file documents the dt bindings for the usb picoPHY driver which is the PHY for both USB2 and USB3
+host controllers (when controlling usb2/1.1 devices) available on STiH407 SoC family from STMicroelectronics.
+
+Required properties:
+- compatible		: should be "st,stih407-usb2-phy"
+- st,syscfg		: phandle of sysconfig bank plus integer array containing phyparam and phyctrl register offsets
+- resets		: list of phandle and reset specifier pairs. There should be two entries, one
+			  for the whole phy and one for the port
+- reset-names		: list of reset signal names. Should be "global" and "port"
+See: Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
+See: Documentation/devicetree/bindings/reset/reset.txt
+
+Example:
+
+usb2_picophy0: usbpicophy {
+	compatible	= "st,stih407-usb2-phy";
+	#phy-cells	= <0>;
+	st,syscfg	= <&syscfg_core 0x100 0xf4>;
+	resets		= <&softreset STIH407_PICOPHY_SOFTRESET>,
+			  <&picophyreset STIH407_PICOPHY0_RESET>;
+	reset-names	= "global", "port";
+};

drivers/phy/Kconfig

@@ -77,4 +77,12 @@ config SPL_PIPE3_PHY
 	  This PHY is found on omap devices supporting SATA such as dra7, am57x
 	  and omap5
 
+config STI_USB_PHY
+	bool "STMicroelectronics USB2 picoPHY driver for STiH407 family"
+	depends on PHY && ARCH_STI
+	help
+	  This is the generic phy driver for the picoPHY ports
+	  used by USB2 and USB3 Host controllers available on
+	  STiH407 SoC families.
+
 endmenu

drivers/phy/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_$(SPL_)PHY) += phy-uclass.o
 obj-$(CONFIG_$(SPL_)NOP_PHY) += nop-phy.o
 obj-$(CONFIG_PHY_SANDBOX) += sandbox-phy.o
 obj-$(CONFIG_$(SPL_)PIPE3_PHY) += ti-pipe3-phy.o
+obj-$(CONFIG_STI_USB_PHY) += sti_usb_phy.o

drivers/phy/sti_usb_phy.c

@@ -0,0 +1,181 @@
+/*
+ * Copyright (c) 2017
+ * Patrice Chotard <patrice.chotard@st.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <bitfield.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <generic-phy.h>
+#include <libfdt.h>
+#include <regmap.h>
+#include <reset-uclass.h>
+#include <syscon.h>
+#include <wait_bit.h>
+
+#include <linux/bitops.h>
+#include <linux/compat.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Default PHY_SEL and REFCLKSEL configuration */
+#define STIH407_USB_PICOPHY_CTRL_PORT_CONF	0x6
+
+/* ports parameters overriding */
+#define STIH407_USB_PICOPHY_PARAM_DEF		0x39a4dc
+
+#define PHYPARAM_REG	1
+#define PHYCTRL_REG	2
+#define PHYPARAM_NB	3
+
+struct sti_usb_phy {
+	struct regmap *regmap;
+	struct reset_ctl global_ctl;
+	struct reset_ctl port_ctl;
+	int param;
+	int ctrl;
+};
+
+static int sti_usb_phy_deassert(struct sti_usb_phy *phy)
+{
+	int ret;
+
+	ret = reset_deassert(&phy->global_ctl);
+	if (ret < 0) {
+		error("PHY global deassert failed: %d", ret);
+		return ret;
+	}
+
+	ret = reset_deassert(&phy->port_ctl);
+	if (ret < 0)
+		error("PHY port deassert failed: %d", ret);
+
+	return ret;
+}
+
+static int sti_usb_phy_init(struct phy *usb_phy)
+{
+	struct udevice *dev = usb_phy->dev;
+	struct sti_usb_phy *phy = dev_get_priv(dev);
+	void __iomem *reg;
+
+	/* set ctrl picophy value */
+	reg = (void __iomem *)phy->regmap->base + phy->ctrl;
+	/* CTRL_PORT mask is 0x1f */
+	clrsetbits_le32(reg, 0x1f, STIH407_USB_PICOPHY_CTRL_PORT_CONF);
+
+	/* set ports parameters overriding */
+	reg = (void __iomem *)phy->regmap->base + phy->param;
+	/* PARAM_DEF mask is 0xffffffff */
+	clrsetbits_le32(reg, 0xffffffff, STIH407_USB_PICOPHY_PARAM_DEF);
+
+	return sti_usb_phy_deassert(phy);
+}
+
+static int sti_usb_phy_exit(struct phy *usb_phy)
+{
+	struct udevice *dev = usb_phy->dev;
+	struct sti_usb_phy *phy = dev_get_priv(dev);
+	int ret;
+
+	ret = reset_assert(&phy->port_ctl);
+	if (ret < 0) {
+		error("PHY port assert failed: %d", ret);
+		return ret;
+	}
+
+	ret = reset_assert(&phy->global_ctl);
+	if (ret < 0)
+		error("PHY global assert failed: %d", ret);
+
+	return ret;
+}
+
+struct phy_ops sti_usb_phy_ops = {
+	.init = sti_usb_phy_init,
+	.exit = sti_usb_phy_exit,
+};
+
+int sti_usb_phy_probe(struct udevice *dev)
+{
+	struct sti_usb_phy *priv = dev_get_priv(dev);
+	struct udevice *syscon;
+	struct ofnode_phandle_args syscfg_phandle;
+	u32 cells[PHYPARAM_NB];
+	int ret, count;
+
+	/* get corresponding syscon phandle */
+	ret = dev_read_phandle_with_args(dev, "st,syscfg", NULL, 0, 0,
+					 &syscfg_phandle);
+
+	if (ret < 0) {
+		error("Can't get syscfg phandle: %d\n", ret);
+		return ret;
+	}
+
+	ret = uclass_get_device_by_ofnode(UCLASS_SYSCON, syscfg_phandle.node,
+					  &syscon);
+	if (ret) {
+		error("unable to find syscon device (%d)\n", ret);
+		return ret;
+	}
+
+	priv->regmap = syscon_get_regmap(syscon);
+	if (!priv->regmap) {
+		error("unable to find regmap\n");
+		return -ENODEV;
+	}
+
+	/* get phy param offset */
+	count = fdtdec_get_int_array_count(gd->fdt_blob, dev_of_offset(dev),
+					   "st,syscfg", cells,
+					   ARRAY_SIZE(cells));
+
+	if (count < 0) {
+		error("Bad PHY st,syscfg property %d\n", count);
+		return -EINVAL;
+	}
+
+	if (count > PHYPARAM_NB) {
+		error("Unsupported PHY param count %d\n", count);
+		return -EINVAL;
+	}
+
+	priv->param = cells[PHYPARAM_REG];
+	priv->ctrl = cells[PHYCTRL_REG];
+
+	/* get global reset control */
+	ret = reset_get_by_name(dev, "global", &priv->global_ctl);
+	if (ret) {
+		error("can't get global reset for %s (%d)", dev->name, ret);
+		return ret;
+	}
+
+	/* get port reset control */
+	ret = reset_get_by_name(dev, "port", &priv->port_ctl);
+	if (ret) {
+		error("can't get port reset for %s (%d)", dev->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id sti_usb_phy_ids[] = {
+	{ .compatible = "st,stih407-usb2-phy" },
+	{ }
+};
+
+U_BOOT_DRIVER(sti_usb_phy) = {
+	.name = "sti_usb_phy",
+	.id = UCLASS_PHY,
+	.of_match = sti_usb_phy_ids,
+	.probe = sti_usb_phy_probe,
+	.ops = &sti_usb_phy_ops,
+	.priv_auto_alloc_size = sizeof(struct sti_usb_phy),
+};