phy: sr-usb: Add Stingray USB PHY driver

USB PHY driver supports two types of stingray USB PHYs
- Type 1 is a combo PHY contains two PHYs, one SS and one HS.
- Type 2 is a single HS PHY.

These two PHY versons support both Generic xHCI host controller driver
and BDC Broadcom device controller driver.

Signed-off-by: Srinath Mannam <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/broadcom/Kconfig

···
 	  Enable this to support the Broadcom Cygnus PCIe PHY.
 	  If unsure, say N.
 
+config PHY_BCM_SR_USB
+	tristate "Broadcom Stingray USB PHY driver"
+	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
+	select GENERIC_PHY
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Stingray USB PHY
+	  driver. It supports all versions of Superspeed and
+	  Highspeed PHYs.
+	  If unsure, say N.
+
 config BCM_KONA_USB2_PHY
 	tristate "Broadcom Kona USB2 PHY Driver"
 	depends on HAS_IOMEM

drivers/phy/broadcom/Makefile

···
 phy-brcm-usb-dvr-objs := phy-brcm-usb.o phy-brcm-usb-init.o
 
 obj-$(CONFIG_PHY_BCM_SR_PCIE)		+= phy-bcm-sr-pcie.o
+obj-$(CONFIG_PHY_BCM_SR_USB)		+= phy-bcm-sr-usb.o

drivers/phy/broadcom/phy-bcm-sr-usb.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016-2018 Broadcom
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+enum bcm_usb_phy_version {
+	BCM_SR_USB_COMBO_PHY,
+	BCM_SR_USB_HS_PHY,
+};
+
+enum bcm_usb_phy_reg {
+	PLL_NDIV_FRAC,
+	PLL_NDIV_INT,
+	PLL_CTRL,
+	PHY_CTRL,
+	PHY_PLL_CTRL,
+};
+
+/* USB PHY registers */
+
+static const u8 bcm_usb_combo_phy_ss[] = {
+	[PLL_CTRL]		= 0x18,
+	[PHY_CTRL]		= 0x14,
+};
+
+static const u8 bcm_usb_combo_phy_hs[] = {
+	[PLL_NDIV_FRAC]	= 0x04,
+	[PLL_NDIV_INT]	= 0x08,
+	[PLL_CTRL]	= 0x0c,
+	[PHY_CTRL]	= 0x10,
+};
+
+#define HSPLL_NDIV_INT_VAL	0x13
+#define HSPLL_NDIV_FRAC_VAL	0x1005
+
+static const u8 bcm_usb_hs_phy[] = {
+	[PLL_NDIV_FRAC]	= 0x0,
+	[PLL_NDIV_INT]	= 0x4,
+	[PLL_CTRL]	= 0x8,
+	[PHY_CTRL]	= 0xc,
+};
+
+enum pll_ctrl_bits {
+	PLL_RESETB,
+	SSPLL_SUSPEND_EN,
+	PLL_SEQ_START,
+	PLL_LOCK,
+	PLL_PDIV,
+};
+
+static const u8 u3pll_ctrl[] = {
+	[PLL_RESETB]		= 0,
+	[SSPLL_SUSPEND_EN]	= 1,
+	[PLL_SEQ_START]		= 2,
+	[PLL_LOCK]		= 3,
+};
+
+#define HSPLL_PDIV_MASK		0xF
+#define HSPLL_PDIV_VAL		0x1
+
+static const u8 u2pll_ctrl[] = {
+	[PLL_PDIV]	= 1,
+	[PLL_RESETB]	= 5,
+	[PLL_LOCK]	= 6,
+};
+
+enum bcm_usb_phy_ctrl_bits {
+	CORERDY,
+	AFE_LDO_PWRDWNB,
+	AFE_PLL_PWRDWNB,
+	AFE_BG_PWRDWNB,
+	PHY_ISO,
+	PHY_RESETB,
+	PHY_PCTL,
+};
+
+#define PHY_PCTL_MASK	0xffff
+/*
+ * 0x0806 of PCTL_VAL has below bits set
+ * BIT-8 : refclk divider 1
+ * BIT-3:2: device mode; mode is not effect
+ * BIT-1: soft reset active low
+ */
+#define HSPHY_PCTL_VAL	0x0806
+#define SSPHY_PCTL_VAL	0x0006
+
+static const u8 u3phy_ctrl[] = {
+	[PHY_RESETB]	= 1,
+	[PHY_PCTL]	= 2,
+};
+
+static const u8 u2phy_ctrl[] = {
+	[CORERDY]		= 0,
+	[AFE_LDO_PWRDWNB]	= 1,
+	[AFE_PLL_PWRDWNB]	= 2,
+	[AFE_BG_PWRDWNB]	= 3,
+	[PHY_ISO]		= 4,
+	[PHY_RESETB]		= 5,
+	[PHY_PCTL]		= 6,
+};
+
+struct bcm_usb_phy_cfg {
+	uint32_t type;
+	uint32_t version;
+	void __iomem *regs;
+	struct phy *phy;
+	const u8 *offset;
+};
+
+#define PLL_LOCK_RETRY_COUNT	1000
+
+enum bcm_usb_phy_type {
+	USB_HS_PHY,
+	USB_SS_PHY,
+};
+
+#define NUM_BCM_SR_USB_COMBO_PHYS	2
+
+static inline void bcm_usb_reg32_clrbits(void __iomem *addr, uint32_t clear)
+{
+	writel(readl(addr) & ~clear, addr);
+}
+
+static inline void bcm_usb_reg32_setbits(void __iomem *addr, uint32_t set)
+{
+	writel(readl(addr) | set, addr);
+}
+
+static int bcm_usb_pll_lock_check(void __iomem *addr, u32 bit)
+{
+	int retry;
+	u32 rd_data;
+
+	retry = PLL_LOCK_RETRY_COUNT;
+	do {
+		rd_data = readl(addr);
+		if (rd_data & bit)
+			return 0;
+		udelay(1);
+	} while (--retry > 0);
+
+	pr_err("%s: FAIL\n", __func__);
+	return -ETIMEDOUT;
+}
+
+static int bcm_usb_ss_phy_init(struct bcm_usb_phy_cfg *phy_cfg)
+{
+	int ret = 0;
+	void __iomem *regs = phy_cfg->regs;
+	const u8 *offset;
+	u32 rd_data;
+
+	offset = phy_cfg->offset;
+
+	/* Set pctl with mode and soft reset */
+	rd_data = readl(regs + offset[PHY_CTRL]);
+	rd_data &= ~(PHY_PCTL_MASK << u3phy_ctrl[PHY_PCTL]);
+	rd_data |= (SSPHY_PCTL_VAL << u3phy_ctrl[PHY_PCTL]);
+	writel(rd_data, regs + offset[PHY_CTRL]);
+
+	bcm_usb_reg32_clrbits(regs + offset[PLL_CTRL],
+			      BIT(u3pll_ctrl[SSPLL_SUSPEND_EN]));
+	bcm_usb_reg32_setbits(regs + offset[PLL_CTRL],
+			      BIT(u3pll_ctrl[PLL_SEQ_START]));
+	bcm_usb_reg32_setbits(regs + offset[PLL_CTRL],
+			      BIT(u3pll_ctrl[PLL_RESETB]));
+
+	/* Maximum timeout for PLL reset done */
+	msleep(30);
+
+	ret = bcm_usb_pll_lock_check(regs + offset[PLL_CTRL],
+				     BIT(u3pll_ctrl[PLL_LOCK]));
+
+	return ret;
+}
+
+static int bcm_usb_hs_phy_init(struct bcm_usb_phy_cfg *phy_cfg)
+{
+	int ret = 0;
+	void __iomem *regs = phy_cfg->regs;
+	const u8 *offset;
+	u32 rd_data;
+
+	offset = phy_cfg->offset;
+
+	writel(HSPLL_NDIV_INT_VAL, regs + offset[PLL_NDIV_INT]);
+	writel(HSPLL_NDIV_FRAC_VAL, regs + offset[PLL_NDIV_FRAC]);
+
+	rd_data = readl(regs + offset[PLL_CTRL]);
+	rd_data &= ~(HSPLL_PDIV_MASK << u2pll_ctrl[PLL_PDIV]);
+	rd_data |= (HSPLL_PDIV_VAL << u2pll_ctrl[PLL_PDIV]);
+	writel(rd_data, regs + offset[PLL_CTRL]);
+
+	/* Set Core Ready high */
+	bcm_usb_reg32_setbits(regs + offset[PHY_CTRL],
+			      BIT(u2phy_ctrl[CORERDY]));
+
+	/* Maximum timeout for Core Ready done */
+	msleep(30);
+
+	bcm_usb_reg32_setbits(regs + offset[PLL_CTRL],
+			      BIT(u2pll_ctrl[PLL_RESETB]));
+	bcm_usb_reg32_setbits(regs + offset[PHY_CTRL],
+			      BIT(u2phy_ctrl[PHY_RESETB]));
+
+
+	rd_data = readl(regs + offset[PHY_CTRL]);
+	rd_data &= ~(PHY_PCTL_MASK << u2phy_ctrl[PHY_PCTL]);
+	rd_data |= (HSPHY_PCTL_VAL << u2phy_ctrl[PHY_PCTL]);
+	writel(rd_data, regs + offset[PHY_CTRL]);
+
+	/* Maximum timeout for PLL reset done */
+	msleep(30);
+
+	ret = bcm_usb_pll_lock_check(regs + offset[PLL_CTRL],
+				     BIT(u2pll_ctrl[PLL_LOCK]));
+
+	return ret;
+}
+
+static int bcm_usb_phy_reset(struct phy *phy)
+{
+	struct bcm_usb_phy_cfg *phy_cfg = phy_get_drvdata(phy);
+	void __iomem *regs = phy_cfg->regs;
+	const u8 *offset;
+
+	offset = phy_cfg->offset;
+
+	if (phy_cfg->type == USB_HS_PHY) {
+		bcm_usb_reg32_clrbits(regs + offset[PHY_CTRL],
+				      BIT(u2phy_ctrl[CORERDY]));
+		bcm_usb_reg32_setbits(regs + offset[PHY_CTRL],
+				      BIT(u2phy_ctrl[CORERDY]));
+	}
+
+	return 0;
+}
+
+static int bcm_usb_phy_init(struct phy *phy)
+{
+	struct bcm_usb_phy_cfg *phy_cfg = phy_get_drvdata(phy);
+	int ret = -EINVAL;
+
+	if (phy_cfg->type == USB_SS_PHY)
+		ret = bcm_usb_ss_phy_init(phy_cfg);
+	else if (phy_cfg->type == USB_HS_PHY)
+		ret = bcm_usb_hs_phy_init(phy_cfg);
+
+	return ret;
+}
+
+static struct phy_ops sr_phy_ops = {
+	.init		= bcm_usb_phy_init,
+	.reset		= bcm_usb_phy_reset,
+	.owner		= THIS_MODULE,
+};
+
+static struct phy *bcm_usb_phy_xlate(struct device *dev,
+				     struct of_phandle_args *args)
+{
+	struct bcm_usb_phy_cfg *phy_cfg;
+	int phy_idx;
+
+	phy_cfg = dev_get_drvdata(dev);
+	if (!phy_cfg)
+		return ERR_PTR(-EINVAL);
+
+	if (phy_cfg->version == BCM_SR_USB_COMBO_PHY) {
+		phy_idx = args->args[0];
+
+		if (WARN_ON(phy_idx > 1))
+			return ERR_PTR(-ENODEV);
+
+		return phy_cfg[phy_idx].phy;
+	} else
+		return phy_cfg->phy;
+}
+
+static int bcm_usb_phy_create(struct device *dev, struct device_node *node,
+			      void __iomem *regs, uint32_t version)
+{
+	struct bcm_usb_phy_cfg *phy_cfg;
+	int idx;
+
+	if (version == BCM_SR_USB_COMBO_PHY) {
+		phy_cfg = devm_kzalloc(dev, NUM_BCM_SR_USB_COMBO_PHYS *
+				       sizeof(struct bcm_usb_phy_cfg),
+				       GFP_KERNEL);
+		if (!phy_cfg)
+			return -ENOMEM;
+
+		for (idx = 0; idx < NUM_BCM_SR_USB_COMBO_PHYS; idx++) {
+			phy_cfg[idx].regs = regs;
+			phy_cfg[idx].version = version;
+			if (idx == 0) {
+				phy_cfg[idx].offset = bcm_usb_combo_phy_hs;
+				phy_cfg[idx].type = USB_HS_PHY;
+			} else {
+				phy_cfg[idx].offset = bcm_usb_combo_phy_ss;
+				phy_cfg[idx].type = USB_SS_PHY;
+			}
+			phy_cfg[idx].phy = devm_phy_create(dev, node,
+							   &sr_phy_ops);
+			if (IS_ERR(phy_cfg[idx].phy))
+				return PTR_ERR(phy_cfg[idx].phy);
+
+			phy_set_drvdata(phy_cfg[idx].phy, &phy_cfg[idx]);
+		}
+	} else if (version == BCM_SR_USB_HS_PHY) {
+		phy_cfg = devm_kzalloc(dev, sizeof(struct bcm_usb_phy_cfg),
+				       GFP_KERNEL);
+		if (!phy_cfg)
+			return -ENOMEM;
+
+		phy_cfg->regs = regs;
+		phy_cfg->version = version;
+		phy_cfg->offset = bcm_usb_hs_phy;
+		phy_cfg->type = USB_HS_PHY;
+		phy_cfg->phy = devm_phy_create(dev, node, &sr_phy_ops);
+		if (IS_ERR(phy_cfg->phy))
+			return PTR_ERR(phy_cfg->phy);
+
+		phy_set_drvdata(phy_cfg->phy, phy_cfg);
+	} else
+		return -ENODEV;
+
+	dev_set_drvdata(dev, phy_cfg);
+
+	return 0;
+}
+
+static const struct of_device_id bcm_usb_phy_of_match[] = {
+	{
+		.compatible = "brcm,sr-usb-combo-phy",
+		.data = (void *)BCM_SR_USB_COMBO_PHY,
+	},
+	{
+		.compatible = "brcm,sr-usb-hs-phy",
+		.data = (void *)BCM_SR_USB_HS_PHY,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, bcm_usb_phy_of_match);
+
+static int bcm_usb_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *dn = dev->of_node;
+	const struct of_device_id *of_id;
+	struct resource *res;
+	void __iomem *regs;
+	int ret;
+	enum bcm_usb_phy_version version;
+	struct phy_provider *phy_provider;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	of_id = of_match_node(bcm_usb_phy_of_match, dn);
+	if (of_id)
+		version = (enum bcm_usb_phy_version)of_id->data;
+	else
+		return -ENODEV;
+
+	ret = bcm_usb_phy_create(dev, dn, regs, version);
+	if (ret)
+		return ret;
+
+	phy_provider = devm_of_phy_provider_register(dev, bcm_usb_phy_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct platform_driver bcm_usb_phy_driver = {
+	.driver = {
+		.name = "phy-bcm-sr-usb",
+		.of_match_table = bcm_usb_phy_of_match,
+	},
+	.probe = bcm_usb_phy_probe,
+};
+module_platform_driver(bcm_usb_phy_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("Broadcom stingray USB Phy driver");
+MODULE_LICENSE("GPL v2");