[PATCH 2/2] phy: stm32: add support for STM32 USB PHY Controller (USBPHYC)

[Amelie Delaunay]

This patch adds phy transceiver driver for STM32 USB PHY Controller
(USBPHYC) that provides dual port High-Speed phy for OTG (single port)
and EHCI/OHCI host controller (two ports).
One port of the phy is shared between the two USB controllers through
a UTMI+ switch.

Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---
 drivers/phy/st/Kconfig             |  14 ++
 drivers/phy/st/Makefile            |   1 +
 drivers/phy/st/phy-stm32-usbphyc.c | 375 +++++++++++++++++++++++++++++++++++++
 3 files changed, 390 insertions(+)
 create mode 100644 drivers/phy/st/phy-stm32-usbphyc.c

diff --git a/drivers/phy/st/Kconfig b/drivers/phy/st/Kconfig
index 0814d3f..609719b 100644
--- a/drivers/phy/st/Kconfig
+++ b/drivers/phy/st/Kconfig
@@ -31,3 +31,17 @@ config PHY_STIH407_USB
 	help
 	  Enable this support to enable the picoPHY device used by USB2
 	  and USB3 controllers on STMicroelectronics STiH407 SoC families.
+
+config PHY_STM32_USBPHYC
+	tristate "STMicroelectronics STM32 USB HS PHY Controller driver"
+	depends on ARCH_STM32 || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the High-Speed USB transceivers that are part
+	  of some STMicroelectronics STM32 SoCs.
+
+	  This driver controls the entire USB PHY block: the USB PHY controller
+	  (USBPHYC) and the two 8-bit wide UTMI+ interfaces. First interface is
+	  used by an HS USB Host controller, and the second one is shared
+	  between an HS USB OTG controller and an HS USB Host controller,
+	  selected by a USB switch.
diff --git a/drivers/phy/st/Makefile b/drivers/phy/st/Makefile
index e2adfe2..c0091ad 100644
--- a/drivers/phy/st/Makefile
+++ b/drivers/phy/st/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_PHY_MIPHY28LP) 		+= phy-miphy28lp.o
 obj-$(CONFIG_PHY_ST_SPEAR1310_MIPHY)	+= phy-spear1310-miphy.o
 obj-$(CONFIG_PHY_ST_SPEAR1340_MIPHY)	+= phy-spear1340-miphy.o
 obj-$(CONFIG_PHY_STIH407_USB)		+= phy-stih407-usb.o
+obj-$(CONFIG_PHY_STM32_USBPHYC) 	+= phy-stm32-usbphyc.o
diff --git a/drivers/phy/st/phy-stm32-usbphyc.c b/drivers/phy/st/phy-stm32-usbphyc.c
new file mode 100644
index 0000000..24f078b
--- /dev/null
+++ b/drivers/phy/st/phy-stm32-usbphyc.c
@@ -0,0 +1,375 @@
+// SPDX-Licence-Identifier: GPL-2.0
+/*
+ * STMicroelectronics STM32 USB PHY Controller driver
+ *
+ * Copyright (C) 2018 STMicroelectronics
+ * Author(s): Amelie Delaunay <amelie.delaunay@xxxxxx> for STMicroelectronics.
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+#include <linux/reset.h>
+
+#define STM32_USBPHYC_PLL	0x0
+#define STM32_USBPHYC_MISC	0x8
+#define STM32_USBPHYC_VERSION	0x3F4
+
+/* STM32_USBPHYC_PLL bit fields */
+#define PLLNDIV			GENMASK(6, 0)
+#define PLLFRACIN		GENMASK(25, 10)
+#define PLLEN			BIT(26)
+#define PLLSTRB			BIT(27)
+#define PLLSTRBYP		BIT(28)
+#define PLLFRACCTL		BIT(29)
+#define PLLDITHEN0		BIT(30)
+#define PLLDITHEN1		BIT(31)
+
+/* STM32_USBPHYC_MISC bit fields */
+#define SWITHOST		BIT(0)
+
+/* STM32_USBPHYC_VERSION bit fields */
+#define MINREV			GENMASK(3, 0)
+#define MAJREV			GENMASK(7, 4)
+
+#define MAX_PHYS		2
+
+static const char * const stm32_usbphyc_supply_names[] = {
+	"vdda1v1",	/* 1V1 */
+	"vdda1v8",	/* 1V8 */
+};
+
+#define NUM_SUPPLIES		ARRAY_SIZE(stm32_usbphyc_supply_names)
+
+#define PLL_LOCK_TIME_US	100
+#define PLL_PWR_DOWN_TIME_US	5
+#define PLL_FVCO		2880 /* in MHz */
+#define PLL_INFF_MIN_RATE	19200000 /* in Hz */
+#define PLL_INFF_MAX_RATE	38400000 /* in Hz */
+
+struct pll_params {
+	u8 ndiv;
+	u16 frac;
+};
+
+struct stm32_usbphyc {
+	struct device *dev;
+	void __iomem *base;
+	struct clk *clk;
+	struct reset_control *rst;
+	struct regulator_bulk_data supplies[NUM_SUPPLIES];
+	struct stm32_usbphyc_phy {
+		struct phy *phy;
+		int index;
+		bool init;
+	} phys[MAX_PHYS];
+};
+
+static inline struct stm32_usbphyc *
+to_usbphyc(struct stm32_usbphyc_phy *usbphyc_phy)
+{
+	return container_of(usbphyc_phy, struct stm32_usbphyc,
+			    phys[usbphyc_phy->index]);
+}
+
+static inline void stm32_usbphyc_set_bits(void __iomem *reg, u32 bits)
+{
+	writel_relaxed(readl_relaxed(reg) | bits, reg);
+}
+
+static inline void stm32_usbphyc_clr_bits(void __iomem *reg, u32 bits)
+{
+	writel_relaxed(readl_relaxed(reg) & ~bits, reg);
+}
+
+void stm32_usbphyc_get_pll_params(u32 clk_rate, struct pll_params *pll_params)
+{
+	unsigned long long fvco, ndiv, frac;
+
+	/*    _
+	 *   | FVCO = INFF*2*(NDIV + FRACT/2^16) when DITHER_DISABLE[1] = 1
+	 *   | FVCO = 2880MHz
+	 *  <
+	 *   | NDIV = integer part of input bits to set the LDF
+	 *   |_FRACT = fractional part of input bits to set the LDF
+	 *  =>	PLLNDIV = integer part of (FVCO / (INFF*2))
+	 *  =>	PLLFRACIN = fractional part of(FVCO / INFF*2) * 2^16
+	 * <=>  PLLFRACIN = ((FVCO / (INFF*2)) - PLLNDIV) * 2^16
+	 */
+	fvco = (unsigned long long)PLL_FVCO * 1000000; /* In Hz */
+
+	ndiv = fvco;
+	do_div(ndiv, (clk_rate * 2));
+	pll_params->ndiv = (u8)ndiv;
+
+	frac = fvco * (1 << 16);
+	do_div(frac, (clk_rate * 2));
+	frac = frac - (ndiv * (1 << 16));
+	pll_params->frac = (u16)frac;
+}
+
+static int stm32_usbphyc_pll_init(struct stm32_usbphyc *usbphyc)
+{
+	struct pll_params pll_params;
+	u32 clk_rate = clk_get_rate(usbphyc->clk);
+	u32 ndiv, frac;
+	u32 usbphyc_pll;
+
+	if ((clk_rate < PLL_INFF_MIN_RATE) || (clk_rate > PLL_INFF_MAX_RATE)) {
+		dev_err(usbphyc->dev, "input clk freq (%dHz) out of range\n",
+			clk_rate);
+		return -EINVAL;
+	}
+
+	stm32_usbphyc_get_pll_params(clk_rate, &pll_params);
+	ndiv = FIELD_PREP(PLLNDIV, pll_params.ndiv);
+	frac = FIELD_PREP(PLLFRACIN, pll_params.frac);
+
+	usbphyc_pll = PLLDITHEN1 | PLLDITHEN0 | PLLSTRBYP | ndiv;
+
+	if (pll_params.frac)
+		usbphyc_pll |= PLLFRACCTL | frac;
+
+	writel_relaxed(usbphyc_pll, usbphyc->base + STM32_USBPHYC_PLL);
+
+	dev_dbg(usbphyc->dev, "input clk freq=%dHz, ndiv=%lu, frac=%lu\n",
+		clk_rate, FIELD_GET(PLLNDIV, usbphyc_pll),
+		FIELD_GET(PLLFRACIN, usbphyc_pll));
+
+	return 0;
+}
+
+static bool stm32_usbphyc_is_init(struct stm32_usbphyc *usbphyc)
+{
+	int i;
+
+	for (i = 0; i < MAX_PHYS; i++) {
+		if (usbphyc->phys[i].init)
+			return true;
+	}
+
+	return false;
+}
+
+static int stm32_usbphyc_phy_init(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+	struct stm32_usbphyc *usbphyc = to_usbphyc(usbphyc_phy);
+	void __iomem *pll_reg = usbphyc->base + STM32_USBPHYC_PLL;
+	bool pllen = !!(readl_relaxed(pll_reg) & PLLEN);
+	int ret;
+
+	/* Check if one phy port has already configured the pll */
+	if (pllen && stm32_usbphyc_is_init(usbphyc))
+		goto initialized;
+
+	if (pllen) {
+		stm32_usbphyc_clr_bits(pll_reg, PLLEN);
+		udelay(PLL_PWR_DOWN_TIME_US);
+	}
+
+	ret = stm32_usbphyc_pll_init(usbphyc);
+	if (ret)
+		return ret;
+
+	stm32_usbphyc_set_bits(pll_reg, PLLEN);
+
+	udelay(PLL_LOCK_TIME_US);
+
+	if (!(readl_relaxed(pll_reg) & PLLEN)) {
+		dev_err(usbphyc->dev, "PLLEN not set\n");
+		return -EIO;
+	}
+
+initialized:
+	usbphyc_phy->init = true;
+
+	return 0;
+}
+
+static int stm32_usbphyc_phy_exit(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+	struct stm32_usbphyc *usbphyc = to_usbphyc(usbphyc_phy);
+	void __iomem *pll_reg = usbphyc->base + STM32_USBPHYC_PLL;
+
+	usbphyc_phy->init = false;
+
+	/* Check if other phy port requires pllen */
+	if (stm32_usbphyc_is_init(usbphyc))
+		return 0;
+
+	stm32_usbphyc_clr_bits(pll_reg, PLLEN);
+
+	udelay(PLL_PWR_DOWN_TIME_US);
+
+	if (readl_relaxed(pll_reg) & PLLEN) {
+		dev_err(usbphyc->dev, "PLL not reset\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int stm32_usbphyc_phy_power_on(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+	struct stm32_usbphyc *usbphyc = to_usbphyc(usbphyc_phy);
+
+	return regulator_bulk_enable(NUM_SUPPLIES, usbphyc->supplies);
+}
+
+static int stm32_usbphyc_phy_power_off(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+	struct stm32_usbphyc *usbphyc = to_usbphyc(usbphyc_phy);
+
+	return regulator_bulk_disable(NUM_SUPPLIES, usbphyc->supplies);
+}
+
+static const struct phy_ops stm32_usbphyc_phy_ops = {
+	.init = stm32_usbphyc_phy_init,
+	.exit = stm32_usbphyc_phy_exit,
+	.power_on = stm32_usbphyc_phy_power_on,
+	.power_off = stm32_usbphyc_phy_power_off,
+	.owner = THIS_MODULE,
+};
+
+static struct phy *stm32_usbphyc_of_xlate(struct device *dev,
+					  struct of_phandle_args *args)
+{
+	struct stm32_usbphyc *usbphyc = dev_get_drvdata(dev);
+
+	if (args->args[0] >= MAX_PHYS)
+		return ERR_PTR(-ENODEV);
+
+	return usbphyc->phys[args->args[0]].phy;
+}
+
+static int stm32_usbphyc_probe(struct platform_device *pdev)
+{
+	struct stm32_usbphyc *usbphyc;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *res;
+	struct phy_provider *phy_provider;
+	bool switch_to_host;
+	u32 version;
+	int i, ret;
+
+	usbphyc = devm_kzalloc(dev, sizeof(*usbphyc), GFP_KERNEL);
+	if (!usbphyc)
+		return -ENOMEM;
+	usbphyc->dev = dev;
+	dev_set_drvdata(dev, usbphyc);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	usbphyc->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(usbphyc->base))
+		return PTR_ERR(usbphyc->base);
+
+	usbphyc->clk = devm_clk_get(dev, 0);
+	if (IS_ERR(usbphyc->clk)) {
+		ret = PTR_ERR(usbphyc->clk);
+		dev_err(dev, "clk get failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(usbphyc->clk);
+	if (ret) {
+		dev_err(dev, "clk enable failed: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < NUM_SUPPLIES; i++)
+		usbphyc->supplies[i].supply = stm32_usbphyc_supply_names[i];
+
+	ret = devm_regulator_bulk_get(dev, NUM_SUPPLIES, usbphyc->supplies);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "failed to get regulators: %d\n", ret);
+		goto clk_disable;
+	}
+
+	for (i = 0; i < MAX_PHYS; i++) {
+		struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys + i;
+
+		usbphyc_phy->phy = devm_phy_create(dev, NULL,
+						   &stm32_usbphyc_phy_ops);
+		if (IS_ERR(usbphyc_phy->phy)) {
+			ret = PTR_ERR(usbphyc_phy->phy);
+			dev_err(dev, "failed to create phy%d: %d\n", i, ret);
+			goto clk_disable;
+		}
+
+		usbphyc_phy->index = i;
+		usbphyc_phy->init = false;
+		phy_set_bus_width(usbphyc_phy->phy, 8);
+		phy_set_drvdata(usbphyc_phy->phy, usbphyc_phy);
+	}
+
+	usbphyc->rst = devm_reset_control_get(dev, 0);
+	if (!IS_ERR(usbphyc->rst)) {
+		reset_control_assert(usbphyc->rst);
+		udelay(2);
+		reset_control_deassert(usbphyc->rst);
+	}
+
+	phy_provider = devm_of_phy_provider_register(dev,
+						     stm32_usbphyc_of_xlate);
+	if (IS_ERR(phy_provider)) {
+		ret = PTR_ERR(phy_provider);
+		dev_err(dev, "failed to register phy provider: %d\n", ret);
+		goto clk_disable;
+	}
+
+	/* Check if second port has to be used for host controller */
+	switch_to_host = of_property_read_bool(np, "st,port2-switch-to-host");
+	if (switch_to_host)
+		stm32_usbphyc_set_bits(usbphyc->base + STM32_USBPHYC_MISC,
+				       SWITHOST);
+
+	version = readl_relaxed(usbphyc->base + STM32_USBPHYC_VERSION);
+	dev_info(dev, "registered rev:%lu.%lu\n",
+		 FIELD_GET(MAJREV, version), FIELD_GET(MINREV, version));
+
+	return 0;
+
+clk_disable:
+	clk_disable_unprepare(usbphyc->clk);
+
+	return ret;
+}
+
+static int stm32_usbphyc_remove(struct platform_device *pdev)
+{
+	struct stm32_usbphyc *usbphyc = dev_get_drvdata(&pdev->dev);
+
+	clk_disable_unprepare(usbphyc->clk);
+
+	return 0;
+}
+
+static const struct of_device_id stm32_usbphyc_of_match[] = {
+	{ .compatible = "st,stm32mp1-usbphyc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, stm32_usbphyc_of_match);
+
+static struct platform_driver stm32_usbphyc_driver = {
+	.probe = stm32_usbphyc_probe,
+	.remove = stm32_usbphyc_remove,
+	.driver = {
+		.of_match_table = stm32_usbphyc_of_match,
+		.name = "stm32-usbphyc",
+	}
+};
+module_platform_driver(stm32_usbphyc_driver);
+
+MODULE_DESCRIPTION("STMicroelectronics STM32 USBPHYC driver");
+MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@xxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4