phy: Add support for Qualcomm's USB HSIC phy

The HSIC USB controller on qcom SoCs has an integrated all
digital phy controlled via the ULPI viewport.

Cc: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/qcom,usb-hsic-phy.txt

+Qualcomm's USB HSIC PHY
+
+PROPERTIES
+
+- compatible:
+    Usage: required
+    Value type: <string>
+    Definition: Should contain "qcom,usb-hsic-phy" and more specifically one of the
+		following:
+
+			"qcom,usb-hsic-phy-mdm9615"
+			"qcom,usb-hsic-phy-msm8974"
+
+- #phy-cells:
+    Usage: required
+    Value type: <u32>
+    Definition: Should contain 0
+
+- clocks:
+    Usage: required
+    Value type: <prop-encoded-array>
+    Definition: Should contain clock specifier for phy, calibration and
+                a calibration sleep clock
+
+- clock-names:
+    Usage: required
+    Value type: <stringlist>
+    Definition: Should contain "phy, "cal" and "cal_sleep"
+
+- pinctrl-names:
+    Usage: required
+    Value type: <stringlist>
+    Definition: Should contain "init" and "default" in that order
+
+- pinctrl-0:
+    Usage: required
+    Value type: <prop-encoded-array>
+    Definition: List of pinctrl settings to apply to keep HSIC pins in a glitch
+                free state
+
+- pinctrl-1:
+    Usage: required
+    Value type: <prop-encoded-array>
+    Definition: List of pinctrl settings to apply to mux out the HSIC pins
+
+EXAMPLE
+
+usb-controller {
+	ulpi {
+		phy {
+			compatible = "qcom,usb-hsic-phy-msm8974",
+				     "qcom,usb-hsic-phy";
+			#phy-cells = <0>;
+			pinctrl-names = "init", "default";
+			pinctrl-0 = <&hsic_sleep>;
+			pinctrl-1 = <&hsic_default>;
+			clocks = <&gcc GCC_USB_HSIC_CLK>,
+				 <&gcc GCC_USB_HSIC_IO_CAL_CLK>,
+				 <&gcc GCC_USB_HSIC_IO_CAL_SLEEP_CLK>;
+			clock-names = "phy", "cal", "cal_sleep";
+			assigned-clocks = <&gcc GCC_USB_HSIC_IO_CAL_CLK>;
+			assigned-clock-rates = <960000>;
+		};
+	};
+};

drivers/phy/Kconfig

@@ -437,6 +437,13 @@ config PHY_QCOM_UFS
 	help
 	  Support for UFS PHY on QCOM chipsets.
 
+config PHY_QCOM_USB_HSIC
+	tristate "Qualcomm USB HSIC ULPI PHY module"
+	depends on USB_ULPI_BUS
+	select GENERIC_PHY
+	help
+	  Support for the USB HSIC ULPI compliant PHY on QCOM chipsets.
+
 config PHY_TUSB1210
 	tristate "TI TUSB1210 ULPI PHY module"
 	depends on USB_ULPI_BUS

drivers/phy/Makefile

@@ -52,6 +52,7 @@ obj-$(CONFIG_PHY_STIH407_USB)		+= phy-stih407-usb.o
 obj-$(CONFIG_PHY_QCOM_UFS) 	+= phy-qcom-ufs.o
 obj-$(CONFIG_PHY_QCOM_UFS) 	+= phy-qcom-ufs-qmp-20nm.o
 obj-$(CONFIG_PHY_QCOM_UFS) 	+= phy-qcom-ufs-qmp-14nm.o
+obj-$(CONFIG_PHY_QCOM_USB_HSIC) 	+= phy-qcom-usb-hsic.o
 obj-$(CONFIG_PHY_TUSB1210)		+= phy-tusb1210.o
 obj-$(CONFIG_PHY_BRCM_SATA)		+= phy-brcm-sata.o
 obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o

drivers/phy/phy-qcom-usb-hsic.c

+/**
+ * Copyright (C) 2016 Linaro Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/ulpi/driver.h>
+#include <linux/ulpi/regs.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pinctrl/pinctrl-state.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+
+#include "ulpi_phy.h"
+
+#define ULPI_HSIC_CFG		0x30
+#define ULPI_HSIC_IO_CAL	0x33
+
+struct qcom_usb_hsic_phy {
+	struct ulpi *ulpi;
+	struct phy *phy;
+	struct pinctrl *pctl;
+	struct clk *phy_clk;
+	struct clk *cal_clk;
+	struct clk *cal_sleep_clk;
+};
+
+static int qcom_usb_hsic_phy_power_on(struct phy *phy)
+{
+	struct qcom_usb_hsic_phy *uphy = phy_get_drvdata(phy);
+	struct ulpi *ulpi = uphy->ulpi;
+	struct pinctrl_state *pins_default;
+	int ret;
+
+	ret = clk_prepare_enable(uphy->phy_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(uphy->cal_clk);
+	if (ret)
+		goto err_cal;
+
+	ret = clk_prepare_enable(uphy->cal_sleep_clk);
+	if (ret)
+		goto err_sleep;
+
+	/* Set periodic calibration interval to ~2.048sec in HSIC_IO_CAL_REG */
+	ret = ulpi_write(ulpi, ULPI_HSIC_IO_CAL, 0xff);
+	if (ret)
+		goto err_ulpi;
+
+	/* Enable periodic IO calibration in HSIC_CFG register */
+	ret = ulpi_write(ulpi, ULPI_HSIC_CFG, 0xa8);
+	if (ret)
+		goto err_ulpi;
+
+	/* Configure pins for HSIC functionality */
+	pins_default = pinctrl_lookup_state(uphy->pctl, PINCTRL_STATE_DEFAULT);
+	if (IS_ERR(pins_default))
+		return PTR_ERR(pins_default);
+
+	ret = pinctrl_select_state(uphy->pctl, pins_default);
+	if (ret)
+		goto err_ulpi;
+
+	 /* Enable HSIC mode in HSIC_CFG register */
+	ret = ulpi_write(ulpi, ULPI_SET(ULPI_HSIC_CFG), 0x01);
+	if (ret)
+		goto err_ulpi;
+
+	/* Disable auto-resume */
+	ret = ulpi_write(ulpi, ULPI_CLR(ULPI_IFC_CTRL),
+			 ULPI_IFC_CTRL_AUTORESUME);
+	if (ret)
+		goto err_ulpi;
+
+	return ret;
+err_ulpi:
+	clk_disable_unprepare(uphy->cal_sleep_clk);
+err_sleep:
+	clk_disable_unprepare(uphy->cal_clk);
+err_cal:
+	clk_disable_unprepare(uphy->phy_clk);
+	return ret;
+}
+
+static int qcom_usb_hsic_phy_power_off(struct phy *phy)
+{
+	struct qcom_usb_hsic_phy *uphy = phy_get_drvdata(phy);
+
+	clk_disable_unprepare(uphy->cal_sleep_clk);
+	clk_disable_unprepare(uphy->cal_clk);
+	clk_disable_unprepare(uphy->phy_clk);
+
+	return 0;
+}
+
+static const struct phy_ops qcom_usb_hsic_phy_ops = {
+	.power_on = qcom_usb_hsic_phy_power_on,
+	.power_off = qcom_usb_hsic_phy_power_off,
+	.owner = THIS_MODULE,
+};
+
+static int qcom_usb_hsic_phy_probe(struct ulpi *ulpi)
+{
+	struct qcom_usb_hsic_phy *uphy;
+	struct phy_provider *p;
+	struct clk *clk;
+
+	uphy = devm_kzalloc(&ulpi->dev, sizeof(*uphy), GFP_KERNEL);
+	if (!uphy)
+		return -ENOMEM;
+	ulpi_set_drvdata(ulpi, uphy);
+
+	uphy->ulpi = ulpi;
+	uphy->pctl = devm_pinctrl_get(&ulpi->dev);
+	if (IS_ERR(uphy->pctl))
+		return PTR_ERR(uphy->pctl);
+
+	uphy->phy_clk = clk = devm_clk_get(&ulpi->dev, "phy");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->cal_clk = clk = devm_clk_get(&ulpi->dev, "cal");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->cal_sleep_clk = clk = devm_clk_get(&ulpi->dev, "cal_sleep");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->phy = devm_phy_create(&ulpi->dev, ulpi->dev.of_node,
+				    &qcom_usb_hsic_phy_ops);
+	if (IS_ERR(uphy->phy))
+		return PTR_ERR(uphy->phy);
+	phy_set_drvdata(uphy->phy, uphy);
+
+	p = devm_of_phy_provider_register(&ulpi->dev, of_phy_simple_xlate);
+	return PTR_ERR_OR_ZERO(p);
+}
+
+static const struct of_device_id qcom_usb_hsic_phy_match[] = {
+	{ .compatible = "qcom,usb-hsic-phy", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_usb_hsic_phy_match);
+
+static struct ulpi_driver qcom_usb_hsic_phy_driver = {
+	.probe = qcom_usb_hsic_phy_probe,
+	.driver = {
+		.name = "qcom_usb_hsic_phy",
+		.of_match_table = qcom_usb_hsic_phy_match,
+	},
+};
+module_ulpi_driver(qcom_usb_hsic_phy_driver);
+
+MODULE_DESCRIPTION("Qualcomm USB HSIC phy");
+MODULE_LICENSE("GPL v2");