usb: dwc3: Add Qualcomm DWC3 glue layer driver

DWC3 glue layer is hardware layer around Synopsys DesignWare
USB3 core. Its purpose is to supply Synopsys IP with required
clocks, voltages and interface it with the rest of the SoC.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/Kconfig

@@ -89,6 +89,14 @@ config USB_DWC3_ST
 	  inside (i.e. STiH407).
 	  Say 'Y' or 'M' if you have one such device.
 
+config USB_DWC3_QCOM
+	tristate "Qualcomm Platforms"
+	depends on ARCH_QCOM || COMPILE_TEST
+	default USB_DWC3
+	help
+	  Recent Qualcomm SoCs ship with one DesignWare Core USB3 IP inside,
+	  say 'Y' or 'M' if you have one such device.
+
 comment "Debugging features"
 
 config USB_DWC3_DEBUG

drivers/usb/dwc3/Makefile

@@ -36,4 +36,5 @@ obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
 obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
 obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
+obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom.o
 obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o

drivers/usb/dwc3/dwc3-qcom.c

@@ -0,0 +1,131 @@
+/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+struct dwc3_qcom {
+	struct device		*dev;
+
+	struct clk		*core_clk;
+	struct clk		*iface_clk;
+	struct clk		*sleep_clk;
+};
+
+static int dwc3_qcom_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct dwc3_qcom *qdwc;
+	int ret;
+
+	qdwc = devm_kzalloc(&pdev->dev, sizeof(*qdwc), GFP_KERNEL);
+	if (!qdwc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, qdwc);
+
+	qdwc->dev = &pdev->dev;
+
+	qdwc->core_clk = devm_clk_get(qdwc->dev, "core");
+	if (IS_ERR(qdwc->core_clk)) {
+		dev_err(qdwc->dev, "failed to get core clock\n");
+		return PTR_ERR(qdwc->core_clk);
+	}
+
+	qdwc->iface_clk = devm_clk_get(qdwc->dev, "iface");
+	if (IS_ERR(qdwc->iface_clk)) {
+		dev_dbg(qdwc->dev, "failed to get optional iface clock\n");
+		qdwc->iface_clk = NULL;
+	}
+
+	qdwc->sleep_clk = devm_clk_get(qdwc->dev, "sleep");
+	if (IS_ERR(qdwc->sleep_clk)) {
+		dev_dbg(qdwc->dev, "failed to get optional sleep clock\n");
+		qdwc->sleep_clk = NULL;
+	}
+
+	ret = clk_prepare_enable(qdwc->core_clk);
+	if (ret) {
+		dev_err(qdwc->dev, "failed to enable core clock\n");
+		goto err_core;
+	}
+
+	ret = clk_prepare_enable(qdwc->iface_clk);
+	if (ret) {
+		dev_err(qdwc->dev, "failed to enable optional iface clock\n");
+		goto err_iface;
+	}
+
+	ret = clk_prepare_enable(qdwc->sleep_clk);
+	if (ret) {
+		dev_err(qdwc->dev, "failed to enable optional sleep clock\n");
+		goto err_sleep;
+	}
+
+	ret = of_platform_populate(node, NULL, NULL, qdwc->dev);
+	if (ret) {
+		dev_err(qdwc->dev, "failed to register core - %d\n", ret);
+		goto err_clks;
+	}
+
+	return 0;
+
+err_clks:
+	clk_disable_unprepare(qdwc->sleep_clk);
+err_sleep:
+	clk_disable_unprepare(qdwc->iface_clk);
+err_iface:
+	clk_disable_unprepare(qdwc->core_clk);
+err_core:
+	return ret;
+}
+
+static int dwc3_qcom_remove(struct platform_device *pdev)
+{
+	struct dwc3_qcom *qdwc = platform_get_drvdata(pdev);
+
+	of_platform_depopulate(&pdev->dev);
+
+	clk_disable_unprepare(qdwc->sleep_clk);
+	clk_disable_unprepare(qdwc->iface_clk);
+	clk_disable_unprepare(qdwc->core_clk);
+
+	return 0;
+}
+
+static const struct of_device_id of_dwc3_match[] = {
+	{ .compatible = "qcom,dwc3" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_dwc3_match);
+
+static struct platform_driver dwc3_qcom_driver = {
+	.probe		= dwc3_qcom_probe,
+	.remove		= dwc3_qcom_remove,
+	.driver		= {
+		.name	= "qcom-dwc3",
+		.owner	= THIS_MODULE,
+		.of_match_table	= of_dwc3_match,
+	},
+};
+
+module_platform_driver(dwc3_qcom_driver);
+
+MODULE_ALIAS("platform:qcom-dwc3");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DesignWare USB3 QCOM Glue Layer");
+MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");