[RFC PATCH v2 3/3] usb: dwc3: Add Qualcomm DWC3 glue layer driver

["Ivan T. Ivanov" <iivanov@mm-sol.com>]

From: "Ivan T. Ivanov" <iivanov@mm-sol.com>

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>
---
 drivers/usb/dwc3/Kconfig    |    8 ++
 drivers/usb/dwc3/Makefile   |    1 +
 drivers/usb/dwc3/dwc3-msm.c |  174 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 183 insertions(+)
 create mode 100644 drivers/usb/dwc3/dwc3-msm.c

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 3e225d5..e2032c4 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -70,6 +70,14 @@ config USB_DWC3_PCI
 	  One such PCIe-based platform is Synopsys' PCIe HAPS model of
 	  this IP.
 
+config USB_DWC3_MSM
+	tristate "Qualcomm MSM/APQ Platforms"
+	default USB_DWC3
+	select USB_MSM_DWC3_PHYS
+	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
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index dd17601..5226681 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -32,3 +32,4 @@ endif
 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_MSM)		+= dwc3-msm.o
diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
new file mode 100644
index 0000000..f442249
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-msm.c
@@ -0,0 +1,174 @@
+/* Copyright (c) 2013, 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>
+#include <linux/regulator/consumer.h>
+#include <linux/usb/phy.h>
+
+struct dwc3_msm {
+	struct device		*dev;
+	void __iomem		*base;
+
+	struct clk		*core_clk;
+	struct clk		*iface_clk;
+	struct clk		*sleep_clk;
+	struct clk		*utmi_clk;
+
+	struct regulator	*gdsc;
+};
+
+static int dwc3_msm_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct dwc3_msm *mdwc;
+	struct resource *res;
+	void __iomem *tcsr;
+	int ret = 0;
+
+	dev_info(&pdev->dev, "MSM DWC3\n");
+
+	mdwc = devm_kzalloc(&pdev->dev, sizeof(*mdwc), GFP_KERNEL);
+	if (!mdwc) {
+		dev_err(&pdev->dev, "not enough memory\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, mdwc);
+	mdwc->dev = &pdev->dev;
+
+	mdwc->gdsc = devm_regulator_get(mdwc->dev, "gdsc");
+
+	mdwc->core_clk = devm_clk_get(&pdev->dev, "core_clk");
+	if (IS_ERR(mdwc->core_clk)) {
+		dev_err(&pdev->dev, "failed to get core_clk\n");
+		return PTR_ERR(mdwc->core_clk);
+	}
+
+	mdwc->iface_clk = devm_clk_get(&pdev->dev, "iface_clk");
+	if (IS_ERR(mdwc->iface_clk)) {
+		dev_err(&pdev->dev, "failed to get iface_clk\n");
+		return PTR_ERR(mdwc->iface_clk);
+	}
+
+	mdwc->sleep_clk = devm_clk_get(&pdev->dev, "sleep_clk");
+	if (IS_ERR(mdwc->sleep_clk)) {
+		dev_err(&pdev->dev, "failed to get sleep_clk\n");
+		return  PTR_ERR(mdwc->sleep_clk);
+	}
+
+	mdwc->utmi_clk = devm_clk_get(&pdev->dev, "utmi_clk");
+	if (IS_ERR(mdwc->utmi_clk)) {
+		dev_err(&pdev->dev, "failed to get utmi_clk\n");
+		return  PTR_ERR(mdwc->utmi_clk);
+	}
+
+	if (!IS_ERR(mdwc->gdsc)) {
+		ret = regulator_enable(mdwc->gdsc);
+		if (ret)
+			dev_err(mdwc->dev, "unable to enable usb3 gdsc\n");
+	}
+
+	/*
+	 * DWC3 Core requires its CORE CLK (aka master / bus clk) to
+	 * run at 125Mhz in SSUSB mode and >60MHZ for HSUSB mode.
+	 */
+	clk_set_rate(mdwc->core_clk, 125000000);
+	clk_prepare_enable(mdwc->core_clk);
+	clk_prepare_enable(mdwc->iface_clk);
+	clk_prepare_enable(mdwc->sleep_clk);
+	clk_prepare_enable(mdwc->utmi_clk);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	tcsr = devm_ioremap_resource(&pdev->dev, res);
+	if (!tcsr) {
+		dev_dbg(&pdev->dev, "tcsr ioremap failed\n");
+	} else {
+		/* TODO: This has to be revised */
+
+		/* Enable USB3 on the primary USB port. */
+		writel_relaxed(0x1, tcsr);
+		/*
+		 * Ensure that TCSR write is completed before
+		 * USB registers initialization.
+		 */
+		mb();
+	}
+
+	ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add create dwc3 core\n");
+		goto dis_clks;
+	}
+
+	return 0;
+
+dis_clks:
+	clk_disable_unprepare(mdwc->utmi_clk);
+	clk_disable_unprepare(mdwc->sleep_clk);
+	clk_disable_unprepare(mdwc->iface_clk);
+	clk_disable_unprepare(mdwc->core_clk);
+	if (!IS_ERR(mdwc->gdsc)) {
+		ret = regulator_disable(mdwc->gdsc);
+		if (ret)
+			dev_err(mdwc->dev, "cannot disable usb3 gdsc\n");
+	}
+
+	return ret;
+}
+
+static int dwc3_msm_remove(struct platform_device *pdev)
+{
+	struct dwc3_msm	*mdwc = platform_get_drvdata(pdev);
+	int ret;
+
+	clk_disable_unprepare(mdwc->utmi_clk);
+	clk_disable_unprepare(mdwc->sleep_clk);
+	clk_disable_unprepare(mdwc->iface_clk);
+	clk_disable_unprepare(mdwc->core_clk);
+
+	if (!IS_ERR(mdwc->gdsc)) {
+		ret = regulator_disable(mdwc->gdsc);
+		if (ret)
+			dev_err(mdwc->dev, "cannot disable usb3 gdsc\n");
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_dwc3_matach[] = {
+	{
+		.compatible = "qcom,dwc3",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, of_dwc3_matach);
+
+static struct platform_driver dwc3_msm_driver = {
+	.probe		= dwc3_msm_probe,
+	.remove		= dwc3_msm_remove,
+	.driver		= {
+		.name	= "msm-dwc3",
+		.owner	= THIS_MODULE,
+		.of_match_table	= of_dwc3_matach,
+	},
+};
+
+module_platform_driver(dwc3_msm_driver);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DesignWare USB3 MSM Glue Layer");
-- 
1.7.9.5