phy: add a driver for the Rockchip SoC internal USB2.0 PHY

This patch to add a generic PHY driver for ROCKCHIP usb PHYs,
currently this driver can support RK3288. The RK3288 SoC have
three independent USB PHY IPs which are all configured through a
set of registers located in the GRF (general register files)
module.

Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/Kconfig

@@ -239,6 +239,13 @@ config PHY_QCOM_IPQ806X_SATA
 	depends on OF
 	select GENERIC_PHY
 
+config PHY_ROCKCHIP_USB
+	tristate "Rockchip USB2 PHY Driver"
+	depends on ARCH_ROCKCHIP && OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the Rockchip USB 2.0 PHY.
+
 config PHY_ST_SPEAR1310_MIPHY
 	tristate "ST SPEAR1310-MIPHY driver"
 	select GENERIC_PHY

drivers/phy/Makefile

@@ -28,6 +28,7 @@ phy-exynos-usb2-$(CONFIG_PHY_EXYNOS5250_USB2)	+= phy-exynos5250-usb2.o
 phy-exynos-usb2-$(CONFIG_PHY_S5PV210_USB2)	+= phy-s5pv210-usb2.o
 obj-$(CONFIG_PHY_EXYNOS5_USBDRD)	+= phy-exynos5-usbdrd.o
 obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
+obj-$(CONFIG_PHY_ROCKCHIP_USB) += phy-rockchip-usb.o
 obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA)	+= phy-qcom-ipq806x-sata.o
 obj-$(CONFIG_PHY_ST_SPEAR1310_MIPHY)	+= phy-spear1310-miphy.o
 obj-$(CONFIG_PHY_ST_SPEAR1340_MIPHY)	+= phy-spear1340-miphy.o

drivers/phy/phy-rockchip-usb.c

@@ -0,0 +1,158 @@
+/*
+ * Rockchip usb PHY driver
+ *
+ * Copyright (C) 2014 Yunzhi Li <lyz@rock-chips.com>
+ * Copyright (C) 2014 ROCKCHIP, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License.
+ *
+ * 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/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+/*
+ * The higher 16-bit of this register is used for write protection
+ * only if BIT(13 + 16) set to 1 the BIT(13) can be written.
+ */
+#define SIDDQ_WRITE_ENA	BIT(29)
+#define SIDDQ_ON		BIT(13)
+#define SIDDQ_OFF		(0 << 13)
+
+struct rockchip_usb_phy {
+	unsigned int	reg_offset;
+	struct regmap	*reg_base;
+	struct clk	*clk;
+	struct phy	*phy;
+};
+
+static int rockchip_usb_phy_power(struct rockchip_usb_phy *phy,
+					   bool siddq)
+{
+	return regmap_write(phy->reg_base, phy->reg_offset,
+			    SIDDQ_WRITE_ENA | (siddq ? SIDDQ_ON : SIDDQ_OFF));
+}
+
+static int rockchip_usb_phy_power_off(struct phy *_phy)
+{
+	struct rockchip_usb_phy *phy = phy_get_drvdata(_phy);
+	int ret = 0;
+
+	/* Power down usb phy analog blocks by set siddq 1 */
+	ret = rockchip_usb_phy_power(phy, 1);
+	if (ret)
+		return ret;
+
+	clk_disable_unprepare(phy->clk);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int rockchip_usb_phy_power_on(struct phy *_phy)
+{
+	struct rockchip_usb_phy *phy = phy_get_drvdata(_phy);
+	int ret = 0;
+
+	ret = clk_prepare_enable(phy->clk);
+	if (ret)
+		return ret;
+
+	/* Power up usb phy analog blocks by set siddq 0 */
+	ret = rockchip_usb_phy_power(phy, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static struct phy_ops ops = {
+	.power_on	= rockchip_usb_phy_power_on,
+	.power_off	= rockchip_usb_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int rockchip_usb_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_usb_phy *rk_phy;
+	struct phy_provider *phy_provider;
+	struct device_node *child;
+	struct regmap *grf;
+	unsigned int reg_offset;
+
+	grf = syscon_regmap_lookup_by_phandle(dev->of_node, "rockchip,grf");
+	if (IS_ERR(grf)) {
+		dev_err(&pdev->dev, "Missing rockchip,grf property\n");
+		return PTR_ERR(grf);
+	}
+
+	for_each_available_child_of_node(dev->of_node, child) {
+		rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
+		if (!rk_phy)
+			return -ENOMEM;
+
+		if (of_property_read_u32(child, "reg", &reg_offset)) {
+			dev_err(dev, "missing reg property in node %s\n",
+				child->name);
+			return -EINVAL;
+		}
+
+		rk_phy->reg_offset = reg_offset;
+		rk_phy->reg_base = grf;
+
+		rk_phy->clk = of_clk_get_by_name(child, "phyclk");
+		if (IS_ERR(rk_phy->clk))
+			rk_phy->clk = NULL;
+
+		rk_phy->phy = devm_phy_create(dev, child, &ops);
+		if (IS_ERR(rk_phy->phy)) {
+			dev_err(dev, "failed to create PHY\n");
+			return PTR_ERR(rk_phy->phy);
+		}
+		phy_set_drvdata(rk_phy->phy, rk_phy);
+	}
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id rockchip_usb_phy_dt_ids[] = {
+	{ .compatible = "rockchip,rk3288-usb-phy" },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, rockchip_usb_phy_dt_ids);
+
+static struct platform_driver rockchip_usb_driver = {
+	.probe		= rockchip_usb_phy_probe,
+	.driver		= {
+		.name	= "rockchip-usb-phy",
+		.owner	= THIS_MODULE,
+		.of_match_table = rockchip_usb_phy_dt_ids,
+	},
+};
+
+module_platform_driver(rockchip_usb_driver);
+
+MODULE_AUTHOR("Yunzhi Li <lyz@rock-chips.com>");
+MODULE_DESCRIPTION("Rockchip USB 2.0 PHY driver");
+MODULE_LICENSE("GPL v2");