phy: Add driver for rockchip Display Port PHY

Add phy driver for the Rockchip DisplayPort PHY module. This
is required to get DisplayPort working in Rockchip SoCs.

Signed-off-by: Yakir Yang <[e-mail]>
Reviewed-by: Heiko Stuebner <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/Kconfig

···
 	help
 	  Enable this to support the Rockchip EMMC PHY.
 
+config PHY_ROCKCHIP_DP
+	tristate "Rockchip Display Port PHY Driver"
+	depends on ARCH_ROCKCHIP && OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the Rockchip Display Port PHY.
+
 config PHY_ST_SPEAR1310_MIPHY
 	tristate "ST SPEAR1310-MIPHY driver"
 	select GENERIC_PHY

drivers/phy/Makefile

···
 obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
 obj-$(CONFIG_PHY_ROCKCHIP_USB) += phy-rockchip-usb.o
 obj-$(CONFIG_PHY_ROCKCHIP_EMMC) += phy-rockchip-emmc.o
+obj-$(CONFIG_PHY_ROCKCHIP_DP)		+= phy-rockchip-dp.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-dp.c

···
+/*
+ * Rockchip DP PHY driver
+ *
+ * Copyright (C) 2016 FuZhou Rockchip Co., Ltd.
+ * Author: Yakir Yang <ykk@@rock-chips.com>
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define GRF_SOC_CON12                           0x0274
+
+#define GRF_EDP_REF_CLK_SEL_INTER_HIWORD_MASK   BIT(20)
+#define GRF_EDP_REF_CLK_SEL_INTER               BIT(4)
+
+#define GRF_EDP_PHY_SIDDQ_HIWORD_MASK           BIT(21)
+#define GRF_EDP_PHY_SIDDQ_ON                    0
+#define GRF_EDP_PHY_SIDDQ_OFF                   BIT(5)
+
+struct rockchip_dp_phy {
+	struct device  *dev;
+	struct regmap  *grf;
+	struct clk     *phy_24m;
+};
+
+static int rockchip_set_phy_state(struct phy *phy, bool enable)
+{
+	struct rockchip_dp_phy *dp = phy_get_drvdata(phy);
+	int ret;
+
+	if (enable) {
+		ret = regmap_write(dp->grf, GRF_SOC_CON12,
+				   GRF_EDP_PHY_SIDDQ_HIWORD_MASK |
+				   GRF_EDP_PHY_SIDDQ_ON);
+		if (ret < 0) {
+			dev_err(dp->dev, "Can't enable PHY power %d\n", ret);
+			return ret;
+		}
+
+		ret = clk_prepare_enable(dp->phy_24m);
+	} else {
+		clk_disable_unprepare(dp->phy_24m);
+
+		ret = regmap_write(dp->grf, GRF_SOC_CON12,
+				   GRF_EDP_PHY_SIDDQ_HIWORD_MASK |
+				   GRF_EDP_PHY_SIDDQ_OFF);
+	}
+
+	return ret;
+}
+
+static int rockchip_dp_phy_power_on(struct phy *phy)
+{
+	return rockchip_set_phy_state(phy, true);
+}
+
+static int rockchip_dp_phy_power_off(struct phy *phy)
+{
+	return rockchip_set_phy_state(phy, false);
+}
+
+static const struct phy_ops rockchip_dp_phy_ops = {
+	.power_on	= rockchip_dp_phy_power_on,
+	.power_off	= rockchip_dp_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int rockchip_dp_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct phy_provider *phy_provider;
+	struct rockchip_dp_phy *dp;
+	struct phy *phy;
+	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
+	if (IS_ERR(dp))
+		return -ENOMEM;
+
+	dp->dev = dev;
+
+	dp->phy_24m = devm_clk_get(dev, "24m");
+	if (IS_ERR(dp->phy_24m)) {
+		dev_err(dev, "cannot get clock 24m\n");
+		return PTR_ERR(dp->phy_24m);
+	}
+
+	ret = clk_set_rate(dp->phy_24m, 24000000);
+	if (ret < 0) {
+		dev_err(dp->dev, "cannot set clock phy_24m %d\n", ret);
+		return ret;
+	}
+
+	dp->grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
+	if (IS_ERR(dp->grf)) {
+		dev_err(dev, "rk3288-dp needs rockchip,grf property\n");
+		return PTR_ERR(dp->grf);
+	}
+
+	ret = regmap_write(dp->grf, GRF_SOC_CON12, GRF_EDP_REF_CLK_SEL_INTER |
+			   GRF_EDP_REF_CLK_SEL_INTER_HIWORD_MASK);
+	if (ret != 0) {
+		dev_err(dp->dev, "Could not config GRF edp ref clk: %d\n", ret);
+		return ret;
+	}
+
+	phy = devm_phy_create(dev, np, &rockchip_dp_phy_ops);
+	if (IS_ERR(phy)) {
+		dev_err(dev, "failed to create phy\n");
+		return PTR_ERR(phy);
+	}
+	phy_set_drvdata(phy, dp);
+
+	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_dp_phy_dt_ids[] = {
+	{ .compatible = "rockchip,rk3288-dp-phy" },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, rockchip_dp_phy_dt_ids);
+
+static struct platform_driver rockchip_dp_phy_driver = {
+	.probe		= rockchip_dp_phy_probe,
+	.driver		= {
+		.name	= "rockchip-dp-phy",
+		.of_match_table = rockchip_dp_phy_dt_ids,
+	},
+};
+
+module_platform_driver(rockchip_dp_phy_driver);
+
+MODULE_AUTHOR("Yakir Yang <[e-mail]>");
+MODULE_DESCRIPTION("Rockchip DP PHY driver");
+MODULE_LICENSE("GPL v2");