phy: add a driver for the Rockchip SoC internal eMMC PHY

This patch to add a generic PHY driver for ROCKCHIP eMMC PHY.
Access the PHY via registers provided by GRF (general register
files) module.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/Kconfig

@@ -337,6 +337,13 @@ config PHY_ROCKCHIP_USB
 	help
 	  Enable this to support the Rockchip USB 2.0 PHY.
 
+config PHY_ROCKCHIP_EMMC
+	tristate "Rockchip EMMC PHY Driver"
+	depends on ARCH_ROCKCHIP && OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the Rockchip EMMC PHY.
+
 config PHY_ST_SPEAR1310_MIPHY
 	tristate "ST SPEAR1310-MIPHY driver"
 	select GENERIC_PHY

drivers/phy/Makefile

@@ -37,6 +37,7 @@ 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-$(CONFIG_PHY_ROCKCHIP_EMMC) += phy-rockchip-emmc.o
 obj-$(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-emmc.c

+/*
+ * Rockchip emmc PHY driver
+ *
+ * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
+ * Copyright (C) 2016 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/delay.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/*
+ * The higher 16-bit of this register is used for write protection
+ * only if BIT(x + 16) set to 1 the BIT(x) can be written.
+ */
+#define HIWORD_UPDATE(val, mask, shift) \
+		((val) << (shift) | (mask) << ((shift) + 16))
+
+/* Register definition */
+#define GRF_EMMCPHY_CON0	0x0
+#define GRF_EMMCPHY_CON1	0x4
+#define GRF_EMMCPHY_CON2	0x8
+#define GRF_EMMCPHY_CON3	0xc
+#define GRF_EMMCPHY_CON4	0x10
+#define GRF_EMMCPHY_CON5	0x14
+#define GRF_EMMCPHY_CON6	0x18
+#define GRF_EMMCPHY_STATUS	0x20
+
+#define PHYCTRL_PDB_MASK	0x1
+#define PHYCTRL_PDB_SHIFT	0x0
+#define PHYCTRL_PDB_PWR_ON	0x1
+#define PHYCTRL_PDB_PWR_OFF	0x0
+#define PHYCTRL_ENDLL_MASK	0x1
+#define PHYCTRL_ENDLL_SHIFT     0x1
+#define PHYCTRL_ENDLL_ENABLE	0x1
+#define PHYCTRL_ENDLL_DISABLE	0x0
+#define PHYCTRL_CALDONE_MASK	0x1
+#define PHYCTRL_CALDONE_SHIFT   0x6
+#define PHYCTRL_CALDONE_DONE	0x1
+#define PHYCTRL_CALDONE_GOING	0x0
+#define PHYCTRL_DLLRDY_MASK	0x1
+#define PHYCTRL_DLLRDY_SHIFT	0x5
+#define PHYCTRL_DLLRDY_DONE	0x1
+#define PHYCTRL_DLLRDY_GOING	0x0
+
+struct rockchip_emmc_phy {
+	unsigned int	reg_offset;
+	struct regmap	*reg_base;
+};
+
+static int rockchip_emmc_phy_power(struct rockchip_emmc_phy *rk_phy,
+				   bool on_off)
+{
+	unsigned int caldone;
+	unsigned int dllrdy;
+
+	/*
+	 * Keep phyctrl_pdb and phyctrl_endll low to allow
+	 * initialization of CALIO state M/C DFFs
+	 */
+	regmap_write(rk_phy->reg_base,
+		     rk_phy->reg_offset + GRF_EMMCPHY_CON6,
+		     HIWORD_UPDATE(PHYCTRL_PDB_PWR_OFF,
+				   PHYCTRL_PDB_MASK,
+				   PHYCTRL_PDB_SHIFT));
+	regmap_write(rk_phy->reg_base,
+		     rk_phy->reg_offset + GRF_EMMCPHY_CON6,
+		     HIWORD_UPDATE(PHYCTRL_ENDLL_DISABLE,
+				   PHYCTRL_ENDLL_MASK,
+				   PHYCTRL_ENDLL_SHIFT));
+
+	/* Already finish power_off above */
+	if (on_off == PHYCTRL_PDB_PWR_OFF)
+		return 0;
+
+	/*
+	 * According to the user manual, calpad calibration
+	 * cycle takes more than 2us without the minimal recommended
+	 * value, so we may need a little margin here
+	 */
+	udelay(3);
+	regmap_write(rk_phy->reg_base,
+		     rk_phy->reg_offset + GRF_EMMCPHY_CON6,
+		     HIWORD_UPDATE(PHYCTRL_PDB_PWR_ON,
+				   PHYCTRL_PDB_MASK,
+				   PHYCTRL_PDB_SHIFT));
+
+	/*
+	 * According to the user manual, it asks driver to
+	 * wait 5us for calpad busy trimming
+	 */
+	udelay(5);
+	regmap_read(rk_phy->reg_base,
+		    rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
+		    &caldone);
+	caldone = (caldone >> PHYCTRL_CALDONE_SHIFT) & PHYCTRL_CALDONE_MASK;
+	if (caldone != PHYCTRL_CALDONE_DONE) {
+		pr_err("rockchip_emmc_phy_power: caldone timeout.\n");
+		return -ETIMEDOUT;
+	}
+
+	regmap_write(rk_phy->reg_base,
+		     rk_phy->reg_offset + GRF_EMMCPHY_CON6,
+		     HIWORD_UPDATE(PHYCTRL_ENDLL_ENABLE,
+				   PHYCTRL_ENDLL_MASK,
+				   PHYCTRL_ENDLL_SHIFT));
+	/*
+	 * After enable analog DLL circuits, we need extra 10.2us
+	 * for dll to be ready for work.
+	 */
+	udelay(11);
+	regmap_read(rk_phy->reg_base,
+		    rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
+		    &dllrdy);
+	dllrdy = (dllrdy >> PHYCTRL_DLLRDY_SHIFT) & PHYCTRL_DLLRDY_MASK;
+	if (dllrdy != PHYCTRL_DLLRDY_DONE) {
+		pr_err("rockchip_emmc_phy_power: dllrdy timeout.\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int rockchip_emmc_phy_power_off(struct phy *phy)
+{
+	struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
+	int ret = 0;
+
+	/* Power down emmc phy analog blocks */
+	ret = rockchip_emmc_phy_power(rk_phy, PHYCTRL_PDB_PWR_OFF);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int rockchip_emmc_phy_power_on(struct phy *phy)
+{
+	struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
+	int ret = 0;
+
+	/* Power up emmc phy analog blocks */
+	ret = rockchip_emmc_phy_power(rk_phy, PHYCTRL_PDB_PWR_ON);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct phy_ops ops = {
+	.power_on	= rockchip_emmc_phy_power_on,
+	.power_off	= rockchip_emmc_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int rockchip_emmc_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_emmc_phy *rk_phy;
+	struct phy *generic_phy;
+	struct phy_provider *phy_provider;
+	struct regmap *grf;
+	unsigned int reg_offset;
+
+	grf = syscon_regmap_lookup_by_phandle(dev->of_node, "rockchip,grf");
+	if (IS_ERR(grf)) {
+		dev_err(dev, "Missing rockchip,grf property\n");
+		return PTR_ERR(grf);
+	}
+
+	rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
+	if (!rk_phy)
+		return -ENOMEM;
+
+	if (of_property_read_u32(dev->of_node, "reg", &reg_offset)) {
+		dev_err(dev, "missing reg property in node %s\n",
+			dev->of_node->name);
+		return -EINVAL;
+	}
+
+	rk_phy->reg_offset = reg_offset;
+	rk_phy->reg_base = grf;
+
+	generic_phy = devm_phy_create(dev, dev->of_node, &ops);
+	if (IS_ERR(generic_phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(generic_phy);
+	}
+
+	phy_set_drvdata(generic_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_emmc_phy_dt_ids[] = {
+	{ .compatible = "rockchip,rk3399-emmc-phy" },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, rockchip_emmc_phy_dt_ids);
+
+static struct platform_driver rockchip_emmc_driver = {
+	.probe		= rockchip_emmc_phy_probe,
+	.driver		= {
+		.name	= "rockchip-emmc-phy",
+		.of_match_table = rockchip_emmc_phy_dt_ids,
+	},
+};
+
+module_platform_driver(rockchip_emmc_driver);
+
+MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
+MODULE_DESCRIPTION("Rockchip EMMC PHY driver");
+MODULE_LICENSE("GPL v2");