/*
 * Copyright (C) 2014 STMicroelectronics
 *
 * STMicroelectronics PHY driver for STiH41x USB.
 *
 * Author: Maxime Coquelin <maxime.coquelin@st.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2, as
 * published by the Free Software Foundation.
 *
 */

#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/clk.h>
#include <linux/phy/phy.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>

#define SYSCFG332  0x80
#define SYSCFG2520 0x820

/**
 * struct stih41x_usb_cfg - SoC specific PHY register mapping
 * @syscfg: Offset in syscfg registers bank
 * @cfg_mask: Bits mask for PHY configuration
 * @cfg: Static configuration value for PHY
 * @oscok: Notify the PHY oscillator clock is ready
 *	   Setting this bit enable the PHY
 */
struct stih41x_usb_cfg {
	u32 syscfg;
	u32 cfg_mask;
	u32 cfg;
	u32 oscok;
};

/**
 * struct stih41x_usb_phy - Private data for the PHY
 * @dev: device for this controller
 * @regmap: Syscfg registers bank in which PHY is configured
 * @cfg: SoC specific PHY register mapping
 * @clk: Oscillator used by the PHY
 */
struct stih41x_usb_phy {
	struct device *dev;
	struct regmap *regmap;
	const struct stih41x_usb_cfg *cfg;
	struct clk *clk;
};

static struct stih41x_usb_cfg stih415_usb_phy_cfg = {
	.syscfg = SYSCFG332,
	.cfg_mask = 0x3f,
	.cfg = 0x38,
	.oscok = BIT(6),
};

static struct stih41x_usb_cfg stih416_usb_phy_cfg = {
	.syscfg = SYSCFG2520,
	.cfg_mask = 0x33f,
	.cfg = 0x238,
	.oscok = BIT(6),
};

static int stih41x_usb_phy_init(struct phy *phy)
{
	struct stih41x_usb_phy *phy_dev = phy_get_drvdata(phy);

	return regmap_update_bits(phy_dev->regmap, phy_dev->cfg->syscfg,
			   phy_dev->cfg->cfg_mask, phy_dev->cfg->cfg);
}

static int stih41x_usb_phy_power_on(struct phy *phy)
{
	struct stih41x_usb_phy *phy_dev = phy_get_drvdata(phy);
	int ret;

	ret = clk_prepare_enable(phy_dev->clk);
	if (ret) {
		dev_err(phy_dev->dev, "Failed to enable osc_phy clock\n");
		return ret;
	}

	ret = regmap_update_bits(phy_dev->regmap, phy_dev->cfg->syscfg,
				 phy_dev->cfg->oscok, phy_dev->cfg->oscok);
	if (ret)
		clk_disable_unprepare(phy_dev->clk);

	return ret;
}

static int stih41x_usb_phy_power_off(struct phy *phy)
{
	struct stih41x_usb_phy *phy_dev = phy_get_drvdata(phy);
	int ret;

	ret = regmap_update_bits(phy_dev->regmap, phy_dev->cfg->syscfg,
			phy_dev->cfg->oscok, 0);
	if (ret) {
		dev_err(phy_dev->dev, "Failed to clear oscok bit\n");
		return ret;
	}

	clk_disable_unprepare(phy_dev->clk);

	return 0;
}

static const struct phy_ops stih41x_usb_phy_ops = {
	.init		= stih41x_usb_phy_init,
	.power_on	= stih41x_usb_phy_power_on,
	.power_off	= stih41x_usb_phy_power_off,
	.owner		= THIS_MODULE,
};

static const struct of_device_id stih41x_usb_phy_of_match[];

static int stih41x_usb_phy_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *match;
	struct stih41x_usb_phy *phy_dev;
	struct device *dev = &pdev->dev;
	struct phy_provider *phy_provider;
	struct phy *phy;

	phy_dev = devm_kzalloc(dev, sizeof(*phy_dev), GFP_KERNEL);
	if (!phy_dev)
		return -ENOMEM;

	match = of_match_device(stih41x_usb_phy_of_match, &pdev->dev);
	if (!match)
		return -ENODEV;

	phy_dev->cfg = match->data;

	phy_dev->regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
	if (IS_ERR(phy_dev->regmap)) {
		dev_err(dev, "No syscfg phandle specified\n");
		return PTR_ERR(phy_dev->regmap);
	}

	phy_dev->clk = devm_clk_get(dev, "osc_phy");
	if (IS_ERR(phy_dev->clk)) {
		dev_err(dev, "osc_phy clk not found\n");
		return PTR_ERR(phy_dev->clk);
	}

	phy = devm_phy_create(dev, NULL, &stih41x_usb_phy_ops);

	if (IS_ERR(phy)) {
		dev_err(dev, "failed to create phy\n");
		return PTR_ERR(phy);
	}

	phy_dev->dev = dev;

	phy_set_drvdata(phy, phy_dev);

	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 stih41x_usb_phy_of_match[] = {
	{ .compatible = "st,stih415-usb-phy", .data = &stih415_usb_phy_cfg },
	{ .compatible = "st,stih416-usb-phy", .data = &stih416_usb_phy_cfg },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, stih41x_usb_phy_of_match);

static struct platform_driver stih41x_usb_phy_driver = {
	.probe	= stih41x_usb_phy_probe,
	.driver = {
		.name	= "stih41x-usb-phy",
		.of_match_table	= stih41x_usb_phy_of_match,
	}
};
module_platform_driver(stih41x_usb_phy_driver);

MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>");
MODULE_DESCRIPTION("STMicroelectronics USB PHY driver for STiH41x series");
MODULE_LICENSE("GPL v2");