// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 STMicroelectronics
 *
 * STMicroelectronics Generic PHY driver for STiH407 USB2.
 *
 * Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
 */
#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/regmap.h>
#include <linux/reset.h>
#include <linux/mfd/syscon.h>
#include <linux/phy/phy.h>

#define PHYPARAM_REG    0
#define PHYCTRL_REG     1

/* Default PHY_SEL and REFCLKSEL configuration */
#define STIH407_USB_PICOPHY_CTRL_PORT_CONF      0x6
#define STIH407_USB_PICOPHY_CTRL_PORT_MASK      0x1f

/* ports parameters overriding */
#define STIH407_USB_PICOPHY_PARAM_DEF           0x39a4dc
#define STIH407_USB_PICOPHY_PARAM_MASK          0xffffffff

struct stih407_usb2_picophy {
        struct phy *phy;
        struct regmap *regmap;
        struct device *dev;
        struct reset_control *rstc;
        struct reset_control *rstport;
        int ctrl;
        int param;
};

static int stih407_usb2_pico_ctrl(struct stih407_usb2_picophy *phy_dev)
{
        reset_control_deassert(phy_dev->rstc);

        return regmap_update_bits(phy_dev->regmap, phy_dev->ctrl,
                                  STIH407_USB_PICOPHY_CTRL_PORT_MASK,
                                  STIH407_USB_PICOPHY_CTRL_PORT_CONF);
}

static int stih407_usb2_init_port(struct phy *phy)
{
        int ret;
        struct stih407_usb2_picophy *phy_dev = phy_get_drvdata(phy);

        stih407_usb2_pico_ctrl(phy_dev);

        ret = regmap_update_bits(phy_dev->regmap,
                                 phy_dev->param,
                                 STIH407_USB_PICOPHY_PARAM_MASK,
                                 STIH407_USB_PICOPHY_PARAM_DEF);
        if (ret)
                return ret;

        return reset_control_deassert(phy_dev->rstport);
}

static int stih407_usb2_exit_port(struct phy *phy)
{
        struct stih407_usb2_picophy *phy_dev = phy_get_drvdata(phy);

        /*
         * Only port reset is asserted, phy global reset is kept untouched
         * as other ports may still be active. When all ports are in reset
         * state, assumption is made that power will be cut off on the phy, in
         * case of suspend for instance. Theoretically, asserting individual
         * reset (like here) or global reset should be equivalent.
         */
        return reset_control_assert(phy_dev->rstport);
}

static const struct phy_ops stih407_usb2_picophy_data = {
        .init = stih407_usb2_init_port,
        .exit = stih407_usb2_exit_port,
        .owner = THIS_MODULE,
};

static int stih407_usb2_picophy_probe(struct platform_device *pdev)
{
        struct stih407_usb2_picophy *phy_dev;
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct phy_provider *phy_provider;
        unsigned int syscon_args[2];
        struct phy *phy;

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

        phy_dev->dev = dev;
        dev_set_drvdata(dev, phy_dev);

        phy_dev->rstc = devm_reset_control_get_shared(dev, "global");
        if (IS_ERR(phy_dev->rstc)) {
                dev_err(dev, "failed to ctrl picoPHY reset\n");
                return PTR_ERR(phy_dev->rstc);
        }

        phy_dev->rstport = devm_reset_control_get_exclusive(dev, "port");
        if (IS_ERR(phy_dev->rstport)) {
                dev_err(dev, "failed to ctrl picoPHY reset\n");
                return PTR_ERR(phy_dev->rstport);
        }

        /* Reset port by default: only deassert it in phy init */
        reset_control_assert(phy_dev->rstport);

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

        phy_dev->param = syscon_args[PHYPARAM_REG];
        phy_dev->ctrl = syscon_args[PHYCTRL_REG];

        phy = devm_phy_create(dev, NULL, &stih407_usb2_picophy_data);
        if (IS_ERR(phy)) {
                dev_err(dev, "failed to create Display Port PHY\n");
                return PTR_ERR(phy);
        }

        phy_dev->phy = phy;
        phy_set_drvdata(phy, phy_dev);

        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
        if (IS_ERR(phy_provider))
                return PTR_ERR(phy_provider);

        return 0;
}

static const struct of_device_id stih407_usb2_picophy_of_match[] = {
        { .compatible = "st,stih407-usb2-phy" },
        { /*sentinel */ },
};

MODULE_DEVICE_TABLE(of, stih407_usb2_picophy_of_match);

static struct platform_driver stih407_usb2_picophy_driver = {
        .probe = stih407_usb2_picophy_probe,
        .driver = {
                   .name = "stih407-usb-genphy",
                   .of_match_table = stih407_usb2_picophy_of_match,
                   }
};

module_platform_driver(stih407_usb2_picophy_driver);

MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
MODULE_DESCRIPTION("STMicroelectronics Generic picoPHY driver for STiH407");
MODULE_LICENSE("GPL v2");