root/drivers/phy/hisilicon/phy-histb-combphy.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * COMBPHY driver for HiSilicon STB SoCs
 *
 * Copyright (C) 2016-2017 HiSilicon Co., Ltd. http://www.hisilicon.com
 *
 * Authors: Jianguo Sun <sunjianguo1@huawei.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.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>
#include <linux/reset.h>
#include <dt-bindings/phy/phy.h>

#define COMBPHY_MODE_PCIE               0
#define COMBPHY_MODE_USB3               1
#define COMBPHY_MODE_SATA               2

#define COMBPHY_CFG_REG                 0x0
#define COMBPHY_BYPASS_CODEC            BIT(31)
#define COMBPHY_TEST_WRITE              BIT(24)
#define COMBPHY_TEST_DATA_SHIFT         20
#define COMBPHY_TEST_DATA_MASK          GENMASK(23, 20)
#define COMBPHY_TEST_ADDR_SHIFT         12
#define COMBPHY_TEST_ADDR_MASK          GENMASK(16, 12)
#define COMBPHY_CLKREF_OUT_OEN          BIT(0)

struct histb_combphy_mode {
        int fixed;
        int select;
        u32 reg;
        u32 shift;
        u32 mask;
};

struct histb_combphy_priv {
        void __iomem *mmio;
        struct regmap *syscon;
        struct reset_control *por_rst;
        struct clk *ref_clk;
        struct phy *phy;
        struct histb_combphy_mode mode;
};

static void nano_register_write(struct histb_combphy_priv *priv,
                                u32 addr, u32 data)
{
        void __iomem *reg = priv->mmio + COMBPHY_CFG_REG;
        u32 val;

        /* Set up address and data for the write */
        val = readl(reg);
        val &= ~COMBPHY_TEST_ADDR_MASK;
        val |= addr << COMBPHY_TEST_ADDR_SHIFT;
        val &= ~COMBPHY_TEST_DATA_MASK;
        val |= data << COMBPHY_TEST_DATA_SHIFT;
        writel(val, reg);

        /* Flip strobe control to trigger the write */
        val &= ~COMBPHY_TEST_WRITE;
        writel(val, reg);
        val |= COMBPHY_TEST_WRITE;
        writel(val, reg);
}

static int is_mode_fixed(struct histb_combphy_mode *mode)
{
        return mode->fixed != PHY_NONE;
}

static int histb_combphy_set_mode(struct histb_combphy_priv *priv)
{
        struct histb_combphy_mode *mode = &priv->mode;
        struct regmap *syscon = priv->syscon;
        u32 hw_sel;

        if (is_mode_fixed(mode))
                return 0;

        switch (mode->select) {
        case PHY_TYPE_SATA:
                hw_sel = COMBPHY_MODE_SATA;
                break;
        case PHY_TYPE_PCIE:
                hw_sel = COMBPHY_MODE_PCIE;
                break;
        case PHY_TYPE_USB3:
                hw_sel = COMBPHY_MODE_USB3;
                break;
        default:
                return -EINVAL;
        }

        return regmap_update_bits(syscon, mode->reg, mode->mask,
                                  hw_sel << mode->shift);
}

static int histb_combphy_init(struct phy *phy)
{
        struct histb_combphy_priv *priv = phy_get_drvdata(phy);
        u32 val;
        int ret;

        ret = histb_combphy_set_mode(priv);
        if (ret)
                return ret;

        /* Clear bypass bit to enable encoding/decoding */
        val = readl(priv->mmio + COMBPHY_CFG_REG);
        val &= ~COMBPHY_BYPASS_CODEC;
        writel(val, priv->mmio + COMBPHY_CFG_REG);

        ret = clk_prepare_enable(priv->ref_clk);
        if (ret)
                return ret;

        reset_control_deassert(priv->por_rst);

        /* Enable EP clock */
        val = readl(priv->mmio + COMBPHY_CFG_REG);
        val |= COMBPHY_CLKREF_OUT_OEN;
        writel(val, priv->mmio + COMBPHY_CFG_REG);

        /* Need to wait for EP clock stable */
        mdelay(5);

        /* Configure nano phy registers as suggested by vendor */
        nano_register_write(priv, 0x1, 0x8);
        nano_register_write(priv, 0xc, 0x9);
        nano_register_write(priv, 0x1a, 0x4);

        return 0;
}

static int histb_combphy_exit(struct phy *phy)
{
        struct histb_combphy_priv *priv = phy_get_drvdata(phy);
        u32 val;

        /* Disable EP clock */
        val = readl(priv->mmio + COMBPHY_CFG_REG);
        val &= ~COMBPHY_CLKREF_OUT_OEN;
        writel(val, priv->mmio + COMBPHY_CFG_REG);

        reset_control_assert(priv->por_rst);
        clk_disable_unprepare(priv->ref_clk);

        return 0;
}

static const struct phy_ops histb_combphy_ops = {
        .init = histb_combphy_init,
        .exit = histb_combphy_exit,
        .owner = THIS_MODULE,
};

static struct phy *histb_combphy_xlate(struct device *dev,
                                       const struct of_phandle_args *args)
{
        struct histb_combphy_priv *priv = dev_get_drvdata(dev);
        struct histb_combphy_mode *mode = &priv->mode;

        if (args->args_count < 1) {
                dev_err(dev, "invalid number of arguments\n");
                return ERR_PTR(-EINVAL);
        }

        mode->select = args->args[0];

        if (mode->select < PHY_TYPE_SATA || mode->select > PHY_TYPE_USB3) {
                dev_err(dev, "invalid phy mode select argument\n");
                return ERR_PTR(-EINVAL);
        }

        if (is_mode_fixed(mode) && mode->select != mode->fixed) {
                dev_err(dev, "mode select %d mismatch fixed phy mode %d\n",
                        mode->select, mode->fixed);
                return ERR_PTR(-EINVAL);
        }

        return priv->phy;
}

static int histb_combphy_probe(struct platform_device *pdev)
{
        struct phy_provider *phy_provider;
        struct device *dev = &pdev->dev;
        struct histb_combphy_priv *priv;
        struct device_node *np = dev->of_node;
        struct histb_combphy_mode *mode;
        u32 vals[3];
        int ret;

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

        priv->mmio = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->mmio)) {
                ret = PTR_ERR(priv->mmio);
                return ret;
        }

        priv->syscon = syscon_node_to_regmap(np->parent);
        if (IS_ERR(priv->syscon)) {
                dev_err(dev, "failed to find peri_ctrl syscon regmap\n");
                return PTR_ERR(priv->syscon);
        }

        mode = &priv->mode;
        mode->fixed = PHY_NONE;

        ret = of_property_read_u32(np, "hisilicon,fixed-mode", &mode->fixed);
        if (ret == 0)
                dev_dbg(dev, "found fixed phy mode %d\n", mode->fixed);

        ret = of_property_read_u32_array(np, "hisilicon,mode-select-bits",
                                         vals, ARRAY_SIZE(vals));
        if (ret == 0) {
                if (is_mode_fixed(mode)) {
                        dev_err(dev, "found select bits for fixed mode phy\n");
                        return -EINVAL;
                }

                mode->reg = vals[0];
                mode->shift = vals[1];
                mode->mask = vals[2];
                dev_dbg(dev, "found mode select bits\n");
        } else {
                if (!is_mode_fixed(mode)) {
                        dev_err(dev, "no valid select bits found for non-fixed phy\n");
                        return -ENODEV;
                }
        }

        priv->ref_clk = devm_clk_get(dev, NULL);
        if (IS_ERR(priv->ref_clk)) {
                dev_err(dev, "failed to find ref clock\n");
                return PTR_ERR(priv->ref_clk);
        }

        priv->por_rst = devm_reset_control_get(dev, NULL);
        if (IS_ERR(priv->por_rst)) {
                dev_err(dev, "failed to get poweron reset\n");
                return PTR_ERR(priv->por_rst);
        }

        priv->phy = devm_phy_create(dev, NULL, &histb_combphy_ops);
        if (IS_ERR(priv->phy)) {
                dev_err(dev, "failed to create combphy\n");
                return PTR_ERR(priv->phy);
        }

        dev_set_drvdata(dev, priv);
        phy_set_drvdata(priv->phy, priv);

        phy_provider = devm_of_phy_provider_register(dev, histb_combphy_xlate);
        return PTR_ERR_OR_ZERO(phy_provider);
}

static const struct of_device_id histb_combphy_of_match[] = {
        { .compatible = "hisilicon,hi3798cv200-combphy" },
        { },
};
MODULE_DEVICE_TABLE(of, histb_combphy_of_match);

static struct platform_driver histb_combphy_driver = {
        .probe  = histb_combphy_probe,
        .driver = {
                .name = "combphy",
                .of_match_table = histb_combphy_of_match,
        },
};
module_platform_driver(histb_combphy_driver);

MODULE_DESCRIPTION("HiSilicon STB COMBPHY driver");
MODULE_LICENSE("GPL v2");