linux/drivers/reset/reset-rzg2l-usbphy-ctrl.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Renesas RZ/G2L USBPHY control driver
   4 *
   5 * Copyright (C) 2021 Renesas Electronics Corporation
   6 */
   7
   8#include <linux/io.h>
   9#include <linux/module.h>
  10#include <linux/of.h>
  11#include <linux/platform_device.h>
  12#include <linux/pm_runtime.h>
  13#include <linux/reset.h>
  14#include <linux/reset-controller.h>
  15
  16#define RESET                   0x000
  17
  18#define RESET_SEL_PLLRESET      BIT(12)
  19#define RESET_PLLRESET          BIT(8)
  20
  21#define RESET_SEL_P2RESET       BIT(5)
  22#define RESET_SEL_P1RESET       BIT(4)
  23#define RESET_PHYRST_2          BIT(1)
  24#define RESET_PHYRST_1          BIT(0)
  25
  26#define PHY_RESET_PORT2         (RESET_SEL_P2RESET | RESET_PHYRST_2)
  27#define PHY_RESET_PORT1         (RESET_SEL_P1RESET | RESET_PHYRST_1)
  28
  29#define NUM_PORTS               2
  30
  31struct rzg2l_usbphy_ctrl_priv {
  32        struct reset_controller_dev rcdev;
  33        struct reset_control *rstc;
  34        void __iomem *base;
  35
  36        spinlock_t lock;
  37};
  38
  39#define rcdev_to_priv(x)        container_of(x, struct rzg2l_usbphy_ctrl_priv, rcdev)
  40
  41static int rzg2l_usbphy_ctrl_assert(struct reset_controller_dev *rcdev,
  42                                    unsigned long id)
  43{
  44        struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
  45        u32 port_mask = PHY_RESET_PORT1 | PHY_RESET_PORT2;
  46        void __iomem *base = priv->base;
  47        unsigned long flags;
  48        u32 val;
  49
  50        spin_lock_irqsave(&priv->lock, flags);
  51        val = readl(base + RESET);
  52        val |= id ? PHY_RESET_PORT2 : PHY_RESET_PORT1;
  53        if (port_mask == (val & port_mask))
  54                val |= RESET_PLLRESET;
  55        writel(val, base + RESET);
  56        spin_unlock_irqrestore(&priv->lock, flags);
  57
  58        return 0;
  59}
  60
  61static int rzg2l_usbphy_ctrl_deassert(struct reset_controller_dev *rcdev,
  62                                      unsigned long id)
  63{
  64        struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
  65        void __iomem *base = priv->base;
  66        unsigned long flags;
  67        u32 val;
  68
  69        spin_lock_irqsave(&priv->lock, flags);
  70        val = readl(base + RESET);
  71
  72        val |= RESET_SEL_PLLRESET;
  73        val &= ~(RESET_PLLRESET | (id ? PHY_RESET_PORT2 : PHY_RESET_PORT1));
  74        writel(val, base + RESET);
  75        spin_unlock_irqrestore(&priv->lock, flags);
  76
  77        return 0;
  78}
  79
  80static int rzg2l_usbphy_ctrl_status(struct reset_controller_dev *rcdev,
  81                                    unsigned long id)
  82{
  83        struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
  84        u32 port_mask;
  85
  86        port_mask = id ? PHY_RESET_PORT2 : PHY_RESET_PORT1;
  87
  88        return !!(readl(priv->base + RESET) & port_mask);
  89}
  90
  91static const struct of_device_id rzg2l_usbphy_ctrl_match_table[] = {
  92        { .compatible = "renesas,rzg2l-usbphy-ctrl" },
  93        { /* Sentinel */ }
  94};
  95MODULE_DEVICE_TABLE(of, rzg2l_usbphy_ctrl_match_table);
  96
  97static const struct reset_control_ops rzg2l_usbphy_ctrl_reset_ops = {
  98        .assert = rzg2l_usbphy_ctrl_assert,
  99        .deassert = rzg2l_usbphy_ctrl_deassert,
 100        .status = rzg2l_usbphy_ctrl_status,
 101};
 102
 103static int rzg2l_usbphy_ctrl_probe(struct platform_device *pdev)
 104{
 105        struct device *dev = &pdev->dev;
 106        struct rzg2l_usbphy_ctrl_priv *priv;
 107        unsigned long flags;
 108        int error;
 109        u32 val;
 110
 111        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 112        if (!priv)
 113                return -ENOMEM;
 114
 115        priv->base = devm_platform_ioremap_resource(pdev, 0);
 116        if (IS_ERR(priv->base))
 117                return PTR_ERR(priv->base);
 118
 119        priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 120        if (IS_ERR(priv->rstc))
 121                return dev_err_probe(dev, PTR_ERR(priv->rstc),
 122                                     "failed to get reset\n");
 123
 124        reset_control_deassert(priv->rstc);
 125
 126        priv->rcdev.ops = &rzg2l_usbphy_ctrl_reset_ops;
 127        priv->rcdev.of_reset_n_cells = 1;
 128        priv->rcdev.nr_resets = NUM_PORTS;
 129        priv->rcdev.of_node = dev->of_node;
 130        priv->rcdev.dev = dev;
 131
 132        error = devm_reset_controller_register(dev, &priv->rcdev);
 133        if (error)
 134                return error;
 135
 136        spin_lock_init(&priv->lock);
 137        dev_set_drvdata(dev, priv);
 138
 139        pm_runtime_enable(&pdev->dev);
 140        pm_runtime_resume_and_get(&pdev->dev);
 141
 142        /* put pll and phy into reset state */
 143        spin_lock_irqsave(&priv->lock, flags);
 144        val = readl(priv->base + RESET);
 145        val |= RESET_SEL_PLLRESET | RESET_PLLRESET | PHY_RESET_PORT2 | PHY_RESET_PORT1;
 146        writel(val, priv->base + RESET);
 147        spin_unlock_irqrestore(&priv->lock, flags);
 148
 149        return 0;
 150}
 151
 152static int rzg2l_usbphy_ctrl_remove(struct platform_device *pdev)
 153{
 154        struct rzg2l_usbphy_ctrl_priv *priv = dev_get_drvdata(&pdev->dev);
 155
 156        pm_runtime_put(&pdev->dev);
 157        pm_runtime_disable(&pdev->dev);
 158        reset_control_assert(priv->rstc);
 159
 160        return 0;
 161}
 162
 163static struct platform_driver rzg2l_usbphy_ctrl_driver = {
 164        .driver = {
 165                .name           = "rzg2l_usbphy_ctrl",
 166                .of_match_table = rzg2l_usbphy_ctrl_match_table,
 167        },
 168        .probe  = rzg2l_usbphy_ctrl_probe,
 169        .remove = rzg2l_usbphy_ctrl_remove,
 170};
 171module_platform_driver(rzg2l_usbphy_ctrl_driver);
 172
 173MODULE_LICENSE("GPL v2");
 174MODULE_DESCRIPTION("Renesas RZ/G2L USBPHY Control");
 175MODULE_AUTHOR("biju.das.jz@bp.renesas.com>");
 176