drivers/clk/renesas/rcar-usb2-clock-sel.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Renesas R-Car USB2.0 clock selector
   4  *
   5  * Copyright (C) 2017 Renesas Electronics Corp.
   6  *
   7  * Based on renesas-cpg-mssr.c
   8  *
   9  * Copyright (C) 2015 Glider bvba
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/clk-provider.h>
  14 #include <linux/device.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pm.h>
  20 #include <linux/pm_runtime.h>
  21 #include <linux/reset.h>
  22 #include <linux/slab.h>
  23
  24 #define USB20_CLKSET0           0x00
  25 #define CLKSET0_INTCLK_EN       BIT(11)
  26 #define CLKSET0_PRIVATE         BIT(0)
  27 #define CLKSET0_EXTAL_ONLY      (CLKSET0_INTCLK_EN | CLKSET0_PRIVATE)
  28
  29 static const struct clk_bulk_data rcar_usb2_clocks[] = {
  30         { .id = "ehci_ohci", },
  31         { .id = "hs-usb-if", },
  32 };
  33
  34 struct usb2_clock_sel_priv {
  35         void __iomem *base;
  36         struct clk_hw hw;
  37         struct clk_bulk_data clks[ARRAY_SIZE(rcar_usb2_clocks)];
  38         struct reset_control *rsts;
  39         bool extal;
  40         bool xtal;
  41 };
  42 #define to_priv(_hw)    container_of(_hw, struct usb2_clock_sel_priv, hw)
  43
  44 static void usb2_clock_sel_enable_extal_only(struct usb2_clock_sel_priv *priv)
  45 {
  46         u16 val = readw(priv->base + USB20_CLKSET0);
  47
  48         pr_debug("%s: enter %d %d %x\n", __func__,
  49                  priv->extal, priv->xtal, val);
  50
  51         if (priv->extal && !priv->xtal && val != CLKSET0_EXTAL_ONLY)
  52                 writew(CLKSET0_EXTAL_ONLY, priv->base + USB20_CLKSET0);
  53 }
  54
  55 static void usb2_clock_sel_disable_extal_only(struct usb2_clock_sel_priv *priv)
  56 {
  57         if (priv->extal && !priv->xtal)
  58                 writew(CLKSET0_PRIVATE, priv->base + USB20_CLKSET0);
  59 }
  60
  61 static int usb2_clock_sel_enable(struct clk_hw *hw)
  62 {
  63         struct usb2_clock_sel_priv *priv = to_priv(hw);
  64         int ret;
  65
  66         ret = reset_control_deassert(priv->rsts);
  67         if (ret)
  68                 return ret;
  69
  70         ret = clk_bulk_prepare_enable(ARRAY_SIZE(priv->clks), priv->clks);
  71         if (ret) {
  72                 reset_control_assert(priv->rsts);
  73                 return ret;
  74         }
  75
  76         usb2_clock_sel_enable_extal_only(priv);
  77
  78         return 0;
  79 }
  80
  81 static void usb2_clock_sel_disable(struct clk_hw *hw)
  82 {
  83         struct usb2_clock_sel_priv *priv = to_priv(hw);
  84
  85         usb2_clock_sel_disable_extal_only(priv);
  86
  87         clk_bulk_disable_unprepare(ARRAY_SIZE(priv->clks), priv->clks);
  88         reset_control_assert(priv->rsts);
  89 }
  90
  91 /*
  92  * This module seems a mux, but this driver assumes a gate because
  93  * ehci/ohci platform drivers don't support clk_set_parent() for now.
  94  * If this driver acts as a gate, ehci/ohci-platform drivers don't need
  95  * any modification.
  96  */
  97 static const struct clk_ops usb2_clock_sel_clock_ops = {
  98         .enable = usb2_clock_sel_enable,
  99         .disable = usb2_clock_sel_disable,
 100 };
 101
 102 static const struct of_device_id rcar_usb2_clock_sel_match[] = {
 103         { .compatible = "renesas,rcar-gen3-usb2-clock-sel" },
 104         { }
 105 };
 106
 107 static int rcar_usb2_clock_sel_suspend(struct device *dev)
 108 {
 109         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
 110
 111         usb2_clock_sel_disable_extal_only(priv);
 112         pm_runtime_put(dev);
 113
 114         return 0;
 115 }
 116
 117 static int rcar_usb2_clock_sel_resume(struct device *dev)
 118 {
 119         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
 120
 121         pm_runtime_get_sync(dev);
 122         usb2_clock_sel_enable_extal_only(priv);
 123
 124         return 0;
 125 }
 126
 127 static void rcar_usb2_clock_sel_remove(struct platform_device *pdev)
 128 {
 129         struct device *dev = &pdev->dev;
 130
 131         of_clk_del_provider(dev->of_node);
 132         pm_runtime_put(dev);
 133         pm_runtime_disable(dev);
 134 }
 135
 136 static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
 137 {
 138         struct device *dev = &pdev->dev;
 139         struct device_node *np = dev->of_node;
 140         struct usb2_clock_sel_priv *priv;
 141         struct clk *clk;
 142         struct clk_init_data init = {};
 143         int ret;
 144
 145         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 146         if (!priv)
 147                 return -ENOMEM;
 148
 149         priv->base = devm_platform_ioremap_resource(pdev, 0);
 150         if (IS_ERR(priv->base))
 151                 return PTR_ERR(priv->base);
 152
 153         memcpy(priv->clks, rcar_usb2_clocks, sizeof(priv->clks));
 154         ret = devm_clk_bulk_get(dev, ARRAY_SIZE(priv->clks), priv->clks);
 155         if (ret < 0)
 156                 return ret;
 157
 158         priv->rsts = devm_reset_control_array_get_shared(dev);
 159         if (IS_ERR(priv->rsts))
 160                 return PTR_ERR(priv->rsts);
 161
 162         clk = devm_clk_get(dev, "usb_extal");
 163         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 164                 priv->extal = !!clk_get_rate(clk);
 165                 clk_disable_unprepare(clk);
 166         }
 167         clk = devm_clk_get(dev, "usb_xtal");
 168         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 169                 priv->xtal = !!clk_get_rate(clk);
 170                 clk_disable_unprepare(clk);
 171         }
 172
 173         if (!priv->extal && !priv->xtal) {
 174                 dev_err(dev, "This driver needs usb_extal or usb_xtal\n");
 175                 return -ENOENT;
 176         }
 177
 178         pm_runtime_enable(dev);
 179         pm_runtime_get_sync(dev);
 180         platform_set_drvdata(pdev, priv);
 181         dev_set_drvdata(dev, priv);
 182
 183         init.name = "rcar_usb2_clock_sel";
 184         init.ops = &usb2_clock_sel_clock_ops;
 185         priv->hw.init = &init;
 186
 187         ret = devm_clk_hw_register(dev, &priv->hw);
 188         if (ret)
 189                 goto pm_put;
 190
 191         ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 192         if (ret)
 193                 goto pm_put;
 194
 195         return 0;
 196
 197 pm_put:
 198         pm_runtime_put(dev);
 199         pm_runtime_disable(dev);
 200         return ret;
 201 }
 202
 203 static const struct dev_pm_ops rcar_usb2_clock_sel_pm_ops = {
 204         .suspend        = rcar_usb2_clock_sel_suspend,
 205         .resume         = rcar_usb2_clock_sel_resume,
 206 };
 207
 208 static struct platform_driver rcar_usb2_clock_sel_driver = {
 209         .driver         = {
 210                 .name   = "rcar-usb2-clock-sel",
 211                 .of_match_table = rcar_usb2_clock_sel_match,
 212                 .pm     = &rcar_usb2_clock_sel_pm_ops,
 213         },
 214         .probe          = rcar_usb2_clock_sel_probe,
 215         .remove         = rcar_usb2_clock_sel_remove,
 216 };
 217 builtin_platform_driver(rcar_usb2_clock_sel_driver);
 218
 219 MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver");
 220 MODULE_LICENSE("GPL v2");