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