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/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 struct usb2_clock_sel_priv {
  30         void __iomem *base;
  31         struct clk_hw hw;
  32         bool extal;
  33         bool xtal;
  34 };
  35 #define to_priv(_hw)    container_of(_hw, struct usb2_clock_sel_priv, hw)
  36
  37 static void usb2_clock_sel_enable_extal_only(struct usb2_clock_sel_priv *priv)
  38 {
  39         u16 val = readw(priv->base + USB20_CLKSET0);
  40
  41         pr_debug("%s: enter %d %d %x\n", __func__,
  42                  priv->extal, priv->xtal, val);
  43
  44         if (priv->extal && !priv->xtal && val != CLKSET0_EXTAL_ONLY)
  45                 writew(CLKSET0_EXTAL_ONLY, priv->base + USB20_CLKSET0);
  46 }
  47
  48 static void usb2_clock_sel_disable_extal_only(struct usb2_clock_sel_priv *priv)
  49 {
  50         if (priv->extal && !priv->xtal)
  51                 writew(CLKSET0_PRIVATE, priv->base + USB20_CLKSET0);
  52 }
  53
  54 static int usb2_clock_sel_enable(struct clk_hw *hw)
  55 {
  56         usb2_clock_sel_enable_extal_only(to_priv(hw));
  57
  58         return 0;
  59 }
  60
  61 static void usb2_clock_sel_disable(struct clk_hw *hw)
  62 {
  63         usb2_clock_sel_disable_extal_only(to_priv(hw));
  64 }
  65
  66 /*
  67  * This module seems a mux, but this driver assumes a gate because
  68  * ehci/ohci platform drivers don't support clk_set_parent() for now.
  69  * If this driver acts as a gate, ehci/ohci-platform drivers don't need
  70  * any modification.
  71  */
  72 static const struct clk_ops usb2_clock_sel_clock_ops = {
  73         .enable = usb2_clock_sel_enable,
  74         .disable = usb2_clock_sel_disable,
  75 };
  76
  77 static const struct of_device_id rcar_usb2_clock_sel_match[] = {
  78         { .compatible = "renesas,rcar-gen3-usb2-clock-sel" },
  79         { }
  80 };
  81
  82 static int rcar_usb2_clock_sel_suspend(struct device *dev)
  83 {
  84         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
  85
  86         usb2_clock_sel_disable_extal_only(priv);
  87         pm_runtime_put(dev);
  88
  89         return 0;
  90 }
  91
  92 static int rcar_usb2_clock_sel_resume(struct device *dev)
  93 {
  94         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
  95
  96         pm_runtime_get_sync(dev);
  97         usb2_clock_sel_enable_extal_only(priv);
  98
  99         return 0;
 100 }
 101
 102 static int rcar_usb2_clock_sel_remove(struct platform_device *pdev)
 103 {
 104         struct device *dev = &pdev->dev;
 105         struct usb2_clock_sel_priv *priv = platform_get_drvdata(pdev);
 106
 107         of_clk_del_provider(dev->of_node);
 108         clk_hw_unregister(&priv->hw);
 109         pm_runtime_put(dev);
 110         pm_runtime_disable(dev);
 111
 112         return 0;
 113 }
 114
 115 static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
 116 {
 117         struct device *dev = &pdev->dev;
 118         struct device_node *np = dev->of_node;
 119         struct usb2_clock_sel_priv *priv;
 120         struct clk *clk;
 121         struct clk_init_data init;
 122
 123         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 124         if (!priv)
 125                 return -ENOMEM;
 126
 127         priv->base = devm_platform_ioremap_resource(pdev, 0);
 128         if (IS_ERR(priv->base))
 129                 return PTR_ERR(priv->base);
 130
 131         pm_runtime_enable(dev);
 132         pm_runtime_get_sync(dev);
 133
 134         clk = devm_clk_get(dev, "usb_extal");
 135         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 136                 priv->extal = !!clk_get_rate(clk);
 137                 clk_disable_unprepare(clk);
 138         }
 139         clk = devm_clk_get(dev, "usb_xtal");
 140         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 141                 priv->xtal = !!clk_get_rate(clk);
 142                 clk_disable_unprepare(clk);
 143         }
 144
 145         if (!priv->extal && !priv->xtal) {
 146                 dev_err(dev, "This driver needs usb_extal or usb_xtal\n");
 147                 return -ENOENT;
 148         }
 149
 150         platform_set_drvdata(pdev, priv);
 151         dev_set_drvdata(dev, priv);
 152
 153         init.name = "rcar_usb2_clock_sel";
 154         init.ops = &usb2_clock_sel_clock_ops;
 155         init.flags = 0;
 156         init.parent_names = NULL;
 157         init.num_parents = 0;
 158         priv->hw.init = &init;
 159
 160         clk = clk_register(NULL, &priv->hw);
 161         if (IS_ERR(clk))
 162                 return PTR_ERR(clk);
 163
 164         return of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 165 }
 166
 167 static const struct dev_pm_ops rcar_usb2_clock_sel_pm_ops = {
 168         .suspend        = rcar_usb2_clock_sel_suspend,
 169         .resume         = rcar_usb2_clock_sel_resume,
 170 };
 171
 172 static struct platform_driver rcar_usb2_clock_sel_driver = {
 173         .driver         = {
 174                 .name   = "rcar-usb2-clock-sel",
 175                 .of_match_table = rcar_usb2_clock_sel_match,
 176                 .pm     = &rcar_usb2_clock_sel_pm_ops,
 177         },
 178         .probe          = rcar_usb2_clock_sel_probe,
 179         .remove         = rcar_usb2_clock_sel_remove,
 180 };
 181 builtin_platform_driver(rcar_usb2_clock_sel_driver);
 182
 183 MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver");
 184 MODULE_LICENSE("GPL v2");