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

   1 /*
   2  * Renesas R-Car USB2.0 clock selector
   3  *
   4  * Copyright (C) 2017 Renesas Electronics Corp.
   5  *
   6  * Based on renesas-cpg-mssr.c
   7  *
   8  * Copyright (C) 2015 Glider bvba
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; version 2 of the License.
  13  */
  14
  15 #include <linux/clk.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/device.h>
  18 #include <linux/init.h>
  19 #include <linux/module.h>
  20 #include <linux/of_device.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/pm.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/slab.h>
  25
  26 #define USB20_CLKSET0           0x00
  27 #define CLKSET0_INTCLK_EN       BIT(11)
  28 #define CLKSET0_PRIVATE         BIT(0)
  29 #define CLKSET0_EXTAL_ONLY      (CLKSET0_INTCLK_EN | CLKSET0_PRIVATE)
  30
  31 struct usb2_clock_sel_priv {
  32         void __iomem *base;
  33         struct clk_hw hw;
  34         bool extal;
  35         bool xtal;
  36 };
  37 #define to_priv(_hw)    container_of(_hw, struct usb2_clock_sel_priv, hw)
  38
  39 static void usb2_clock_sel_enable_extal_only(struct usb2_clock_sel_priv *priv)
  40 {
  41         u16 val = readw(priv->base + USB20_CLKSET0);
  42
  43         pr_debug("%s: enter %d %d %x\n", __func__,
  44                  priv->extal, priv->xtal, val);
  45
  46         if (priv->extal && !priv->xtal && val != CLKSET0_EXTAL_ONLY)
  47                 writew(CLKSET0_EXTAL_ONLY, priv->base + USB20_CLKSET0);
  48 }
  49
  50 static void usb2_clock_sel_disable_extal_only(struct usb2_clock_sel_priv *priv)
  51 {
  52         if (priv->extal && !priv->xtal)
  53                 writew(CLKSET0_PRIVATE, priv->base + USB20_CLKSET0);
  54 }
  55
  56 static int usb2_clock_sel_enable(struct clk_hw *hw)
  57 {
  58         usb2_clock_sel_enable_extal_only(to_priv(hw));
  59
  60         return 0;
  61 }
  62
  63 static void usb2_clock_sel_disable(struct clk_hw *hw)
  64 {
  65         usb2_clock_sel_disable_extal_only(to_priv(hw));
  66 }
  67
  68 /*
  69  * This module seems a mux, but this driver assumes a gate because
  70  * ehci/ohci platform drivers don't support clk_set_parent() for now.
  71  * If this driver acts as a gate, ehci/ohci-platform drivers don't need
  72  * any modification.
  73  */
  74 static const struct clk_ops usb2_clock_sel_clock_ops = {
  75         .enable = usb2_clock_sel_enable,
  76         .disable = usb2_clock_sel_disable,
  77 };
  78
  79 static const struct of_device_id rcar_usb2_clock_sel_match[] = {
  80         { .compatible = "renesas,rcar-gen3-usb2-clock-sel" },
  81         { }
  82 };
  83
  84 static int rcar_usb2_clock_sel_suspend(struct device *dev)
  85 {
  86         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
  87
  88         usb2_clock_sel_disable_extal_only(priv);
  89         pm_runtime_put(dev);
  90
  91         return 0;
  92 }
  93
  94 static int rcar_usb2_clock_sel_resume(struct device *dev)
  95 {
  96         struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
  97
  98         pm_runtime_get_sync(dev);
  99         usb2_clock_sel_enable_extal_only(priv);
 100
 101         return 0;
 102 }
 103
 104 static int rcar_usb2_clock_sel_remove(struct platform_device *pdev)
 105 {
 106         struct device *dev = &pdev->dev;
 107         struct usb2_clock_sel_priv *priv = platform_get_drvdata(pdev);
 108
 109         of_clk_del_provider(dev->of_node);
 110         clk_hw_unregister(&priv->hw);
 111         pm_runtime_put(dev);
 112         pm_runtime_disable(dev);
 113
 114         return 0;
 115 }
 116
 117 static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
 118 {
 119         struct device *dev = &pdev->dev;
 120         struct device_node *np = dev->of_node;
 121         struct usb2_clock_sel_priv *priv;
 122         struct resource *res;
 123         struct clk *clk;
 124         struct clk_init_data init;
 125
 126         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 127         if (!priv)
 128                 return -ENOMEM;
 129
 130         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 131         priv->base = devm_ioremap_resource(dev, res);
 132         if (IS_ERR(priv->base))
 133                 return PTR_ERR(priv->base);
 134
 135         pm_runtime_enable(dev);
 136         pm_runtime_get_sync(dev);
 137
 138         clk = devm_clk_get(dev, "usb_extal");
 139         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 140                 priv->extal = !!clk_get_rate(clk);
 141                 clk_disable_unprepare(clk);
 142         }
 143         clk = devm_clk_get(dev, "usb_xtal");
 144         if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
 145                 priv->xtal = !!clk_get_rate(clk);
 146                 clk_disable_unprepare(clk);
 147         }
 148
 149         if (!priv->extal && !priv->xtal) {
 150                 dev_err(dev, "This driver needs usb_extal or usb_xtal\n");
 151                 return -ENOENT;
 152         }
 153
 154         platform_set_drvdata(pdev, priv);
 155         dev_set_drvdata(dev, priv);
 156
 157         init.name = "rcar_usb2_clock_sel";
 158         init.ops = &usb2_clock_sel_clock_ops;
 159         init.flags = 0;
 160         init.parent_names = NULL;
 161         init.num_parents = 0;
 162         priv->hw.init = &init;
 163
 164         clk = clk_register(NULL, &priv->hw);
 165         if (IS_ERR(clk))
 166                 return PTR_ERR(clk);
 167
 168         return of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 169 }
 170
 171 static const struct dev_pm_ops rcar_usb2_clock_sel_pm_ops = {
 172         .suspend        = rcar_usb2_clock_sel_suspend,
 173         .resume         = rcar_usb2_clock_sel_resume,
 174 };
 175
 176 static struct platform_driver rcar_usb2_clock_sel_driver = {
 177         .driver         = {
 178                 .name   = "rcar-usb2-clock-sel",
 179                 .of_match_table = rcar_usb2_clock_sel_match,
 180                 .pm     = &rcar_usb2_clock_sel_pm_ops,
 181         },
 182         .probe          = rcar_usb2_clock_sel_probe,
 183         .remove         = rcar_usb2_clock_sel_remove,
 184 };
 185 builtin_platform_driver(rcar_usb2_clock_sel_driver);
 186
 187 MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver");
 188 MODULE_LICENSE("GPL v2");