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"); 185