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
usb2_clock_sel_enable_extal_only(struct usb2_clock_sel_priv * priv)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
usb2_clock_sel_disable_extal_only(struct usb2_clock_sel_priv * priv)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
usb2_clock_sel_enable(struct clk_hw * hw)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
usb2_clock_sel_disable(struct clk_hw * hw)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
rcar_usb2_clock_sel_suspend(struct device * dev)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
rcar_usb2_clock_sel_resume(struct device * dev)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
rcar_usb2_clock_sel_remove(struct platform_device * pdev)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
rcar_usb2_clock_sel_probe(struct platform_device * pdev)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");
221