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/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
 29static const struct clk_bulk_data rcar_usb2_clocks[] = {
 30	{ .id = "ehci_ohci", },
 31	{ .id = "hs-usb-if", },
 32};
 33
 34struct 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
 44static 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
 55static 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
 61static 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
 81static 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 */
 97static const struct clk_ops usb2_clock_sel_clock_ops = {
 98	.enable = usb2_clock_sel_enable,
 99	.disable = usb2_clock_sel_disable,
100};
101
102static const struct of_device_id rcar_usb2_clock_sel_match[] = {
103	{ .compatible = "renesas,rcar-gen3-usb2-clock-sel" },
104	{ }
105};
106
107static 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
117static 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
127static 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
136static 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
197pm_put:
198	pm_runtime_put(dev);
199	pm_runtime_disable(dev);
200	return ret;
201}
202
203static 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
208static 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};
217builtin_platform_driver(rcar_usb2_clock_sel_driver);
218
219MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver");
220MODULE_LICENSE("GPL v2");