1/*
  2 * Renesas R-Car Gen2 PHY driver
  3 *
  4 * Copyright (C) 2014 Renesas Solutions Corp.
  5 * Copyright (C) 2014 Cogent Embedded, Inc.
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11
 12#include <linux/clk.h>
 13#include <linux/delay.h>
 14#include <linux/io.h>
 15#include <linux/module.h>
 16#include <linux/of.h>
 17#include <linux/phy/phy.h>
 18#include <linux/platform_device.h>
 19#include <linux/spinlock.h>
 20#include <linux/atomic.h>
 21
 22#define USBHS_LPSTS			0x02
 23#define USBHS_UGCTRL			0x80
 24#define USBHS_UGCTRL2			0x84
 25#define USBHS_UGSTS			0x88	/* From technical update */
 26
 27/* Low Power Status register (LPSTS) */
 28#define USBHS_LPSTS_SUSPM		0x4000
 29
 30/* USB General control register (UGCTRL) */
 31#define USBHS_UGCTRL_CONNECT		0x00000004
 32#define USBHS_UGCTRL_PLLRESET		0x00000001
 33
 34/* USB General control register 2 (UGCTRL2) */
 35#define USBHS_UGCTRL2_USB2SEL		0x80000000
 36#define USBHS_UGCTRL2_USB2SEL_PCI	0x00000000
 37#define USBHS_UGCTRL2_USB2SEL_USB30	0x80000000
 38#define USBHS_UGCTRL2_USB0SEL		0x00000030
 39#define USBHS_UGCTRL2_USB0SEL_PCI	0x00000010
 40#define USBHS_UGCTRL2_USB0SEL_HS_USB	0x00000030
 41
 42/* USB General status register (UGSTS) */
 43#define USBHS_UGSTS_LOCK		0x00000100 /* From technical update */
 44
 45#define PHYS_PER_CHANNEL	2
 46
 47struct rcar_gen2_phy {
 48	struct phy *phy;
 49	struct rcar_gen2_channel *channel;
 50	int number;
 51	u32 select_value;
 52};
 53
 54struct rcar_gen2_channel {
 55	struct device_node *of_node;
 56	struct rcar_gen2_phy_driver *drv;
 57	struct rcar_gen2_phy phys[PHYS_PER_CHANNEL];
 58	int selected_phy;
 59	u32 select_mask;
 60};
 61
 62struct rcar_gen2_phy_driver {
 63	void __iomem *base;
 64	struct clk *clk;
 65	spinlock_t lock;
 66	int num_channels;
 67	struct rcar_gen2_channel *channels;
 68};
 69
 70static int rcar_gen2_phy_init(struct phy *p)
 71{
 72	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
 73	struct rcar_gen2_channel *channel = phy->channel;
 74	struct rcar_gen2_phy_driver *drv = channel->drv;
 75	unsigned long flags;
 76	u32 ugctrl2;
 77
 78	/*
 79	 * Try to acquire exclusive access to PHY.  The first driver calling
 80	 * phy_init()  on a given channel wins, and all attempts  to use another
 81	 * PHY on this channel will fail until phy_exit() is called by the first
 82	 * driver.   Achieving this with cmpxcgh() should be SMP-safe.
 83	 */
 84	if (cmpxchg(&channel->selected_phy, -1, phy->number) != -1)
 85		return -EBUSY;
 86
 87	clk_prepare_enable(drv->clk);
 88
 89	spin_lock_irqsave(&drv->lock, flags);
 90	ugctrl2 = readl(drv->base + USBHS_UGCTRL2);
 91	ugctrl2 &= ~channel->select_mask;
 92	ugctrl2 |= phy->select_value;
 93	writel(ugctrl2, drv->base + USBHS_UGCTRL2);
 94	spin_unlock_irqrestore(&drv->lock, flags);
 95	return 0;
 96}
 97
 98static int rcar_gen2_phy_exit(struct phy *p)
 99{
100	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
101	struct rcar_gen2_channel *channel = phy->channel;
102
103	clk_disable_unprepare(channel->drv->clk);
104
105	channel->selected_phy = -1;
106
107	return 0;
108}
109
110static int rcar_gen2_phy_power_on(struct phy *p)
111{
112	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
113	struct rcar_gen2_phy_driver *drv = phy->channel->drv;
114	void __iomem *base = drv->base;
115	unsigned long flags;
116	u32 value;
117	int err = 0, i;
118
119	/* Skip if it's not USBHS */
120	if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
121		return 0;
122
123	spin_lock_irqsave(&drv->lock, flags);
124
125	/* Power on USBHS PHY */
126	value = readl(base + USBHS_UGCTRL);
127	value &= ~USBHS_UGCTRL_PLLRESET;
128	writel(value, base + USBHS_UGCTRL);
129
130	value = readw(base + USBHS_LPSTS);
131	value |= USBHS_LPSTS_SUSPM;
132	writew(value, base + USBHS_LPSTS);
133
134	for (i = 0; i < 20; i++) {
135		value = readl(base + USBHS_UGSTS);
136		if ((value & USBHS_UGSTS_LOCK) == USBHS_UGSTS_LOCK) {
137			value = readl(base + USBHS_UGCTRL);
138			value |= USBHS_UGCTRL_CONNECT;
139			writel(value, base + USBHS_UGCTRL);
140			goto out;
141		}
142		udelay(1);
143	}
144
145	/* Timed out waiting for the PLL lock */
146	err = -ETIMEDOUT;
147
148out:
149	spin_unlock_irqrestore(&drv->lock, flags);
150
151	return err;
152}
153
154static int rcar_gen2_phy_power_off(struct phy *p)
155{
156	struct rcar_gen2_phy *phy = phy_get_drvdata(p);
157	struct rcar_gen2_phy_driver *drv = phy->channel->drv;
158	void __iomem *base = drv->base;
159	unsigned long flags;
160	u32 value;
161
162	/* Skip if it's not USBHS */
163	if (phy->select_value != USBHS_UGCTRL2_USB0SEL_HS_USB)
164		return 0;
165
166	spin_lock_irqsave(&drv->lock, flags);
167
168	/* Power off USBHS PHY */
169	value = readl(base + USBHS_UGCTRL);
170	value &= ~USBHS_UGCTRL_CONNECT;
171	writel(value, base + USBHS_UGCTRL);
172
173	value = readw(base + USBHS_LPSTS);
174	value &= ~USBHS_LPSTS_SUSPM;
175	writew(value, base + USBHS_LPSTS);
176
177	value = readl(base + USBHS_UGCTRL);
178	value |= USBHS_UGCTRL_PLLRESET;
179	writel(value, base + USBHS_UGCTRL);
180
181	spin_unlock_irqrestore(&drv->lock, flags);
182
183	return 0;
184}
185
186static const struct phy_ops rcar_gen2_phy_ops = {
187	.init		= rcar_gen2_phy_init,
188	.exit		= rcar_gen2_phy_exit,
189	.power_on	= rcar_gen2_phy_power_on,
190	.power_off	= rcar_gen2_phy_power_off,
191	.owner		= THIS_MODULE,
192};
193
194static const struct of_device_id rcar_gen2_phy_match_table[] = {
195	{ .compatible = "renesas,usb-phy-r8a7790" },
196	{ .compatible = "renesas,usb-phy-r8a7791" },
197	{ .compatible = "renesas,usb-phy-r8a7794" },
198	{ .compatible = "renesas,rcar-gen2-usb-phy" },
199	{ }
200};
201MODULE_DEVICE_TABLE(of, rcar_gen2_phy_match_table);
202
203static struct phy *rcar_gen2_phy_xlate(struct device *dev,
204				       struct of_phandle_args *args)
205{
206	struct rcar_gen2_phy_driver *drv;
207	struct device_node *np = args->np;
208	int i;
209
210	drv = dev_get_drvdata(dev);
211	if (!drv)
212		return ERR_PTR(-EINVAL);
213
214	for (i = 0; i < drv->num_channels; i++) {
215		if (np == drv->channels[i].of_node)
216			break;
217	}
218
219	if (i >= drv->num_channels || args->args[0] >= 2)
220		return ERR_PTR(-ENODEV);
221
222	return drv->channels[i].phys[args->args[0]].phy;
223}
224
225static const u32 select_mask[] = {
226	[0]	= USBHS_UGCTRL2_USB0SEL,
227	[2]	= USBHS_UGCTRL2_USB2SEL,
228};
229
230static const u32 select_value[][PHYS_PER_CHANNEL] = {
231	[0]	= { USBHS_UGCTRL2_USB0SEL_PCI, USBHS_UGCTRL2_USB0SEL_HS_USB },
232	[2]	= { USBHS_UGCTRL2_USB2SEL_PCI, USBHS_UGCTRL2_USB2SEL_USB30 },
233};
234
235static int rcar_gen2_phy_probe(struct platform_device *pdev)
236{
237	struct device *dev = &pdev->dev;
238	struct rcar_gen2_phy_driver *drv;
239	struct phy_provider *provider;
240	struct device_node *np;
241	struct resource *res;
242	void __iomem *base;
243	struct clk *clk;
244	int i = 0;
245
246	if (!dev->of_node) {
247		dev_err(dev,
248			"This driver is required to be instantiated from device tree\n");
249		return -EINVAL;
250	}
251
252	clk = devm_clk_get(dev, "usbhs");
253	if (IS_ERR(clk)) {
254		dev_err(dev, "Can't get USBHS clock\n");
255		return PTR_ERR(clk);
256	}
257
258	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
259	base = devm_ioremap_resource(dev, res);
260	if (IS_ERR(base))
261		return PTR_ERR(base);
262
263	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
264	if (!drv)
265		return -ENOMEM;
266
267	spin_lock_init(&drv->lock);
268
269	drv->clk = clk;
270	drv->base = base;
271
272	drv->num_channels = of_get_child_count(dev->of_node);
273	drv->channels = devm_kcalloc(dev, drv->num_channels,
274				     sizeof(struct rcar_gen2_channel),
275				     GFP_KERNEL);
276	if (!drv->channels)
277		return -ENOMEM;
278
279	for_each_child_of_node(dev->of_node, np) {
280		struct rcar_gen2_channel *channel = drv->channels + i;
281		u32 channel_num;
282		int error, n;
283
284		channel->of_node = np;
285		channel->drv = drv;
286		channel->selected_phy = -1;
287
288		error = of_property_read_u32(np, "reg", &channel_num);
289		if (error || channel_num > 2) {
290			dev_err(dev, "Invalid \"reg\" property\n");
291			return error;
292		}
293		channel->select_mask = select_mask[channel_num];
294
295		for (n = 0; n < PHYS_PER_CHANNEL; n++) {
296			struct rcar_gen2_phy *phy = &channel->phys[n];
297
298			phy->channel = channel;
299			phy->number = n;
300			phy->select_value = select_value[channel_num][n];
301
302			phy->phy = devm_phy_create(dev, NULL,
303						   &rcar_gen2_phy_ops);
304			if (IS_ERR(phy->phy)) {
305				dev_err(dev, "Failed to create PHY\n");
306				return PTR_ERR(phy->phy);
307			}
308			phy_set_drvdata(phy->phy, phy);
309		}
310
311		i++;
312	}
313
314	provider = devm_of_phy_provider_register(dev, rcar_gen2_phy_xlate);
315	if (IS_ERR(provider)) {
316		dev_err(dev, "Failed to register PHY provider\n");
317		return PTR_ERR(provider);
318	}
319
320	dev_set_drvdata(dev, drv);
321
322	return 0;
323}
324
325static struct platform_driver rcar_gen2_phy_driver = {
326	.driver = {
327		.name		= "phy_rcar_gen2",
328		.of_match_table	= rcar_gen2_phy_match_table,
329	},
330	.probe	= rcar_gen2_phy_probe,
331};
332
333module_platform_driver(rcar_gen2_phy_driver);
334
335MODULE_LICENSE("GPL v2");
336MODULE_DESCRIPTION("Renesas R-Car Gen2 PHY");
337MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>");