1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * NOP USB transceiver for all USB transceiver which are either built-in
4 * into USB IP or which are mostly autonomous.
5 *
6 * Copyright (C) 2009 Texas Instruments Inc
7 * Author: Ajay Kumar Gupta <ajay.gupta@ti.com>
8 *
9 * Current status:
10 *	This provides a "nop" transceiver for PHYs which are
11 *	autonomous such as isp1504, isp1707, etc.
12 */
13
14#include <linux/module.h>
15#include <linux/platform_device.h>
16#include <linux/dma-mapping.h>
17#include <linux/usb/gadget.h>
18#include <linux/usb/otg.h>
19#include <linux/usb/usb_phy_generic.h>
20#include <linux/slab.h>
21#include <linux/clk.h>
22#include <linux/regulator/consumer.h>
23#include <linux/of.h>
24#include <linux/gpio/consumer.h>
25#include <linux/delay.h>
26
27#include "phy-generic.h"
28
29#define VBUS_IRQ_FLAGS \
30	(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | \
31		IRQF_ONESHOT)
32
33struct platform_device *usb_phy_generic_register(void)
34{
35	return platform_device_register_simple("usb_phy_generic",
36			PLATFORM_DEVID_AUTO, NULL, 0);
37}
38EXPORT_SYMBOL_GPL(usb_phy_generic_register);
39
40void usb_phy_generic_unregister(struct platform_device *pdev)
41{
42	platform_device_unregister(pdev);
43}
44EXPORT_SYMBOL_GPL(usb_phy_generic_unregister);
45
46static int nop_set_suspend(struct usb_phy *x, int suspend)
47{
48	struct usb_phy_generic *nop = dev_get_drvdata(x->dev);
49
50	if (!IS_ERR(nop->clk)) {
51		if (suspend)
52			clk_disable_unprepare(nop->clk);
53		else
54			clk_prepare_enable(nop->clk);
55	}
56
57	return 0;
58}
59
60static void nop_reset(struct usb_phy_generic *nop)
61{
62	if (!nop->gpiod_reset)
63		return;
64
65	gpiod_set_value_cansleep(nop->gpiod_reset, 1);
66	usleep_range(10000, 20000);
67	gpiod_set_value_cansleep(nop->gpiod_reset, 0);
68}
69
70/* interface to regulator framework */
71static void nop_set_vbus_draw(struct usb_phy_generic *nop, unsigned mA)
72{
73	struct regulator *vbus_draw = nop->vbus_draw;
74	int enabled;
75	int ret;
76
77	if (!vbus_draw)
78		return;
79
80	enabled = nop->vbus_draw_enabled;
81	if (mA) {
82		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
83		if (!enabled) {
84			ret = regulator_enable(vbus_draw);
85			if (ret < 0)
86				return;
87			nop->vbus_draw_enabled = 1;
88		}
89	} else {
90		if (enabled) {
91			ret = regulator_disable(vbus_draw);
92			if (ret < 0)
93				return;
94			nop->vbus_draw_enabled = 0;
95		}
96	}
97	nop->mA = mA;
98}
99
100
101static irqreturn_t nop_gpio_vbus_thread(int irq, void *data)
102{
103	struct usb_phy_generic *nop = data;
104	struct usb_otg *otg = nop->phy.otg;
105	int vbus, status;
106
107	vbus = gpiod_get_value(nop->gpiod_vbus);
108	if ((vbus ^ nop->vbus) == 0)
109		return IRQ_HANDLED;
110	nop->vbus = vbus;
111
112	if (vbus) {
113		status = USB_EVENT_VBUS;
114		otg->state = OTG_STATE_B_PERIPHERAL;
115		nop->phy.last_event = status;
116
117		/* drawing a "unit load" is *always* OK, except for OTG */
118		nop_set_vbus_draw(nop, 100);
119
120		atomic_notifier_call_chain(&nop->phy.notifier, status,
121					   otg->gadget);
122	} else {
123		nop_set_vbus_draw(nop, 0);
124
125		status = USB_EVENT_NONE;
126		otg->state = OTG_STATE_B_IDLE;
127		nop->phy.last_event = status;
128
129		atomic_notifier_call_chain(&nop->phy.notifier, status,
130					   otg->gadget);
131	}
132	return IRQ_HANDLED;
133}
134
135int usb_gen_phy_init(struct usb_phy *phy)
136{
137	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
138	int ret;
139
140	if (!IS_ERR(nop->vcc)) {
141		if (regulator_enable(nop->vcc))
142			dev_err(phy->dev, "Failed to enable power\n");
143	}
144
145	if (!IS_ERR(nop->clk)) {
146		ret = clk_prepare_enable(nop->clk);
147		if (ret)
148			return ret;
149	}
150
151	nop_reset(nop);
152
153	return 0;
154}
155EXPORT_SYMBOL_GPL(usb_gen_phy_init);
156
157void usb_gen_phy_shutdown(struct usb_phy *phy)
158{
159	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
160
161	gpiod_set_value_cansleep(nop->gpiod_reset, 1);
162
163	if (!IS_ERR(nop->clk))
164		clk_disable_unprepare(nop->clk);
165
166	if (!IS_ERR(nop->vcc)) {
167		if (regulator_disable(nop->vcc))
168			dev_err(phy->dev, "Failed to disable power\n");
169	}
170}
171EXPORT_SYMBOL_GPL(usb_gen_phy_shutdown);
172
173static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
174{
175	if (!otg)
176		return -ENODEV;
177
178	if (!gadget) {
179		otg->gadget = NULL;
180		return -ENODEV;
181	}
182
183	otg->gadget = gadget;
184	if (otg->state == OTG_STATE_B_PERIPHERAL)
185		atomic_notifier_call_chain(&otg->usb_phy->notifier,
186					   USB_EVENT_VBUS, otg->gadget);
187	else
188		otg->state = OTG_STATE_B_IDLE;
189	return 0;
190}
191
192static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
193{
194	if (!otg)
195		return -ENODEV;
196
197	if (!host) {
198		otg->host = NULL;
199		return -ENODEV;
200	}
201
202	otg->host = host;
203	return 0;
204}
205
206int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop)
207{
208	enum usb_phy_type type = USB_PHY_TYPE_USB2;
209	int err = 0;
210
211	u32 clk_rate = 0;
212	bool needs_vcc = false, needs_clk = false;
213
214	if (dev->of_node) {
215		struct device_node *node = dev->of_node;
216
217		if (of_property_read_u32(node, "clock-frequency", &clk_rate))
218			clk_rate = 0;
219
220		needs_vcc = of_property_read_bool(node, "vcc-supply");
221		needs_clk = of_property_read_bool(node, "clocks");
222	}
223	nop->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
224						   GPIOD_ASIS);
225	err = PTR_ERR_OR_ZERO(nop->gpiod_reset);
226	if (!err) {
227		nop->gpiod_vbus = devm_gpiod_get_optional(dev,
228						 "vbus-detect",
229						 GPIOD_ASIS);
230		err = PTR_ERR_OR_ZERO(nop->gpiod_vbus);
231	}
232
233	if (err == -EPROBE_DEFER)
234		return -EPROBE_DEFER;
235	if (err) {
236		dev_err(dev, "Error requesting RESET or VBUS GPIO\n");
237		return err;
238	}
239	if (nop->gpiod_reset)
240		gpiod_direction_output(nop->gpiod_reset, 1);
241
242	nop->phy.otg = devm_kzalloc(dev, sizeof(*nop->phy.otg),
243			GFP_KERNEL);
244	if (!nop->phy.otg)
245		return -ENOMEM;
246
247	nop->clk = devm_clk_get(dev, "main_clk");
248	if (IS_ERR(nop->clk)) {
249		dev_dbg(dev, "Can't get phy clock: %ld\n",
250					PTR_ERR(nop->clk));
251		if (needs_clk)
252			return PTR_ERR(nop->clk);
253	}
254
255	if (!IS_ERR(nop->clk) && clk_rate) {
256		err = clk_set_rate(nop->clk, clk_rate);
257		if (err) {
258			dev_err(dev, "Error setting clock rate\n");
259			return err;
260		}
261	}
262
263	nop->vcc = devm_regulator_get(dev, "vcc");
264	if (IS_ERR(nop->vcc)) {
265		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
266					PTR_ERR(nop->vcc));
267		if (needs_vcc)
268			return -EPROBE_DEFER;
269	}
270
271	nop->vbus_draw = devm_regulator_get_exclusive(dev, "vbus");
272	if (PTR_ERR(nop->vbus_draw) == -ENODEV)
273		nop->vbus_draw = NULL;
274	if (IS_ERR(nop->vbus_draw))
275		return dev_err_probe(dev, PTR_ERR(nop->vbus_draw),
276				     "could not get vbus regulator\n");
277
278	nop->dev		= dev;
279	nop->phy.dev		= nop->dev;
280	nop->phy.label		= "nop-xceiv";
281	nop->phy.set_suspend	= nop_set_suspend;
282	nop->phy.type		= type;
283
284	nop->phy.otg->state		= OTG_STATE_UNDEFINED;
285	nop->phy.otg->usb_phy		= &nop->phy;
286	nop->phy.otg->set_host		= nop_set_host;
287	nop->phy.otg->set_peripheral	= nop_set_peripheral;
288
289	return 0;
290}
291EXPORT_SYMBOL_GPL(usb_phy_gen_create_phy);
292
293static int usb_phy_generic_probe(struct platform_device *pdev)
294{
295	struct device *dev = &pdev->dev;
296	struct usb_phy_generic	*nop;
297	int err;
298
299	nop = devm_kzalloc(dev, sizeof(*nop), GFP_KERNEL);
300	if (!nop)
301		return -ENOMEM;
302
303	err = usb_phy_gen_create_phy(dev, nop);
304	if (err)
305		return err;
306	if (nop->gpiod_vbus) {
307		err = devm_request_threaded_irq(&pdev->dev,
308						gpiod_to_irq(nop->gpiod_vbus),
309						NULL, nop_gpio_vbus_thread,
310						VBUS_IRQ_FLAGS, "vbus_detect",
311						nop);
312		if (err) {
313			dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
314				gpiod_to_irq(nop->gpiod_vbus), err);
315			return err;
316		}
317		nop->phy.otg->state = gpiod_get_value(nop->gpiod_vbus) ?
318			OTG_STATE_B_PERIPHERAL : OTG_STATE_B_IDLE;
319	}
320
321	nop->phy.init		= usb_gen_phy_init;
322	nop->phy.shutdown	= usb_gen_phy_shutdown;
323
324	err = usb_add_phy_dev(&nop->phy);
325	if (err) {
326		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
327			err);
328		return err;
329	}
330
331	platform_set_drvdata(pdev, nop);
332
333	return 0;
334}
335
336static int usb_phy_generic_remove(struct platform_device *pdev)
337{
338	struct usb_phy_generic *nop = platform_get_drvdata(pdev);
339
340	usb_remove_phy(&nop->phy);
341
342	return 0;
343}
344
345static const struct of_device_id nop_xceiv_dt_ids[] = {
346	{ .compatible = "usb-nop-xceiv" },
347	{ }
348};
349
350MODULE_DEVICE_TABLE(of, nop_xceiv_dt_ids);
351
352static struct platform_driver usb_phy_generic_driver = {
353	.probe		= usb_phy_generic_probe,
354	.remove		= usb_phy_generic_remove,
355	.driver		= {
356		.name	= "usb_phy_generic",
357		.of_match_table = nop_xceiv_dt_ids,
358	},
359};
360
361static int __init usb_phy_generic_init(void)
362{
363	return platform_driver_register(&usb_phy_generic_driver);
364}
365subsys_initcall(usb_phy_generic_init);
366
367static void __exit usb_phy_generic_exit(void)
368{
369	platform_driver_unregister(&usb_phy_generic_driver);
370}
371module_exit(usb_phy_generic_exit);
372
373MODULE_ALIAS("platform:usb_phy_generic");
374MODULE_AUTHOR("Texas Instruments Inc");
375MODULE_DESCRIPTION("NOP USB Transceiver driver");
376MODULE_LICENSE("GPL");
377