1/*
  2 * NOP USB transceiver for all USB transceiver which are either built-in
  3 * into USB IP or which are mostly autonomous.
  4 *
  5 * Copyright (C) 2009 Texas Instruments Inc
  6 * Author: Ajay Kumar Gupta <ajay.gupta@ti.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License as published by
 10 * the Free Software Foundation; either version 2 of the License, or
 11 * (at your option) any later version.
 12 *
 13 * This program is distributed in the hope that it will be useful,
 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16 * GNU General Public License for more details.
 17 *
 18 * You should have received a copy of the GNU General Public License
 19 * along with this program; if not, write to the Free Software
 20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 21 *
 22 * Current status:
 23 *	This provides a "nop" transceiver for PHYs which are
 24 *	autonomous such as isp1504, isp1707, etc.
 25 */
 26
 27#include <linux/module.h>
 28#include <linux/platform_device.h>
 29#include <linux/dma-mapping.h>
 30#include <linux/usb/gadget.h>
 31#include <linux/usb/otg.h>
 32#include <linux/usb/usb_phy_generic.h>
 33#include <linux/slab.h>
 34#include <linux/clk.h>
 35#include <linux/regulator/consumer.h>
 36#include <linux/of.h>
 37#include <linux/of_gpio.h>
 38#include <linux/gpio.h>
 39#include <linux/delay.h>
 40
 41#include "phy-generic.h"
 42
 43#define VBUS_IRQ_FLAGS \
 44	(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | \
 45		IRQF_ONESHOT)
 46
 47struct platform_device *usb_phy_generic_register(void)
 48{
 49	return platform_device_register_simple("usb_phy_generic",
 50			PLATFORM_DEVID_AUTO, NULL, 0);
 51}
 52EXPORT_SYMBOL_GPL(usb_phy_generic_register);
 53
 54void usb_phy_generic_unregister(struct platform_device *pdev)
 55{
 56	platform_device_unregister(pdev);
 57}
 58EXPORT_SYMBOL_GPL(usb_phy_generic_unregister);
 59
 60static int nop_set_suspend(struct usb_phy *x, int suspend)
 61{
 62	struct usb_phy_generic *nop = dev_get_drvdata(x->dev);
 63
 64	if (!IS_ERR(nop->clk)) {
 65		if (suspend)
 66			clk_disable_unprepare(nop->clk);
 67		else
 68			clk_prepare_enable(nop->clk);
 69	}
 70
 71	return 0;
 72}
 73
 74static void nop_reset(struct usb_phy_generic *nop)
 75{
 76	if (!nop->gpiod_reset)
 77		return;
 78
 79	gpiod_set_value(nop->gpiod_reset, 1);
 80	usleep_range(10000, 20000);
 81	gpiod_set_value(nop->gpiod_reset, 0);
 82}
 83
 84/* interface to regulator framework */
 85static void nop_set_vbus_draw(struct usb_phy_generic *nop, unsigned mA)
 86{
 87	struct regulator *vbus_draw = nop->vbus_draw;
 88	int enabled;
 89	int ret;
 90
 91	if (!vbus_draw)
 92		return;
 93
 94	enabled = nop->vbus_draw_enabled;
 95	if (mA) {
 96		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
 97		if (!enabled) {
 98			ret = regulator_enable(vbus_draw);
 99			if (ret < 0)
100				return;
101			nop->vbus_draw_enabled = 1;
102		}
103	} else {
104		if (enabled) {
105			ret = regulator_disable(vbus_draw);
106			if (ret < 0)
107				return;
108			nop->vbus_draw_enabled = 0;
109		}
110	}
111	nop->mA = mA;
112}
113
114
115static irqreturn_t nop_gpio_vbus_thread(int irq, void *data)
116{
117	struct usb_phy_generic *nop = data;
118	struct usb_otg *otg = nop->phy.otg;
119	int vbus, status;
120
121	vbus = gpiod_get_value(nop->gpiod_vbus);
122	if ((vbus ^ nop->vbus) == 0)
123		return IRQ_HANDLED;
124	nop->vbus = vbus;
125
126	if (vbus) {
127		status = USB_EVENT_VBUS;
128		otg->state = OTG_STATE_B_PERIPHERAL;
129		nop->phy.last_event = status;
130
131		/* drawing a "unit load" is *always* OK, except for OTG */
132		nop_set_vbus_draw(nop, 100);
133
134		atomic_notifier_call_chain(&nop->phy.notifier, status,
135					   otg->gadget);
136	} else {
137		nop_set_vbus_draw(nop, 0);
138
139		status = USB_EVENT_NONE;
140		otg->state = OTG_STATE_B_IDLE;
141		nop->phy.last_event = status;
142
143		atomic_notifier_call_chain(&nop->phy.notifier, status,
144					   otg->gadget);
145	}
146	return IRQ_HANDLED;
147}
148
149int usb_gen_phy_init(struct usb_phy *phy)
150{
151	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
152	int ret;
153
154	if (!IS_ERR(nop->vcc)) {
155		if (regulator_enable(nop->vcc))
156			dev_err(phy->dev, "Failed to enable power\n");
157	}
158
159	if (!IS_ERR(nop->clk)) {
160		ret = clk_prepare_enable(nop->clk);
161		if (ret)
162			return ret;
163	}
164
165	nop_reset(nop);
166
167	return 0;
168}
169EXPORT_SYMBOL_GPL(usb_gen_phy_init);
170
171void usb_gen_phy_shutdown(struct usb_phy *phy)
172{
173	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
174
175	gpiod_set_value(nop->gpiod_reset, 1);
176
177	if (!IS_ERR(nop->clk))
178		clk_disable_unprepare(nop->clk);
179
180	if (!IS_ERR(nop->vcc)) {
181		if (regulator_disable(nop->vcc))
182			dev_err(phy->dev, "Failed to disable power\n");
183	}
184}
185EXPORT_SYMBOL_GPL(usb_gen_phy_shutdown);
186
187static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
188{
189	if (!otg)
190		return -ENODEV;
191
192	if (!gadget) {
193		otg->gadget = NULL;
194		return -ENODEV;
195	}
196
197	otg->gadget = gadget;
198	if (otg->state == OTG_STATE_B_PERIPHERAL)
199		atomic_notifier_call_chain(&otg->usb_phy->notifier,
200					   USB_EVENT_VBUS, otg->gadget);
201	else
202		otg->state = OTG_STATE_B_IDLE;
203	return 0;
204}
205
206static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
207{
208	if (!otg)
209		return -ENODEV;
210
211	if (!host) {
212		otg->host = NULL;
213		return -ENODEV;
214	}
215
216	otg->host = host;
217	return 0;
218}
219
220int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop,
221		struct usb_phy_generic_platform_data *pdata)
222{
223	enum usb_phy_type type = USB_PHY_TYPE_USB2;
224	int err = 0;
225
226	u32 clk_rate = 0;
227	bool needs_vcc = false;
228
229	if (dev->of_node) {
230		struct device_node *node = dev->of_node;
231
232		if (of_property_read_u32(node, "clock-frequency", &clk_rate))
233			clk_rate = 0;
234
235		needs_vcc = of_property_read_bool(node, "vcc-supply");
236		nop->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
237							   GPIOD_ASIS);
238		err = PTR_ERR_OR_ZERO(nop->gpiod_reset);
239		if (!err) {
240			nop->gpiod_vbus = devm_gpiod_get_optional(dev,
241							 "vbus-detect",
242							 GPIOD_ASIS);
243			err = PTR_ERR_OR_ZERO(nop->gpiod_vbus);
244		}
245	} else if (pdata) {
246		type = pdata->type;
247		clk_rate = pdata->clk_rate;
248		needs_vcc = pdata->needs_vcc;
249		if (gpio_is_valid(pdata->gpio_reset)) {
250			err = devm_gpio_request_one(dev, pdata->gpio_reset,
251						    GPIOF_ACTIVE_LOW,
252						    dev_name(dev));
253			if (!err)
254				nop->gpiod_reset =
255					gpio_to_desc(pdata->gpio_reset);
256		}
257		nop->gpiod_vbus = pdata->gpiod_vbus;
258	}
259
260	if (err == -EPROBE_DEFER)
261		return -EPROBE_DEFER;
262	if (err) {
263		dev_err(dev, "Error requesting RESET or VBUS GPIO\n");
264		return err;
265	}
266	if (nop->gpiod_reset)
267		gpiod_direction_output(nop->gpiod_reset, 1);
268
269	nop->phy.otg = devm_kzalloc(dev, sizeof(*nop->phy.otg),
270			GFP_KERNEL);
271	if (!nop->phy.otg)
272		return -ENOMEM;
273
274	nop->clk = devm_clk_get(dev, "main_clk");
275	if (IS_ERR(nop->clk)) {
276		dev_dbg(dev, "Can't get phy clock: %ld\n",
277					PTR_ERR(nop->clk));
278	}
279
280	if (!IS_ERR(nop->clk) && clk_rate) {
281		err = clk_set_rate(nop->clk, clk_rate);
282		if (err) {
283			dev_err(dev, "Error setting clock rate\n");
284			return err;
285		}
286	}
287
288	nop->vcc = devm_regulator_get(dev, "vcc");
289	if (IS_ERR(nop->vcc)) {
290		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
291					PTR_ERR(nop->vcc));
292		if (needs_vcc)
293			return -EPROBE_DEFER;
294	}
295
296	nop->dev		= dev;
297	nop->phy.dev		= nop->dev;
298	nop->phy.label		= "nop-xceiv";
299	nop->phy.set_suspend	= nop_set_suspend;
300	nop->phy.type		= type;
301
302	nop->phy.otg->state		= OTG_STATE_UNDEFINED;
303	nop->phy.otg->usb_phy		= &nop->phy;
304	nop->phy.otg->set_host		= nop_set_host;
305	nop->phy.otg->set_peripheral	= nop_set_peripheral;
306
307	return 0;
308}
309EXPORT_SYMBOL_GPL(usb_phy_gen_create_phy);
310
311static int usb_phy_generic_probe(struct platform_device *pdev)
312{
313	struct device *dev = &pdev->dev;
314	struct usb_phy_generic	*nop;
315	int err;
316
317	nop = devm_kzalloc(dev, sizeof(*nop), GFP_KERNEL);
318	if (!nop)
319		return -ENOMEM;
320
321	err = usb_phy_gen_create_phy(dev, nop, dev_get_platdata(&pdev->dev));
322	if (err)
323		return err;
324	if (nop->gpiod_vbus) {
325		err = devm_request_threaded_irq(&pdev->dev,
326						gpiod_to_irq(nop->gpiod_vbus),
327						NULL, nop_gpio_vbus_thread,
328						VBUS_IRQ_FLAGS, "vbus_detect",
329						nop);
330		if (err) {
331			dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
332				gpiod_to_irq(nop->gpiod_vbus), err);
333			return err;
334		}
335		nop->phy.otg->state = gpiod_get_value(nop->gpiod_vbus) ?
336			OTG_STATE_B_PERIPHERAL : OTG_STATE_B_IDLE;
337	}
338
339	nop->phy.init		= usb_gen_phy_init;
340	nop->phy.shutdown	= usb_gen_phy_shutdown;
341
342	err = usb_add_phy_dev(&nop->phy);
343	if (err) {
344		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
345			err);
346		return err;
347	}
348
349	platform_set_drvdata(pdev, nop);
350
351	return 0;
352}
353
354static int usb_phy_generic_remove(struct platform_device *pdev)
355{
356	struct usb_phy_generic *nop = platform_get_drvdata(pdev);
357
358	usb_remove_phy(&nop->phy);
359
360	return 0;
361}
362
363static const struct of_device_id nop_xceiv_dt_ids[] = {
364	{ .compatible = "usb-nop-xceiv" },
365	{ }
366};
367
368MODULE_DEVICE_TABLE(of, nop_xceiv_dt_ids);
369
370static struct platform_driver usb_phy_generic_driver = {
371	.probe		= usb_phy_generic_probe,
372	.remove		= usb_phy_generic_remove,
373	.driver		= {
374		.name	= "usb_phy_generic",
375		.of_match_table = nop_xceiv_dt_ids,
376	},
377};
378
379static int __init usb_phy_generic_init(void)
380{
381	return platform_driver_register(&usb_phy_generic_driver);
382}
383subsys_initcall(usb_phy_generic_init);
384
385static void __exit usb_phy_generic_exit(void)
386{
387	platform_driver_unregister(&usb_phy_generic_driver);
388}
389module_exit(usb_phy_generic_exit);
390
391MODULE_ALIAS("platform:usb_phy_generic");
392MODULE_AUTHOR("Texas Instruments Inc");
393MODULE_DESCRIPTION("NOP USB Transceiver driver");
394MODULE_LICENSE("GPL");