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	return 0;
 63}
 64
 65static void nop_reset(struct usb_phy_generic *nop)
 66{
 67	if (!nop->gpiod_reset)
 68		return;
 69
 70	gpiod_set_value(nop->gpiod_reset, 1);
 71	usleep_range(10000, 20000);
 72	gpiod_set_value(nop->gpiod_reset, 0);
 73}
 74
 75/* interface to regulator framework */
 76static void nop_set_vbus_draw(struct usb_phy_generic *nop, unsigned mA)
 77{
 78	struct regulator *vbus_draw = nop->vbus_draw;
 79	int enabled;
 80	int ret;
 81
 82	if (!vbus_draw)
 83		return;
 84
 85	enabled = nop->vbus_draw_enabled;
 86	if (mA) {
 87		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
 88		if (!enabled) {
 89			ret = regulator_enable(vbus_draw);
 90			if (ret < 0)
 91				return;
 92			nop->vbus_draw_enabled = 1;
 93		}
 94	} else {
 95		if (enabled) {
 96			ret = regulator_disable(vbus_draw);
 97			if (ret < 0)
 98				return;
 99			nop->vbus_draw_enabled = 0;
100		}
101	}
102	nop->mA = mA;
103}
104
105
106static irqreturn_t nop_gpio_vbus_thread(int irq, void *data)
107{
108	struct usb_phy_generic *nop = data;
109	struct usb_otg *otg = nop->phy.otg;
110	int vbus, status;
111
112	vbus = gpiod_get_value(nop->gpiod_vbus);
113	if ((vbus ^ nop->vbus) == 0)
114		return IRQ_HANDLED;
115	nop->vbus = vbus;
116
117	if (vbus) {
118		status = USB_EVENT_VBUS;
119		otg->state = OTG_STATE_B_PERIPHERAL;
120		nop->phy.last_event = status;
121		if (otg->gadget)
122			usb_gadget_vbus_connect(otg->gadget);
123
124		/* drawing a "unit load" is *always* OK, except for OTG */
125		nop_set_vbus_draw(nop, 100);
126
127		atomic_notifier_call_chain(&nop->phy.notifier, status,
128					   otg->gadget);
129	} else {
130		nop_set_vbus_draw(nop, 0);
131
132		if (otg->gadget)
133			usb_gadget_vbus_disconnect(otg->gadget);
134		status = USB_EVENT_NONE;
135		otg->state = OTG_STATE_B_IDLE;
136		nop->phy.last_event = status;
137
138		atomic_notifier_call_chain(&nop->phy.notifier, status,
139					   otg->gadget);
140	}
141	return IRQ_HANDLED;
142}
143
144int usb_gen_phy_init(struct usb_phy *phy)
145{
146	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
147
148	if (!IS_ERR(nop->vcc)) {
149		if (regulator_enable(nop->vcc))
150			dev_err(phy->dev, "Failed to enable power\n");
151	}
152
153	if (!IS_ERR(nop->clk))
154		clk_prepare_enable(nop->clk);
155
156	nop_reset(nop);
157
158	return 0;
159}
160EXPORT_SYMBOL_GPL(usb_gen_phy_init);
161
162void usb_gen_phy_shutdown(struct usb_phy *phy)
163{
164	struct usb_phy_generic *nop = dev_get_drvdata(phy->dev);
165
166	gpiod_set_value(nop->gpiod_reset, 1);
167
168	if (!IS_ERR(nop->clk))
169		clk_disable_unprepare(nop->clk);
170
171	if (!IS_ERR(nop->vcc)) {
172		if (regulator_disable(nop->vcc))
173			dev_err(phy->dev, "Failed to disable power\n");
174	}
175}
176EXPORT_SYMBOL_GPL(usb_gen_phy_shutdown);
177
178static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
179{
180	if (!otg)
181		return -ENODEV;
182
183	if (!gadget) {
184		otg->gadget = NULL;
185		return -ENODEV;
186	}
187
188	otg->gadget = gadget;
189	if (otg->state == OTG_STATE_B_PERIPHERAL)
190		usb_gadget_vbus_connect(gadget);
191	else
192		otg->state = OTG_STATE_B_IDLE;
193	return 0;
194}
195
196static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
197{
198	if (!otg)
199		return -ENODEV;
200
201	if (!host) {
202		otg->host = NULL;
203		return -ENODEV;
204	}
205
206	otg->host = host;
207	return 0;
208}
209
210int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop,
211		struct usb_phy_generic_platform_data *pdata)
212{
213	enum usb_phy_type type = USB_PHY_TYPE_USB2;
214	int err = 0;
215
216	u32 clk_rate = 0;
217	bool needs_vcc = false;
218
219	if (dev->of_node) {
220		struct device_node *node = dev->of_node;
221
222		if (of_property_read_u32(node, "clock-frequency", &clk_rate))
223			clk_rate = 0;
224
225		needs_vcc = of_property_read_bool(node, "vcc-supply");
226		nop->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
227							   GPIOD_ASIS);
228		err = PTR_ERR_OR_ZERO(nop->gpiod_reset);
229		if (!err) {
230			nop->gpiod_vbus = devm_gpiod_get_optional(dev,
231							 "vbus-detect",
232							 GPIOD_ASIS);
233			err = PTR_ERR_OR_ZERO(nop->gpiod_vbus);
234		}
235	} else if (pdata) {
236		type = pdata->type;
237		clk_rate = pdata->clk_rate;
238		needs_vcc = pdata->needs_vcc;
239		if (gpio_is_valid(pdata->gpio_reset)) {
240			err = devm_gpio_request_one(dev, pdata->gpio_reset,
241						    GPIOF_ACTIVE_LOW,
242						    dev_name(dev));
243			if (!err)
244				nop->gpiod_reset =
245					gpio_to_desc(pdata->gpio_reset);
246		}
247		nop->gpiod_vbus = pdata->gpiod_vbus;
248	}
249
250	if (err == -EPROBE_DEFER)
251		return -EPROBE_DEFER;
252	if (err) {
253		dev_err(dev, "Error requesting RESET or VBUS GPIO\n");
254		return err;
255	}
256	if (nop->gpiod_reset)
257		gpiod_direction_output(nop->gpiod_reset, 1);
258
259	nop->phy.otg = devm_kzalloc(dev, sizeof(*nop->phy.otg),
260			GFP_KERNEL);
261	if (!nop->phy.otg)
262		return -ENOMEM;
263
264	nop->clk = devm_clk_get(dev, "main_clk");
265	if (IS_ERR(nop->clk)) {
266		dev_dbg(dev, "Can't get phy clock: %ld\n",
267					PTR_ERR(nop->clk));
268	}
269
270	if (!IS_ERR(nop->clk) && clk_rate) {
271		err = clk_set_rate(nop->clk, clk_rate);
272		if (err) {
273			dev_err(dev, "Error setting clock rate\n");
274			return err;
275		}
276	}
277
278	nop->vcc = devm_regulator_get(dev, "vcc");
279	if (IS_ERR(nop->vcc)) {
280		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
281					PTR_ERR(nop->vcc));
282		if (needs_vcc)
283			return -EPROBE_DEFER;
284	}
285
286	nop->dev		= dev;
287	nop->phy.dev		= nop->dev;
288	nop->phy.label		= "nop-xceiv";
289	nop->phy.set_suspend	= nop_set_suspend;
290	nop->phy.type		= type;
291
292	nop->phy.otg->state		= OTG_STATE_UNDEFINED;
293	nop->phy.otg->usb_phy		= &nop->phy;
294	nop->phy.otg->set_host		= nop_set_host;
295	nop->phy.otg->set_peripheral	= nop_set_peripheral;
296
297	return 0;
298}
299EXPORT_SYMBOL_GPL(usb_phy_gen_create_phy);
300
301static int usb_phy_generic_probe(struct platform_device *pdev)
302{
303	struct device *dev = &pdev->dev;
304	struct usb_phy_generic	*nop;
305	int err;
306
307	nop = devm_kzalloc(dev, sizeof(*nop), GFP_KERNEL);
308	if (!nop)
309		return -ENOMEM;
310
311	err = usb_phy_gen_create_phy(dev, nop, dev_get_platdata(&pdev->dev));
312	if (err)
313		return err;
314	if (nop->gpiod_vbus) {
315		err = devm_request_threaded_irq(&pdev->dev,
316						gpiod_to_irq(nop->gpiod_vbus),
317						NULL, nop_gpio_vbus_thread,
318						VBUS_IRQ_FLAGS, "vbus_detect",
319						nop);
320		if (err) {
321			dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
322				gpiod_to_irq(nop->gpiod_vbus), err);
323			return err;
324		}
325	}
326
327	nop->phy.init		= usb_gen_phy_init;
328	nop->phy.shutdown	= usb_gen_phy_shutdown;
329
330	err = usb_add_phy_dev(&nop->phy);
331	if (err) {
332		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
333			err);
334		return err;
335	}
336
337	platform_set_drvdata(pdev, nop);
338
339	return 0;
340}
341
342static int usb_phy_generic_remove(struct platform_device *pdev)
343{
344	struct usb_phy_generic *nop = platform_get_drvdata(pdev);
345
346	usb_remove_phy(&nop->phy);
347
348	return 0;
349}
350
351static const struct of_device_id nop_xceiv_dt_ids[] = {
352	{ .compatible = "usb-nop-xceiv" },
353	{ }
354};
355
356MODULE_DEVICE_TABLE(of, nop_xceiv_dt_ids);
357
358static struct platform_driver usb_phy_generic_driver = {
359	.probe		= usb_phy_generic_probe,
360	.remove		= usb_phy_generic_remove,
361	.driver		= {
362		.name	= "usb_phy_generic",
363		.of_match_table = nop_xceiv_dt_ids,
364	},
365};
366
367static int __init usb_phy_generic_init(void)
368{
369	return platform_driver_register(&usb_phy_generic_driver);
370}
371subsys_initcall(usb_phy_generic_init);
372
373static void __exit usb_phy_generic_exit(void)
374{
375	platform_driver_unregister(&usb_phy_generic_driver);
376}
377module_exit(usb_phy_generic_exit);
378
379MODULE_ALIAS("platform:usb_phy_generic");
380MODULE_AUTHOR("Texas Instruments Inc");
381MODULE_DESCRIPTION("NOP USB Transceiver driver");
382MODULE_LICENSE("GPL");