1/*
2 * Tahvo USB transceiver driver
3 *
4 * Copyright (C) 2005-2006 Nokia Corporation
5 *
6 * Parts copied from isp1301_omap.c.
7 * Copyright (C) 2004 Texas Instruments
8 * Copyright (C) 2004 David Brownell
9 *
10 * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
11 * Modified for Retu/Tahvo MFD by Aaro Koskinen.
12 *
13 * This file is subject to the terms and conditions of the GNU General
14 * Public License. See the file "COPYING" in the main directory of this
15 * archive for more details.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 */
22
23#include <linux/io.h>
24#include <linux/clk.h>
25#include <linux/usb.h>
26#include <linux/extcon.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/usb/otg.h>
30#include <linux/mfd/retu.h>
31#include <linux/usb/gadget.h>
32#include <linux/platform_device.h>
33
34#define DRIVER_NAME     "tahvo-usb"
35
36#define TAHVO_REG_IDSR	0x02
37#define TAHVO_REG_USBR	0x06
38
39#define USBR_SLAVE_CONTROL	(1 << 8)
40#define USBR_VPPVIO_SW		(1 << 7)
41#define USBR_SPEED		(1 << 6)
42#define USBR_REGOUT		(1 << 5)
43#define USBR_MASTER_SW2		(1 << 4)
44#define USBR_MASTER_SW1		(1 << 3)
45#define USBR_SLAVE_SW		(1 << 2)
46#define USBR_NSUSPEND		(1 << 1)
47#define USBR_SEMODE		(1 << 0)
48
49#define TAHVO_MODE_HOST		0
50#define TAHVO_MODE_PERIPHERAL	1
51
52struct tahvo_usb {
53	struct platform_device	*pt_dev;
54	struct usb_phy		phy;
55	int			vbus_state;
56	struct mutex		serialize;
57	struct clk		*ick;
58	int			irq;
59	int			tahvo_mode;
60	struct extcon_dev	extcon;
61};
62
63static const char *tahvo_cable[] = {
64	"USB-HOST",
65	"USB",
66	NULL,
67};
68
69static ssize_t vbus_state_show(struct device *device,
70			       struct device_attribute *attr, char *buf)
71{
72	struct tahvo_usb *tu = dev_get_drvdata(device);
73	return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
74}
75static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);
76
77static void check_vbus_state(struct tahvo_usb *tu)
78{
79	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
80	int reg, prev_state;
81
82	reg = retu_read(rdev, TAHVO_REG_IDSR);
83	if (reg & TAHVO_STAT_VBUS) {
84		switch (tu->phy.otg->state) {
85		case OTG_STATE_B_IDLE:
86			/* Enable the gadget driver */
87			if (tu->phy.otg->gadget)
88				usb_gadget_vbus_connect(tu->phy.otg->gadget);
89			tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
90			usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
91			break;
92		case OTG_STATE_A_IDLE:
93			/*
94			 * Session is now valid assuming the USB hub is driving
95			 * Vbus.
96			 */
97			tu->phy.otg->state = OTG_STATE_A_HOST;
98			break;
99		default:
100			break;
101		}
102		dev_info(&tu->pt_dev->dev, "USB cable connected\n");
103	} else {
104		switch (tu->phy.otg->state) {
105		case OTG_STATE_B_PERIPHERAL:
106			if (tu->phy.otg->gadget)
107				usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
108			tu->phy.otg->state = OTG_STATE_B_IDLE;
109			usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
110			break;
111		case OTG_STATE_A_HOST:
112			tu->phy.otg->state = OTG_STATE_A_IDLE;
113			break;
114		default:
115			break;
116		}
117		dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
118	}
119
120	prev_state = tu->vbus_state;
121	tu->vbus_state = reg & TAHVO_STAT_VBUS;
122	if (prev_state != tu->vbus_state) {
123		extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);
124		sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
125	}
126}
127
128static void tahvo_usb_become_host(struct tahvo_usb *tu)
129{
130	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
131
132	extcon_set_cable_state(&tu->extcon, "USB-HOST", true);
133
134	/* Power up the transceiver in USB host mode */
135	retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
136		   USBR_MASTER_SW2 | USBR_MASTER_SW1);
137	tu->phy.otg->state = OTG_STATE_A_IDLE;
138
139	check_vbus_state(tu);
140}
141
142static void tahvo_usb_stop_host(struct tahvo_usb *tu)
143{
144	tu->phy.otg->state = OTG_STATE_A_IDLE;
145}
146
147static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
148{
149	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
150
151	extcon_set_cable_state(&tu->extcon, "USB-HOST", false);
152
153	/* Power up transceiver and set it in USB peripheral mode */
154	retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
155		   USBR_NSUSPEND | USBR_SLAVE_SW);
156	tu->phy.otg->state = OTG_STATE_B_IDLE;
157
158	check_vbus_state(tu);
159}
160
161static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
162{
163	if (tu->phy.otg->gadget)
164		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
165	tu->phy.otg->state = OTG_STATE_B_IDLE;
166}
167
168static void tahvo_usb_power_off(struct tahvo_usb *tu)
169{
170	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
171
172	/* Disable gadget controller if any */
173	if (tu->phy.otg->gadget)
174		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
175
176	/* Power off transceiver */
177	retu_write(rdev, TAHVO_REG_USBR, 0);
178	tu->phy.otg->state = OTG_STATE_UNDEFINED;
179}
180
181static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
182{
183	struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
184	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
185	u16 w;
186
187	dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);
188
189	w = retu_read(rdev, TAHVO_REG_USBR);
190	if (suspend)
191		w &= ~USBR_NSUSPEND;
192	else
193		w |= USBR_NSUSPEND;
194	retu_write(rdev, TAHVO_REG_USBR, w);
195
196	return 0;
197}
198
199static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
200{
201	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
202					    phy);
203
204	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);
205
206	mutex_lock(&tu->serialize);
207
208	if (host == NULL) {
209		if (tu->tahvo_mode == TAHVO_MODE_HOST)
210			tahvo_usb_power_off(tu);
211		otg->host = NULL;
212		mutex_unlock(&tu->serialize);
213		return 0;
214	}
215
216	if (tu->tahvo_mode == TAHVO_MODE_HOST) {
217		otg->host = NULL;
218		tahvo_usb_become_host(tu);
219	}
220
221	otg->host = host;
222
223	mutex_unlock(&tu->serialize);
224
225	return 0;
226}
227
228static int tahvo_usb_set_peripheral(struct usb_otg *otg,
229				    struct usb_gadget *gadget)
230{
231	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
232					    phy);
233
234	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);
235
236	mutex_lock(&tu->serialize);
237
238	if (!gadget) {
239		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
240			tahvo_usb_power_off(tu);
241		tu->phy.otg->gadget = NULL;
242		mutex_unlock(&tu->serialize);
243		return 0;
244	}
245
246	tu->phy.otg->gadget = gadget;
247	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
248		tahvo_usb_become_peripheral(tu);
249
250	mutex_unlock(&tu->serialize);
251
252	return 0;
253}
254
255static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
256{
257	struct tahvo_usb *tu = _tu;
258
259	mutex_lock(&tu->serialize);
260	check_vbus_state(tu);
261	mutex_unlock(&tu->serialize);
262
263	return IRQ_HANDLED;
264}
265
266static ssize_t otg_mode_show(struct device *device,
267			     struct device_attribute *attr, char *buf)
268{
269	struct tahvo_usb *tu = dev_get_drvdata(device);
270
271	switch (tu->tahvo_mode) {
272	case TAHVO_MODE_HOST:
273		return sprintf(buf, "host\n");
274	case TAHVO_MODE_PERIPHERAL:
275		return sprintf(buf, "peripheral\n");
276	}
277
278	return -EINVAL;
279}
280
281static ssize_t otg_mode_store(struct device *device,
282			      struct device_attribute *attr,
283			      const char *buf, size_t count)
284{
285	struct tahvo_usb *tu = dev_get_drvdata(device);
286	int r;
287
288	mutex_lock(&tu->serialize);
289	if (count >= 4 && strncmp(buf, "host", 4) == 0) {
290		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
291			tahvo_usb_stop_peripheral(tu);
292		tu->tahvo_mode = TAHVO_MODE_HOST;
293		if (tu->phy.otg->host) {
294			dev_info(device, "HOST mode: host controller present\n");
295			tahvo_usb_become_host(tu);
296		} else {
297			dev_info(device, "HOST mode: no host controller, powering off\n");
298			tahvo_usb_power_off(tu);
299		}
300		r = strlen(buf);
301	} else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
302		if (tu->tahvo_mode == TAHVO_MODE_HOST)
303			tahvo_usb_stop_host(tu);
304		tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
305		if (tu->phy.otg->gadget) {
306			dev_info(device, "PERIPHERAL mode: gadget driver present\n");
307			tahvo_usb_become_peripheral(tu);
308		} else {
309			dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
310			tahvo_usb_power_off(tu);
311		}
312		r = strlen(buf);
313	} else {
314		r = -EINVAL;
315	}
316	mutex_unlock(&tu->serialize);
317
318	return r;
319}
320static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);
321
322static struct attribute *tahvo_attributes[] = {
323	&dev_attr_vbus.attr,
324	&dev_attr_otg_mode.attr,
325	NULL
326};
327
328static struct attribute_group tahvo_attr_group = {
329	.attrs = tahvo_attributes,
330};
331
332static int tahvo_usb_probe(struct platform_device *pdev)
333{
334	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
335	struct tahvo_usb *tu;
336	int ret;
337
338	tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
339	if (!tu)
340		return -ENOMEM;
341
342	tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
343				   GFP_KERNEL);
344	if (!tu->phy.otg)
345		return -ENOMEM;
346
347	tu->pt_dev = pdev;
348
349	/* Default mode */
350#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
351	tu->tahvo_mode = TAHVO_MODE_HOST;
352#else
353	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
354#endif
355
356	mutex_init(&tu->serialize);
357
358	tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
359	if (!IS_ERR(tu->ick))
360		clk_enable(tu->ick);
361
362	/*
363	 * Set initial state, so that we generate kevents only on state changes.
364	 */
365	tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;
366
367	tu->extcon.name = DRIVER_NAME;
368	tu->extcon.supported_cable = tahvo_cable;
369	tu->extcon.dev.parent = &pdev->dev;
370
371	ret = extcon_dev_register(&tu->extcon);
372	if (ret) {
373		dev_err(&pdev->dev, "could not register extcon device: %d\n",
374			ret);
375		goto err_disable_clk;
376	}
377
378	/* Set the initial cable state. */
379	extcon_set_cable_state(&tu->extcon, "USB-HOST",
380			       tu->tahvo_mode == TAHVO_MODE_HOST);
381	extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);
382
383	/* Create OTG interface */
384	tahvo_usb_power_off(tu);
385	tu->phy.dev = &pdev->dev;
386	tu->phy.otg->state = OTG_STATE_UNDEFINED;
387	tu->phy.label = DRIVER_NAME;
388	tu->phy.set_suspend = tahvo_usb_set_suspend;
389
390	tu->phy.otg->usb_phy = &tu->phy;
391	tu->phy.otg->set_host = tahvo_usb_set_host;
392	tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;
393
394	ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
395	if (ret < 0) {
396		dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
397			ret);
398		goto err_extcon_unreg;
399	}
400
401	dev_set_drvdata(&pdev->dev, tu);
402
403	tu->irq = platform_get_irq(pdev, 0);
404	ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
405				   IRQF_ONESHOT,
406				   "tahvo-vbus", tu);
407	if (ret) {
408		dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
409			ret);
410		goto err_remove_phy;
411	}
412
413	/* Attributes */
414	ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
415	if (ret) {
416		dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
417		goto err_free_irq;
418	}
419
420	return 0;
421
422err_free_irq:
423	free_irq(tu->irq, tu);
424err_remove_phy:
425	usb_remove_phy(&tu->phy);
426err_extcon_unreg:
427	extcon_dev_unregister(&tu->extcon);
428err_disable_clk:
429	if (!IS_ERR(tu->ick))
430		clk_disable(tu->ick);
431
432	return ret;
433}
434
435static int tahvo_usb_remove(struct platform_device *pdev)
436{
437	struct tahvo_usb *tu = platform_get_drvdata(pdev);
438
439	sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
440	free_irq(tu->irq, tu);
441	usb_remove_phy(&tu->phy);
442	extcon_dev_unregister(&tu->extcon);
443	if (!IS_ERR(tu->ick))
444		clk_disable(tu->ick);
445
446	return 0;
447}
448
449static struct platform_driver tahvo_usb_driver = {
450	.probe		= tahvo_usb_probe,
451	.remove		= tahvo_usb_remove,
452	.driver		= {
453		.name	= "tahvo-usb",
454	},
455};
456module_platform_driver(tahvo_usb_driver);
457
458MODULE_DESCRIPTION("Tahvo USB transceiver driver");
459MODULE_LICENSE("GPL");
460MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
461MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
462