summaryrefslogtreecommitdiffstats
path: root/drivers/usb/phy/phy-tahvo.c
blob: d391c79a542a831bd2ef2a76d63541a0ed8e85d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
/*
 * Tahvo USB transceiver driver
 *
 * Copyright (C) 2005-2006 Nokia Corporation
 *
 * Parts copied from isp1301_omap.c.
 * Copyright (C) 2004 Texas Instruments
 * Copyright (C) 2004 David Brownell
 *
 * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
 * Modified for Retu/Tahvo MFD by Aaro Koskinen.
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License. See the file "COPYING" in the main directory of this
 * archive for more details.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#include <linux/io.h>
#include <linux/clk.h>
#include <linux/usb.h>
#include <linux/extcon.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb/otg.h>
#include <linux/mfd/retu.h>
#include <linux/usb/gadget.h>
#include <linux/platform_device.h>

#define DRIVER_NAME     "tahvo-usb"

#define TAHVO_REG_IDSR	0x02
#define TAHVO_REG_USBR	0x06

#define USBR_SLAVE_CONTROL	(1 << 8)
#define USBR_VPPVIO_SW		(1 << 7)
#define USBR_SPEED		(1 << 6)
#define USBR_REGOUT		(1 << 5)
#define USBR_MASTER_SW2		(1 << 4)
#define USBR_MASTER_SW1		(1 << 3)
#define USBR_SLAVE_SW		(1 << 2)
#define USBR_NSUSPEND		(1 << 1)
#define USBR_SEMODE		(1 << 0)

#define TAHVO_MODE_HOST		0
#define TAHVO_MODE_PERIPHERAL	1

struct tahvo_usb {
	struct platform_device	*pt_dev;
	struct usb_phy		phy;
	int			vbus_state;
	struct mutex		serialize;
	struct clk		*ick;
	int			irq;
	int			tahvo_mode;
	struct extcon_dev	extcon;
};

static const char *tahvo_cable[] = {
	"USB-HOST",
	"USB",
	NULL,
};

static ssize_t vbus_state_show(struct device *device,
			       struct device_attribute *attr, char *buf)
{
	struct tahvo_usb *tu = dev_get_drvdata(device);
	return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
}
static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);

static void check_vbus_state(struct tahvo_usb *tu)
{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
	int reg, prev_state;

	reg = retu_read(rdev, TAHVO_REG_IDSR);
	if (reg & TAHVO_STAT_VBUS) {
		switch (tu->phy.otg->state) {
		case OTG_STATE_B_IDLE:
			/* Enable the gadget driver */
			if (tu->phy.otg->gadget)
				usb_gadget_vbus_connect(tu->phy.otg->gadget);
			tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
			usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
			break;
		case OTG_STATE_A_IDLE:
			/*
			 * Session is now valid assuming the USB hub is driving
			 * Vbus.
			 */
			tu->phy.otg->state = OTG_STATE_A_HOST;
			break;
		default:
			break;
		}
		dev_info(&tu->pt_dev->dev, "USB cable connected\n");
	} else {
		switch (tu->phy.otg->state) {
		case OTG_STATE_B_PERIPHERAL:
			if (tu->phy.otg->gadget)
				usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
			tu->phy.otg->state = OTG_STATE_B_IDLE;
			usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
			break;
		case OTG_STATE_A_HOST:
			tu->phy.otg->state = OTG_STATE_A_IDLE;
			break;
		default:
			break;
		}
		dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
	}

	prev_state = tu->vbus_state;
	tu->vbus_state = reg & TAHVO_STAT_VBUS;
	if (prev_state != tu->vbus_state) {
		extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);
		sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
	}
}

static void tahvo_usb_become_host(struct tahvo_usb *tu)
{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	extcon_set_cable_state(&tu->extcon, "USB-HOST", true);

	/* Power up the transceiver in USB host mode */
	retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
		   USBR_MASTER_SW2 | USBR_MASTER_SW1);
	tu->phy.otg->state = OTG_STATE_A_IDLE;

	check_vbus_state(tu);
}

static void tahvo_usb_stop_host(struct tahvo_usb *tu)
{
	tu->phy.otg->state = OTG_STATE_A_IDLE;
}

static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	extcon_set_cable_state(&tu->extcon, "USB-HOST", false);

	/* Power up transceiver and set it in USB peripheral mode */
	retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
		   USBR_NSUSPEND | USBR_SLAVE_SW);
	tu->phy.otg->state = OTG_STATE_B_IDLE;

	check_vbus_state(tu);
}

static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
{
	if (tu->phy.otg->gadget)
		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
	tu->phy.otg->state = OTG_STATE_B_IDLE;
}

static void tahvo_usb_power_off(struct tahvo_usb *tu)
{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	/* Disable gadget controller if any */
	if (tu->phy.otg->gadget)
		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);

	/* Power off transceiver */
	retu_write(rdev, TAHVO_REG_USBR, 0);
	tu->phy.otg->state = OTG_STATE_UNDEFINED;
}

static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
{
	struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
	u16 w;

	dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);

	w = retu_read(rdev, TAHVO_REG_USBR);
	if (suspend)
		w &= ~USBR_NSUSPEND;
	else
		w |= USBR_NSUSPEND;
	retu_write(rdev, TAHVO_REG_USBR, w);

	return 0;
}

static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
{
	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
					    phy);

	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);

	mutex_lock(&tu->serialize);

	if (host == NULL) {
		if (tu->tahvo_mode == TAHVO_MODE_HOST)
			tahvo_usb_power_off(tu);
		otg->host = NULL;
		mutex_unlock(&tu->serialize);
		return 0;
	}

	if (tu->tahvo_mode == TAHVO_MODE_HOST) {
		otg->host = NULL;
		tahvo_usb_become_host(tu);
	}

	otg->host = host;

	mutex_unlock(&tu->serialize);

	return 0;
}

static int tahvo_usb_set_peripheral(struct usb_otg *otg,
				    struct usb_gadget *gadget)
{
	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
					    phy);

	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);

	mutex_lock(&tu->serialize);

	if (!gadget) {
		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
			tahvo_usb_power_off(tu);
		tu->phy.otg->gadget = NULL;
		mutex_unlock(&tu->serialize);
		return 0;
	}

	tu->phy.otg->gadget = gadget;
	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
		tahvo_usb_become_peripheral(tu);

	mutex_unlock(&tu->serialize);

	return 0;
}

static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
{
	struct tahvo_usb *tu = _tu;

	mutex_lock(&tu->serialize);
	check_vbus_state(tu);
	mutex_unlock(&tu->serialize);

	return IRQ_HANDLED;
}

static ssize_t otg_mode_show(struct device *device,
			     struct device_attribute *attr, char *buf)
{
	struct tahvo_usb *tu = dev_get_drvdata(device);

	switch (tu->tahvo_mode) {
	case TAHVO_MODE_HOST:
		return sprintf(buf, "host\n");
	case TAHVO_MODE_PERIPHERAL:
		return sprintf(buf, "peripheral\n");
	}

	return -EINVAL;
}

static ssize_t otg_mode_store(struct device *device,
			      struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct tahvo_usb *tu = dev_get_drvdata(device);
	int r;

	mutex_lock(&tu->serialize);
	if (count >= 4 && strncmp(buf, "host", 4) == 0) {
		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
			tahvo_usb_stop_peripheral(tu);
		tu->tahvo_mode = TAHVO_MODE_HOST;
		if (tu->phy.otg->host) {
			dev_info(device, "HOST mode: host controller present\n");
			tahvo_usb_become_host(tu);
		} else {
			dev_info(device, "HOST mode: no host controller, powering off\n");
			tahvo_usb_power_off(tu);
		}
		r = strlen(buf);
	} else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
		if (tu->tahvo_mode == TAHVO_MODE_HOST)
			tahvo_usb_stop_host(tu);
		tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
		if (tu->phy.otg->gadget) {
			dev_info(device, "PERIPHERAL mode: gadget driver present\n");
			tahvo_usb_become_peripheral(tu);
		} else {
			dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
			tahvo_usb_power_off(tu);
		}
		r = strlen(buf);
	} else {
		r = -EINVAL;
	}
	mutex_unlock(&tu->serialize);

	return r;
}
static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);

static struct attribute *tahvo_attributes[] = {
	&dev_attr_vbus.attr,
	&dev_attr_otg_mode.attr,
	NULL
};

static struct attribute_group tahvo_attr_group = {
	.attrs = tahvo_attributes,
};

static int tahvo_usb_probe(struct platform_device *pdev)
{
	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
	struct tahvo_usb *tu;
	int ret;

	tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
	if (!tu)
		return -ENOMEM;

	tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
				   GFP_KERNEL);
	if (!tu->phy.otg)
		return -ENOMEM;

	tu->pt_dev = pdev;

	/* Default mode */
#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
	tu->tahvo_mode = TAHVO_MODE_HOST;
#else
	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
#endif

	mutex_init(&tu->serialize);

	tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
	if (!IS_ERR(tu->ick))
		clk_enable(tu->ick);

	/*
	 * Set initial state, so that we generate kevents only on state changes.
	 */
	tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;

	tu->extcon.name = DRIVER_NAME;
	tu->extcon.supported_cable = tahvo_cable;
	tu->extcon.dev.parent = &pdev->dev;

	ret = extcon_dev_register(&tu->extcon);
	if (ret) {
		dev_err(&pdev->dev, "could not register extcon device: %d\n",
			ret);
		goto err_disable_clk;
	}

	/* Set the initial cable state. */
	extcon_set_cable_state(&tu->extcon, "USB-HOST",
			       tu->tahvo_mode == TAHVO_MODE_HOST);
	extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);

	/* Create OTG interface */
	tahvo_usb_power_off(tu);
	tu->phy.dev = &pdev->dev;
	tu->phy.otg->state = OTG_STATE_UNDEFINED;
	tu->phy.label = DRIVER_NAME;
	tu->phy.set_suspend = tahvo_usb_set_suspend;

	tu->phy.otg->usb_phy = &tu->phy;
	tu->phy.otg->set_host = tahvo_usb_set_host;
	tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;

	ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
	if (ret < 0) {
		dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
			ret);
		goto err_extcon_unreg;
	}

	dev_set_drvdata(&pdev->dev, tu);

	tu->irq = platform_get_irq(pdev, 0);
	ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt, 0,
				   "tahvo-vbus", tu);
	if (ret) {
		dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
			ret);
		goto err_remove_phy;
	}

	/* Attributes */
	ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
	if (ret) {
		dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
		goto err_free_irq;
	}

	return 0;

err_free_irq:
	free_irq(tu->irq, tu);
err_remove_phy:
	usb_remove_phy(&tu->phy);
err_extcon_unreg:
	extcon_dev_unregister(&tu->extcon);
err_disable_clk:
	if (!IS_ERR(tu->ick))
		clk_disable(tu->ick);

	return ret;
}

static int tahvo_usb_remove(struct platform_device *pdev)
{
	struct tahvo_usb *tu = platform_get_drvdata(pdev);

	sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
	free_irq(tu->irq, tu);
	usb_remove_phy(&tu->phy);
	extcon_dev_unregister(&tu->extcon);
	if (!IS_ERR(tu->ick))
		clk_disable(tu->ick);

	return 0;
}

static struct platform_driver tahvo_usb_driver = {
	.probe		= tahvo_usb_probe,
	.remove		= tahvo_usb_remove,
	.driver		= {
		.name	= "tahvo-usb",
		.owner	= THIS_MODULE,
	},
};
module_platform_driver(tahvo_usb_driver);

MODULE_DESCRIPTION("Tahvo USB transceiver driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");