xref: /openbmc/linux/drivers/usb/phy/phy-tahvo.c (revision 2c684d89) 
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 
52 struct 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 
63 static const unsigned int tahvo_cable[] = {
64 	EXTCON_USB,
65 	EXTCON_USB_HOST,
66 
67 	EXTCON_NONE,
68 };
69 
70 static ssize_t vbus_state_show(struct device *device,
71 			       struct device_attribute *attr, char *buf)
72 {
73 	struct tahvo_usb *tu = dev_get_drvdata(device);
74 	return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
75 }
76 static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);
77 
78 static void check_vbus_state(struct tahvo_usb *tu)
79 {
80 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
81 	int reg, prev_state;
82 
83 	reg = retu_read(rdev, TAHVO_REG_IDSR);
84 	if (reg & TAHVO_STAT_VBUS) {
85 		switch (tu->phy.otg->state) {
86 		case OTG_STATE_B_IDLE:
87 			/* Enable the gadget driver */
88 			if (tu->phy.otg->gadget)
89 				usb_gadget_vbus_connect(tu->phy.otg->gadget);
90 			tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
91 			usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
92 			break;
93 		case OTG_STATE_A_IDLE:
94 			/*
95 			 * Session is now valid assuming the USB hub is driving
96 			 * Vbus.
97 			 */
98 			tu->phy.otg->state = OTG_STATE_A_HOST;
99 			break;
100 		default:
101 			break;
102 		}
103 		dev_info(&tu->pt_dev->dev, "USB cable connected\n");
104 	} else {
105 		switch (tu->phy.otg->state) {
106 		case OTG_STATE_B_PERIPHERAL:
107 			if (tu->phy.otg->gadget)
108 				usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
109 			tu->phy.otg->state = OTG_STATE_B_IDLE;
110 			usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
111 			break;
112 		case OTG_STATE_A_HOST:
113 			tu->phy.otg->state = OTG_STATE_A_IDLE;
114 			break;
115 		default:
116 			break;
117 		}
118 		dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
119 	}
120 
121 	prev_state = tu->vbus_state;
122 	tu->vbus_state = reg & TAHVO_STAT_VBUS;
123 	if (prev_state != tu->vbus_state) {
124 		extcon_set_cable_state_(tu->extcon, EXTCON_USB, tu->vbus_state);
125 		sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
126 	}
127 }
128 
129 static void tahvo_usb_become_host(struct tahvo_usb *tu)
130 {
131 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
132 
133 	extcon_set_cable_state_(tu->extcon, EXTCON_USB_HOST, true);
134 
135 	/* Power up the transceiver in USB host mode */
136 	retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
137 		   USBR_MASTER_SW2 | USBR_MASTER_SW1);
138 	tu->phy.otg->state = OTG_STATE_A_IDLE;
139 
140 	check_vbus_state(tu);
141 }
142 
143 static void tahvo_usb_stop_host(struct tahvo_usb *tu)
144 {
145 	tu->phy.otg->state = OTG_STATE_A_IDLE;
146 }
147 
148 static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
149 {
150 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
151 
152 	extcon_set_cable_state_(tu->extcon, EXTCON_USB_HOST, false);
153 
154 	/* Power up transceiver and set it in USB peripheral mode */
155 	retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
156 		   USBR_NSUSPEND | USBR_SLAVE_SW);
157 	tu->phy.otg->state = OTG_STATE_B_IDLE;
158 
159 	check_vbus_state(tu);
160 }
161 
162 static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
163 {
164 	if (tu->phy.otg->gadget)
165 		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
166 	tu->phy.otg->state = OTG_STATE_B_IDLE;
167 }
168 
169 static void tahvo_usb_power_off(struct tahvo_usb *tu)
170 {
171 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
172 
173 	/* Disable gadget controller if any */
174 	if (tu->phy.otg->gadget)
175 		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
176 
177 	/* Power off transceiver */
178 	retu_write(rdev, TAHVO_REG_USBR, 0);
179 	tu->phy.otg->state = OTG_STATE_UNDEFINED;
180 }
181 
182 static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
183 {
184 	struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
185 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
186 	u16 w;
187 
188 	dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);
189 
190 	w = retu_read(rdev, TAHVO_REG_USBR);
191 	if (suspend)
192 		w &= ~USBR_NSUSPEND;
193 	else
194 		w |= USBR_NSUSPEND;
195 	retu_write(rdev, TAHVO_REG_USBR, w);
196 
197 	return 0;
198 }
199 
200 static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
201 {
202 	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
203 					    phy);
204 
205 	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);
206 
207 	mutex_lock(&tu->serialize);
208 
209 	if (host == NULL) {
210 		if (tu->tahvo_mode == TAHVO_MODE_HOST)
211 			tahvo_usb_power_off(tu);
212 		otg->host = NULL;
213 		mutex_unlock(&tu->serialize);
214 		return 0;
215 	}
216 
217 	if (tu->tahvo_mode == TAHVO_MODE_HOST) {
218 		otg->host = NULL;
219 		tahvo_usb_become_host(tu);
220 	}
221 
222 	otg->host = host;
223 
224 	mutex_unlock(&tu->serialize);
225 
226 	return 0;
227 }
228 
229 static int tahvo_usb_set_peripheral(struct usb_otg *otg,
230 				    struct usb_gadget *gadget)
231 {
232 	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
233 					    phy);
234 
235 	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);
236 
237 	mutex_lock(&tu->serialize);
238 
239 	if (!gadget) {
240 		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
241 			tahvo_usb_power_off(tu);
242 		tu->phy.otg->gadget = NULL;
243 		mutex_unlock(&tu->serialize);
244 		return 0;
245 	}
246 
247 	tu->phy.otg->gadget = gadget;
248 	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
249 		tahvo_usb_become_peripheral(tu);
250 
251 	mutex_unlock(&tu->serialize);
252 
253 	return 0;
254 }
255 
256 static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
257 {
258 	struct tahvo_usb *tu = _tu;
259 
260 	mutex_lock(&tu->serialize);
261 	check_vbus_state(tu);
262 	mutex_unlock(&tu->serialize);
263 
264 	return IRQ_HANDLED;
265 }
266 
267 static ssize_t otg_mode_show(struct device *device,
268 			     struct device_attribute *attr, char *buf)
269 {
270 	struct tahvo_usb *tu = dev_get_drvdata(device);
271 
272 	switch (tu->tahvo_mode) {
273 	case TAHVO_MODE_HOST:
274 		return sprintf(buf, "host\n");
275 	case TAHVO_MODE_PERIPHERAL:
276 		return sprintf(buf, "peripheral\n");
277 	}
278 
279 	return -EINVAL;
280 }
281 
282 static ssize_t otg_mode_store(struct device *device,
283 			      struct device_attribute *attr,
284 			      const char *buf, size_t count)
285 {
286 	struct tahvo_usb *tu = dev_get_drvdata(device);
287 	int r;
288 
289 	mutex_lock(&tu->serialize);
290 	if (count >= 4 && strncmp(buf, "host", 4) == 0) {
291 		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
292 			tahvo_usb_stop_peripheral(tu);
293 		tu->tahvo_mode = TAHVO_MODE_HOST;
294 		if (tu->phy.otg->host) {
295 			dev_info(device, "HOST mode: host controller present\n");
296 			tahvo_usb_become_host(tu);
297 		} else {
298 			dev_info(device, "HOST mode: no host controller, powering off\n");
299 			tahvo_usb_power_off(tu);
300 		}
301 		r = strlen(buf);
302 	} else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
303 		if (tu->tahvo_mode == TAHVO_MODE_HOST)
304 			tahvo_usb_stop_host(tu);
305 		tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
306 		if (tu->phy.otg->gadget) {
307 			dev_info(device, "PERIPHERAL mode: gadget driver present\n");
308 			tahvo_usb_become_peripheral(tu);
309 		} else {
310 			dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
311 			tahvo_usb_power_off(tu);
312 		}
313 		r = strlen(buf);
314 	} else {
315 		r = -EINVAL;
316 	}
317 	mutex_unlock(&tu->serialize);
318 
319 	return r;
320 }
321 static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);
322 
323 static struct attribute *tahvo_attributes[] = {
324 	&dev_attr_vbus.attr,
325 	&dev_attr_otg_mode.attr,
326 	NULL
327 };
328 
329 static struct attribute_group tahvo_attr_group = {
330 	.attrs = tahvo_attributes,
331 };
332 
333 static int tahvo_usb_probe(struct platform_device *pdev)
334 {
335 	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
336 	struct tahvo_usb *tu;
337 	int ret;
338 
339 	tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
340 	if (!tu)
341 		return -ENOMEM;
342 
343 	tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
344 				   GFP_KERNEL);
345 	if (!tu->phy.otg)
346 		return -ENOMEM;
347 
348 	tu->pt_dev = pdev;
349 
350 	/* Default mode */
351 #ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
352 	tu->tahvo_mode = TAHVO_MODE_HOST;
353 #else
354 	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
355 #endif
356 
357 	mutex_init(&tu->serialize);
358 
359 	tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
360 	if (!IS_ERR(tu->ick))
361 		clk_enable(tu->ick);
362 
363 	/*
364 	 * Set initial state, so that we generate kevents only on state changes.
365 	 */
366 	tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;
367 
368 	tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable);
369 	if (IS_ERR(tu->extcon)) {
370 		dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
371 		return -ENOMEM;
372 	}
373 
374 	ret = devm_extcon_dev_register(&pdev->dev, tu->extcon);
375 	if (ret) {
376 		dev_err(&pdev->dev, "could not register extcon device: %d\n",
377 			ret);
378 		goto err_disable_clk;
379 	}
380 
381 	/* Set the initial cable state. */
382 	extcon_set_cable_state_(tu->extcon, EXTCON_USB_HOST,
383 			       tu->tahvo_mode == TAHVO_MODE_HOST);
384 	extcon_set_cable_state_(tu->extcon, EXTCON_USB, tu->vbus_state);
385 
386 	/* Create OTG interface */
387 	tahvo_usb_power_off(tu);
388 	tu->phy.dev = &pdev->dev;
389 	tu->phy.otg->state = OTG_STATE_UNDEFINED;
390 	tu->phy.label = DRIVER_NAME;
391 	tu->phy.set_suspend = tahvo_usb_set_suspend;
392 
393 	tu->phy.otg->usb_phy = &tu->phy;
394 	tu->phy.otg->set_host = tahvo_usb_set_host;
395 	tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;
396 
397 	ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
398 	if (ret < 0) {
399 		dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
400 			ret);
401 		goto err_disable_clk;
402 	}
403 
404 	dev_set_drvdata(&pdev->dev, tu);
405 
406 	tu->irq = platform_get_irq(pdev, 0);
407 	ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
408 				   IRQF_ONESHOT,
409 				   "tahvo-vbus", tu);
410 	if (ret) {
411 		dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
412 			ret);
413 		goto err_remove_phy;
414 	}
415 
416 	/* Attributes */
417 	ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
418 	if (ret) {
419 		dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
420 		goto err_free_irq;
421 	}
422 
423 	return 0;
424 
425 err_free_irq:
426 	free_irq(tu->irq, tu);
427 err_remove_phy:
428 	usb_remove_phy(&tu->phy);
429 err_disable_clk:
430 	if (!IS_ERR(tu->ick))
431 		clk_disable(tu->ick);
432 
433 	return ret;
434 }
435 
436 static int tahvo_usb_remove(struct platform_device *pdev)
437 {
438 	struct tahvo_usb *tu = platform_get_drvdata(pdev);
439 
440 	sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
441 	free_irq(tu->irq, tu);
442 	usb_remove_phy(&tu->phy);
443 	if (!IS_ERR(tu->ick))
444 		clk_disable(tu->ick);
445 
446 	return 0;
447 }
448 
449 static struct platform_driver tahvo_usb_driver = {
450 	.probe		= tahvo_usb_probe,
451 	.remove		= tahvo_usb_remove,
452 	.driver		= {
453 		.name	= "tahvo-usb",
454 	},
455 };
456 module_platform_driver(tahvo_usb_driver);
457 
458 MODULE_DESCRIPTION("Tahvo USB transceiver driver");
459 MODULE_LICENSE("GPL");
460 MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
461 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
462