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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Tahvo USB transceiver driver
4 *
5 * Copyright (C) 2005-2006 Nokia Corporation
6 *
7 * Parts copied from isp1301_omap.c.
8 * Copyright (C) 2004 Texas Instruments
9 * Copyright (C) 2004 David Brownell
10 *
11 * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
12 * Modified for Retu/Tahvo MFD by Aaro Koskinen.
13 */
14
15#include <linux/io.h>
16#include <linux/clk.h>
17#include <linux/usb.h>
18#include <linux/extcon-provider.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/usb/otg.h>
22#include <linux/mfd/retu.h>
23#include <linux/usb/gadget.h>
24#include <linux/platform_device.h>
25
26#define DRIVER_NAME "tahvo-usb"
27
28#define TAHVO_REG_IDSR 0x02
29#define TAHVO_REG_USBR 0x06
30
31#define USBR_SLAVE_CONTROL (1 << 8)
32#define USBR_VPPVIO_SW (1 << 7)
33#define USBR_SPEED (1 << 6)
34#define USBR_REGOUT (1 << 5)
35#define USBR_MASTER_SW2 (1 << 4)
36#define USBR_MASTER_SW1 (1 << 3)
37#define USBR_SLAVE_SW (1 << 2)
38#define USBR_NSUSPEND (1 << 1)
39#define USBR_SEMODE (1 << 0)
40
41#define TAHVO_MODE_HOST 0
42#define TAHVO_MODE_PERIPHERAL 1
43
44struct tahvo_usb {
45 struct platform_device *pt_dev;
46 struct usb_phy phy;
47 int vbus_state;
48 struct mutex serialize;
49 struct clk *ick;
50 int irq;
51 int tahvo_mode;
52 struct extcon_dev *extcon;
53};
54
55static const unsigned int tahvo_cable[] = {
56 EXTCON_USB,
57 EXTCON_USB_HOST,
58
59 EXTCON_NONE,
60};
61
62static ssize_t vbus_show(struct device *device,
63 struct device_attribute *attr, char *buf)
64{
65 struct tahvo_usb *tu = dev_get_drvdata(device);
66 return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
67}
68static DEVICE_ATTR_RO(vbus);
69
70static void check_vbus_state(struct tahvo_usb *tu)
71{
72 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
73 int reg, prev_state;
74
75 reg = retu_read(rdev, TAHVO_REG_IDSR);
76 if (reg & TAHVO_STAT_VBUS) {
77 switch (tu->phy.otg->state) {
78 case OTG_STATE_B_IDLE:
79 /* Enable the gadget driver */
80 if (tu->phy.otg->gadget)
81 usb_gadget_vbus_connect(tu->phy.otg->gadget);
82 tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
83 usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
84 break;
85 case OTG_STATE_A_IDLE:
86 /*
87 * Session is now valid assuming the USB hub is driving
88 * Vbus.
89 */
90 tu->phy.otg->state = OTG_STATE_A_HOST;
91 break;
92 default:
93 break;
94 }
95 dev_info(&tu->pt_dev->dev, "USB cable connected\n");
96 } else {
97 switch (tu->phy.otg->state) {
98 case OTG_STATE_B_PERIPHERAL:
99 if (tu->phy.otg->gadget)
100 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
101 tu->phy.otg->state = OTG_STATE_B_IDLE;
102 usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
103 break;
104 case OTG_STATE_A_HOST:
105 tu->phy.otg->state = OTG_STATE_A_IDLE;
106 break;
107 default:
108 break;
109 }
110 dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
111 }
112
113 prev_state = tu->vbus_state;
114 tu->vbus_state = reg & TAHVO_STAT_VBUS;
115 if (prev_state != tu->vbus_state) {
116 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
117 sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
118 }
119}
120
121static void tahvo_usb_become_host(struct tahvo_usb *tu)
122{
123 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
124
125 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, true);
126
127 /* Power up the transceiver in USB host mode */
128 retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
129 USBR_MASTER_SW2 | USBR_MASTER_SW1);
130 tu->phy.otg->state = OTG_STATE_A_IDLE;
131
132 check_vbus_state(tu);
133}
134
135static void tahvo_usb_stop_host(struct tahvo_usb *tu)
136{
137 tu->phy.otg->state = OTG_STATE_A_IDLE;
138}
139
140static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
141{
142 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
143
144 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, false);
145
146 /* Power up transceiver and set it in USB peripheral mode */
147 retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
148 USBR_NSUSPEND | USBR_SLAVE_SW);
149 tu->phy.otg->state = OTG_STATE_B_IDLE;
150
151 check_vbus_state(tu);
152}
153
154static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
155{
156 if (tu->phy.otg->gadget)
157 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
158 tu->phy.otg->state = OTG_STATE_B_IDLE;
159}
160
161static void tahvo_usb_power_off(struct tahvo_usb *tu)
162{
163 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
164
165 /* Disable gadget controller if any */
166 if (tu->phy.otg->gadget)
167 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
168
169 /* Power off transceiver */
170 retu_write(rdev, TAHVO_REG_USBR, 0);
171 tu->phy.otg->state = OTG_STATE_UNDEFINED;
172}
173
174static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
175{
176 struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
177 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
178 u16 w;
179
180 dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);
181
182 w = retu_read(rdev, TAHVO_REG_USBR);
183 if (suspend)
184 w &= ~USBR_NSUSPEND;
185 else
186 w |= USBR_NSUSPEND;
187 retu_write(rdev, TAHVO_REG_USBR, w);
188
189 return 0;
190}
191
192static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
193{
194 struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
195 phy);
196
197 mutex_lock(&tu->serialize);
198
199 if (host == NULL) {
200 if (tu->tahvo_mode == TAHVO_MODE_HOST)
201 tahvo_usb_power_off(tu);
202 otg->host = NULL;
203 mutex_unlock(&tu->serialize);
204 return 0;
205 }
206
207 if (tu->tahvo_mode == TAHVO_MODE_HOST) {
208 otg->host = NULL;
209 tahvo_usb_become_host(tu);
210 }
211
212 otg->host = host;
213
214 mutex_unlock(&tu->serialize);
215
216 return 0;
217}
218
219static int tahvo_usb_set_peripheral(struct usb_otg *otg,
220 struct usb_gadget *gadget)
221{
222 struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
223 phy);
224
225 mutex_lock(&tu->serialize);
226
227 if (!gadget) {
228 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
229 tahvo_usb_power_off(tu);
230 tu->phy.otg->gadget = NULL;
231 mutex_unlock(&tu->serialize);
232 return 0;
233 }
234
235 tu->phy.otg->gadget = gadget;
236 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
237 tahvo_usb_become_peripheral(tu);
238
239 mutex_unlock(&tu->serialize);
240
241 return 0;
242}
243
244static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
245{
246 struct tahvo_usb *tu = _tu;
247
248 mutex_lock(&tu->serialize);
249 check_vbus_state(tu);
250 mutex_unlock(&tu->serialize);
251
252 return IRQ_HANDLED;
253}
254
255static ssize_t otg_mode_show(struct device *device,
256 struct device_attribute *attr, char *buf)
257{
258 struct tahvo_usb *tu = dev_get_drvdata(device);
259
260 switch (tu->tahvo_mode) {
261 case TAHVO_MODE_HOST:
262 return sprintf(buf, "host\n");
263 case TAHVO_MODE_PERIPHERAL:
264 return sprintf(buf, "peripheral\n");
265 }
266
267 return -EINVAL;
268}
269
270static ssize_t otg_mode_store(struct device *device,
271 struct device_attribute *attr,
272 const char *buf, size_t count)
273{
274 struct tahvo_usb *tu = dev_get_drvdata(device);
275 int r;
276
277 mutex_lock(&tu->serialize);
278 if (count >= 4 && strncmp(buf, "host", 4) == 0) {
279 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
280 tahvo_usb_stop_peripheral(tu);
281 tu->tahvo_mode = TAHVO_MODE_HOST;
282 if (tu->phy.otg->host) {
283 dev_info(device, "HOST mode: host controller present\n");
284 tahvo_usb_become_host(tu);
285 } else {
286 dev_info(device, "HOST mode: no host controller, powering off\n");
287 tahvo_usb_power_off(tu);
288 }
289 r = strlen(buf);
290 } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
291 if (tu->tahvo_mode == TAHVO_MODE_HOST)
292 tahvo_usb_stop_host(tu);
293 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
294 if (tu->phy.otg->gadget) {
295 dev_info(device, "PERIPHERAL mode: gadget driver present\n");
296 tahvo_usb_become_peripheral(tu);
297 } else {
298 dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
299 tahvo_usb_power_off(tu);
300 }
301 r = strlen(buf);
302 } else {
303 r = -EINVAL;
304 }
305 mutex_unlock(&tu->serialize);
306
307 return r;
308}
309static DEVICE_ATTR_RW(otg_mode);
310
311static struct attribute *tahvo_attrs[] = {
312 &dev_attr_vbus.attr,
313 &dev_attr_otg_mode.attr,
314 NULL
315};
316ATTRIBUTE_GROUPS(tahvo);
317
318static int tahvo_usb_probe(struct platform_device *pdev)
319{
320 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
321 struct tahvo_usb *tu;
322 int ret;
323
324 tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
325 if (!tu)
326 return -ENOMEM;
327
328 tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
329 GFP_KERNEL);
330 if (!tu->phy.otg)
331 return -ENOMEM;
332
333 tu->pt_dev = pdev;
334
335 /* Default mode */
336#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
337 tu->tahvo_mode = TAHVO_MODE_HOST;
338#else
339 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
340#endif
341
342 mutex_init(&tu->serialize);
343
344 tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
345 if (!IS_ERR(tu->ick))
346 clk_enable(tu->ick);
347
348 /*
349 * Set initial state, so that we generate kevents only on state changes.
350 */
351 tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;
352
353 tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable);
354 if (IS_ERR(tu->extcon)) {
355 dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
356 ret = PTR_ERR(tu->extcon);
357 goto err_disable_clk;
358 }
359
360 ret = devm_extcon_dev_register(&pdev->dev, tu->extcon);
361 if (ret) {
362 dev_err(&pdev->dev, "could not register extcon device: %d\n",
363 ret);
364 goto err_disable_clk;
365 }
366
367 /* Set the initial cable state. */
368 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST,
369 tu->tahvo_mode == TAHVO_MODE_HOST);
370 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
371
372 /* Create OTG interface */
373 tahvo_usb_power_off(tu);
374 tu->phy.dev = &pdev->dev;
375 tu->phy.otg->state = OTG_STATE_UNDEFINED;
376 tu->phy.label = DRIVER_NAME;
377 tu->phy.set_suspend = tahvo_usb_set_suspend;
378
379 tu->phy.otg->usb_phy = &tu->phy;
380 tu->phy.otg->set_host = tahvo_usb_set_host;
381 tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;
382
383 ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
384 if (ret < 0) {
385 dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
386 ret);
387 goto err_disable_clk;
388 }
389
390 dev_set_drvdata(&pdev->dev, tu);
391
392 tu->irq = ret = platform_get_irq(pdev, 0);
393 if (ret < 0)
394 goto err_remove_phy;
395 ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
396 IRQF_ONESHOT,
397 "tahvo-vbus", tu);
398 if (ret) {
399 dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
400 ret);
401 goto err_remove_phy;
402 }
403
404 return 0;
405
406err_remove_phy:
407 usb_remove_phy(&tu->phy);
408err_disable_clk:
409 if (!IS_ERR(tu->ick))
410 clk_disable(tu->ick);
411
412 return ret;
413}
414
415static void tahvo_usb_remove(struct platform_device *pdev)
416{
417 struct tahvo_usb *tu = platform_get_drvdata(pdev);
418
419 free_irq(tu->irq, tu);
420 usb_remove_phy(&tu->phy);
421 if (!IS_ERR(tu->ick))
422 clk_disable(tu->ick);
423}
424
425static struct platform_driver tahvo_usb_driver = {
426 .probe = tahvo_usb_probe,
427 .remove_new = tahvo_usb_remove,
428 .driver = {
429 .name = "tahvo-usb",
430 .dev_groups = tahvo_groups,
431 },
432};
433module_platform_driver(tahvo_usb_driver);
434
435MODULE_DESCRIPTION("Tahvo USB transceiver driver");
436MODULE_LICENSE("GPL");
437MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
438MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");