xref: /openbmc/linux/drivers/usb/gadget/udc/max3420_udc.c (revision c900529f3d9161bfde5cca0754f83b4d3c3e0220)
1  // SPDX-License-Identifier: GPL-2.0+
2  /*
3   * MAX3420 Device Controller driver for USB.
4   *
5   * Author: Jaswinder Singh Brar <jaswinder.singh@linaro.org>
6   * (C) Copyright 2019-2020 Linaro Ltd
7   *
8   * Based on:
9   *	o MAX3420E datasheet
10   *		https://datasheets.maximintegrated.com/en/ds/MAX3420E.pdf
11   *	o MAX342{0,1}E Programming Guides
12   *		https://pdfserv.maximintegrated.com/en/an/AN3598.pdf
13   *		https://pdfserv.maximintegrated.com/en/an/AN3785.pdf
14   */
15  
16  #include <linux/delay.h>
17  #include <linux/device.h>
18  #include <linux/interrupt.h>
19  #include <linux/io.h>
20  #include <linux/module.h>
21  #include <linux/bitfield.h>
22  #include <linux/of.h>
23  #include <linux/of_irq.h>
24  #include <linux/prefetch.h>
25  #include <linux/usb/ch9.h>
26  #include <linux/usb/gadget.h>
27  #include <linux/spi/spi.h>
28  #include <linux/gpio/consumer.h>
29  
30  #define MAX3420_MAX_EPS		4
31  #define MAX3420_EP_MAX_PACKET		64  /* Same for all Endpoints */
32  #define MAX3420_EPNAME_SIZE		16  /* Buffer size for endpoint name */
33  
34  #define MAX3420_ACKSTAT		BIT(0)
35  
36  #define MAX3420_SPI_DIR_RD	0	/* read register from MAX3420 */
37  #define MAX3420_SPI_DIR_WR	1	/* write register to MAX3420 */
38  
39  /* SPI commands: */
40  #define MAX3420_SPI_DIR_SHIFT	1
41  #define MAX3420_SPI_REG_SHIFT	3
42  
43  #define MAX3420_REG_EP0FIFO	0
44  #define MAX3420_REG_EP1FIFO	1
45  #define MAX3420_REG_EP2FIFO	2
46  #define MAX3420_REG_EP3FIFO	3
47  #define MAX3420_REG_SUDFIFO	4
48  #define MAX3420_REG_EP0BC	5
49  #define MAX3420_REG_EP1BC	6
50  #define MAX3420_REG_EP2BC	7
51  #define MAX3420_REG_EP3BC	8
52  
53  #define MAX3420_REG_EPSTALLS	9
54  	#define ACKSTAT		BIT(6)
55  	#define STLSTAT		BIT(5)
56  	#define STLEP3IN	BIT(4)
57  	#define STLEP2IN	BIT(3)
58  	#define STLEP1OUT	BIT(2)
59  	#define STLEP0OUT	BIT(1)
60  	#define STLEP0IN	BIT(0)
61  
62  #define MAX3420_REG_CLRTOGS	10
63  	#define EP3DISAB	BIT(7)
64  	#define EP2DISAB	BIT(6)
65  	#define EP1DISAB	BIT(5)
66  	#define CTGEP3IN	BIT(4)
67  	#define CTGEP2IN	BIT(3)
68  	#define CTGEP1OUT	BIT(2)
69  
70  #define MAX3420_REG_EPIRQ	11
71  #define MAX3420_REG_EPIEN	12
72  	#define SUDAVIRQ	BIT(5)
73  	#define IN3BAVIRQ	BIT(4)
74  	#define IN2BAVIRQ	BIT(3)
75  	#define OUT1DAVIRQ	BIT(2)
76  	#define OUT0DAVIRQ	BIT(1)
77  	#define IN0BAVIRQ	BIT(0)
78  
79  #define MAX3420_REG_USBIRQ	13
80  #define MAX3420_REG_USBIEN	14
81  	#define OSCOKIRQ	BIT(0)
82  	#define RWUDNIRQ	BIT(1)
83  	#define BUSACTIRQ	BIT(2)
84  	#define URESIRQ		BIT(3)
85  	#define SUSPIRQ		BIT(4)
86  	#define NOVBUSIRQ	BIT(5)
87  	#define VBUSIRQ		BIT(6)
88  	#define URESDNIRQ	BIT(7)
89  
90  #define MAX3420_REG_USBCTL	15
91  	#define HOSCSTEN	BIT(7)
92  	#define VBGATE		BIT(6)
93  	#define CHIPRES		BIT(5)
94  	#define PWRDOWN		BIT(4)
95  	#define CONNECT		BIT(3)
96  	#define SIGRWU		BIT(2)
97  
98  #define MAX3420_REG_CPUCTL	16
99  	#define IE		BIT(0)
100  
101  #define MAX3420_REG_PINCTL	17
102  	#define EP3INAK		BIT(7)
103  	#define EP2INAK		BIT(6)
104  	#define EP0INAK		BIT(5)
105  	#define FDUPSPI		BIT(4)
106  	#define INTLEVEL	BIT(3)
107  	#define POSINT		BIT(2)
108  	#define GPXB		BIT(1)
109  	#define GPXA		BIT(0)
110  
111  #define MAX3420_REG_REVISION	18
112  
113  #define MAX3420_REG_FNADDR	19
114  	#define FNADDR_MASK	0x7f
115  
116  #define MAX3420_REG_IOPINS	20
117  #define MAX3420_REG_IOPINS2	21
118  #define MAX3420_REG_GPINIRQ	22
119  #define MAX3420_REG_GPINIEN	23
120  #define MAX3420_REG_GPINPOL	24
121  #define MAX3420_REG_HIRQ	25
122  #define MAX3420_REG_HIEN	26
123  #define MAX3420_REG_MODE	27
124  #define MAX3420_REG_PERADDR	28
125  #define MAX3420_REG_HCTL	29
126  #define MAX3420_REG_HXFR	30
127  #define MAX3420_REG_HRSL	31
128  
129  #define ENABLE_IRQ	BIT(0)
130  #define IOPIN_UPDATE	BIT(1)
131  #define REMOTE_WAKEUP	BIT(2)
132  #define CONNECT_HOST	GENMASK(4, 3)
133  #define	HCONNECT	(1 << 3)
134  #define	HDISCONNECT	(3 << 3)
135  #define UDC_START	GENMASK(6, 5)
136  #define	START		(1 << 5)
137  #define	STOP		(3 << 5)
138  #define ENABLE_EP	GENMASK(8, 7)
139  #define	ENABLE		(1 << 7)
140  #define	DISABLE		(3 << 7)
141  #define STALL_EP	GENMASK(10, 9)
142  #define	STALL		(1 << 9)
143  #define	UNSTALL		(3 << 9)
144  
145  #define MAX3420_CMD(c)		FIELD_PREP(GENMASK(7, 3), c)
146  #define MAX3420_SPI_CMD_RD(c)	(MAX3420_CMD(c) | (0 << 1))
147  #define MAX3420_SPI_CMD_WR(c)	(MAX3420_CMD(c) | (1 << 1))
148  
149  struct max3420_req {
150  	struct usb_request usb_req;
151  	struct list_head queue;
152  	struct max3420_ep *ep;
153  };
154  
155  struct max3420_ep {
156  	struct usb_ep ep_usb;
157  	struct max3420_udc *udc;
158  	struct list_head queue;
159  	char name[MAX3420_EPNAME_SIZE];
160  	unsigned int maxpacket;
161  	spinlock_t lock;
162  	int halted;
163  	u32 todo;
164  	int id;
165  };
166  
167  struct max3420_udc {
168  	struct usb_gadget gadget;
169  	struct max3420_ep ep[MAX3420_MAX_EPS];
170  	struct usb_gadget_driver *driver;
171  	struct task_struct *thread_task;
172  	int remote_wkp, is_selfpowered;
173  	bool vbus_active, softconnect;
174  	struct usb_ctrlrequest setup;
175  	struct mutex spi_bus_mutex;
176  	struct max3420_req ep0req;
177  	struct spi_device *spi;
178  	struct device *dev;
179  	spinlock_t lock;
180  	bool suspended;
181  	u8 ep0buf[64];
182  	u32 todo;
183  };
184  
185  #define to_max3420_req(r)	container_of((r), struct max3420_req, usb_req)
186  #define to_max3420_ep(e)	container_of((e), struct max3420_ep, ep_usb)
187  #define to_udc(g)		container_of((g), struct max3420_udc, gadget)
188  
189  #define DRIVER_DESC     "MAX3420 USB Device-Mode Driver"
190  static const char driver_name[] = "max3420-udc";
191  
192  /* Control endpoint configuration.*/
193  static const struct usb_endpoint_descriptor ep0_desc = {
194  	.bEndpointAddress	= USB_DIR_OUT,
195  	.bmAttributes		= USB_ENDPOINT_XFER_CONTROL,
196  	.wMaxPacketSize		= cpu_to_le16(MAX3420_EP_MAX_PACKET),
197  };
198  
spi_ack_ctrl(struct max3420_udc * udc)199  static void spi_ack_ctrl(struct max3420_udc *udc)
200  {
201  	struct spi_device *spi = udc->spi;
202  	struct spi_transfer transfer;
203  	struct spi_message msg;
204  	u8 txdata[1];
205  
206  	memset(&transfer, 0, sizeof(transfer));
207  
208  	spi_message_init(&msg);
209  
210  	txdata[0] = MAX3420_ACKSTAT;
211  	transfer.tx_buf = txdata;
212  	transfer.len = 1;
213  
214  	spi_message_add_tail(&transfer, &msg);
215  	spi_sync(spi, &msg);
216  }
217  
spi_rd8_ack(struct max3420_udc * udc,u8 reg,int actstat)218  static u8 spi_rd8_ack(struct max3420_udc *udc, u8 reg, int actstat)
219  {
220  	struct spi_device *spi = udc->spi;
221  	struct spi_transfer transfer;
222  	struct spi_message msg;
223  	u8 txdata[2], rxdata[2];
224  
225  	memset(&transfer, 0, sizeof(transfer));
226  
227  	spi_message_init(&msg);
228  
229  	txdata[0] = MAX3420_SPI_CMD_RD(reg) | (actstat ? MAX3420_ACKSTAT : 0);
230  	transfer.tx_buf = txdata;
231  	transfer.rx_buf = rxdata;
232  	transfer.len = 2;
233  
234  	spi_message_add_tail(&transfer, &msg);
235  	spi_sync(spi, &msg);
236  
237  	return rxdata[1];
238  }
239  
spi_rd8(struct max3420_udc * udc,u8 reg)240  static u8 spi_rd8(struct max3420_udc *udc, u8 reg)
241  {
242  	return spi_rd8_ack(udc, reg, 0);
243  }
244  
spi_wr8_ack(struct max3420_udc * udc,u8 reg,u8 val,int actstat)245  static void spi_wr8_ack(struct max3420_udc *udc, u8 reg, u8 val, int actstat)
246  {
247  	struct spi_device *spi = udc->spi;
248  	struct spi_transfer transfer;
249  	struct spi_message msg;
250  	u8 txdata[2];
251  
252  	memset(&transfer, 0, sizeof(transfer));
253  
254  	spi_message_init(&msg);
255  
256  	txdata[0] = MAX3420_SPI_CMD_WR(reg) | (actstat ? MAX3420_ACKSTAT : 0);
257  	txdata[1] = val;
258  
259  	transfer.tx_buf = txdata;
260  	transfer.len = 2;
261  
262  	spi_message_add_tail(&transfer, &msg);
263  	spi_sync(spi, &msg);
264  }
265  
spi_wr8(struct max3420_udc * udc,u8 reg,u8 val)266  static void spi_wr8(struct max3420_udc *udc, u8 reg, u8 val)
267  {
268  	spi_wr8_ack(udc, reg, val, 0);
269  }
270  
spi_rd_buf(struct max3420_udc * udc,u8 reg,void * buf,u8 len)271  static void spi_rd_buf(struct max3420_udc *udc, u8 reg, void *buf, u8 len)
272  {
273  	struct spi_device *spi = udc->spi;
274  	struct spi_transfer transfer;
275  	struct spi_message msg;
276  	u8 local_buf[MAX3420_EP_MAX_PACKET + 1] = {};
277  
278  	memset(&transfer, 0, sizeof(transfer));
279  
280  	spi_message_init(&msg);
281  
282  	local_buf[0] = MAX3420_SPI_CMD_RD(reg);
283  	transfer.tx_buf = &local_buf[0];
284  	transfer.rx_buf = &local_buf[0];
285  	transfer.len = len + 1;
286  
287  	spi_message_add_tail(&transfer, &msg);
288  	spi_sync(spi, &msg);
289  
290  	memcpy(buf, &local_buf[1], len);
291  }
292  
spi_wr_buf(struct max3420_udc * udc,u8 reg,void * buf,u8 len)293  static void spi_wr_buf(struct max3420_udc *udc, u8 reg, void *buf, u8 len)
294  {
295  	struct spi_device *spi = udc->spi;
296  	struct spi_transfer transfer;
297  	struct spi_message msg;
298  	u8 local_buf[MAX3420_EP_MAX_PACKET + 1] = {};
299  
300  	memset(&transfer, 0, sizeof(transfer));
301  
302  	spi_message_init(&msg);
303  
304  	local_buf[0] = MAX3420_SPI_CMD_WR(reg);
305  	memcpy(&local_buf[1], buf, len);
306  
307  	transfer.tx_buf = local_buf;
308  	transfer.len = len + 1;
309  
310  	spi_message_add_tail(&transfer, &msg);
311  	spi_sync(spi, &msg);
312  }
313  
spi_max3420_enable(struct max3420_ep * ep)314  static int spi_max3420_enable(struct max3420_ep *ep)
315  {
316  	struct max3420_udc *udc = ep->udc;
317  	unsigned long flags;
318  	u8 epdis, epien;
319  	int todo;
320  
321  	spin_lock_irqsave(&ep->lock, flags);
322  	todo = ep->todo & ENABLE_EP;
323  	ep->todo &= ~ENABLE_EP;
324  	spin_unlock_irqrestore(&ep->lock, flags);
325  
326  	if (!todo || ep->id == 0)
327  		return false;
328  
329  	epien = spi_rd8(udc, MAX3420_REG_EPIEN);
330  	epdis = spi_rd8(udc, MAX3420_REG_CLRTOGS);
331  
332  	if (todo == ENABLE) {
333  		epdis &= ~BIT(ep->id + 4);
334  		epien |= BIT(ep->id + 1);
335  	} else {
336  		epdis |= BIT(ep->id + 4);
337  		epien &= ~BIT(ep->id + 1);
338  	}
339  
340  	spi_wr8(udc, MAX3420_REG_CLRTOGS, epdis);
341  	spi_wr8(udc, MAX3420_REG_EPIEN, epien);
342  
343  	return true;
344  }
345  
spi_max3420_stall(struct max3420_ep * ep)346  static int spi_max3420_stall(struct max3420_ep *ep)
347  {
348  	struct max3420_udc *udc = ep->udc;
349  	unsigned long flags;
350  	u8 epstalls;
351  	int todo;
352  
353  	spin_lock_irqsave(&ep->lock, flags);
354  	todo = ep->todo & STALL_EP;
355  	ep->todo &= ~STALL_EP;
356  	spin_unlock_irqrestore(&ep->lock, flags);
357  
358  	if (!todo || ep->id == 0)
359  		return false;
360  
361  	epstalls = spi_rd8(udc, MAX3420_REG_EPSTALLS);
362  	if (todo == STALL) {
363  		ep->halted = 1;
364  		epstalls |= BIT(ep->id + 1);
365  	} else {
366  		u8 clrtogs;
367  
368  		ep->halted = 0;
369  		epstalls &= ~BIT(ep->id + 1);
370  		clrtogs = spi_rd8(udc, MAX3420_REG_CLRTOGS);
371  		clrtogs |= BIT(ep->id + 1);
372  		spi_wr8(udc, MAX3420_REG_CLRTOGS, clrtogs);
373  	}
374  	spi_wr8(udc, MAX3420_REG_EPSTALLS, epstalls | ACKSTAT);
375  
376  	return true;
377  }
378  
spi_max3420_rwkup(struct max3420_udc * udc)379  static int spi_max3420_rwkup(struct max3420_udc *udc)
380  {
381  	unsigned long flags;
382  	int wake_remote;
383  	u8 usbctl;
384  
385  	spin_lock_irqsave(&udc->lock, flags);
386  	wake_remote = udc->todo & REMOTE_WAKEUP;
387  	udc->todo &= ~REMOTE_WAKEUP;
388  	spin_unlock_irqrestore(&udc->lock, flags);
389  
390  	if (!wake_remote || !udc->suspended)
391  		return false;
392  
393  	/* Set Remote-WkUp Signal*/
394  	usbctl = spi_rd8(udc, MAX3420_REG_USBCTL);
395  	usbctl |= SIGRWU;
396  	spi_wr8(udc, MAX3420_REG_USBCTL, usbctl);
397  
398  	msleep_interruptible(5);
399  
400  	/* Clear Remote-WkUp Signal*/
401  	usbctl = spi_rd8(udc, MAX3420_REG_USBCTL);
402  	usbctl &= ~SIGRWU;
403  	spi_wr8(udc, MAX3420_REG_USBCTL, usbctl);
404  
405  	udc->suspended = false;
406  
407  	return true;
408  }
409  
410  static void max3420_nuke(struct max3420_ep *ep, int status);
__max3420_stop(struct max3420_udc * udc)411  static void __max3420_stop(struct max3420_udc *udc)
412  {
413  	u8 val;
414  	int i;
415  
416  	/* clear all pending requests */
417  	for (i = 1; i < MAX3420_MAX_EPS; i++)
418  		max3420_nuke(&udc->ep[i], -ECONNRESET);
419  
420  	/* Disable IRQ to CPU */
421  	spi_wr8(udc, MAX3420_REG_CPUCTL, 0);
422  
423  	val = spi_rd8(udc, MAX3420_REG_USBCTL);
424  	val |= PWRDOWN;
425  	if (udc->is_selfpowered)
426  		val &= ~HOSCSTEN;
427  	else
428  		val |= HOSCSTEN;
429  	spi_wr8(udc, MAX3420_REG_USBCTL, val);
430  }
431  
__max3420_start(struct max3420_udc * udc)432  static void __max3420_start(struct max3420_udc *udc)
433  {
434  	u8 val;
435  
436  	/* Need this delay if bus-powered,
437  	 * but even for self-powered it helps stability
438  	 */
439  	msleep_interruptible(250);
440  
441  	/* configure SPI */
442  	spi_wr8(udc, MAX3420_REG_PINCTL, FDUPSPI);
443  
444  	/* Chip Reset */
445  	spi_wr8(udc, MAX3420_REG_USBCTL, CHIPRES);
446  	msleep_interruptible(5);
447  	spi_wr8(udc, MAX3420_REG_USBCTL, 0);
448  
449  	/* Poll for OSC to stabilize */
450  	while (1) {
451  		val = spi_rd8(udc, MAX3420_REG_USBIRQ);
452  		if (val & OSCOKIRQ)
453  			break;
454  		cond_resched();
455  	}
456  
457  	/* Enable PULL-UP only when Vbus detected */
458  	val = spi_rd8(udc, MAX3420_REG_USBCTL);
459  	val |= VBGATE | CONNECT;
460  	spi_wr8(udc, MAX3420_REG_USBCTL, val);
461  
462  	val = URESDNIRQ | URESIRQ;
463  	if (udc->is_selfpowered)
464  		val |= NOVBUSIRQ;
465  	spi_wr8(udc, MAX3420_REG_USBIEN, val);
466  
467  	/* Enable only EP0 interrupts */
468  	val = IN0BAVIRQ | OUT0DAVIRQ | SUDAVIRQ;
469  	spi_wr8(udc, MAX3420_REG_EPIEN, val);
470  
471  	/* Enable IRQ to CPU */
472  	spi_wr8(udc, MAX3420_REG_CPUCTL, IE);
473  }
474  
max3420_start(struct max3420_udc * udc)475  static int max3420_start(struct max3420_udc *udc)
476  {
477  	unsigned long flags;
478  	int todo;
479  
480  	spin_lock_irqsave(&udc->lock, flags);
481  	todo = udc->todo & UDC_START;
482  	udc->todo &= ~UDC_START;
483  	spin_unlock_irqrestore(&udc->lock, flags);
484  
485  	if (!todo)
486  		return false;
487  
488  	if (udc->vbus_active && udc->softconnect)
489  		__max3420_start(udc);
490  	else
491  		__max3420_stop(udc);
492  
493  	return true;
494  }
495  
max3420_vbus_handler(int irq,void * dev_id)496  static irqreturn_t max3420_vbus_handler(int irq, void *dev_id)
497  {
498  	struct max3420_udc *udc = dev_id;
499  	unsigned long flags;
500  
501  	spin_lock_irqsave(&udc->lock, flags);
502  	/* its a vbus change interrupt */
503  	udc->vbus_active = !udc->vbus_active;
504  	udc->todo |= UDC_START;
505  	usb_udc_vbus_handler(&udc->gadget, udc->vbus_active);
506  	usb_gadget_set_state(&udc->gadget, udc->vbus_active
507  			     ? USB_STATE_POWERED : USB_STATE_NOTATTACHED);
508  	spin_unlock_irqrestore(&udc->lock, flags);
509  
510  	if (udc->thread_task)
511  		wake_up_process(udc->thread_task);
512  
513  	return IRQ_HANDLED;
514  }
515  
max3420_irq_handler(int irq,void * dev_id)516  static irqreturn_t max3420_irq_handler(int irq, void *dev_id)
517  {
518  	struct max3420_udc *udc = dev_id;
519  	struct spi_device *spi = udc->spi;
520  	unsigned long flags;
521  
522  	spin_lock_irqsave(&udc->lock, flags);
523  	if ((udc->todo & ENABLE_IRQ) == 0) {
524  		disable_irq_nosync(spi->irq);
525  		udc->todo |= ENABLE_IRQ;
526  	}
527  	spin_unlock_irqrestore(&udc->lock, flags);
528  
529  	if (udc->thread_task)
530  		wake_up_process(udc->thread_task);
531  
532  	return IRQ_HANDLED;
533  }
534  
max3420_getstatus(struct max3420_udc * udc)535  static void max3420_getstatus(struct max3420_udc *udc)
536  {
537  	struct max3420_ep *ep;
538  	u16 status = 0;
539  
540  	switch (udc->setup.bRequestType & USB_RECIP_MASK) {
541  	case USB_RECIP_DEVICE:
542  		/* Get device status */
543  		status = udc->gadget.is_selfpowered << USB_DEVICE_SELF_POWERED;
544  		status |= (udc->remote_wkp << USB_DEVICE_REMOTE_WAKEUP);
545  		break;
546  	case USB_RECIP_INTERFACE:
547  		if (udc->driver->setup(&udc->gadget, &udc->setup) < 0)
548  			goto stall;
549  		break;
550  	case USB_RECIP_ENDPOINT:
551  		ep = &udc->ep[udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK];
552  		if (udc->setup.wIndex & USB_DIR_IN) {
553  			if (!ep->ep_usb.caps.dir_in)
554  				goto stall;
555  		} else {
556  			if (!ep->ep_usb.caps.dir_out)
557  				goto stall;
558  		}
559  		if (ep->halted)
560  			status = 1 << USB_ENDPOINT_HALT;
561  		break;
562  	default:
563  		goto stall;
564  	}
565  
566  	status = cpu_to_le16(status);
567  	spi_wr_buf(udc, MAX3420_REG_EP0FIFO, &status, 2);
568  	spi_wr8_ack(udc, MAX3420_REG_EP0BC, 2, 1);
569  	return;
570  stall:
571  	dev_err(udc->dev, "Can't respond to getstatus request\n");
572  	spi_wr8(udc, MAX3420_REG_EPSTALLS, STLEP0IN | STLEP0OUT | STLSTAT);
573  }
574  
max3420_set_clear_feature(struct max3420_udc * udc)575  static void max3420_set_clear_feature(struct max3420_udc *udc)
576  {
577  	struct max3420_ep *ep;
578  	int set = udc->setup.bRequest == USB_REQ_SET_FEATURE;
579  	unsigned long flags;
580  	int id;
581  
582  	switch (udc->setup.bRequestType) {
583  	case USB_RECIP_DEVICE:
584  		if (udc->setup.wValue != USB_DEVICE_REMOTE_WAKEUP)
585  			break;
586  
587  		if (udc->setup.bRequest == USB_REQ_SET_FEATURE)
588  			udc->remote_wkp = 1;
589  		else
590  			udc->remote_wkp = 0;
591  
592  		return spi_ack_ctrl(udc);
593  
594  	case USB_RECIP_ENDPOINT:
595  		if (udc->setup.wValue != USB_ENDPOINT_HALT)
596  			break;
597  
598  		id = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
599  		ep = &udc->ep[id];
600  
601  		spin_lock_irqsave(&ep->lock, flags);
602  		ep->todo &= ~STALL_EP;
603  		if (set)
604  			ep->todo |= STALL;
605  		else
606  			ep->todo |= UNSTALL;
607  		spin_unlock_irqrestore(&ep->lock, flags);
608  
609  		spi_max3420_stall(ep);
610  		return;
611  	default:
612  		break;
613  	}
614  
615  	dev_err(udc->dev, "Can't respond to SET/CLEAR FEATURE\n");
616  	spi_wr8(udc, MAX3420_REG_EPSTALLS, STLEP0IN | STLEP0OUT | STLSTAT);
617  }
618  
max3420_handle_setup(struct max3420_udc * udc)619  static void max3420_handle_setup(struct max3420_udc *udc)
620  {
621  	struct usb_ctrlrequest setup;
622  
623  	spi_rd_buf(udc, MAX3420_REG_SUDFIFO, (void *)&setup, 8);
624  
625  	udc->setup = setup;
626  	udc->setup.wValue = cpu_to_le16(setup.wValue);
627  	udc->setup.wIndex = cpu_to_le16(setup.wIndex);
628  	udc->setup.wLength = cpu_to_le16(setup.wLength);
629  
630  	switch (udc->setup.bRequest) {
631  	case USB_REQ_GET_STATUS:
632  		/* Data+Status phase form udc */
633  		if ((udc->setup.bRequestType &
634  				(USB_DIR_IN | USB_TYPE_MASK)) !=
635  				(USB_DIR_IN | USB_TYPE_STANDARD)) {
636  			break;
637  		}
638  		return max3420_getstatus(udc);
639  	case USB_REQ_SET_ADDRESS:
640  		/* Status phase from udc */
641  		if (udc->setup.bRequestType != (USB_DIR_OUT |
642  				USB_TYPE_STANDARD | USB_RECIP_DEVICE)) {
643  			break;
644  		}
645  		spi_rd8_ack(udc, MAX3420_REG_FNADDR, 1);
646  		dev_dbg(udc->dev, "Assigned Address=%d\n", udc->setup.wValue);
647  		return;
648  	case USB_REQ_CLEAR_FEATURE:
649  	case USB_REQ_SET_FEATURE:
650  		/* Requests with no data phase, status phase from udc */
651  		if ((udc->setup.bRequestType & USB_TYPE_MASK)
652  				!= USB_TYPE_STANDARD)
653  			break;
654  		return max3420_set_clear_feature(udc);
655  	default:
656  		break;
657  	}
658  
659  	if (udc->driver->setup(&udc->gadget, &setup) < 0) {
660  		/* Stall EP0 */
661  		spi_wr8(udc, MAX3420_REG_EPSTALLS,
662  			STLEP0IN | STLEP0OUT | STLSTAT);
663  	}
664  }
665  
max3420_req_done(struct max3420_req * req,int status)666  static void max3420_req_done(struct max3420_req *req, int status)
667  {
668  	struct max3420_ep *ep = req->ep;
669  	struct max3420_udc *udc = ep->udc;
670  
671  	if (req->usb_req.status == -EINPROGRESS)
672  		req->usb_req.status = status;
673  	else
674  		status = req->usb_req.status;
675  
676  	if (status && status != -ESHUTDOWN)
677  		dev_err(udc->dev, "%s done %p, status %d\n",
678  			ep->ep_usb.name, req, status);
679  
680  	if (req->usb_req.complete)
681  		req->usb_req.complete(&ep->ep_usb, &req->usb_req);
682  }
683  
max3420_do_data(struct max3420_udc * udc,int ep_id,int in)684  static int max3420_do_data(struct max3420_udc *udc, int ep_id, int in)
685  {
686  	struct max3420_ep *ep = &udc->ep[ep_id];
687  	struct max3420_req *req;
688  	int done, length, psz;
689  	void *buf;
690  
691  	if (list_empty(&ep->queue))
692  		return false;
693  
694  	req = list_first_entry(&ep->queue, struct max3420_req, queue);
695  	buf = req->usb_req.buf + req->usb_req.actual;
696  
697  	psz = ep->ep_usb.maxpacket;
698  	length = req->usb_req.length - req->usb_req.actual;
699  	length = min(length, psz);
700  
701  	if (length == 0) {
702  		done = 1;
703  		goto xfer_done;
704  	}
705  
706  	done = 0;
707  	if (in) {
708  		prefetch(buf);
709  		spi_wr_buf(udc, MAX3420_REG_EP0FIFO + ep_id, buf, length);
710  		spi_wr8(udc, MAX3420_REG_EP0BC + ep_id, length);
711  		if (length < psz)
712  			done = 1;
713  	} else {
714  		psz = spi_rd8(udc, MAX3420_REG_EP0BC + ep_id);
715  		length = min(length, psz);
716  		prefetchw(buf);
717  		spi_rd_buf(udc, MAX3420_REG_EP0FIFO + ep_id, buf, length);
718  		if (length < ep->ep_usb.maxpacket)
719  			done = 1;
720  	}
721  
722  	req->usb_req.actual += length;
723  
724  	if (req->usb_req.actual == req->usb_req.length)
725  		done = 1;
726  
727  xfer_done:
728  	if (done) {
729  		unsigned long flags;
730  
731  		spin_lock_irqsave(&ep->lock, flags);
732  		list_del_init(&req->queue);
733  		spin_unlock_irqrestore(&ep->lock, flags);
734  
735  		if (ep_id == 0)
736  			spi_ack_ctrl(udc);
737  
738  		max3420_req_done(req, 0);
739  	}
740  
741  	return true;
742  }
743  
max3420_handle_irqs(struct max3420_udc * udc)744  static int max3420_handle_irqs(struct max3420_udc *udc)
745  {
746  	u8 epien, epirq, usbirq, usbien, reg[4];
747  	bool ret = false;
748  
749  	spi_rd_buf(udc, MAX3420_REG_EPIRQ, reg, 4);
750  	epirq = reg[0];
751  	epien = reg[1];
752  	usbirq = reg[2];
753  	usbien = reg[3];
754  
755  	usbirq &= usbien;
756  	epirq &= epien;
757  
758  	if (epirq & SUDAVIRQ) {
759  		spi_wr8(udc, MAX3420_REG_EPIRQ, SUDAVIRQ);
760  		max3420_handle_setup(udc);
761  		return true;
762  	}
763  
764  	if (usbirq & VBUSIRQ) {
765  		spi_wr8(udc, MAX3420_REG_USBIRQ, VBUSIRQ);
766  		dev_dbg(udc->dev, "Cable plugged in\n");
767  		return true;
768  	}
769  
770  	if (usbirq & NOVBUSIRQ) {
771  		spi_wr8(udc, MAX3420_REG_USBIRQ, NOVBUSIRQ);
772  		dev_dbg(udc->dev, "Cable pulled out\n");
773  		return true;
774  	}
775  
776  	if (usbirq & URESIRQ) {
777  		spi_wr8(udc, MAX3420_REG_USBIRQ, URESIRQ);
778  		dev_dbg(udc->dev, "USB Reset - Start\n");
779  		return true;
780  	}
781  
782  	if (usbirq & URESDNIRQ) {
783  		spi_wr8(udc, MAX3420_REG_USBIRQ, URESDNIRQ);
784  		dev_dbg(udc->dev, "USB Reset - END\n");
785  		spi_wr8(udc, MAX3420_REG_USBIEN, URESDNIRQ | URESIRQ);
786  		spi_wr8(udc, MAX3420_REG_EPIEN, SUDAVIRQ | IN0BAVIRQ
787  			| OUT0DAVIRQ);
788  		return true;
789  	}
790  
791  	if (usbirq & SUSPIRQ) {
792  		spi_wr8(udc, MAX3420_REG_USBIRQ, SUSPIRQ);
793  		dev_dbg(udc->dev, "USB Suspend - Enter\n");
794  		udc->suspended = true;
795  		return true;
796  	}
797  
798  	if (usbirq & BUSACTIRQ) {
799  		spi_wr8(udc, MAX3420_REG_USBIRQ, BUSACTIRQ);
800  		dev_dbg(udc->dev, "USB Suspend - Exit\n");
801  		udc->suspended = false;
802  		return true;
803  	}
804  
805  	if (usbirq & RWUDNIRQ) {
806  		spi_wr8(udc, MAX3420_REG_USBIRQ, RWUDNIRQ);
807  		dev_dbg(udc->dev, "Asked Host to wakeup\n");
808  		return true;
809  	}
810  
811  	if (usbirq & OSCOKIRQ) {
812  		spi_wr8(udc, MAX3420_REG_USBIRQ, OSCOKIRQ);
813  		dev_dbg(udc->dev, "Osc stabilized, start work\n");
814  		return true;
815  	}
816  
817  	if (epirq & OUT0DAVIRQ && max3420_do_data(udc, 0, 0)) {
818  		spi_wr8_ack(udc, MAX3420_REG_EPIRQ, OUT0DAVIRQ, 1);
819  		ret = true;
820  	}
821  
822  	if (epirq & IN0BAVIRQ && max3420_do_data(udc, 0, 1))
823  		ret = true;
824  
825  	if (epirq & OUT1DAVIRQ && max3420_do_data(udc, 1, 0)) {
826  		spi_wr8_ack(udc, MAX3420_REG_EPIRQ, OUT1DAVIRQ, 1);
827  		ret = true;
828  	}
829  
830  	if (epirq & IN2BAVIRQ && max3420_do_data(udc, 2, 1))
831  		ret = true;
832  
833  	if (epirq & IN3BAVIRQ && max3420_do_data(udc, 3, 1))
834  		ret = true;
835  
836  	return ret;
837  }
838  
max3420_thread(void * dev_id)839  static int max3420_thread(void *dev_id)
840  {
841  	struct max3420_udc *udc = dev_id;
842  	struct spi_device *spi = udc->spi;
843  	int i, loop_again = 1;
844  	unsigned long flags;
845  
846  	while (!kthread_should_stop()) {
847  		if (!loop_again) {
848  			ktime_t kt = ns_to_ktime(1000 * 1000 * 250); /* 250ms */
849  
850  			set_current_state(TASK_INTERRUPTIBLE);
851  
852  			spin_lock_irqsave(&udc->lock, flags);
853  			if (udc->todo & ENABLE_IRQ) {
854  				enable_irq(spi->irq);
855  				udc->todo &= ~ENABLE_IRQ;
856  			}
857  			spin_unlock_irqrestore(&udc->lock, flags);
858  
859  			schedule_hrtimeout(&kt, HRTIMER_MODE_REL);
860  		}
861  		loop_again = 0;
862  
863  		mutex_lock(&udc->spi_bus_mutex);
864  
865  		/* If bus-vbus_active and disconnected */
866  		if (!udc->vbus_active || !udc->softconnect)
867  			goto loop;
868  
869  		if (max3420_start(udc)) {
870  			loop_again = 1;
871  			goto loop;
872  		}
873  
874  		if (max3420_handle_irqs(udc)) {
875  			loop_again = 1;
876  			goto loop;
877  		}
878  
879  		if (spi_max3420_rwkup(udc)) {
880  			loop_again = 1;
881  			goto loop;
882  		}
883  
884  		max3420_do_data(udc, 0, 1); /* get done with the EP0 ZLP */
885  
886  		for (i = 1; i < MAX3420_MAX_EPS; i++) {
887  			struct max3420_ep *ep = &udc->ep[i];
888  
889  			if (spi_max3420_enable(ep))
890  				loop_again = 1;
891  			if (spi_max3420_stall(ep))
892  				loop_again = 1;
893  		}
894  loop:
895  		mutex_unlock(&udc->spi_bus_mutex);
896  	}
897  
898  	set_current_state(TASK_RUNNING);
899  	dev_info(udc->dev, "SPI thread exiting\n");
900  	return 0;
901  }
902  
max3420_ep_set_halt(struct usb_ep * _ep,int stall)903  static int max3420_ep_set_halt(struct usb_ep *_ep, int stall)
904  {
905  	struct max3420_ep *ep = to_max3420_ep(_ep);
906  	struct max3420_udc *udc = ep->udc;
907  	unsigned long flags;
908  
909  	spin_lock_irqsave(&ep->lock, flags);
910  
911  	ep->todo &= ~STALL_EP;
912  	if (stall)
913  		ep->todo |= STALL;
914  	else
915  		ep->todo |= UNSTALL;
916  
917  	spin_unlock_irqrestore(&ep->lock, flags);
918  
919  	wake_up_process(udc->thread_task);
920  
921  	dev_dbg(udc->dev, "%sStall %s\n", stall ? "" : "Un", ep->name);
922  	return 0;
923  }
924  
__max3420_ep_enable(struct max3420_ep * ep,const struct usb_endpoint_descriptor * desc)925  static int __max3420_ep_enable(struct max3420_ep *ep,
926  			       const struct usb_endpoint_descriptor *desc)
927  {
928  	unsigned int maxp = usb_endpoint_maxp(desc);
929  	unsigned long flags;
930  
931  	spin_lock_irqsave(&ep->lock, flags);
932  	ep->ep_usb.desc = desc;
933  	ep->ep_usb.maxpacket = maxp;
934  
935  	ep->todo &= ~ENABLE_EP;
936  	ep->todo |= ENABLE;
937  	spin_unlock_irqrestore(&ep->lock, flags);
938  
939  	return 0;
940  }
941  
max3420_ep_enable(struct usb_ep * _ep,const struct usb_endpoint_descriptor * desc)942  static int max3420_ep_enable(struct usb_ep *_ep,
943  			     const struct usb_endpoint_descriptor *desc)
944  {
945  	struct max3420_ep *ep = to_max3420_ep(_ep);
946  	struct max3420_udc *udc = ep->udc;
947  
948  	__max3420_ep_enable(ep, desc);
949  
950  	wake_up_process(udc->thread_task);
951  
952  	return 0;
953  }
954  
max3420_nuke(struct max3420_ep * ep,int status)955  static void max3420_nuke(struct max3420_ep *ep, int status)
956  {
957  	struct max3420_req *req, *r;
958  	unsigned long flags;
959  
960  	spin_lock_irqsave(&ep->lock, flags);
961  
962  	list_for_each_entry_safe(req, r, &ep->queue, queue) {
963  		list_del_init(&req->queue);
964  
965  		spin_unlock_irqrestore(&ep->lock, flags);
966  		max3420_req_done(req, status);
967  		spin_lock_irqsave(&ep->lock, flags);
968  	}
969  
970  	spin_unlock_irqrestore(&ep->lock, flags);
971  }
972  
__max3420_ep_disable(struct max3420_ep * ep)973  static void __max3420_ep_disable(struct max3420_ep *ep)
974  {
975  	struct max3420_udc *udc = ep->udc;
976  	unsigned long flags;
977  
978  	spin_lock_irqsave(&ep->lock, flags);
979  
980  	ep->ep_usb.desc = NULL;
981  
982  	ep->todo &= ~ENABLE_EP;
983  	ep->todo |= DISABLE;
984  
985  	spin_unlock_irqrestore(&ep->lock, flags);
986  
987  	dev_dbg(udc->dev, "Disabled %s\n", ep->name);
988  }
989  
max3420_ep_disable(struct usb_ep * _ep)990  static int max3420_ep_disable(struct usb_ep *_ep)
991  {
992  	struct max3420_ep *ep = to_max3420_ep(_ep);
993  	struct max3420_udc *udc = ep->udc;
994  
995  	max3420_nuke(ep, -ESHUTDOWN);
996  
997  	__max3420_ep_disable(ep);
998  
999  	wake_up_process(udc->thread_task);
1000  
1001  	return 0;
1002  }
1003  
max3420_alloc_request(struct usb_ep * _ep,gfp_t gfp_flags)1004  static struct usb_request *max3420_alloc_request(struct usb_ep *_ep,
1005  						 gfp_t gfp_flags)
1006  {
1007  	struct max3420_ep *ep = to_max3420_ep(_ep);
1008  	struct max3420_req *req;
1009  
1010  	req = kzalloc(sizeof(*req), gfp_flags);
1011  	if (!req)
1012  		return NULL;
1013  
1014  	req->ep = ep;
1015  
1016  	return &req->usb_req;
1017  }
1018  
max3420_free_request(struct usb_ep * _ep,struct usb_request * _req)1019  static void max3420_free_request(struct usb_ep *_ep, struct usb_request *_req)
1020  {
1021  	kfree(to_max3420_req(_req));
1022  }
1023  
max3420_ep_queue(struct usb_ep * _ep,struct usb_request * _req,gfp_t ignored)1024  static int max3420_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
1025  			    gfp_t ignored)
1026  {
1027  	struct max3420_req *req = to_max3420_req(_req);
1028  	struct max3420_ep *ep  = to_max3420_ep(_ep);
1029  	struct max3420_udc *udc = ep->udc;
1030  	unsigned long flags;
1031  
1032  	_req->status = -EINPROGRESS;
1033  	_req->actual = 0;
1034  
1035  	spin_lock_irqsave(&ep->lock, flags);
1036  	list_add_tail(&req->queue, &ep->queue);
1037  	spin_unlock_irqrestore(&ep->lock, flags);
1038  
1039  	wake_up_process(udc->thread_task);
1040  	return 0;
1041  }
1042  
max3420_ep_dequeue(struct usb_ep * _ep,struct usb_request * _req)1043  static int max3420_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
1044  {
1045  	struct max3420_req *t = NULL;
1046  	struct max3420_req *req = to_max3420_req(_req);
1047  	struct max3420_req *iter;
1048  	struct max3420_ep *ep = to_max3420_ep(_ep);
1049  	unsigned long flags;
1050  
1051  	spin_lock_irqsave(&ep->lock, flags);
1052  
1053  	/* Pluck the descriptor from queue */
1054  	list_for_each_entry(iter, &ep->queue, queue) {
1055  		if (iter != req)
1056  			continue;
1057  		list_del_init(&req->queue);
1058  		t = iter;
1059  		break;
1060  	}
1061  
1062  	spin_unlock_irqrestore(&ep->lock, flags);
1063  
1064  	if (t)
1065  		max3420_req_done(req, -ECONNRESET);
1066  
1067  	return 0;
1068  }
1069  
1070  static const struct usb_ep_ops max3420_ep_ops = {
1071  	.enable		= max3420_ep_enable,
1072  	.disable	= max3420_ep_disable,
1073  	.alloc_request	= max3420_alloc_request,
1074  	.free_request	= max3420_free_request,
1075  	.queue		= max3420_ep_queue,
1076  	.dequeue	= max3420_ep_dequeue,
1077  	.set_halt	= max3420_ep_set_halt,
1078  };
1079  
max3420_wakeup(struct usb_gadget * gadget)1080  static int max3420_wakeup(struct usb_gadget *gadget)
1081  {
1082  	struct max3420_udc *udc = to_udc(gadget);
1083  	unsigned long flags;
1084  	int ret = -EINVAL;
1085  
1086  	spin_lock_irqsave(&udc->lock, flags);
1087  
1088  	/* Only if wakeup allowed by host */
1089  	if (udc->remote_wkp) {
1090  		udc->todo |= REMOTE_WAKEUP;
1091  		ret = 0;
1092  	}
1093  
1094  	spin_unlock_irqrestore(&udc->lock, flags);
1095  
1096  	if (udc->thread_task)
1097  		wake_up_process(udc->thread_task);
1098  	return ret;
1099  }
1100  
max3420_udc_start(struct usb_gadget * gadget,struct usb_gadget_driver * driver)1101  static int max3420_udc_start(struct usb_gadget *gadget,
1102  			     struct usb_gadget_driver *driver)
1103  {
1104  	struct max3420_udc *udc = to_udc(gadget);
1105  	unsigned long flags;
1106  
1107  	spin_lock_irqsave(&udc->lock, flags);
1108  	/* hook up the driver */
1109  	udc->driver = driver;
1110  	udc->gadget.speed = USB_SPEED_FULL;
1111  
1112  	udc->gadget.is_selfpowered = udc->is_selfpowered;
1113  	udc->remote_wkp = 0;
1114  	udc->softconnect = true;
1115  	udc->todo |= UDC_START;
1116  	spin_unlock_irqrestore(&udc->lock, flags);
1117  
1118  	if (udc->thread_task)
1119  		wake_up_process(udc->thread_task);
1120  
1121  	return 0;
1122  }
1123  
max3420_udc_stop(struct usb_gadget * gadget)1124  static int max3420_udc_stop(struct usb_gadget *gadget)
1125  {
1126  	struct max3420_udc *udc = to_udc(gadget);
1127  	unsigned long flags;
1128  
1129  	spin_lock_irqsave(&udc->lock, flags);
1130  	udc->is_selfpowered = udc->gadget.is_selfpowered;
1131  	udc->gadget.speed = USB_SPEED_UNKNOWN;
1132  	udc->driver = NULL;
1133  	udc->softconnect = false;
1134  	udc->todo |= UDC_START;
1135  	spin_unlock_irqrestore(&udc->lock, flags);
1136  
1137  	if (udc->thread_task)
1138  		wake_up_process(udc->thread_task);
1139  
1140  	return 0;
1141  }
1142  
1143  static const struct usb_gadget_ops max3420_udc_ops = {
1144  	.udc_start	= max3420_udc_start,
1145  	.udc_stop	= max3420_udc_stop,
1146  	.wakeup		= max3420_wakeup,
1147  };
1148  
max3420_eps_init(struct max3420_udc * udc)1149  static void max3420_eps_init(struct max3420_udc *udc)
1150  {
1151  	int idx;
1152  
1153  	INIT_LIST_HEAD(&udc->gadget.ep_list);
1154  
1155  	for (idx = 0; idx < MAX3420_MAX_EPS; idx++) {
1156  		struct max3420_ep *ep = &udc->ep[idx];
1157  
1158  		spin_lock_init(&ep->lock);
1159  		INIT_LIST_HEAD(&ep->queue);
1160  
1161  		ep->udc = udc;
1162  		ep->id = idx;
1163  		ep->halted = 0;
1164  		ep->maxpacket = 0;
1165  		ep->ep_usb.name = ep->name;
1166  		ep->ep_usb.ops = &max3420_ep_ops;
1167  		usb_ep_set_maxpacket_limit(&ep->ep_usb, MAX3420_EP_MAX_PACKET);
1168  
1169  		if (idx == 0) { /* For EP0 */
1170  			ep->ep_usb.desc = &ep0_desc;
1171  			ep->ep_usb.maxpacket = usb_endpoint_maxp(&ep0_desc);
1172  			ep->ep_usb.caps.type_control = true;
1173  			ep->ep_usb.caps.dir_in = true;
1174  			ep->ep_usb.caps.dir_out = true;
1175  			snprintf(ep->name, MAX3420_EPNAME_SIZE, "ep0");
1176  			continue;
1177  		}
1178  
1179  		if (idx == 1) { /* EP1 is OUT */
1180  			ep->ep_usb.caps.dir_in = false;
1181  			ep->ep_usb.caps.dir_out = true;
1182  			snprintf(ep->name, MAX3420_EPNAME_SIZE, "ep1-bulk-out");
1183  		} else { /* EP2 & EP3 are IN */
1184  			ep->ep_usb.caps.dir_in = true;
1185  			ep->ep_usb.caps.dir_out = false;
1186  			snprintf(ep->name, MAX3420_EPNAME_SIZE,
1187  				 "ep%d-bulk-in", idx);
1188  		}
1189  		ep->ep_usb.caps.type_iso = false;
1190  		ep->ep_usb.caps.type_int = false;
1191  		ep->ep_usb.caps.type_bulk = true;
1192  
1193  		list_add_tail(&ep->ep_usb.ep_list,
1194  			      &udc->gadget.ep_list);
1195  	}
1196  }
1197  
max3420_probe(struct spi_device * spi)1198  static int max3420_probe(struct spi_device *spi)
1199  {
1200  	struct max3420_udc *udc;
1201  	int err, irq;
1202  	u8 reg[8];
1203  
1204  	if (spi->master->flags & SPI_MASTER_HALF_DUPLEX) {
1205  		dev_err(&spi->dev, "UDC needs full duplex to work\n");
1206  		return -EINVAL;
1207  	}
1208  
1209  	spi->mode = SPI_MODE_3;
1210  	spi->bits_per_word = 8;
1211  
1212  	err = spi_setup(spi);
1213  	if (err) {
1214  		dev_err(&spi->dev, "Unable to setup SPI bus\n");
1215  		return -EFAULT;
1216  	}
1217  
1218  	udc = devm_kzalloc(&spi->dev, sizeof(*udc), GFP_KERNEL);
1219  	if (!udc)
1220  		return -ENOMEM;
1221  
1222  	udc->spi = spi;
1223  
1224  	udc->remote_wkp = 0;
1225  
1226  	/* Setup gadget structure */
1227  	udc->gadget.ops = &max3420_udc_ops;
1228  	udc->gadget.max_speed = USB_SPEED_FULL;
1229  	udc->gadget.speed = USB_SPEED_UNKNOWN;
1230  	udc->gadget.ep0 = &udc->ep[0].ep_usb;
1231  	udc->gadget.name = driver_name;
1232  
1233  	spin_lock_init(&udc->lock);
1234  	mutex_init(&udc->spi_bus_mutex);
1235  
1236  	udc->ep0req.ep = &udc->ep[0];
1237  	udc->ep0req.usb_req.buf = udc->ep0buf;
1238  	INIT_LIST_HEAD(&udc->ep0req.queue);
1239  
1240  	/* setup Endpoints */
1241  	max3420_eps_init(udc);
1242  
1243  	/* configure SPI */
1244  	spi_rd_buf(udc, MAX3420_REG_EPIRQ, reg, 8);
1245  	spi_wr8(udc, MAX3420_REG_PINCTL, FDUPSPI);
1246  
1247  	err = usb_add_gadget_udc(&spi->dev, &udc->gadget);
1248  	if (err)
1249  		return err;
1250  
1251  	udc->dev = &udc->gadget.dev;
1252  
1253  	spi_set_drvdata(spi, udc);
1254  
1255  	irq = of_irq_get_byname(spi->dev.of_node, "udc");
1256  	err = devm_request_irq(&spi->dev, irq, max3420_irq_handler, 0,
1257  			       "max3420", udc);
1258  	if (err < 0)
1259  		goto del_gadget;
1260  
1261  	udc->thread_task = kthread_create(max3420_thread, udc,
1262  					  "max3420-thread");
1263  	if (IS_ERR(udc->thread_task)) {
1264  		err = PTR_ERR(udc->thread_task);
1265  		goto del_gadget;
1266  	}
1267  
1268  	irq = of_irq_get_byname(spi->dev.of_node, "vbus");
1269  	if (irq <= 0) { /* no vbus irq implies self-powered design */
1270  		udc->is_selfpowered = 1;
1271  		udc->vbus_active = true;
1272  		udc->todo |= UDC_START;
1273  		usb_udc_vbus_handler(&udc->gadget, udc->vbus_active);
1274  		usb_gadget_set_state(&udc->gadget, USB_STATE_POWERED);
1275  		max3420_start(udc);
1276  	} else {
1277  		udc->is_selfpowered = 0;
1278  		/* Detect current vbus status */
1279  		spi_rd_buf(udc, MAX3420_REG_EPIRQ, reg, 8);
1280  		if (reg[7] != 0xff)
1281  			udc->vbus_active = true;
1282  
1283  		err = devm_request_irq(&spi->dev, irq,
1284  				       max3420_vbus_handler, 0, "vbus", udc);
1285  		if (err < 0)
1286  			goto del_gadget;
1287  	}
1288  
1289  	return 0;
1290  
1291  del_gadget:
1292  	usb_del_gadget_udc(&udc->gadget);
1293  	return err;
1294  }
1295  
max3420_remove(struct spi_device * spi)1296  static void max3420_remove(struct spi_device *spi)
1297  {
1298  	struct max3420_udc *udc = spi_get_drvdata(spi);
1299  	unsigned long flags;
1300  
1301  	usb_del_gadget_udc(&udc->gadget);
1302  
1303  	spin_lock_irqsave(&udc->lock, flags);
1304  
1305  	kthread_stop(udc->thread_task);
1306  
1307  	spin_unlock_irqrestore(&udc->lock, flags);
1308  }
1309  
1310  static const struct of_device_id max3420_udc_of_match[] = {
1311  	{ .compatible = "maxim,max3420-udc"},
1312  	{ .compatible = "maxim,max3421-udc"},
1313  	{},
1314  };
1315  MODULE_DEVICE_TABLE(of, max3420_udc_of_match);
1316  
1317  static struct spi_driver max3420_driver = {
1318  	.driver = {
1319  		.name = "max3420-udc",
1320  		.of_match_table = max3420_udc_of_match,
1321  	},
1322  	.probe = max3420_probe,
1323  	.remove = max3420_remove,
1324  };
1325  
1326  module_spi_driver(max3420_driver);
1327  
1328  MODULE_DESCRIPTION(DRIVER_DESC);
1329  MODULE_AUTHOR("Jassi Brar <jaswinder.singh@linaro.org>");
1330  MODULE_LICENSE("GPL");
1331