xref: /linux/drivers/hid/i2c-hid/i2c-hid-core.c (revision 4b660dbd9ee2059850fd30e0df420ca7a38a1856)
1 /*
2  * HID over I2C protocol implementation
3  *
4  * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
5  * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
6  * Copyright (c) 2012 Red Hat, Inc
7  *
8  * This code is partly based on "USB HID support for Linux":
9  *
10  *  Copyright (c) 1999 Andreas Gal
11  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
12  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
13  *  Copyright (c) 2007-2008 Oliver Neukum
14  *  Copyright (c) 2006-2010 Jiri Kosina
15  *
16  * This file is subject to the terms and conditions of the GNU General Public
17  * License.  See the file COPYING in the main directory of this archive for
18  * more details.
19  */
20 
21 #include <linux/module.h>
22 #include <linux/i2c.h>
23 #include <linux/interrupt.h>
24 #include <linux/input.h>
25 #include <linux/irq.h>
26 #include <linux/delay.h>
27 #include <linux/slab.h>
28 #include <linux/pm.h>
29 #include <linux/pm_wakeirq.h>
30 #include <linux/device.h>
31 #include <linux/wait.h>
32 #include <linux/err.h>
33 #include <linux/string.h>
34 #include <linux/list.h>
35 #include <linux/jiffies.h>
36 #include <linux/kernel.h>
37 #include <linux/hid.h>
38 #include <linux/mutex.h>
39 #include <asm/unaligned.h>
40 
41 #include <drm/drm_panel.h>
42 
43 #include "../hid-ids.h"
44 #include "i2c-hid.h"
45 
46 /* quirks to control the device */
47 #define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET	BIT(0)
48 #define I2C_HID_QUIRK_BOGUS_IRQ			BIT(1)
49 #define I2C_HID_QUIRK_RESET_ON_RESUME		BIT(2)
50 #define I2C_HID_QUIRK_BAD_INPUT_SIZE		BIT(3)
51 #define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET	BIT(4)
52 #define I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND	BIT(5)
53 
54 /* Command opcodes */
55 #define I2C_HID_OPCODE_RESET			0x01
56 #define I2C_HID_OPCODE_GET_REPORT		0x02
57 #define I2C_HID_OPCODE_SET_REPORT		0x03
58 #define I2C_HID_OPCODE_GET_IDLE			0x04
59 #define I2C_HID_OPCODE_SET_IDLE			0x05
60 #define I2C_HID_OPCODE_GET_PROTOCOL		0x06
61 #define I2C_HID_OPCODE_SET_PROTOCOL		0x07
62 #define I2C_HID_OPCODE_SET_POWER		0x08
63 
64 /* flags */
65 #define I2C_HID_STARTED		0
66 #define I2C_HID_RESET_PENDING	1
67 #define I2C_HID_READ_PENDING	2
68 
69 #define I2C_HID_PWR_ON		0x00
70 #define I2C_HID_PWR_SLEEP	0x01
71 
72 #define i2c_hid_dbg(ihid, ...) dev_dbg(&(ihid)->client->dev, __VA_ARGS__)
73 
74 struct i2c_hid_desc {
75 	__le16 wHIDDescLength;
76 	__le16 bcdVersion;
77 	__le16 wReportDescLength;
78 	__le16 wReportDescRegister;
79 	__le16 wInputRegister;
80 	__le16 wMaxInputLength;
81 	__le16 wOutputRegister;
82 	__le16 wMaxOutputLength;
83 	__le16 wCommandRegister;
84 	__le16 wDataRegister;
85 	__le16 wVendorID;
86 	__le16 wProductID;
87 	__le16 wVersionID;
88 	__le32 reserved;
89 } __packed;
90 
91 /* The main device structure */
92 struct i2c_hid {
93 	struct i2c_client	*client;	/* i2c client */
94 	struct hid_device	*hid;	/* pointer to corresponding HID dev */
95 	struct i2c_hid_desc hdesc;		/* the HID Descriptor */
96 	__le16			wHIDDescRegister; /* location of the i2c
97 						   * register of the HID
98 						   * descriptor. */
99 	unsigned int		bufsize;	/* i2c buffer size */
100 	u8			*inbuf;		/* Input buffer */
101 	u8			*rawbuf;	/* Raw Input buffer */
102 	u8			*cmdbuf;	/* Command buffer */
103 
104 	unsigned long		flags;		/* device flags */
105 	unsigned long		quirks;		/* Various quirks */
106 
107 	wait_queue_head_t	wait;		/* For waiting the interrupt */
108 
109 	struct mutex		reset_lock;
110 
111 	struct i2chid_ops	*ops;
112 	struct drm_panel_follower panel_follower;
113 	struct work_struct	panel_follower_prepare_work;
114 	bool			is_panel_follower;
115 	bool			prepare_work_finished;
116 };
117 
118 static const struct i2c_hid_quirks {
119 	__u16 idVendor;
120 	__u16 idProduct;
121 	__u32 quirks;
122 } i2c_hid_quirks[] = {
123 	{ I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
124 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
125 	{ I2C_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_VOYO_WINPAD_A15,
126 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
127 	{ I2C_VENDOR_ID_RAYDIUM, I2C_PRODUCT_ID_RAYDIUM_3118,
128 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
129 	{ USB_VENDOR_ID_ALPS_JP, HID_ANY_ID,
130 		 I2C_HID_QUIRK_RESET_ON_RESUME },
131 	{ I2C_VENDOR_ID_SYNAPTICS, I2C_PRODUCT_ID_SYNAPTICS_SYNA2393,
132 		 I2C_HID_QUIRK_RESET_ON_RESUME },
133 	{ USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
134 		I2C_HID_QUIRK_BAD_INPUT_SIZE },
135 	{ I2C_VENDOR_ID_CIRQUE, I2C_PRODUCT_ID_CIRQUE_1063,
136 		I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND },
137 	/*
138 	 * Sending the wakeup after reset actually break ELAN touchscreen controller
139 	 */
140 	{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
141 		 I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET |
142 		 I2C_HID_QUIRK_BOGUS_IRQ },
143 	{ 0, 0 }
144 };
145 
146 /*
147  * i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
148  * @idVendor: the 16-bit vendor ID
149  * @idProduct: the 16-bit product ID
150  *
151  * Returns: a u32 quirks value.
152  */
153 static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
154 {
155 	u32 quirks = 0;
156 	int n;
157 
158 	for (n = 0; i2c_hid_quirks[n].idVendor; n++)
159 		if (i2c_hid_quirks[n].idVendor == idVendor &&
160 		    (i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
161 		     i2c_hid_quirks[n].idProduct == idProduct))
162 			quirks = i2c_hid_quirks[n].quirks;
163 
164 	return quirks;
165 }
166 
167 static int i2c_hid_xfer(struct i2c_hid *ihid,
168 			u8 *send_buf, int send_len, u8 *recv_buf, int recv_len)
169 {
170 	struct i2c_client *client = ihid->client;
171 	struct i2c_msg msgs[2] = { 0 };
172 	int n = 0;
173 	int ret;
174 
175 	if (send_len) {
176 		i2c_hid_dbg(ihid, "%s: cmd=%*ph\n",
177 			    __func__, send_len, send_buf);
178 
179 		msgs[n].addr = client->addr;
180 		msgs[n].flags = (client->flags & I2C_M_TEN) | I2C_M_DMA_SAFE;
181 		msgs[n].len = send_len;
182 		msgs[n].buf = send_buf;
183 		n++;
184 	}
185 
186 	if (recv_len) {
187 		msgs[n].addr = client->addr;
188 		msgs[n].flags = (client->flags & I2C_M_TEN) |
189 				I2C_M_RD | I2C_M_DMA_SAFE;
190 		msgs[n].len = recv_len;
191 		msgs[n].buf = recv_buf;
192 		n++;
193 
194 		set_bit(I2C_HID_READ_PENDING, &ihid->flags);
195 	}
196 
197 	ret = i2c_transfer(client->adapter, msgs, n);
198 
199 	if (recv_len)
200 		clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
201 
202 	if (ret != n)
203 		return ret < 0 ? ret : -EIO;
204 
205 	return 0;
206 }
207 
208 static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
209 				 void *buf, size_t len)
210 {
211 	*(__le16 *)ihid->cmdbuf = reg;
212 
213 	return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
214 }
215 
216 static size_t i2c_hid_encode_command(u8 *buf, u8 opcode,
217 				     int report_type, int report_id)
218 {
219 	size_t length = 0;
220 
221 	if (report_id < 0x0F) {
222 		buf[length++] = report_type << 4 | report_id;
223 		buf[length++] = opcode;
224 	} else {
225 		buf[length++] = report_type << 4 | 0x0F;
226 		buf[length++] = opcode;
227 		buf[length++] = report_id;
228 	}
229 
230 	return length;
231 }
232 
233 static int i2c_hid_get_report(struct i2c_hid *ihid,
234 			      u8 report_type, u8 report_id,
235 			      u8 *recv_buf, size_t recv_len)
236 {
237 	size_t length = 0;
238 	size_t ret_count;
239 	int error;
240 
241 	i2c_hid_dbg(ihid, "%s\n", __func__);
242 
243 	/* Command register goes first */
244 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
245 	length += sizeof(__le16);
246 	/* Next is GET_REPORT command */
247 	length += i2c_hid_encode_command(ihid->cmdbuf + length,
248 					 I2C_HID_OPCODE_GET_REPORT,
249 					 report_type, report_id);
250 	/*
251 	 * Device will send report data through data register. Because
252 	 * command can be either 2 or 3 bytes destination for the data
253 	 * register may be not aligned.
254 	 */
255 	put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
256 			   ihid->cmdbuf + length);
257 	length += sizeof(__le16);
258 
259 	/*
260 	 * In addition to report data device will supply data length
261 	 * in the first 2 bytes of the response, so adjust .
262 	 */
263 	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length,
264 			     ihid->rawbuf, recv_len + sizeof(__le16));
265 	if (error) {
266 		dev_err(&ihid->client->dev,
267 			"failed to set a report to device: %d\n", error);
268 		return error;
269 	}
270 
271 	/* The buffer is sufficiently aligned */
272 	ret_count = le16_to_cpup((__le16 *)ihid->rawbuf);
273 
274 	/* Check for empty report response */
275 	if (ret_count <= sizeof(__le16))
276 		return 0;
277 
278 	recv_len = min(recv_len, ret_count - sizeof(__le16));
279 	memcpy(recv_buf, ihid->rawbuf + sizeof(__le16), recv_len);
280 
281 	if (report_id && recv_len != 0 && recv_buf[0] != report_id) {
282 		dev_err(&ihid->client->dev,
283 			"device returned incorrect report (%d vs %d expected)\n",
284 			recv_buf[0], report_id);
285 		return -EINVAL;
286 	}
287 
288 	return recv_len;
289 }
290 
291 static size_t i2c_hid_format_report(u8 *buf, int report_id,
292 				    const u8 *data, size_t size)
293 {
294 	size_t length = sizeof(__le16); /* reserve space to store size */
295 
296 	if (report_id)
297 		buf[length++] = report_id;
298 
299 	memcpy(buf + length, data, size);
300 	length += size;
301 
302 	/* Store overall size in the beginning of the buffer */
303 	put_unaligned_le16(length, buf);
304 
305 	return length;
306 }
307 
308 /**
309  * i2c_hid_set_or_send_report: forward an incoming report to the device
310  * @ihid: the i2c hid device
311  * @report_type: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
312  * @report_id: the report ID
313  * @buf: the actual data to transfer, without the report ID
314  * @data_len: size of buf
315  * @do_set: true: use SET_REPORT HID command, false: send plain OUTPUT report
316  */
317 static int i2c_hid_set_or_send_report(struct i2c_hid *ihid,
318 				      u8 report_type, u8 report_id,
319 				      const u8 *buf, size_t data_len,
320 				      bool do_set)
321 {
322 	size_t length = 0;
323 	int error;
324 
325 	i2c_hid_dbg(ihid, "%s\n", __func__);
326 
327 	if (data_len > ihid->bufsize)
328 		return -EINVAL;
329 
330 	if (!do_set && le16_to_cpu(ihid->hdesc.wMaxOutputLength) == 0)
331 		return -ENOSYS;
332 
333 	if (do_set) {
334 		/* Command register goes first */
335 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
336 		length += sizeof(__le16);
337 		/* Next is SET_REPORT command */
338 		length += i2c_hid_encode_command(ihid->cmdbuf + length,
339 						 I2C_HID_OPCODE_SET_REPORT,
340 						 report_type, report_id);
341 		/*
342 		 * Report data will go into the data register. Because
343 		 * command can be either 2 or 3 bytes destination for
344 		 * the data register may be not aligned.
345 		*/
346 		put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
347 				   ihid->cmdbuf + length);
348 		length += sizeof(__le16);
349 	} else {
350 		/*
351 		 * With simple "send report" all data goes into the output
352 		 * register.
353 		 */
354 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wOutputRegister;
355 		length += sizeof(__le16);
356 	}
357 
358 	length += i2c_hid_format_report(ihid->cmdbuf + length,
359 					report_id, buf, data_len);
360 
361 	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
362 	if (error) {
363 		dev_err(&ihid->client->dev,
364 			"failed to set a report to device: %d\n", error);
365 		return error;
366 	}
367 
368 	return data_len;
369 }
370 
371 static int i2c_hid_set_power_command(struct i2c_hid *ihid, int power_state)
372 {
373 	size_t length;
374 
375 	/* SET_POWER uses command register */
376 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
377 	length = sizeof(__le16);
378 
379 	/* Now the command itself */
380 	length += i2c_hid_encode_command(ihid->cmdbuf + length,
381 					 I2C_HID_OPCODE_SET_POWER,
382 					 0, power_state);
383 
384 	return i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
385 }
386 
387 static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state)
388 {
389 	int ret;
390 
391 	i2c_hid_dbg(ihid, "%s\n", __func__);
392 
393 	/*
394 	 * Some devices require to send a command to wakeup before power on.
395 	 * The call will get a return value (EREMOTEIO) but device will be
396 	 * triggered and activated. After that, it goes like a normal device.
397 	 */
398 	if (power_state == I2C_HID_PWR_ON) {
399 		ret = i2c_hid_set_power_command(ihid, I2C_HID_PWR_ON);
400 
401 		/* Device was already activated */
402 		if (!ret)
403 			goto set_pwr_exit;
404 	}
405 
406 	ret = i2c_hid_set_power_command(ihid, power_state);
407 	if (ret)
408 		dev_err(&ihid->client->dev,
409 			"failed to change power setting.\n");
410 
411 set_pwr_exit:
412 
413 	/*
414 	 * The HID over I2C specification states that if a DEVICE needs time
415 	 * after the PWR_ON request, it should utilise CLOCK stretching.
416 	 * However, it has been observered that the Windows driver provides a
417 	 * 1ms sleep between the PWR_ON and RESET requests.
418 	 * According to Goodix Windows even waits 60 ms after (other?)
419 	 * PWR_ON requests. Testing has confirmed that several devices
420 	 * will not work properly without a delay after a PWR_ON request.
421 	 */
422 	if (!ret && power_state == I2C_HID_PWR_ON)
423 		msleep(60);
424 
425 	return ret;
426 }
427 
428 static int i2c_hid_start_hwreset(struct i2c_hid *ihid)
429 {
430 	size_t length = 0;
431 	int ret;
432 
433 	i2c_hid_dbg(ihid, "%s\n", __func__);
434 
435 	/*
436 	 * This prevents sending feature reports while the device is
437 	 * being reset. Otherwise we may lose the reset complete
438 	 * interrupt.
439 	 */
440 	lockdep_assert_held(&ihid->reset_lock);
441 
442 	ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
443 	if (ret)
444 		return ret;
445 
446 	/* Prepare reset command. Command register goes first. */
447 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
448 	length += sizeof(__le16);
449 	/* Next is RESET command itself */
450 	length += i2c_hid_encode_command(ihid->cmdbuf + length,
451 					 I2C_HID_OPCODE_RESET, 0, 0);
452 
453 	set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
454 
455 	ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
456 	if (ret) {
457 		dev_err(&ihid->client->dev,
458 			"failed to reset device: %d\n", ret);
459 		goto err_clear_reset;
460 	}
461 
462 	return 0;
463 
464 err_clear_reset:
465 	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
466 	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
467 	return ret;
468 }
469 
470 static int i2c_hid_finish_hwreset(struct i2c_hid *ihid)
471 {
472 	int ret = 0;
473 
474 	i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
475 
476 	if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
477 		msleep(100);
478 		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
479 	} else if (!wait_event_timeout(ihid->wait,
480 				       !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
481 				       msecs_to_jiffies(1000))) {
482 		dev_warn(&ihid->client->dev, "device did not ack reset within 1000 ms\n");
483 		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
484 	}
485 	i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
486 
487 	/* At least some SIS devices need this after reset */
488 	if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
489 		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
490 
491 	return ret;
492 }
493 
494 static void i2c_hid_get_input(struct i2c_hid *ihid)
495 {
496 	u16 size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
497 	u16 ret_size;
498 	int ret;
499 
500 	if (size > ihid->bufsize)
501 		size = ihid->bufsize;
502 
503 	ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
504 	if (ret != size) {
505 		if (ret < 0)
506 			return;
507 
508 		dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
509 			__func__, ret, size);
510 		return;
511 	}
512 
513 	/* Receiving buffer is properly aligned */
514 	ret_size = le16_to_cpup((__le16 *)ihid->inbuf);
515 	if (!ret_size) {
516 		/* host or device initiated RESET completed */
517 		if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
518 			wake_up(&ihid->wait);
519 		return;
520 	}
521 
522 	if ((ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ) && ret_size == 0xffff) {
523 		dev_warn_once(&ihid->client->dev,
524 			      "%s: IRQ triggered but there's no data\n",
525 			      __func__);
526 		return;
527 	}
528 
529 	if (ret_size > size || ret_size < sizeof(__le16)) {
530 		if (ihid->quirks & I2C_HID_QUIRK_BAD_INPUT_SIZE) {
531 			*(__le16 *)ihid->inbuf = cpu_to_le16(size);
532 			ret_size = size;
533 		} else {
534 			dev_err(&ihid->client->dev,
535 				"%s: incomplete report (%d/%d)\n",
536 				__func__, size, ret_size);
537 			return;
538 		}
539 	}
540 
541 	i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
542 
543 	if (test_bit(I2C_HID_STARTED, &ihid->flags)) {
544 		if (ihid->hid->group != HID_GROUP_RMI)
545 			pm_wakeup_event(&ihid->client->dev, 0);
546 
547 		hid_input_report(ihid->hid, HID_INPUT_REPORT,
548 				ihid->inbuf + sizeof(__le16),
549 				ret_size - sizeof(__le16), 1);
550 	}
551 
552 	return;
553 }
554 
555 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
556 {
557 	struct i2c_hid *ihid = dev_id;
558 
559 	if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
560 		return IRQ_HANDLED;
561 
562 	i2c_hid_get_input(ihid);
563 
564 	return IRQ_HANDLED;
565 }
566 
567 static int i2c_hid_get_report_length(struct hid_report *report)
568 {
569 	return ((report->size - 1) >> 3) + 1 +
570 		report->device->report_enum[report->type].numbered + 2;
571 }
572 
573 /*
574  * Traverse the supplied list of reports and find the longest
575  */
576 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
577 		unsigned int *max)
578 {
579 	struct hid_report *report;
580 	unsigned int size;
581 
582 	/* We should not rely on wMaxInputLength, as some devices may set it to
583 	 * a wrong length. */
584 	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
585 		size = i2c_hid_get_report_length(report);
586 		if (*max < size)
587 			*max = size;
588 	}
589 }
590 
591 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
592 {
593 	kfree(ihid->inbuf);
594 	kfree(ihid->rawbuf);
595 	kfree(ihid->cmdbuf);
596 	ihid->inbuf = NULL;
597 	ihid->rawbuf = NULL;
598 	ihid->cmdbuf = NULL;
599 	ihid->bufsize = 0;
600 }
601 
602 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
603 {
604 	/*
605 	 * The worst case is computed from the set_report command with a
606 	 * reportID > 15 and the maximum report length.
607 	 */
608 	int cmd_len = sizeof(__le16) +	/* command register */
609 		      sizeof(u8) +	/* encoded report type/ID */
610 		      sizeof(u8) +	/* opcode */
611 		      sizeof(u8) +	/* optional 3rd byte report ID */
612 		      sizeof(__le16) +	/* data register */
613 		      sizeof(__le16) +	/* report data size */
614 		      sizeof(u8) +	/* report ID if numbered report */
615 		      report_size;
616 
617 	ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
618 	ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
619 	ihid->cmdbuf = kzalloc(cmd_len, GFP_KERNEL);
620 
621 	if (!ihid->inbuf || !ihid->rawbuf || !ihid->cmdbuf) {
622 		i2c_hid_free_buffers(ihid);
623 		return -ENOMEM;
624 	}
625 
626 	ihid->bufsize = report_size;
627 
628 	return 0;
629 }
630 
631 static int i2c_hid_get_raw_report(struct hid_device *hid,
632 				  u8 report_type, u8 report_id,
633 				  u8 *buf, size_t count)
634 {
635 	struct i2c_client *client = hid->driver_data;
636 	struct i2c_hid *ihid = i2c_get_clientdata(client);
637 	int ret_count;
638 
639 	if (report_type == HID_OUTPUT_REPORT)
640 		return -EINVAL;
641 
642 	/*
643 	 * In case of unnumbered reports the response from the device will
644 	 * not have the report ID that the upper layers expect, so we need
645 	 * to stash it the buffer ourselves and adjust the data size.
646 	 */
647 	if (!report_id) {
648 		buf[0] = 0;
649 		buf++;
650 		count--;
651 	}
652 
653 	ret_count = i2c_hid_get_report(ihid,
654 			report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
655 			report_id, buf, count);
656 
657 	if (ret_count > 0 && !report_id)
658 		ret_count++;
659 
660 	return ret_count;
661 }
662 
663 static int i2c_hid_output_raw_report(struct hid_device *hid, u8 report_type,
664 				     const u8 *buf, size_t count, bool do_set)
665 {
666 	struct i2c_client *client = hid->driver_data;
667 	struct i2c_hid *ihid = i2c_get_clientdata(client);
668 	int report_id = buf[0];
669 	int ret;
670 
671 	if (report_type == HID_INPUT_REPORT)
672 		return -EINVAL;
673 
674 	mutex_lock(&ihid->reset_lock);
675 
676 	/*
677 	 * Note that both numbered and unnumbered reports passed here
678 	 * are supposed to have report ID stored in the 1st byte of the
679 	 * buffer, so we strip it off unconditionally before passing payload
680 	 * to i2c_hid_set_or_send_report which takes care of encoding
681 	 * everything properly.
682 	 */
683 	ret = i2c_hid_set_or_send_report(ihid,
684 				report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
685 				report_id, buf + 1, count - 1, do_set);
686 
687 	if (ret >= 0)
688 		ret++; /* add report_id to the number of transferred bytes */
689 
690 	mutex_unlock(&ihid->reset_lock);
691 
692 	return ret;
693 }
694 
695 static int i2c_hid_output_report(struct hid_device *hid, u8 *buf, size_t count)
696 {
697 	return i2c_hid_output_raw_report(hid, HID_OUTPUT_REPORT, buf, count,
698 					 false);
699 }
700 
701 static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
702 			       __u8 *buf, size_t len, unsigned char rtype,
703 			       int reqtype)
704 {
705 	switch (reqtype) {
706 	case HID_REQ_GET_REPORT:
707 		return i2c_hid_get_raw_report(hid, rtype, reportnum, buf, len);
708 	case HID_REQ_SET_REPORT:
709 		if (buf[0] != reportnum)
710 			return -EINVAL;
711 		return i2c_hid_output_raw_report(hid, rtype, buf, len, true);
712 	default:
713 		return -EIO;
714 	}
715 }
716 
717 static int i2c_hid_parse(struct hid_device *hid)
718 {
719 	struct i2c_client *client = hid->driver_data;
720 	struct i2c_hid *ihid = i2c_get_clientdata(client);
721 	struct i2c_hid_desc *hdesc = &ihid->hdesc;
722 	char *rdesc = NULL, *use_override = NULL;
723 	unsigned int rsize;
724 	int ret;
725 	int tries = 3;
726 
727 	i2c_hid_dbg(ihid, "entering %s\n", __func__);
728 
729 	rsize = le16_to_cpu(hdesc->wReportDescLength);
730 	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
731 		dbg_hid("weird size of report descriptor (%u)\n", rsize);
732 		return -EINVAL;
733 	}
734 
735 	mutex_lock(&ihid->reset_lock);
736 	do {
737 		ret = i2c_hid_start_hwreset(ihid);
738 		if (ret)
739 			msleep(1000);
740 	} while (tries-- > 0 && ret);
741 
742 	if (ret)
743 		goto abort_reset;
744 
745 	use_override = i2c_hid_get_dmi_hid_report_desc_override(client->name,
746 								&rsize);
747 
748 	if (use_override) {
749 		rdesc = use_override;
750 		i2c_hid_dbg(ihid, "Using a HID report descriptor override\n");
751 	} else {
752 		rdesc = kzalloc(rsize, GFP_KERNEL);
753 
754 		if (!rdesc) {
755 			ret = -ENOMEM;
756 			goto abort_reset;
757 		}
758 
759 		i2c_hid_dbg(ihid, "asking HID report descriptor\n");
760 
761 		ret = i2c_hid_read_register(ihid,
762 					    ihid->hdesc.wReportDescRegister,
763 					    rdesc, rsize);
764 		if (ret) {
765 			hid_err(hid, "reading report descriptor failed\n");
766 			goto abort_reset;
767 		}
768 	}
769 
770 	/*
771 	 * Windows directly reads the report-descriptor after sending reset
772 	 * and then waits for resets completion afterwards. Some touchpads
773 	 * actually wait for the report-descriptor to be read before signalling
774 	 * reset completion.
775 	 */
776 	ret = i2c_hid_finish_hwreset(ihid);
777 abort_reset:
778 	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
779 	mutex_unlock(&ihid->reset_lock);
780 	if (ret)
781 		goto out;
782 
783 	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
784 
785 	ret = hid_parse_report(hid, rdesc, rsize);
786 	if (ret)
787 		dbg_hid("parsing report descriptor failed\n");
788 
789 out:
790 	if (!use_override)
791 		kfree(rdesc);
792 
793 	return ret;
794 }
795 
796 static int i2c_hid_start(struct hid_device *hid)
797 {
798 	struct i2c_client *client = hid->driver_data;
799 	struct i2c_hid *ihid = i2c_get_clientdata(client);
800 	int ret;
801 	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
802 
803 	i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
804 	i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
805 	i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
806 
807 	if (bufsize > ihid->bufsize) {
808 		disable_irq(client->irq);
809 		i2c_hid_free_buffers(ihid);
810 
811 		ret = i2c_hid_alloc_buffers(ihid, bufsize);
812 		enable_irq(client->irq);
813 
814 		if (ret)
815 			return ret;
816 	}
817 
818 	return 0;
819 }
820 
821 static void i2c_hid_stop(struct hid_device *hid)
822 {
823 	hid->claimed = 0;
824 }
825 
826 static int i2c_hid_open(struct hid_device *hid)
827 {
828 	struct i2c_client *client = hid->driver_data;
829 	struct i2c_hid *ihid = i2c_get_clientdata(client);
830 
831 	set_bit(I2C_HID_STARTED, &ihid->flags);
832 	return 0;
833 }
834 
835 static void i2c_hid_close(struct hid_device *hid)
836 {
837 	struct i2c_client *client = hid->driver_data;
838 	struct i2c_hid *ihid = i2c_get_clientdata(client);
839 
840 	clear_bit(I2C_HID_STARTED, &ihid->flags);
841 }
842 
843 static const struct hid_ll_driver i2c_hid_ll_driver = {
844 	.parse = i2c_hid_parse,
845 	.start = i2c_hid_start,
846 	.stop = i2c_hid_stop,
847 	.open = i2c_hid_open,
848 	.close = i2c_hid_close,
849 	.output_report = i2c_hid_output_report,
850 	.raw_request = i2c_hid_raw_request,
851 };
852 
853 static int i2c_hid_init_irq(struct i2c_client *client)
854 {
855 	struct i2c_hid *ihid = i2c_get_clientdata(client);
856 	unsigned long irqflags = 0;
857 	int ret;
858 
859 	i2c_hid_dbg(ihid, "Requesting IRQ: %d\n", client->irq);
860 
861 	if (!irq_get_trigger_type(client->irq))
862 		irqflags = IRQF_TRIGGER_LOW;
863 
864 	ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
865 				   irqflags | IRQF_ONESHOT | IRQF_NO_AUTOEN,
866 				   client->name, ihid);
867 	if (ret < 0) {
868 		dev_warn(&client->dev,
869 			"Could not register for %s interrupt, irq = %d,"
870 			" ret = %d\n",
871 			client->name, client->irq, ret);
872 
873 		return ret;
874 	}
875 
876 	return 0;
877 }
878 
879 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
880 {
881 	struct i2c_client *client = ihid->client;
882 	struct i2c_hid_desc *hdesc = &ihid->hdesc;
883 	unsigned int dsize;
884 	int error;
885 
886 	/* i2c hid fetch using a fixed descriptor size (30 bytes) */
887 	if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
888 		i2c_hid_dbg(ihid, "Using a HID descriptor override\n");
889 		ihid->hdesc =
890 			*i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
891 	} else {
892 		i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
893 		error = i2c_hid_read_register(ihid,
894 					      ihid->wHIDDescRegister,
895 					      &ihid->hdesc,
896 					      sizeof(ihid->hdesc));
897 		if (error) {
898 			dev_err(&ihid->client->dev,
899 				"failed to fetch HID descriptor: %d\n",
900 				error);
901 			return -ENODEV;
902 		}
903 	}
904 
905 	/* Validate the length of HID descriptor, the 4 first bytes:
906 	 * bytes 0-1 -> length
907 	 * bytes 2-3 -> bcdVersion (has to be 1.00) */
908 	/* check bcdVersion == 1.0 */
909 	if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
910 		dev_err(&ihid->client->dev,
911 			"unexpected HID descriptor bcdVersion (0x%04hx)\n",
912 			le16_to_cpu(hdesc->bcdVersion));
913 		return -ENODEV;
914 	}
915 
916 	/* Descriptor length should be 30 bytes as per the specification */
917 	dsize = le16_to_cpu(hdesc->wHIDDescLength);
918 	if (dsize != sizeof(struct i2c_hid_desc)) {
919 		dev_err(&ihid->client->dev,
920 			"weird size of HID descriptor (%u)\n", dsize);
921 		return -ENODEV;
922 	}
923 	i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, &ihid->hdesc);
924 	return 0;
925 }
926 
927 static int i2c_hid_core_power_up(struct i2c_hid *ihid)
928 {
929 	if (!ihid->ops->power_up)
930 		return 0;
931 
932 	return ihid->ops->power_up(ihid->ops);
933 }
934 
935 static void i2c_hid_core_power_down(struct i2c_hid *ihid)
936 {
937 	if (!ihid->ops->power_down)
938 		return;
939 
940 	ihid->ops->power_down(ihid->ops);
941 }
942 
943 static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
944 {
945 	if (!ihid->ops->shutdown_tail)
946 		return;
947 
948 	ihid->ops->shutdown_tail(ihid->ops);
949 }
950 
951 static int i2c_hid_core_suspend(struct i2c_hid *ihid, bool force_poweroff)
952 {
953 	struct i2c_client *client = ihid->client;
954 	struct hid_device *hid = ihid->hid;
955 	int ret;
956 
957 	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
958 	if (ret < 0)
959 		return ret;
960 
961 	/* Save some power */
962 	if (!(ihid->quirks & I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND))
963 		i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
964 
965 	disable_irq(client->irq);
966 
967 	if (force_poweroff || !device_may_wakeup(&client->dev))
968 		i2c_hid_core_power_down(ihid);
969 
970 	return 0;
971 }
972 
973 static int i2c_hid_core_resume(struct i2c_hid *ihid)
974 {
975 	struct i2c_client *client = ihid->client;
976 	struct hid_device *hid = ihid->hid;
977 	int ret;
978 
979 	if (!device_may_wakeup(&client->dev))
980 		i2c_hid_core_power_up(ihid);
981 
982 	enable_irq(client->irq);
983 
984 	/* Instead of resetting device, simply powers the device on. This
985 	 * solves "incomplete reports" on Raydium devices 2386:3118 and
986 	 * 2386:4B33 and fixes various SIS touchscreens no longer sending
987 	 * data after a suspend/resume.
988 	 *
989 	 * However some ALPS touchpads generate IRQ storm without reset, so
990 	 * let's still reset them here.
991 	 */
992 	if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME) {
993 		mutex_lock(&ihid->reset_lock);
994 		ret = i2c_hid_start_hwreset(ihid);
995 		if (ret == 0)
996 			ret = i2c_hid_finish_hwreset(ihid);
997 		mutex_unlock(&ihid->reset_lock);
998 	} else {
999 		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
1000 	}
1001 
1002 	if (ret)
1003 		return ret;
1004 
1005 	return hid_driver_reset_resume(hid);
1006 }
1007 
1008 /*
1009  * Check that the device exists and parse the HID descriptor.
1010  */
1011 static int __i2c_hid_core_probe(struct i2c_hid *ihid)
1012 {
1013 	struct i2c_client *client = ihid->client;
1014 	struct hid_device *hid = ihid->hid;
1015 	int ret;
1016 
1017 	/* Make sure there is something at this address */
1018 	ret = i2c_smbus_read_byte(client);
1019 	if (ret < 0) {
1020 		i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
1021 		return -ENXIO;
1022 	}
1023 
1024 	ret = i2c_hid_fetch_hid_descriptor(ihid);
1025 	if (ret < 0) {
1026 		dev_err(&client->dev,
1027 			"Failed to fetch the HID Descriptor\n");
1028 		return ret;
1029 	}
1030 
1031 	hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1032 	hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1033 	hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1034 
1035 	hid->initial_quirks |= i2c_hid_get_dmi_quirks(hid->vendor,
1036 						      hid->product);
1037 
1038 	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
1039 		 client->name, (u16)hid->vendor, (u16)hid->product);
1040 	strscpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1041 
1042 	ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
1043 
1044 	return 0;
1045 }
1046 
1047 static int i2c_hid_core_register_hid(struct i2c_hid *ihid)
1048 {
1049 	struct i2c_client *client = ihid->client;
1050 	struct hid_device *hid = ihid->hid;
1051 	int ret;
1052 
1053 	enable_irq(client->irq);
1054 
1055 	ret = hid_add_device(hid);
1056 	if (ret) {
1057 		if (ret != -ENODEV)
1058 			hid_err(client, "can't add hid device: %d\n", ret);
1059 		disable_irq(client->irq);
1060 		return ret;
1061 	}
1062 
1063 	return 0;
1064 }
1065 
1066 static int i2c_hid_core_probe_panel_follower(struct i2c_hid *ihid)
1067 {
1068 	int ret;
1069 
1070 	ret = i2c_hid_core_power_up(ihid);
1071 	if (ret)
1072 		return ret;
1073 
1074 	ret = __i2c_hid_core_probe(ihid);
1075 	if (ret)
1076 		goto err_power_down;
1077 
1078 	ret = i2c_hid_core_register_hid(ihid);
1079 	if (ret)
1080 		goto err_power_down;
1081 
1082 	return 0;
1083 
1084 err_power_down:
1085 	i2c_hid_core_power_down(ihid);
1086 
1087 	return ret;
1088 }
1089 
1090 static void ihid_core_panel_prepare_work(struct work_struct *work)
1091 {
1092 	struct i2c_hid *ihid = container_of(work, struct i2c_hid,
1093 					    panel_follower_prepare_work);
1094 	struct hid_device *hid = ihid->hid;
1095 	int ret;
1096 
1097 	/*
1098 	 * hid->version is set on the first power up. If it's still zero then
1099 	 * this is the first power on so we should perform initial power up
1100 	 * steps.
1101 	 */
1102 	if (!hid->version)
1103 		ret = i2c_hid_core_probe_panel_follower(ihid);
1104 	else
1105 		ret = i2c_hid_core_resume(ihid);
1106 
1107 	if (ret)
1108 		dev_warn(&ihid->client->dev, "Power on failed: %d\n", ret);
1109 	else
1110 		WRITE_ONCE(ihid->prepare_work_finished, true);
1111 
1112 	/*
1113 	 * The work APIs provide a number of memory ordering guarantees
1114 	 * including one that says that memory writes before schedule_work()
1115 	 * are always visible to the work function, but they don't appear to
1116 	 * guarantee that a write that happened in the work is visible after
1117 	 * cancel_work_sync(). We'll add a write memory barrier here to match
1118 	 * with i2c_hid_core_panel_unpreparing() to ensure that our write to
1119 	 * prepare_work_finished is visible there.
1120 	 */
1121 	smp_wmb();
1122 }
1123 
1124 static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
1125 {
1126 	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
1127 
1128 	/*
1129 	 * Powering on a touchscreen can be a slow process. Queue the work to
1130 	 * the system workqueue so we don't block the panel's power up.
1131 	 */
1132 	WRITE_ONCE(ihid->prepare_work_finished, false);
1133 	schedule_work(&ihid->panel_follower_prepare_work);
1134 
1135 	return 0;
1136 }
1137 
1138 static int i2c_hid_core_panel_unpreparing(struct drm_panel_follower *follower)
1139 {
1140 	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
1141 
1142 	cancel_work_sync(&ihid->panel_follower_prepare_work);
1143 
1144 	/* Match with ihid_core_panel_prepare_work() */
1145 	smp_rmb();
1146 	if (!READ_ONCE(ihid->prepare_work_finished))
1147 		return 0;
1148 
1149 	return i2c_hid_core_suspend(ihid, true);
1150 }
1151 
1152 static const struct drm_panel_follower_funcs i2c_hid_core_panel_follower_funcs = {
1153 	.panel_prepared = i2c_hid_core_panel_prepared,
1154 	.panel_unpreparing = i2c_hid_core_panel_unpreparing,
1155 };
1156 
1157 static int i2c_hid_core_register_panel_follower(struct i2c_hid *ihid)
1158 {
1159 	struct device *dev = &ihid->client->dev;
1160 	int ret;
1161 
1162 	ihid->panel_follower.funcs = &i2c_hid_core_panel_follower_funcs;
1163 
1164 	/*
1165 	 * If we're not in control of our own power up/power down then we can't
1166 	 * do the logic to manage wakeups. Give a warning if a user thought
1167 	 * that was possible then force the capability off.
1168 	 */
1169 	if (device_can_wakeup(dev)) {
1170 		dev_warn(dev, "Can't wakeup if following panel\n");
1171 		device_set_wakeup_capable(dev, false);
1172 	}
1173 
1174 	ret = drm_panel_add_follower(dev, &ihid->panel_follower);
1175 	if (ret)
1176 		return ret;
1177 
1178 	return 0;
1179 }
1180 
1181 int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
1182 		       u16 hid_descriptor_address, u32 quirks)
1183 {
1184 	int ret;
1185 	struct i2c_hid *ihid;
1186 	struct hid_device *hid;
1187 
1188 	dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
1189 
1190 	if (!client->irq) {
1191 		dev_err(&client->dev,
1192 			"HID over i2c has not been provided an Int IRQ\n");
1193 		return -EINVAL;
1194 	}
1195 
1196 	if (client->irq < 0) {
1197 		if (client->irq != -EPROBE_DEFER)
1198 			dev_err(&client->dev,
1199 				"HID over i2c doesn't have a valid IRQ\n");
1200 		return client->irq;
1201 	}
1202 
1203 	ihid = devm_kzalloc(&client->dev, sizeof(*ihid), GFP_KERNEL);
1204 	if (!ihid)
1205 		return -ENOMEM;
1206 
1207 	i2c_set_clientdata(client, ihid);
1208 
1209 	ihid->ops = ops;
1210 	ihid->client = client;
1211 	ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
1212 	ihid->is_panel_follower = drm_is_panel_follower(&client->dev);
1213 
1214 	init_waitqueue_head(&ihid->wait);
1215 	mutex_init(&ihid->reset_lock);
1216 	INIT_WORK(&ihid->panel_follower_prepare_work, ihid_core_panel_prepare_work);
1217 
1218 	/* we need to allocate the command buffer without knowing the maximum
1219 	 * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
1220 	 * real computation later. */
1221 	ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
1222 	if (ret < 0)
1223 		return ret;
1224 	device_enable_async_suspend(&client->dev);
1225 
1226 	hid = hid_allocate_device();
1227 	if (IS_ERR(hid)) {
1228 		ret = PTR_ERR(hid);
1229 		goto err_free_buffers;
1230 	}
1231 
1232 	ihid->hid = hid;
1233 
1234 	hid->driver_data = client;
1235 	hid->ll_driver = &i2c_hid_ll_driver;
1236 	hid->dev.parent = &client->dev;
1237 	hid->bus = BUS_I2C;
1238 	hid->initial_quirks = quirks;
1239 
1240 	/* Power on and probe unless device is a panel follower. */
1241 	if (!ihid->is_panel_follower) {
1242 		ret = i2c_hid_core_power_up(ihid);
1243 		if (ret < 0)
1244 			goto err_destroy_device;
1245 
1246 		ret = __i2c_hid_core_probe(ihid);
1247 		if (ret < 0)
1248 			goto err_power_down;
1249 	}
1250 
1251 	ret = i2c_hid_init_irq(client);
1252 	if (ret < 0)
1253 		goto err_power_down;
1254 
1255 	/*
1256 	 * If we're a panel follower, we'll register when the panel turns on;
1257 	 * otherwise we do it right away.
1258 	 */
1259 	if (ihid->is_panel_follower)
1260 		ret = i2c_hid_core_register_panel_follower(ihid);
1261 	else
1262 		ret = i2c_hid_core_register_hid(ihid);
1263 	if (ret)
1264 		goto err_free_irq;
1265 
1266 	return 0;
1267 
1268 err_free_irq:
1269 	free_irq(client->irq, ihid);
1270 err_power_down:
1271 	if (!ihid->is_panel_follower)
1272 		i2c_hid_core_power_down(ihid);
1273 err_destroy_device:
1274 	hid_destroy_device(hid);
1275 err_free_buffers:
1276 	i2c_hid_free_buffers(ihid);
1277 
1278 	return ret;
1279 }
1280 EXPORT_SYMBOL_GPL(i2c_hid_core_probe);
1281 
1282 void i2c_hid_core_remove(struct i2c_client *client)
1283 {
1284 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1285 	struct hid_device *hid;
1286 
1287 	/*
1288 	 * If we're a follower, the act of unfollowing will cause us to be
1289 	 * powered down. Otherwise we need to manually do it.
1290 	 */
1291 	if (ihid->is_panel_follower)
1292 		drm_panel_remove_follower(&ihid->panel_follower);
1293 	else
1294 		i2c_hid_core_suspend(ihid, true);
1295 
1296 	hid = ihid->hid;
1297 	hid_destroy_device(hid);
1298 
1299 	free_irq(client->irq, ihid);
1300 
1301 	if (ihid->bufsize)
1302 		i2c_hid_free_buffers(ihid);
1303 }
1304 EXPORT_SYMBOL_GPL(i2c_hid_core_remove);
1305 
1306 void i2c_hid_core_shutdown(struct i2c_client *client)
1307 {
1308 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1309 
1310 	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
1311 	free_irq(client->irq, ihid);
1312 
1313 	i2c_hid_core_shutdown_tail(ihid);
1314 }
1315 EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
1316 
1317 static int i2c_hid_core_pm_suspend(struct device *dev)
1318 {
1319 	struct i2c_client *client = to_i2c_client(dev);
1320 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1321 
1322 	if (ihid->is_panel_follower)
1323 		return 0;
1324 
1325 	return i2c_hid_core_suspend(ihid, false);
1326 }
1327 
1328 static int i2c_hid_core_pm_resume(struct device *dev)
1329 {
1330 	struct i2c_client *client = to_i2c_client(dev);
1331 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1332 
1333 	if (ihid->is_panel_follower)
1334 		return 0;
1335 
1336 	return i2c_hid_core_resume(ihid);
1337 }
1338 
1339 const struct dev_pm_ops i2c_hid_core_pm = {
1340 	SYSTEM_SLEEP_PM_OPS(i2c_hid_core_pm_suspend, i2c_hid_core_pm_resume)
1341 };
1342 EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
1343 
1344 MODULE_DESCRIPTION("HID over I2C core driver");
1345 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1346 MODULE_LICENSE("GPL");
1347