xref: /linux/drivers/hid/i2c-hid/i2c-hid-core.c (revision 848e076317446f9c663771ddec142d7c2eb4cb43)
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 <linux/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 #define I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME BIT(6)
54 #define I2C_HID_QUIRK_RE_POWER_ON		BIT(7)
55 
56 /* Command opcodes */
57 #define I2C_HID_OPCODE_RESET			0x01
58 #define I2C_HID_OPCODE_GET_REPORT		0x02
59 #define I2C_HID_OPCODE_SET_REPORT		0x03
60 #define I2C_HID_OPCODE_GET_IDLE			0x04
61 #define I2C_HID_OPCODE_SET_IDLE			0x05
62 #define I2C_HID_OPCODE_GET_PROTOCOL		0x06
63 #define I2C_HID_OPCODE_SET_PROTOCOL		0x07
64 #define I2C_HID_OPCODE_SET_POWER		0x08
65 
66 /* flags */
67 #define I2C_HID_STARTED		0
68 #define I2C_HID_RESET_PENDING	1
69 
70 #define I2C_HID_PWR_ON		0x00
71 #define I2C_HID_PWR_SLEEP	0x01
72 
73 #define i2c_hid_dbg(ihid, ...) dev_dbg(&(ihid)->client->dev, __VA_ARGS__)
74 
75 struct i2c_hid_desc {
76 	__le16 wHIDDescLength;
77 	__le16 bcdVersion;
78 	__le16 wReportDescLength;
79 	__le16 wReportDescRegister;
80 	__le16 wInputRegister;
81 	__le16 wMaxInputLength;
82 	__le16 wOutputRegister;
83 	__le16 wMaxOutputLength;
84 	__le16 wCommandRegister;
85 	__le16 wDataRegister;
86 	__le16 wVendorID;
87 	__le16 wProductID;
88 	__le16 wVersionID;
89 	__le32 reserved;
90 } __packed;
91 
92 /* The main device structure */
93 struct i2c_hid {
94 	struct i2c_client	*client;	/* i2c client */
95 	struct hid_device	*hid;	/* pointer to corresponding HID dev */
96 	struct i2c_hid_desc hdesc;		/* the HID Descriptor */
97 	__le16			wHIDDescRegister; /* location of the i2c
98 						   * register of the HID
99 						   * descriptor. */
100 	unsigned int		bufsize;	/* i2c buffer size */
101 	u8			*inbuf;		/* Input buffer */
102 	u8			*rawbuf;	/* Raw Input buffer */
103 	u8			*cmdbuf;	/* Command buffer */
104 
105 	unsigned long		flags;		/* device flags */
106 	unsigned long		quirks;		/* Various quirks */
107 
108 	wait_queue_head_t	wait;		/* For waiting the interrupt */
109 
110 	struct mutex		cmd_lock;	/* protects cmdbuf and rawbuf */
111 	struct mutex		reset_lock;
112 
113 	struct i2chid_ops	*ops;
114 	struct drm_panel_follower panel_follower;
115 	struct work_struct	panel_follower_prepare_work;
116 	bool			is_panel_follower;
117 	bool			prepare_work_finished;
118 };
119 
120 static const struct i2c_hid_quirks {
121 	__u16 idVendor;
122 	__u16 idProduct;
123 	__u32 quirks;
124 } i2c_hid_quirks[] = {
125 	{ I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
126 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
127 	{ I2C_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_VOYO_WINPAD_A15,
128 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
129 	{ I2C_VENDOR_ID_RAYDIUM, I2C_PRODUCT_ID_RAYDIUM_3118,
130 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
131 	{ USB_VENDOR_ID_ALPS_JP, HID_ANY_ID,
132 		 I2C_HID_QUIRK_RESET_ON_RESUME },
133 	{ I2C_VENDOR_ID_SYNAPTICS, I2C_PRODUCT_ID_SYNAPTICS_SYNA2393,
134 		 I2C_HID_QUIRK_RESET_ON_RESUME },
135 	{ USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
136 		I2C_HID_QUIRK_BAD_INPUT_SIZE },
137 	{ I2C_VENDOR_ID_CIRQUE, I2C_PRODUCT_ID_CIRQUE_1063,
138 		I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND },
139 	/*
140 	 * Without additional power on command, at least some QTEC devices send garbage
141 	 */
142 	{ I2C_VENDOR_ID_QTEC, HID_ANY_ID,
143 		I2C_HID_QUIRK_RE_POWER_ON },
144 	/*
145 	 * Sending the wakeup after reset actually break ELAN touchscreen controller
146 	 */
147 	{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
148 		 I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET |
149 		 I2C_HID_QUIRK_BOGUS_IRQ },
150 	{ I2C_VENDOR_ID_GOODIX, I2C_DEVICE_ID_GOODIX_0D42,
151 		 I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME },
152 	{ 0, 0 }
153 };
154 
155 /*
156  * i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
157  * @idVendor: the 16-bit vendor ID
158  * @idProduct: the 16-bit product ID
159  *
160  * Returns: a u32 quirks value.
161  */
i2c_hid_lookup_quirk(const u16 idVendor,const u16 idProduct)162 static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
163 {
164 	u32 quirks = 0;
165 	int n;
166 
167 	for (n = 0; i2c_hid_quirks[n].idVendor; n++)
168 		if (i2c_hid_quirks[n].idVendor == idVendor &&
169 		    (i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
170 		     i2c_hid_quirks[n].idProduct == idProduct))
171 			quirks = i2c_hid_quirks[n].quirks;
172 
173 	return quirks;
174 }
175 
i2c_hid_probe_address(struct i2c_hid * ihid)176 static int i2c_hid_probe_address(struct i2c_hid *ihid)
177 {
178 	int ret;
179 
180 	/*
181 	 * Some STM-based devices need 400µs after a rising clock edge to wake
182 	 * from deep sleep, in which case the first read will fail. Try after a
183 	 * short sleep to see if the device came alive on the bus. Certain
184 	 * Weida Tech devices also need this.
185 	 */
186 	ret = i2c_smbus_read_byte(ihid->client);
187 	if (ret < 0) {
188 		usleep_range(400, 500);
189 		ret = i2c_smbus_read_byte(ihid->client);
190 	}
191 	return ret < 0 ? ret : 0;
192 }
193 
i2c_hid_xfer(struct i2c_hid * ihid,u8 * send_buf,int send_len,u8 * recv_buf,int recv_len)194 static int i2c_hid_xfer(struct i2c_hid *ihid,
195 			u8 *send_buf, int send_len, u8 *recv_buf, int recv_len)
196 {
197 	struct i2c_client *client = ihid->client;
198 	struct i2c_msg msgs[2] = { 0 };
199 	int n = 0;
200 	int ret;
201 
202 	if (send_len) {
203 		i2c_hid_dbg(ihid, "%s: cmd=%*ph\n",
204 			    __func__, send_len, send_buf);
205 
206 		msgs[n].addr = client->addr;
207 		msgs[n].flags = (client->flags & I2C_M_TEN) | I2C_M_DMA_SAFE;
208 		msgs[n].len = send_len;
209 		msgs[n].buf = send_buf;
210 		n++;
211 	}
212 
213 	if (recv_len) {
214 		msgs[n].addr = client->addr;
215 		msgs[n].flags = (client->flags & I2C_M_TEN) |
216 				I2C_M_RD | I2C_M_DMA_SAFE;
217 		msgs[n].len = recv_len;
218 		msgs[n].buf = recv_buf;
219 		n++;
220 	}
221 
222 	ret = i2c_transfer(client->adapter, msgs, n);
223 
224 	if (ret != n)
225 		return ret < 0 ? ret : -EIO;
226 
227 	return 0;
228 }
229 
i2c_hid_read_register(struct i2c_hid * ihid,__le16 reg,void * buf,size_t len)230 static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
231 				 void *buf, size_t len)
232 {
233 	guard(mutex)(&ihid->cmd_lock);
234 
235 	*(__le16 *)ihid->cmdbuf = reg;
236 
237 	return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
238 }
239 
i2c_hid_encode_command(u8 * buf,u8 opcode,int report_type,int report_id)240 static size_t i2c_hid_encode_command(u8 *buf, u8 opcode,
241 				     int report_type, int report_id)
242 {
243 	size_t length = 0;
244 
245 	if (report_id < 0x0F) {
246 		buf[length++] = report_type << 4 | report_id;
247 		buf[length++] = opcode;
248 	} else {
249 		buf[length++] = report_type << 4 | 0x0F;
250 		buf[length++] = opcode;
251 		buf[length++] = report_id;
252 	}
253 
254 	return length;
255 }
256 
i2c_hid_get_report(struct i2c_hid * ihid,u8 report_type,u8 report_id,u8 * recv_buf,size_t recv_len)257 static int i2c_hid_get_report(struct i2c_hid *ihid,
258 			      u8 report_type, u8 report_id,
259 			      u8 *recv_buf, size_t recv_len)
260 {
261 	size_t length = 0;
262 	size_t ret_count;
263 	int error;
264 
265 	i2c_hid_dbg(ihid, "%s\n", __func__);
266 
267 	guard(mutex)(&ihid->cmd_lock);
268 
269 	/* Command register goes first */
270 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
271 	length += sizeof(__le16);
272 	/* Next is GET_REPORT command */
273 	length += i2c_hid_encode_command(ihid->cmdbuf + length,
274 					 I2C_HID_OPCODE_GET_REPORT,
275 					 report_type, report_id);
276 	/*
277 	 * Device will send report data through data register. Because
278 	 * command can be either 2 or 3 bytes destination for the data
279 	 * register may be not aligned.
280 	 */
281 	put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
282 			   ihid->cmdbuf + length);
283 	length += sizeof(__le16);
284 
285 	/*
286 	 * In addition to report data device will supply data length
287 	 * in the first 2 bytes of the response, so adjust .
288 	 */
289 	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length,
290 			     ihid->rawbuf, recv_len + sizeof(__le16));
291 	if (error) {
292 		dev_err(&ihid->client->dev,
293 			"failed to get a report from device: %d\n", error);
294 		return error;
295 	}
296 
297 	/* The buffer is sufficiently aligned */
298 	ret_count = le16_to_cpup((__le16 *)ihid->rawbuf);
299 
300 	/* Check for empty report response */
301 	if (ret_count <= sizeof(__le16))
302 		return 0;
303 
304 	recv_len = min(recv_len, ret_count - sizeof(__le16));
305 	memcpy(recv_buf, ihid->rawbuf + sizeof(__le16), recv_len);
306 
307 	if (report_id && recv_len != 0 && recv_buf[0] != report_id) {
308 		dev_err(&ihid->client->dev,
309 			"device returned incorrect report (%d vs %d expected)\n",
310 			recv_buf[0], report_id);
311 		return -EINVAL;
312 	}
313 
314 	return recv_len;
315 }
316 
i2c_hid_format_report(u8 * buf,int report_id,const u8 * data,size_t size)317 static size_t i2c_hid_format_report(u8 *buf, int report_id,
318 				    const u8 *data, size_t size)
319 {
320 	size_t length = sizeof(__le16); /* reserve space to store size */
321 
322 	if (report_id)
323 		buf[length++] = report_id;
324 
325 	memcpy(buf + length, data, size);
326 	length += size;
327 
328 	/* Store overall size in the beginning of the buffer */
329 	put_unaligned_le16(length, buf);
330 
331 	return length;
332 }
333 
334 /**
335  * i2c_hid_set_or_send_report: forward an incoming report to the device
336  * @ihid: the i2c hid device
337  * @report_type: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
338  * @report_id: the report ID
339  * @buf: the actual data to transfer, without the report ID
340  * @data_len: size of buf
341  * @do_set: true: use SET_REPORT HID command, false: send plain OUTPUT report
342  */
i2c_hid_set_or_send_report(struct i2c_hid * ihid,u8 report_type,u8 report_id,const u8 * buf,size_t data_len,bool do_set)343 static int i2c_hid_set_or_send_report(struct i2c_hid *ihid,
344 				      u8 report_type, u8 report_id,
345 				      const u8 *buf, size_t data_len,
346 				      bool do_set)
347 {
348 	size_t length = 0;
349 	int error;
350 
351 	i2c_hid_dbg(ihid, "%s\n", __func__);
352 
353 	if (data_len > ihid->bufsize)
354 		return -EINVAL;
355 
356 	if (!do_set && le16_to_cpu(ihid->hdesc.wMaxOutputLength) == 0)
357 		return -ENOSYS;
358 
359 	guard(mutex)(&ihid->cmd_lock);
360 
361 	if (do_set) {
362 		/* Command register goes first */
363 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
364 		length += sizeof(__le16);
365 		/* Next is SET_REPORT command */
366 		length += i2c_hid_encode_command(ihid->cmdbuf + length,
367 						 I2C_HID_OPCODE_SET_REPORT,
368 						 report_type, report_id);
369 		/*
370 		 * Report data will go into the data register. Because
371 		 * command can be either 2 or 3 bytes destination for
372 		 * the data register may be not aligned.
373 		*/
374 		put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
375 				   ihid->cmdbuf + length);
376 		length += sizeof(__le16);
377 	} else {
378 		/*
379 		 * With simple "send report" all data goes into the output
380 		 * register.
381 		 */
382 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wOutputRegister;
383 		length += sizeof(__le16);
384 	}
385 
386 	length += i2c_hid_format_report(ihid->cmdbuf + length,
387 					report_id, buf, data_len);
388 
389 	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
390 	if (error) {
391 		dev_err(&ihid->client->dev,
392 			"failed to set a report to device: %d\n", error);
393 		return error;
394 	}
395 
396 	return data_len;
397 }
398 
i2c_hid_set_power_command(struct i2c_hid * ihid,int power_state)399 static int i2c_hid_set_power_command(struct i2c_hid *ihid, int power_state)
400 {
401 	size_t length;
402 
403 	guard(mutex)(&ihid->cmd_lock);
404 
405 	/* SET_POWER uses command register */
406 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
407 	length = sizeof(__le16);
408 
409 	/* Now the command itself */
410 	length += i2c_hid_encode_command(ihid->cmdbuf + length,
411 					 I2C_HID_OPCODE_SET_POWER,
412 					 0, power_state);
413 
414 	return i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
415 }
416 
i2c_hid_set_power(struct i2c_hid * ihid,int power_state)417 static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state)
418 {
419 	int ret;
420 
421 	i2c_hid_dbg(ihid, "%s\n", __func__);
422 
423 	/*
424 	 * Some STM-based devices need 400µs after a rising clock edge to wake
425 	 * from deep sleep, in which case the first request will fail due to
426 	 * the address not being acknowledged. Try after a short sleep to see
427 	 * if the device came alive on the bus. Certain Weida Tech devices also
428 	 * need this.
429 	 */
430 	ret = i2c_hid_set_power_command(ihid, power_state);
431 	if (ret && power_state == I2C_HID_PWR_ON) {
432 		usleep_range(400, 500);
433 		ret = i2c_hid_set_power_command(ihid, I2C_HID_PWR_ON);
434 	}
435 
436 	if (ret)
437 		dev_err(&ihid->client->dev,
438 			"failed to change power setting.\n");
439 
440 	/*
441 	 * The HID over I2C specification states that if a DEVICE needs time
442 	 * after the PWR_ON request, it should utilise CLOCK stretching.
443 	 * However, it has been observered that the Windows driver provides a
444 	 * 1ms sleep between the PWR_ON and RESET requests.
445 	 * According to Goodix Windows even waits 60 ms after (other?)
446 	 * PWR_ON requests. Testing has confirmed that several devices
447 	 * will not work properly without a delay after a PWR_ON request.
448 	 */
449 	if (!ret && power_state == I2C_HID_PWR_ON)
450 		msleep(60);
451 
452 	return ret;
453 }
454 
i2c_hid_start_hwreset(struct i2c_hid * ihid)455 static int i2c_hid_start_hwreset(struct i2c_hid *ihid)
456 {
457 	size_t length = 0;
458 	int ret;
459 
460 	i2c_hid_dbg(ihid, "%s\n", __func__);
461 
462 	/*
463 	 * This prevents sending feature reports while the device is
464 	 * being reset. Otherwise we may lose the reset complete
465 	 * interrupt.
466 	 */
467 	lockdep_assert_held(&ihid->reset_lock);
468 
469 	ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
470 	if (ret)
471 		return ret;
472 
473 	scoped_guard(mutex, &ihid->cmd_lock) {
474 		/* Prepare reset command. Command register goes first. */
475 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
476 		length += sizeof(__le16);
477 		/* Next is RESET command itself */
478 		length += i2c_hid_encode_command(ihid->cmdbuf + length,
479 						 I2C_HID_OPCODE_RESET, 0, 0);
480 
481 		set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
482 
483 		ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
484 		if (ret) {
485 			dev_err(&ihid->client->dev,
486 				"failed to reset device: %d\n", ret);
487 			break;
488 		}
489 
490 		return 0;
491 	}
492 
493 	/* Clean up if sending reset command failed */
494 	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
495 	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
496 	return ret;
497 }
498 
i2c_hid_finish_hwreset(struct i2c_hid * ihid)499 static int i2c_hid_finish_hwreset(struct i2c_hid *ihid)
500 {
501 	int ret = 0;
502 
503 	i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
504 
505 	if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
506 		msleep(100);
507 		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
508 	} else if (!wait_event_timeout(ihid->wait,
509 				       !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
510 				       msecs_to_jiffies(1000))) {
511 		dev_warn(&ihid->client->dev, "device did not ack reset within 1000 ms\n");
512 		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
513 	}
514 	i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
515 
516 	/* At least some SIS devices need this after reset */
517 	if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
518 		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
519 
520 	return ret;
521 }
522 
i2c_hid_get_input(struct i2c_hid * ihid)523 static void i2c_hid_get_input(struct i2c_hid *ihid)
524 {
525 	u16 size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
526 	u16 ret_size;
527 	int ret;
528 
529 	if (size > ihid->bufsize)
530 		size = ihid->bufsize;
531 
532 	ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
533 	if (ret != size) {
534 		if (ret < 0)
535 			return;
536 
537 		dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
538 			__func__, ret, size);
539 		return;
540 	}
541 
542 	/* Receiving buffer is properly aligned */
543 	ret_size = le16_to_cpup((__le16 *)ihid->inbuf);
544 	if (!ret_size) {
545 		/* host or device initiated RESET completed */
546 		if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
547 			wake_up(&ihid->wait);
548 		return;
549 	}
550 
551 	if ((ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ) && ret_size == 0xffff) {
552 		dev_warn_once(&ihid->client->dev,
553 			      "%s: IRQ triggered but there's no data\n",
554 			      __func__);
555 		return;
556 	}
557 
558 	if (ret_size > size || ret_size < sizeof(__le16)) {
559 		if (ihid->quirks & I2C_HID_QUIRK_BAD_INPUT_SIZE) {
560 			*(__le16 *)ihid->inbuf = cpu_to_le16(size);
561 			ret_size = size;
562 		} else {
563 			dev_err(&ihid->client->dev,
564 				"%s: incomplete report (%d/%d)\n",
565 				__func__, size, ret_size);
566 			return;
567 		}
568 	}
569 
570 	i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
571 
572 	if (test_bit(I2C_HID_STARTED, &ihid->flags)) {
573 		if (ihid->hid->group != HID_GROUP_RMI)
574 			pm_wakeup_event(&ihid->client->dev, 0);
575 
576 		hid_input_report(ihid->hid, HID_INPUT_REPORT,
577 				ihid->inbuf + sizeof(__le16),
578 				ret_size - sizeof(__le16), 1);
579 	}
580 
581 	return;
582 }
583 
i2c_hid_irq(int irq,void * dev_id)584 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
585 {
586 	struct i2c_hid *ihid = dev_id;
587 
588 	i2c_hid_get_input(ihid);
589 
590 	return IRQ_HANDLED;
591 }
592 
i2c_hid_get_report_length(struct hid_report * report)593 static int i2c_hid_get_report_length(struct hid_report *report)
594 {
595 	return ((report->size - 1) >> 3) + 1 +
596 		report->device->report_enum[report->type].numbered + 2;
597 }
598 
599 /*
600  * Traverse the supplied list of reports and find the longest
601  */
i2c_hid_find_max_report(struct hid_device * hid,unsigned int type,unsigned int * max)602 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
603 		unsigned int *max)
604 {
605 	struct hid_report *report;
606 	unsigned int size;
607 
608 	/* We should not rely on wMaxInputLength, as some devices may set it to
609 	 * a wrong length. */
610 	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
611 		size = i2c_hid_get_report_length(report);
612 		if (*max < size)
613 			*max = size;
614 	}
615 }
616 
i2c_hid_free_buffers(struct i2c_hid * ihid)617 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
618 {
619 	kfree(ihid->inbuf);
620 	kfree(ihid->rawbuf);
621 	kfree(ihid->cmdbuf);
622 	ihid->inbuf = NULL;
623 	ihid->rawbuf = NULL;
624 	ihid->cmdbuf = NULL;
625 	ihid->bufsize = 0;
626 }
627 
i2c_hid_alloc_buffers(struct i2c_hid * ihid,size_t report_size)628 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
629 {
630 	/*
631 	 * The worst case is computed from the set_report command with a
632 	 * reportID > 15 and the maximum report length.
633 	 */
634 	int cmd_len = sizeof(__le16) +	/* command register */
635 		      sizeof(u8) +	/* encoded report type/ID */
636 		      sizeof(u8) +	/* opcode */
637 		      sizeof(u8) +	/* optional 3rd byte report ID */
638 		      sizeof(__le16) +	/* data register */
639 		      sizeof(__le16) +	/* report data size */
640 		      sizeof(u8) +	/* report ID if numbered report */
641 		      report_size;
642 
643 	ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
644 	ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
645 	ihid->cmdbuf = kzalloc(cmd_len, GFP_KERNEL);
646 
647 	if (!ihid->inbuf || !ihid->rawbuf || !ihid->cmdbuf) {
648 		i2c_hid_free_buffers(ihid);
649 		return -ENOMEM;
650 	}
651 
652 	ihid->bufsize = report_size;
653 
654 	return 0;
655 }
656 
i2c_hid_get_raw_report(struct hid_device * hid,u8 report_type,u8 report_id,u8 * buf,size_t count)657 static int i2c_hid_get_raw_report(struct hid_device *hid,
658 				  u8 report_type, u8 report_id,
659 				  u8 *buf, size_t count)
660 {
661 	struct i2c_client *client = hid->driver_data;
662 	struct i2c_hid *ihid = i2c_get_clientdata(client);
663 	int ret_count;
664 
665 	if (report_type == HID_OUTPUT_REPORT)
666 		return -EINVAL;
667 
668 	/*
669 	 * In case of unnumbered reports the response from the device will
670 	 * not have the report ID that the upper layers expect, so we need
671 	 * to stash it the buffer ourselves and adjust the data size.
672 	 */
673 	if (!report_id) {
674 		buf[0] = 0;
675 		buf++;
676 		count--;
677 	}
678 
679 	ret_count = i2c_hid_get_report(ihid,
680 			report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
681 			report_id, buf, count);
682 
683 	if (ret_count > 0 && !report_id)
684 		ret_count++;
685 
686 	return ret_count;
687 }
688 
i2c_hid_output_raw_report(struct hid_device * hid,u8 report_type,const u8 * buf,size_t count,bool do_set)689 static int i2c_hid_output_raw_report(struct hid_device *hid, u8 report_type,
690 				     const u8 *buf, size_t count, bool do_set)
691 {
692 	struct i2c_client *client = hid->driver_data;
693 	struct i2c_hid *ihid = i2c_get_clientdata(client);
694 	int report_id = buf[0];
695 	int ret;
696 
697 	if (report_type == HID_INPUT_REPORT)
698 		return -EINVAL;
699 
700 	mutex_lock(&ihid->reset_lock);
701 
702 	/*
703 	 * Note that both numbered and unnumbered reports passed here
704 	 * are supposed to have report ID stored in the 1st byte of the
705 	 * buffer, so we strip it off unconditionally before passing payload
706 	 * to i2c_hid_set_or_send_report which takes care of encoding
707 	 * everything properly.
708 	 */
709 	ret = i2c_hid_set_or_send_report(ihid,
710 				report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
711 				report_id, buf + 1, count - 1, do_set);
712 
713 	if (ret >= 0)
714 		ret++; /* add report_id to the number of transferred bytes */
715 
716 	mutex_unlock(&ihid->reset_lock);
717 
718 	return ret;
719 }
720 
i2c_hid_output_report(struct hid_device * hid,u8 * buf,size_t count)721 static int i2c_hid_output_report(struct hid_device *hid, u8 *buf, size_t count)
722 {
723 	return i2c_hid_output_raw_report(hid, HID_OUTPUT_REPORT, buf, count,
724 					 false);
725 }
726 
i2c_hid_raw_request(struct hid_device * hid,unsigned char reportnum,__u8 * buf,size_t len,unsigned char rtype,int reqtype)727 static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
728 			       __u8 *buf, size_t len, unsigned char rtype,
729 			       int reqtype)
730 {
731 	switch (reqtype) {
732 	case HID_REQ_GET_REPORT:
733 		return i2c_hid_get_raw_report(hid, rtype, reportnum, buf, len);
734 	case HID_REQ_SET_REPORT:
735 		if (buf[0] != reportnum)
736 			return -EINVAL;
737 		return i2c_hid_output_raw_report(hid, rtype, buf, len, true);
738 	default:
739 		return -EIO;
740 	}
741 }
742 
i2c_hid_parse(struct hid_device * hid)743 static int i2c_hid_parse(struct hid_device *hid)
744 {
745 	struct i2c_client *client = hid->driver_data;
746 	struct i2c_hid *ihid = i2c_get_clientdata(client);
747 	struct i2c_hid_desc *hdesc = &ihid->hdesc;
748 	char *rdesc = NULL, *use_override = NULL;
749 	unsigned int rsize;
750 	int ret;
751 	int tries = 3;
752 
753 	i2c_hid_dbg(ihid, "entering %s\n", __func__);
754 
755 	rsize = le16_to_cpu(hdesc->wReportDescLength);
756 	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
757 		dbg_hid("weird size of report descriptor (%u)\n", rsize);
758 		return -EINVAL;
759 	}
760 
761 	mutex_lock(&ihid->reset_lock);
762 	do {
763 		ret = i2c_hid_start_hwreset(ihid);
764 		if (ret == 0)
765 			ret = i2c_hid_finish_hwreset(ihid);
766 		else
767 			msleep(1000);
768 	} while (tries-- > 0 && ret);
769 	mutex_unlock(&ihid->reset_lock);
770 
771 	if (ret)
772 		return ret;
773 
774 	use_override = i2c_hid_get_dmi_hid_report_desc_override(client->name,
775 								&rsize);
776 
777 	if (use_override) {
778 		rdesc = use_override;
779 		i2c_hid_dbg(ihid, "Using a HID report descriptor override\n");
780 	} else {
781 		rdesc = kzalloc(rsize, GFP_KERNEL);
782 		if (!rdesc)
783 			return -ENOMEM;
784 
785 		i2c_hid_dbg(ihid, "asking HID report descriptor\n");
786 
787 		ret = i2c_hid_read_register(ihid,
788 					    ihid->hdesc.wReportDescRegister,
789 					    rdesc, rsize);
790 		if (ret) {
791 			hid_err(hid, "reading report descriptor failed\n");
792 			goto out;
793 		}
794 	}
795 
796 	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
797 
798 	ret = hid_parse_report(hid, rdesc, rsize);
799 	if (ret)
800 		dbg_hid("parsing report descriptor failed\n");
801 
802 out:
803 	if (!use_override)
804 		kfree(rdesc);
805 
806 	return ret;
807 }
808 
i2c_hid_start(struct hid_device * hid)809 static int i2c_hid_start(struct hid_device *hid)
810 {
811 	struct i2c_client *client = hid->driver_data;
812 	struct i2c_hid *ihid = i2c_get_clientdata(client);
813 	int ret;
814 	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
815 
816 	i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
817 	i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
818 	i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
819 
820 	if (bufsize > ihid->bufsize) {
821 		disable_irq(client->irq);
822 		i2c_hid_free_buffers(ihid);
823 
824 		ret = i2c_hid_alloc_buffers(ihid, bufsize);
825 		enable_irq(client->irq);
826 
827 		if (ret)
828 			return ret;
829 	}
830 
831 	return 0;
832 }
833 
i2c_hid_stop(struct hid_device * hid)834 static void i2c_hid_stop(struct hid_device *hid)
835 {
836 	hid->claimed = 0;
837 }
838 
i2c_hid_open(struct hid_device * hid)839 static int i2c_hid_open(struct hid_device *hid)
840 {
841 	struct i2c_client *client = hid->driver_data;
842 	struct i2c_hid *ihid = i2c_get_clientdata(client);
843 
844 	set_bit(I2C_HID_STARTED, &ihid->flags);
845 	return 0;
846 }
847 
i2c_hid_close(struct hid_device * hid)848 static void i2c_hid_close(struct hid_device *hid)
849 {
850 	struct i2c_client *client = hid->driver_data;
851 	struct i2c_hid *ihid = i2c_get_clientdata(client);
852 
853 	clear_bit(I2C_HID_STARTED, &ihid->flags);
854 }
855 
856 static const struct hid_ll_driver i2c_hid_ll_driver = {
857 	.parse = i2c_hid_parse,
858 	.start = i2c_hid_start,
859 	.stop = i2c_hid_stop,
860 	.open = i2c_hid_open,
861 	.close = i2c_hid_close,
862 	.output_report = i2c_hid_output_report,
863 	.raw_request = i2c_hid_raw_request,
864 };
865 
i2c_hid_init_irq(struct i2c_client * client)866 static int i2c_hid_init_irq(struct i2c_client *client)
867 {
868 	struct i2c_hid *ihid = i2c_get_clientdata(client);
869 	unsigned long irqflags = 0;
870 	int ret;
871 
872 	i2c_hid_dbg(ihid, "Requesting IRQ: %d\n", client->irq);
873 
874 	if (!irq_get_trigger_type(client->irq))
875 		irqflags = IRQF_TRIGGER_LOW;
876 
877 	ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
878 				   irqflags | IRQF_ONESHOT | IRQF_NO_AUTOEN,
879 				   client->name, ihid);
880 	if (ret < 0) {
881 		dev_warn(&client->dev,
882 			"Could not register for %s interrupt, irq = %d,"
883 			" ret = %d\n",
884 			client->name, client->irq, ret);
885 
886 		return ret;
887 	}
888 
889 	return 0;
890 }
891 
i2c_hid_fetch_hid_descriptor(struct i2c_hid * ihid)892 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
893 {
894 	struct i2c_client *client = ihid->client;
895 	struct i2c_hid_desc *hdesc = &ihid->hdesc;
896 	unsigned int dsize;
897 	int error;
898 
899 	/* i2c hid fetch using a fixed descriptor size (30 bytes) */
900 	if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
901 		i2c_hid_dbg(ihid, "Using a HID descriptor override\n");
902 		ihid->hdesc =
903 			*i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
904 	} else {
905 		i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
906 		error = i2c_hid_read_register(ihid,
907 					      ihid->wHIDDescRegister,
908 					      &ihid->hdesc,
909 					      sizeof(ihid->hdesc));
910 		if (error) {
911 			dev_err(&ihid->client->dev,
912 				"failed to fetch HID descriptor: %d\n",
913 				error);
914 			return -ENODEV;
915 		}
916 	}
917 
918 	/* Validate the length of HID descriptor, the 4 first bytes:
919 	 * bytes 0-1 -> length
920 	 * bytes 2-3 -> bcdVersion (has to be 1.00) */
921 	/* check bcdVersion == 1.0 */
922 	if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
923 		dev_err(&ihid->client->dev,
924 			"unexpected HID descriptor bcdVersion (0x%04hx)\n",
925 			le16_to_cpu(hdesc->bcdVersion));
926 		return -ENODEV;
927 	}
928 
929 	/* Descriptor length should be 30 bytes as per the specification */
930 	dsize = le16_to_cpu(hdesc->wHIDDescLength);
931 	if (dsize != sizeof(struct i2c_hid_desc)) {
932 		dev_err(&ihid->client->dev,
933 			"weird size of HID descriptor (%u)\n", dsize);
934 		return -ENODEV;
935 	}
936 	i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, &ihid->hdesc);
937 	return 0;
938 }
939 
i2c_hid_core_power_up(struct i2c_hid * ihid)940 static int i2c_hid_core_power_up(struct i2c_hid *ihid)
941 {
942 	if (!ihid->ops->power_up)
943 		return 0;
944 
945 	return ihid->ops->power_up(ihid->ops);
946 }
947 
i2c_hid_core_power_down(struct i2c_hid * ihid)948 static void i2c_hid_core_power_down(struct i2c_hid *ihid)
949 {
950 	if (!ihid->ops->power_down)
951 		return;
952 
953 	ihid->ops->power_down(ihid->ops);
954 }
955 
i2c_hid_core_shutdown_tail(struct i2c_hid * ihid)956 static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
957 {
958 	if (!ihid->ops->shutdown_tail)
959 		return;
960 
961 	ihid->ops->shutdown_tail(ihid->ops);
962 }
963 
i2c_hid_core_suspend(struct i2c_hid * ihid,bool force_poweroff)964 static int i2c_hid_core_suspend(struct i2c_hid *ihid, bool force_poweroff)
965 {
966 	struct i2c_client *client = ihid->client;
967 	struct hid_device *hid = ihid->hid;
968 	int ret;
969 
970 	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
971 	if (ret < 0)
972 		return ret;
973 
974 	/* Save some power */
975 	if (!(ihid->quirks & I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND))
976 		i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
977 
978 	disable_irq(client->irq);
979 
980 	if (force_poweroff || !device_may_wakeup(&client->dev))
981 		i2c_hid_core_power_down(ihid);
982 
983 	return 0;
984 }
985 
i2c_hid_core_resume(struct i2c_hid * ihid)986 static int i2c_hid_core_resume(struct i2c_hid *ihid)
987 {
988 	struct i2c_client *client = ihid->client;
989 	struct hid_device *hid = ihid->hid;
990 	int ret;
991 
992 	if (!device_may_wakeup(&client->dev))
993 		i2c_hid_core_power_up(ihid);
994 
995 	enable_irq(client->irq);
996 
997 	/* On Goodix 27c6:0d42 wait extra time before device wakeup.
998 	 * It's not clear why but if we send wakeup too early, the device will
999 	 * never trigger input interrupts.
1000 	 */
1001 	if (ihid->quirks & I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME)
1002 		msleep(1500);
1003 
1004 	/* Instead of resetting device, simply powers the device on. This
1005 	 * solves "incomplete reports" on Raydium devices 2386:3118 and
1006 	 * 2386:4B33 and fixes various SIS touchscreens no longer sending
1007 	 * data after a suspend/resume.
1008 	 *
1009 	 * However some ALPS touchpads generate IRQ storm without reset, so
1010 	 * let's still reset them here.
1011 	 */
1012 	if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME) {
1013 		mutex_lock(&ihid->reset_lock);
1014 		ret = i2c_hid_start_hwreset(ihid);
1015 		if (ret == 0)
1016 			ret = i2c_hid_finish_hwreset(ihid);
1017 		mutex_unlock(&ihid->reset_lock);
1018 	} else {
1019 		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
1020 	}
1021 
1022 	if (ret)
1023 		return ret;
1024 
1025 	return hid_driver_reset_resume(hid);
1026 }
1027 
1028 /*
1029  * Check that the device exists and parse the HID descriptor.
1030  */
__i2c_hid_core_probe(struct i2c_hid * ihid)1031 static int __i2c_hid_core_probe(struct i2c_hid *ihid)
1032 {
1033 	struct i2c_client *client = ihid->client;
1034 	struct hid_device *hid = ihid->hid;
1035 	int ret;
1036 
1037 	ret = i2c_hid_probe_address(ihid);
1038 	if (ret < 0) {
1039 		i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
1040 		return -ENXIO;
1041 	}
1042 
1043 	ret = i2c_hid_fetch_hid_descriptor(ihid);
1044 	if (ret < 0) {
1045 		dev_err(&client->dev,
1046 			"Failed to fetch the HID Descriptor\n");
1047 		return ret;
1048 	}
1049 
1050 	hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1051 	hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1052 	hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1053 
1054 	hid->initial_quirks |= i2c_hid_get_dmi_quirks(hid->vendor,
1055 						      hid->product);
1056 
1057 	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
1058 		 client->name, (u16)hid->vendor, (u16)hid->product);
1059 	strscpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1060 
1061 	ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
1062 
1063 	return 0;
1064 }
1065 
i2c_hid_core_register_hid(struct i2c_hid * ihid)1066 static int i2c_hid_core_register_hid(struct i2c_hid *ihid)
1067 {
1068 	struct i2c_client *client = ihid->client;
1069 	struct hid_device *hid = ihid->hid;
1070 	int ret;
1071 
1072 	enable_irq(client->irq);
1073 
1074 	ret = hid_add_device(hid);
1075 	if (ret) {
1076 		if (ret != -ENODEV)
1077 			hid_err(client, "can't add hid device: %d\n", ret);
1078 		disable_irq(client->irq);
1079 		return ret;
1080 	}
1081 
1082 	/* At least some QTEC devices need this after initialization */
1083 	if (ihid->quirks & I2C_HID_QUIRK_RE_POWER_ON)
1084 		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
1085 
1086 	return ret;
1087 }
1088 
i2c_hid_core_probe_panel_follower(struct i2c_hid * ihid)1089 static int i2c_hid_core_probe_panel_follower(struct i2c_hid *ihid)
1090 {
1091 	int ret;
1092 
1093 	ret = i2c_hid_core_power_up(ihid);
1094 	if (ret)
1095 		return ret;
1096 
1097 	ret = __i2c_hid_core_probe(ihid);
1098 	if (ret)
1099 		goto err_power_down;
1100 
1101 	ret = i2c_hid_core_register_hid(ihid);
1102 	if (ret)
1103 		goto err_power_down;
1104 
1105 	return 0;
1106 
1107 err_power_down:
1108 	i2c_hid_core_power_down(ihid);
1109 
1110 	return ret;
1111 }
1112 
ihid_core_panel_prepare_work(struct work_struct * work)1113 static void ihid_core_panel_prepare_work(struct work_struct *work)
1114 {
1115 	struct i2c_hid *ihid = container_of(work, struct i2c_hid,
1116 					    panel_follower_prepare_work);
1117 	struct hid_device *hid = ihid->hid;
1118 	int ret;
1119 
1120 	/*
1121 	 * hid->version is set on the first power up. If it's still zero then
1122 	 * this is the first power on so we should perform initial power up
1123 	 * steps.
1124 	 */
1125 	if (!hid->version)
1126 		ret = i2c_hid_core_probe_panel_follower(ihid);
1127 	else
1128 		ret = i2c_hid_core_resume(ihid);
1129 
1130 	if (ret)
1131 		dev_warn(&ihid->client->dev, "Power on failed: %d\n", ret);
1132 	else
1133 		WRITE_ONCE(ihid->prepare_work_finished, true);
1134 
1135 	/*
1136 	 * The work APIs provide a number of memory ordering guarantees
1137 	 * including one that says that memory writes before schedule_work()
1138 	 * are always visible to the work function, but they don't appear to
1139 	 * guarantee that a write that happened in the work is visible after
1140 	 * cancel_work_sync(). We'll add a write memory barrier here to match
1141 	 * with i2c_hid_core_panel_unpreparing() to ensure that our write to
1142 	 * prepare_work_finished is visible there.
1143 	 */
1144 	smp_wmb();
1145 }
1146 
i2c_hid_core_panel_prepared(struct drm_panel_follower * follower)1147 static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
1148 {
1149 	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
1150 
1151 	/*
1152 	 * Powering on a touchscreen can be a slow process. Queue the work to
1153 	 * the system workqueue so we don't block the panel's power up.
1154 	 */
1155 	WRITE_ONCE(ihid->prepare_work_finished, false);
1156 	schedule_work(&ihid->panel_follower_prepare_work);
1157 
1158 	return 0;
1159 }
1160 
i2c_hid_core_panel_unpreparing(struct drm_panel_follower * follower)1161 static int i2c_hid_core_panel_unpreparing(struct drm_panel_follower *follower)
1162 {
1163 	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
1164 
1165 	cancel_work_sync(&ihid->panel_follower_prepare_work);
1166 
1167 	/* Match with ihid_core_panel_prepare_work() */
1168 	smp_rmb();
1169 	if (!READ_ONCE(ihid->prepare_work_finished))
1170 		return 0;
1171 
1172 	return i2c_hid_core_suspend(ihid, true);
1173 }
1174 
1175 static const struct drm_panel_follower_funcs i2c_hid_core_panel_follower_funcs = {
1176 	.panel_prepared = i2c_hid_core_panel_prepared,
1177 	.panel_unpreparing = i2c_hid_core_panel_unpreparing,
1178 };
1179 
i2c_hid_core_register_panel_follower(struct i2c_hid * ihid)1180 static int i2c_hid_core_register_panel_follower(struct i2c_hid *ihid)
1181 {
1182 	struct device *dev = &ihid->client->dev;
1183 	int ret;
1184 
1185 	ihid->panel_follower.funcs = &i2c_hid_core_panel_follower_funcs;
1186 
1187 	/*
1188 	 * If we're not in control of our own power up/power down then we can't
1189 	 * do the logic to manage wakeups. Give a warning if a user thought
1190 	 * that was possible then force the capability off.
1191 	 */
1192 	if (device_can_wakeup(dev)) {
1193 		dev_warn(dev, "Can't wakeup if following panel\n");
1194 		device_set_wakeup_capable(dev, false);
1195 	}
1196 
1197 	ret = drm_panel_add_follower(dev, &ihid->panel_follower);
1198 	if (ret)
1199 		return ret;
1200 
1201 	return 0;
1202 }
1203 
i2c_hid_core_probe(struct i2c_client * client,struct i2chid_ops * ops,u16 hid_descriptor_address,u32 quirks)1204 int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
1205 		       u16 hid_descriptor_address, u32 quirks)
1206 {
1207 	int ret;
1208 	struct i2c_hid *ihid;
1209 	struct hid_device *hid;
1210 
1211 	dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
1212 
1213 	if (!client->irq) {
1214 		dev_err(&client->dev,
1215 			"HID over i2c has not been provided an Int IRQ\n");
1216 		return -EINVAL;
1217 	}
1218 
1219 	if (client->irq < 0) {
1220 		if (client->irq != -EPROBE_DEFER)
1221 			dev_err(&client->dev,
1222 				"HID over i2c doesn't have a valid IRQ\n");
1223 		return client->irq;
1224 	}
1225 
1226 	ihid = devm_kzalloc(&client->dev, sizeof(*ihid), GFP_KERNEL);
1227 	if (!ihid)
1228 		return -ENOMEM;
1229 
1230 	i2c_set_clientdata(client, ihid);
1231 
1232 	ihid->ops = ops;
1233 	ihid->client = client;
1234 	ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
1235 	ihid->is_panel_follower = drm_is_panel_follower(&client->dev);
1236 
1237 	init_waitqueue_head(&ihid->wait);
1238 	mutex_init(&ihid->cmd_lock);
1239 	mutex_init(&ihid->reset_lock);
1240 	INIT_WORK(&ihid->panel_follower_prepare_work, ihid_core_panel_prepare_work);
1241 
1242 	/* we need to allocate the command buffer without knowing the maximum
1243 	 * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
1244 	 * real computation later. */
1245 	ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
1246 	if (ret < 0)
1247 		return ret;
1248 	device_enable_async_suspend(&client->dev);
1249 
1250 	hid = hid_allocate_device();
1251 	if (IS_ERR(hid)) {
1252 		ret = PTR_ERR(hid);
1253 		goto err_free_buffers;
1254 	}
1255 
1256 	ihid->hid = hid;
1257 
1258 	hid->driver_data = client;
1259 	hid->ll_driver = &i2c_hid_ll_driver;
1260 	hid->dev.parent = &client->dev;
1261 	hid->bus = BUS_I2C;
1262 	hid->initial_quirks = quirks;
1263 
1264 	/* Power on and probe unless device is a panel follower. */
1265 	if (!ihid->is_panel_follower) {
1266 		ret = i2c_hid_core_power_up(ihid);
1267 		if (ret < 0)
1268 			goto err_destroy_device;
1269 
1270 		ret = __i2c_hid_core_probe(ihid);
1271 		if (ret < 0)
1272 			goto err_power_down;
1273 	}
1274 
1275 	ret = i2c_hid_init_irq(client);
1276 	if (ret < 0)
1277 		goto err_power_down;
1278 
1279 	/*
1280 	 * If we're a panel follower, we'll register when the panel turns on;
1281 	 * otherwise we do it right away.
1282 	 */
1283 	if (ihid->is_panel_follower)
1284 		ret = i2c_hid_core_register_panel_follower(ihid);
1285 	else
1286 		ret = i2c_hid_core_register_hid(ihid);
1287 	if (ret)
1288 		goto err_free_irq;
1289 
1290 	return 0;
1291 
1292 err_free_irq:
1293 	free_irq(client->irq, ihid);
1294 err_power_down:
1295 	if (!ihid->is_panel_follower)
1296 		i2c_hid_core_power_down(ihid);
1297 err_destroy_device:
1298 	hid_destroy_device(hid);
1299 err_free_buffers:
1300 	i2c_hid_free_buffers(ihid);
1301 
1302 	return ret;
1303 }
1304 EXPORT_SYMBOL_GPL(i2c_hid_core_probe);
1305 
i2c_hid_core_remove(struct i2c_client * client)1306 void i2c_hid_core_remove(struct i2c_client *client)
1307 {
1308 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1309 	struct hid_device *hid;
1310 
1311 	/*
1312 	 * If we're a follower, the act of unfollowing will cause us to be
1313 	 * powered down. Otherwise we need to manually do it.
1314 	 */
1315 	if (ihid->is_panel_follower)
1316 		drm_panel_remove_follower(&ihid->panel_follower);
1317 	else
1318 		i2c_hid_core_suspend(ihid, true);
1319 
1320 	hid = ihid->hid;
1321 	hid_destroy_device(hid);
1322 
1323 	free_irq(client->irq, ihid);
1324 
1325 	if (ihid->bufsize)
1326 		i2c_hid_free_buffers(ihid);
1327 }
1328 EXPORT_SYMBOL_GPL(i2c_hid_core_remove);
1329 
i2c_hid_core_shutdown(struct i2c_client * client)1330 void i2c_hid_core_shutdown(struct i2c_client *client)
1331 {
1332 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1333 
1334 	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
1335 	free_irq(client->irq, ihid);
1336 
1337 	i2c_hid_core_shutdown_tail(ihid);
1338 }
1339 EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
1340 
i2c_hid_core_pm_suspend(struct device * dev)1341 static int i2c_hid_core_pm_suspend(struct device *dev)
1342 {
1343 	struct i2c_client *client = to_i2c_client(dev);
1344 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1345 
1346 	if (ihid->is_panel_follower)
1347 		return 0;
1348 
1349 	return i2c_hid_core_suspend(ihid, false);
1350 }
1351 
i2c_hid_core_pm_resume(struct device * dev)1352 static int i2c_hid_core_pm_resume(struct device *dev)
1353 {
1354 	struct i2c_client *client = to_i2c_client(dev);
1355 	struct i2c_hid *ihid = i2c_get_clientdata(client);
1356 
1357 	if (ihid->is_panel_follower)
1358 		return 0;
1359 
1360 	return i2c_hid_core_resume(ihid);
1361 }
1362 
1363 const struct dev_pm_ops i2c_hid_core_pm = {
1364 	SYSTEM_SLEEP_PM_OPS(i2c_hid_core_pm_suspend, i2c_hid_core_pm_resume)
1365 };
1366 EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
1367 
1368 MODULE_DESCRIPTION("HID over I2C core driver");
1369 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1370 MODULE_LICENSE("GPL");
1371