Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/hid/i2c-hid/i2c-hid.c

  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/delay.h>
 26 #include <linux/slab.h>
 27 #include <linux/pm.h>
 28 #include <linux/pm_runtime.h>
 29 #include <linux/device.h>
 30 #include <linux/wait.h>
 31 #include <linux/err.h>
 32 #include <linux/string.h>
 33 #include <linux/list.h>
 34 #include <linux/jiffies.h>
 35 #include <linux/kernel.h>
 36 #include <linux/hid.h>
 37 #include <linux/mutex.h>
 38 #include <linux/acpi.h>
 39 #include <linux/of.h>
 40 #include <linux/gpio/consumer.h>
 41 
 42 #include <linux/i2c/i2c-hid.h>
 43 
 44 /* flags */
 45 #define I2C_HID_STARTED         0
 46 #define I2C_HID_RESET_PENDING   1
 47 #define I2C_HID_READ_PENDING    2
 48 
 49 #define I2C_HID_PWR_ON          0x00
 50 #define I2C_HID_PWR_SLEEP       0x01
 51 
 52 /* debug option */
 53 static bool debug;
 54 module_param(debug, bool, 0444);
 55 MODULE_PARM_DESC(debug, "print a lot of debug information");
 56 
 57 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
 58 do {                                                                      \
 59         if (debug)                                                        \
 60                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
 61 } while (0)
 62 
 63 struct i2c_hid_desc {
 64         __le16 wHIDDescLength;
 65         __le16 bcdVersion;
 66         __le16 wReportDescLength;
 67         __le16 wReportDescRegister;
 68         __le16 wInputRegister;
 69         __le16 wMaxInputLength;
 70         __le16 wOutputRegister;
 71         __le16 wMaxOutputLength;
 72         __le16 wCommandRegister;
 73         __le16 wDataRegister;
 74         __le16 wVendorID;
 75         __le16 wProductID;
 76         __le16 wVersionID;
 77         __le32 reserved;
 78 } __packed;
 79 
 80 struct i2c_hid_cmd {
 81         unsigned int registerIndex;
 82         __u8 opcode;
 83         unsigned int length;
 84         bool wait;
 85 };
 86 
 87 union command {
 88         u8 data[0];
 89         struct cmd {
 90                 __le16 reg;
 91                 __u8 reportTypeID;
 92                 __u8 opcode;
 93         } __packed c;
 94 };
 95 
 96 #define I2C_HID_CMD(opcode_) \
 97         .opcode = opcode_, .length = 4, \
 98         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
 99 
100 /* fetch HID descriptor */
101 static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
102 /* fetch report descriptors */
103 static const struct i2c_hid_cmd hid_report_descr_cmd = {
104                 .registerIndex = offsetof(struct i2c_hid_desc,
105                         wReportDescRegister),
106                 .opcode = 0x00,
107                 .length = 2 };
108 /* commands */
109 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01),
110                                                           .wait = true };
111 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
112 static const struct i2c_hid_cmd hid_set_report_cmd =    { I2C_HID_CMD(0x03) };
113 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
114 static const struct i2c_hid_cmd hid_no_cmd =            { .length = 0 };
115 
116 /*
117  * These definitions are not used here, but are defined by the spec.
118  * Keeping them here for documentation purposes.
119  *
120  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
121  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
122  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
123  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
124  */
125 
126 static DEFINE_MUTEX(i2c_hid_open_mut);
127 
128 /* The main device structure */
129 struct i2c_hid {
130         struct i2c_client       *client;        /* i2c client */
131         struct hid_device       *hid;   /* pointer to corresponding HID dev */
132         union {
133                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
134                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
135         };
136         __le16                  wHIDDescRegister; /* location of the i2c
137                                                    * register of the HID
138                                                    * descriptor. */
139         unsigned int            bufsize;        /* i2c buffer size */
140         char                    *inbuf;         /* Input buffer */
141         char                    *rawbuf;        /* Raw Input buffer */
142         char                    *cmdbuf;        /* Command buffer */
143         char                    *argsbuf;       /* Command arguments buffer */
144 
145         unsigned long           flags;          /* device flags */
146 
147         wait_queue_head_t       wait;           /* For waiting the interrupt */
148         struct gpio_desc        *desc;
149         int                     irq;
150 
151         struct i2c_hid_platform_data pdata;
152 
153         bool                    irq_wake_enabled;
154         struct mutex            reset_lock;
155 };
156 
157 static int __i2c_hid_command(struct i2c_client *client,
158                 const struct i2c_hid_cmd *command, u8 reportID,
159                 u8 reportType, u8 *args, int args_len,
160                 unsigned char *buf_recv, int data_len)
161 {
162         struct i2c_hid *ihid = i2c_get_clientdata(client);
163         union command *cmd = (union command *)ihid->cmdbuf;
164         int ret;
165         struct i2c_msg msg[2];
166         int msg_num = 1;
167 
168         int length = command->length;
169         bool wait = command->wait;
170         unsigned int registerIndex = command->registerIndex;
171 
172         /* special case for hid_descr_cmd */
173         if (command == &hid_descr_cmd) {
174                 cmd->c.reg = ihid->wHIDDescRegister;
175         } else {
176                 cmd->data[0] = ihid->hdesc_buffer[registerIndex];
177                 cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
178         }
179 
180         if (length > 2) {
181                 cmd->c.opcode = command->opcode;
182                 cmd->c.reportTypeID = reportID | reportType << 4;
183         }
184 
185         memcpy(cmd->data + length, args, args_len);
186         length += args_len;
187 
188         i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
189 
190         msg[0].addr = client->addr;
191         msg[0].flags = client->flags & I2C_M_TEN;
192         msg[0].len = length;
193         msg[0].buf = cmd->data;
194         if (data_len > 0) {
195                 msg[1].addr = client->addr;
196                 msg[1].flags = client->flags & I2C_M_TEN;
197                 msg[1].flags |= I2C_M_RD;
198                 msg[1].len = data_len;
199                 msg[1].buf = buf_recv;
200                 msg_num = 2;
201                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
202         }
203 
204         if (wait)
205                 set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
206 
207         ret = i2c_transfer(client->adapter, msg, msg_num);
208 
209         if (data_len > 0)
210                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
211 
212         if (ret != msg_num)
213                 return ret < 0 ? ret : -EIO;
214 
215         ret = 0;
216 
217         if (wait) {
218                 i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
219                 if (!wait_event_timeout(ihid->wait,
220                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
221                                 msecs_to_jiffies(5000)))
222                         ret = -ENODATA;
223                 i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
224         }
225 
226         return ret;
227 }
228 
229 static int i2c_hid_command(struct i2c_client *client,
230                 const struct i2c_hid_cmd *command,
231                 unsigned char *buf_recv, int data_len)
232 {
233         return __i2c_hid_command(client, command, 0, 0, NULL, 0,
234                                 buf_recv, data_len);
235 }
236 
237 static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
238                 u8 reportID, unsigned char *buf_recv, int data_len)
239 {
240         struct i2c_hid *ihid = i2c_get_clientdata(client);
241         u8 args[3];
242         int ret;
243         int args_len = 0;
244         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
245 
246         i2c_hid_dbg(ihid, "%s\n", __func__);
247 
248         if (reportID >= 0x0F) {
249                 args[args_len++] = reportID;
250                 reportID = 0x0F;
251         }
252 
253         args[args_len++] = readRegister & 0xFF;
254         args[args_len++] = readRegister >> 8;
255 
256         ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
257                 reportType, args, args_len, buf_recv, data_len);
258         if (ret) {
259                 dev_err(&client->dev,
260                         "failed to retrieve report from device.\n");
261                 return ret;
262         }
263 
264         return 0;
265 }
266 
267 /**
268  * i2c_hid_set_or_send_report: forward an incoming report to the device
269  * @client: the i2c_client of the device
270  * @reportType: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
271  * @reportID: the report ID
272  * @buf: the actual data to transfer, without the report ID
273  * @len: size of buf
274  * @use_data: true: use SET_REPORT HID command, false: send plain OUTPUT report
275  */
276 static int i2c_hid_set_or_send_report(struct i2c_client *client, u8 reportType,
277                 u8 reportID, unsigned char *buf, size_t data_len, bool use_data)
278 {
279         struct i2c_hid *ihid = i2c_get_clientdata(client);
280         u8 *args = ihid->argsbuf;
281         const struct i2c_hid_cmd *hidcmd;
282         int ret;
283         u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
284         u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
285         u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
286         u16 size;
287         int args_len;
288         int index = 0;
289 
290         i2c_hid_dbg(ihid, "%s\n", __func__);
291 
292         if (data_len > ihid->bufsize)
293                 return -EINVAL;
294 
295         size =          2                       /* size */ +
296                         (reportID ? 1 : 0)      /* reportID */ +
297                         data_len                /* buf */;
298         args_len =      (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
299                         2                       /* dataRegister */ +
300                         size                    /* args */;
301 
302         if (!use_data && maxOutputLength == 0)
303                 return -ENOSYS;
304 
305         if (reportID >= 0x0F) {
306                 args[index++] = reportID;
307                 reportID = 0x0F;
308         }
309 
310         /*
311          * use the data register for feature reports or if the device does not
312          * support the output register
313          */
314         if (use_data) {
315                 args[index++] = dataRegister & 0xFF;
316                 args[index++] = dataRegister >> 8;
317                 hidcmd = &hid_set_report_cmd;
318         } else {
319                 args[index++] = outputRegister & 0xFF;
320                 args[index++] = outputRegister >> 8;
321                 hidcmd = &hid_no_cmd;
322         }
323 
324         args[index++] = size & 0xFF;
325         args[index++] = size >> 8;
326 
327         if (reportID)
328                 args[index++] = reportID;
329 
330         memcpy(&args[index], buf, data_len);
331 
332         ret = __i2c_hid_command(client, hidcmd, reportID,
333                 reportType, args, args_len, NULL, 0);
334         if (ret) {
335                 dev_err(&client->dev, "failed to set a report to device.\n");
336                 return ret;
337         }
338 
339         return data_len;
340 }
341 
342 static int i2c_hid_set_power(struct i2c_client *client, int power_state)
343 {
344         struct i2c_hid *ihid = i2c_get_clientdata(client);
345         int ret;
346 
347         i2c_hid_dbg(ihid, "%s\n", __func__);
348 
349         ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
350                 0, NULL, 0, NULL, 0);
351         if (ret)
352                 dev_err(&client->dev, "failed to change power setting.\n");
353 
354         return ret;
355 }
356 
357 static int i2c_hid_hwreset(struct i2c_client *client)
358 {
359         struct i2c_hid *ihid = i2c_get_clientdata(client);
360         int ret;
361 
362         i2c_hid_dbg(ihid, "%s\n", __func__);
363 
364         /*
365          * This prevents sending feature reports while the device is
366          * being reset. Otherwise we may lose the reset complete
367          * interrupt.
368          */
369         mutex_lock(&ihid->reset_lock);
370 
371         ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
372         if (ret)
373                 goto out_unlock;
374 
375         i2c_hid_dbg(ihid, "resetting...\n");
376 
377         ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
378         if (ret) {
379                 dev_err(&client->dev, "failed to reset device.\n");
380                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
381         }
382 
383 out_unlock:
384         mutex_unlock(&ihid->reset_lock);
385         return ret;
386 }
387 
388 static void i2c_hid_get_input(struct i2c_hid *ihid)
389 {
390         int ret, ret_size;
391         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
392 
393         if (size > ihid->bufsize)
394                 size = ihid->bufsize;
395 
396         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
397         if (ret != size) {
398                 if (ret < 0)
399                         return;
400 
401                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
402                         __func__, ret, size);
403                 return;
404         }
405 
406         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
407 
408         if (!ret_size) {
409                 /* host or device initiated RESET completed */
410                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
411                         wake_up(&ihid->wait);
412                 return;
413         }
414 
415         if (ret_size > size) {
416                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
417                         __func__, size, ret_size);
418                 return;
419         }
420 
421         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
422 
423         if (test_bit(I2C_HID_STARTED, &ihid->flags))
424                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
425                                 ret_size - 2, 1);
426 
427         return;
428 }
429 
430 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
431 {
432         struct i2c_hid *ihid = dev_id;
433 
434         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
435                 return IRQ_HANDLED;
436 
437         i2c_hid_get_input(ihid);
438 
439         return IRQ_HANDLED;
440 }
441 
442 static int i2c_hid_get_report_length(struct hid_report *report)
443 {
444         return ((report->size - 1) >> 3) + 1 +
445                 report->device->report_enum[report->type].numbered + 2;
446 }
447 
448 static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
449         size_t bufsize)
450 {
451         struct hid_device *hid = report->device;
452         struct i2c_client *client = hid->driver_data;
453         struct i2c_hid *ihid = i2c_get_clientdata(client);
454         unsigned int size, ret_size;
455 
456         size = i2c_hid_get_report_length(report);
457         if (i2c_hid_get_report(client,
458                         report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
459                         report->id, buffer, size))
460                 return;
461 
462         i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, buffer);
463 
464         ret_size = buffer[0] | (buffer[1] << 8);
465 
466         if (ret_size != size) {
467                 dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
468                         __func__, size, ret_size);
469                 return;
470         }
471 
472         /* hid->driver_lock is held as we are in probe function,
473          * we just need to setup the input fields, so using
474          * hid_report_raw_event is safe. */
475         hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
476 }
477 
478 /*
479  * Initialize all reports
480  */
481 static void i2c_hid_init_reports(struct hid_device *hid)
482 {
483         struct hid_report *report;
484         struct i2c_client *client = hid->driver_data;
485         struct i2c_hid *ihid = i2c_get_clientdata(client);
486         u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
487 
488         if (!inbuf) {
489                 dev_err(&client->dev, "can not retrieve initial reports\n");
490                 return;
491         }
492 
493         /*
494          * The device must be powered on while we fetch initial reports
495          * from it.
496          */
497         pm_runtime_get_sync(&client->dev);
498 
499         list_for_each_entry(report,
500                 &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
501                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
502 
503         pm_runtime_put(&client->dev);
504 
505         kfree(inbuf);
506 }
507 
508 /*
509  * Traverse the supplied list of reports and find the longest
510  */
511 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
512                 unsigned int *max)
513 {
514         struct hid_report *report;
515         unsigned int size;
516 
517         /* We should not rely on wMaxInputLength, as some devices may set it to
518          * a wrong length. */
519         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
520                 size = i2c_hid_get_report_length(report);
521                 if (*max < size)
522                         *max = size;
523         }
524 }
525 
526 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
527 {
528         kfree(ihid->inbuf);
529         kfree(ihid->rawbuf);
530         kfree(ihid->argsbuf);
531         kfree(ihid->cmdbuf);
532         ihid->inbuf = NULL;
533         ihid->rawbuf = NULL;
534         ihid->cmdbuf = NULL;
535         ihid->argsbuf = NULL;
536         ihid->bufsize = 0;
537 }
538 
539 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
540 {
541         /* the worst case is computed from the set_report command with a
542          * reportID > 15 and the maximum report length */
543         int args_len = sizeof(__u8) + /* optional ReportID byte */
544                        sizeof(__u16) + /* data register */
545                        sizeof(__u16) + /* size of the report */
546                        report_size; /* report */
547 
548         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
549         ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
550         ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
551         ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
552 
553         if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) {
554                 i2c_hid_free_buffers(ihid);
555                 return -ENOMEM;
556         }
557 
558         ihid->bufsize = report_size;
559 
560         return 0;
561 }
562 
563 static int i2c_hid_get_raw_report(struct hid_device *hid,
564                 unsigned char report_number, __u8 *buf, size_t count,
565                 unsigned char report_type)
566 {
567         struct i2c_client *client = hid->driver_data;
568         struct i2c_hid *ihid = i2c_get_clientdata(client);
569         size_t ret_count, ask_count;
570         int ret;
571 
572         if (report_type == HID_OUTPUT_REPORT)
573                 return -EINVAL;
574 
575         /* +2 bytes to include the size of the reply in the query buffer */
576         ask_count = min(count + 2, (size_t)ihid->bufsize);
577 
578         ret = i2c_hid_get_report(client,
579                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
580                         report_number, ihid->rawbuf, ask_count);
581 
582         if (ret < 0)
583                 return ret;
584 
585         ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
586 
587         if (ret_count <= 2)
588                 return 0;
589 
590         ret_count = min(ret_count, ask_count);
591 
592         /* The query buffer contains the size, dropping it in the reply */
593         count = min(count, ret_count - 2);
594         memcpy(buf, ihid->rawbuf + 2, count);
595 
596         return count;
597 }
598 
599 static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
600                 size_t count, unsigned char report_type, bool use_data)
601 {
602         struct i2c_client *client = hid->driver_data;
603         struct i2c_hid *ihid = i2c_get_clientdata(client);
604         int report_id = buf[0];
605         int ret;
606 
607         if (report_type == HID_INPUT_REPORT)
608                 return -EINVAL;
609 
610         mutex_lock(&ihid->reset_lock);
611 
612         if (report_id) {
613                 buf++;
614                 count--;
615         }
616 
617         ret = i2c_hid_set_or_send_report(client,
618                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
619                                 report_id, buf, count, use_data);
620 
621         if (report_id && ret >= 0)
622                 ret++; /* add report_id to the number of transfered bytes */
623 
624         mutex_unlock(&ihid->reset_lock);
625 
626         return ret;
627 }
628 
629 static int i2c_hid_output_report(struct hid_device *hid, __u8 *buf,
630                 size_t count)
631 {
632         return i2c_hid_output_raw_report(hid, buf, count, HID_OUTPUT_REPORT,
633                         false);
634 }
635 
636 static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
637                                __u8 *buf, size_t len, unsigned char rtype,
638                                int reqtype)
639 {
640         switch (reqtype) {
641         case HID_REQ_GET_REPORT:
642                 return i2c_hid_get_raw_report(hid, reportnum, buf, len, rtype);
643         case HID_REQ_SET_REPORT:
644                 if (buf[0] != reportnum)
645                         return -EINVAL;
646                 return i2c_hid_output_raw_report(hid, buf, len, rtype, true);
647         default:
648                 return -EIO;
649         }
650 }
651 
652 static int i2c_hid_parse(struct hid_device *hid)
653 {
654         struct i2c_client *client = hid->driver_data;
655         struct i2c_hid *ihid = i2c_get_clientdata(client);
656         struct i2c_hid_desc *hdesc = &ihid->hdesc;
657         unsigned int rsize;
658         char *rdesc;
659         int ret;
660         int tries = 3;
661 
662         i2c_hid_dbg(ihid, "entering %s\n", __func__);
663 
664         rsize = le16_to_cpu(hdesc->wReportDescLength);
665         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
666                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
667                 return -EINVAL;
668         }
669 
670         do {
671                 ret = i2c_hid_hwreset(client);
672                 if (ret)
673                         msleep(1000);
674         } while (tries-- > 0 && ret);
675 
676         if (ret)
677                 return ret;
678 
679         rdesc = kzalloc(rsize, GFP_KERNEL);
680 
681         if (!rdesc) {
682                 dbg_hid("couldn't allocate rdesc memory\n");
683                 return -ENOMEM;
684         }
685 
686         i2c_hid_dbg(ihid, "asking HID report descriptor\n");
687 
688         ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
689         if (ret) {
690                 hid_err(hid, "reading report descriptor failed\n");
691                 kfree(rdesc);
692                 return -EIO;
693         }
694 
695         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
696 
697         ret = hid_parse_report(hid, rdesc, rsize);
698         kfree(rdesc);
699         if (ret) {
700                 dbg_hid("parsing report descriptor failed\n");
701                 return ret;
702         }
703 
704         return 0;
705 }
706 
707 static int i2c_hid_start(struct hid_device *hid)
708 {
709         struct i2c_client *client = hid->driver_data;
710         struct i2c_hid *ihid = i2c_get_clientdata(client);
711         int ret;
712         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
713 
714         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
715         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
716         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
717 
718         if (bufsize > ihid->bufsize) {
719                 i2c_hid_free_buffers(ihid);
720 
721                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
722 
723                 if (ret)
724                         return ret;
725         }
726 
727         if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
728                 i2c_hid_init_reports(hid);
729 
730         return 0;
731 }
732 
733 static void i2c_hid_stop(struct hid_device *hid)
734 {
735         hid->claimed = 0;
736 }
737 
738 static int i2c_hid_open(struct hid_device *hid)
739 {
740         struct i2c_client *client = hid->driver_data;
741         struct i2c_hid *ihid = i2c_get_clientdata(client);
742         int ret = 0;
743 
744         mutex_lock(&i2c_hid_open_mut);
745         if (!hid->open++) {
746                 ret = pm_runtime_get_sync(&client->dev);
747                 if (ret < 0) {
748                         hid->open--;
749                         goto done;
750                 }
751                 set_bit(I2C_HID_STARTED, &ihid->flags);
752         }
753 done:
754         mutex_unlock(&i2c_hid_open_mut);
755         return ret < 0 ? ret : 0;
756 }
757 
758 static void i2c_hid_close(struct hid_device *hid)
759 {
760         struct i2c_client *client = hid->driver_data;
761         struct i2c_hid *ihid = i2c_get_clientdata(client);
762 
763         /* protecting hid->open to make sure we don't restart
764          * data acquistion due to a resumption we no longer
765          * care about
766          */
767         mutex_lock(&i2c_hid_open_mut);
768         if (!--hid->open) {
769                 clear_bit(I2C_HID_STARTED, &ihid->flags);
770 
771                 /* Save some power */
772                 pm_runtime_put(&client->dev);
773         }
774         mutex_unlock(&i2c_hid_open_mut);
775 }
776 
777 static int i2c_hid_power(struct hid_device *hid, int lvl)
778 {
779         struct i2c_client *client = hid->driver_data;
780         struct i2c_hid *ihid = i2c_get_clientdata(client);
781 
782         i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
783 
784         switch (lvl) {
785         case PM_HINT_FULLON:
786                 pm_runtime_get_sync(&client->dev);
787                 break;
788         case PM_HINT_NORMAL:
789                 pm_runtime_put(&client->dev);
790                 break;
791         }
792         return 0;
793 }
794 
795 static struct hid_ll_driver i2c_hid_ll_driver = {
796         .parse = i2c_hid_parse,
797         .start = i2c_hid_start,
798         .stop = i2c_hid_stop,
799         .open = i2c_hid_open,
800         .close = i2c_hid_close,
801         .power = i2c_hid_power,
802         .output_report = i2c_hid_output_report,
803         .raw_request = i2c_hid_raw_request,
804 };
805 
806 static int i2c_hid_init_irq(struct i2c_client *client)
807 {
808         struct i2c_hid *ihid = i2c_get_clientdata(client);
809         int ret;
810 
811         dev_dbg(&client->dev, "Requesting IRQ: %d\n", ihid->irq);
812 
813         ret = request_threaded_irq(ihid->irq, NULL, i2c_hid_irq,
814                         IRQF_TRIGGER_LOW | IRQF_ONESHOT,
815                         client->name, ihid);
816         if (ret < 0) {
817                 dev_warn(&client->dev,
818                         "Could not register for %s interrupt, irq = %d,"
819                         " ret = %d\n",
820                         client->name, ihid->irq, ret);
821 
822                 return ret;
823         }
824 
825         return 0;
826 }
827 
828 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
829 {
830         struct i2c_client *client = ihid->client;
831         struct i2c_hid_desc *hdesc = &ihid->hdesc;
832         unsigned int dsize;
833         int ret;
834 
835         /* i2c hid fetch using a fixed descriptor size (30 bytes) */
836         i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
837         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
838                                 sizeof(struct i2c_hid_desc));
839         if (ret) {
840                 dev_err(&client->dev, "hid_descr_cmd failed\n");
841                 return -ENODEV;
842         }
843 
844         /* Validate the length of HID descriptor, the 4 first bytes:
845          * bytes 0-1 -> length
846          * bytes 2-3 -> bcdVersion (has to be 1.00) */
847         /* check bcdVersion == 1.0 */
848         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
849                 dev_err(&client->dev,
850                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
851                         le16_to_cpu(hdesc->bcdVersion));
852                 return -ENODEV;
853         }
854 
855         /* Descriptor length should be 30 bytes as per the specification */
856         dsize = le16_to_cpu(hdesc->wHIDDescLength);
857         if (dsize != sizeof(struct i2c_hid_desc)) {
858                 dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
859                         dsize);
860                 return -ENODEV;
861         }
862         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
863         return 0;
864 }
865 
866 #ifdef CONFIG_ACPI
867 
868 /* Default GPIO mapping */
869 static const struct acpi_gpio_params i2c_hid_irq_gpio = { 0, 0, true };
870 static const struct acpi_gpio_mapping i2c_hid_acpi_gpios[] = {
871         { "gpios", &i2c_hid_irq_gpio, 1 },
872         { },
873 };
874 
875 static int i2c_hid_acpi_pdata(struct i2c_client *client,
876                 struct i2c_hid_platform_data *pdata)
877 {
878         static u8 i2c_hid_guid[] = {
879                 0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
880                 0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
881         };
882         union acpi_object *obj;
883         struct acpi_device *adev;
884         acpi_handle handle;
885         int ret;
886 
887         handle = ACPI_HANDLE(&client->dev);
888         if (!handle || acpi_bus_get_device(handle, &adev))
889                 return -ENODEV;
890 
891         obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
892                                       ACPI_TYPE_INTEGER);
893         if (!obj) {
894                 dev_err(&client->dev, "device _DSM execution failed\n");
895                 return -ENODEV;
896         }
897 
898         pdata->hid_descriptor_address = obj->integer.value;
899         ACPI_FREE(obj);
900 
901         /* GPIOs are optional */
902         ret = acpi_dev_add_driver_gpios(adev, i2c_hid_acpi_gpios);
903         return ret < 0 && ret != -ENXIO ? ret : 0;
904 }
905 
906 static const struct acpi_device_id i2c_hid_acpi_match[] = {
907         {"ACPI0C50", 0 },
908         {"PNP0C50", 0 },
909         { },
910 };
911 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
912 #else
913 static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
914                 struct i2c_hid_platform_data *pdata)
915 {
916         return -ENODEV;
917 }
918 #endif
919 
920 #ifdef CONFIG_OF
921 static int i2c_hid_of_probe(struct i2c_client *client,
922                 struct i2c_hid_platform_data *pdata)
923 {
924         struct device *dev = &client->dev;
925         u32 val;
926         int ret;
927 
928         ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
929         if (ret) {
930                 dev_err(&client->dev, "HID register address not provided\n");
931                 return -ENODEV;
932         }
933         if (val >> 16) {
934                 dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
935                         val);
936                 return -EINVAL;
937         }
938         pdata->hid_descriptor_address = val;
939 
940         return 0;
941 }
942 
943 static const struct of_device_id i2c_hid_of_match[] = {
944         { .compatible = "hid-over-i2c" },
945         {},
946 };
947 MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
948 #else
949 static inline int i2c_hid_of_probe(struct i2c_client *client,
950                 struct i2c_hid_platform_data *pdata)
951 {
952         return -ENODEV;
953 }
954 #endif
955 
956 static int i2c_hid_probe(struct i2c_client *client,
957                          const struct i2c_device_id *dev_id)
958 {
959         int ret;
960         struct i2c_hid *ihid;
961         struct hid_device *hid;
962         __u16 hidRegister;
963         struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
964 
965         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
966 
967         ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
968         if (!ihid)
969                 return -ENOMEM;
970 
971         if (client->dev.of_node) {
972                 ret = i2c_hid_of_probe(client, &ihid->pdata);
973                 if (ret)
974                         goto err;
975         } else if (!platform_data) {
976                 ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
977                 if (ret) {
978                         dev_err(&client->dev,
979                                 "HID register address not provided\n");
980                         goto err;
981                 }
982         } else {
983                 ihid->pdata = *platform_data;
984         }
985 
986         if (client->irq > 0) {
987                 ihid->irq = client->irq;
988         } else if (ACPI_COMPANION(&client->dev)) {
989                 ihid->desc = gpiod_get(&client->dev, NULL, GPIOD_IN);
990                 if (IS_ERR(ihid->desc)) {
991                         dev_err(&client->dev, "Failed to get GPIO interrupt\n");
992                         return PTR_ERR(ihid->desc);
993                 }
994 
995                 ihid->irq = gpiod_to_irq(ihid->desc);
996                 if (ihid->irq < 0) {
997                         gpiod_put(ihid->desc);
998                         dev_err(&client->dev, "Failed to convert GPIO to IRQ\n");
999                         return ihid->irq;
1000                 }
1001         }
1002 
1003         i2c_set_clientdata(client, ihid);
1004 
1005         ihid->client = client;
1006 
1007         hidRegister = ihid->pdata.hid_descriptor_address;
1008         ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
1009 
1010         init_waitqueue_head(&ihid->wait);
1011         mutex_init(&ihid->reset_lock);
1012 
1013         /* we need to allocate the command buffer without knowing the maximum
1014          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
1015          * real computation later. */
1016         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
1017         if (ret < 0)
1018                 goto err;
1019 
1020         pm_runtime_get_noresume(&client->dev);
1021         pm_runtime_set_active(&client->dev);
1022         pm_runtime_enable(&client->dev);
1023         device_enable_async_suspend(&client->dev);
1024 
1025         ret = i2c_hid_fetch_hid_descriptor(ihid);
1026         if (ret < 0)
1027                 goto err_pm;
1028 
1029         ret = i2c_hid_init_irq(client);
1030         if (ret < 0)
1031                 goto err_pm;
1032 
1033         hid = hid_allocate_device();
1034         if (IS_ERR(hid)) {
1035                 ret = PTR_ERR(hid);
1036                 goto err_irq;
1037         }
1038 
1039         ihid->hid = hid;
1040 
1041         hid->driver_data = client;
1042         hid->ll_driver = &i2c_hid_ll_driver;
1043         hid->dev.parent = &client->dev;
1044         hid->bus = BUS_I2C;
1045         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1046         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1047         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1048 
1049         snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
1050                  client->name, hid->vendor, hid->product);
1051         strlcpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1052 
1053         ret = hid_add_device(hid);
1054         if (ret) {
1055                 if (ret != -ENODEV)
1056                         hid_err(client, "can't add hid device: %d\n", ret);
1057                 goto err_mem_free;
1058         }
1059 
1060         pm_runtime_put(&client->dev);
1061         return 0;
1062 
1063 err_mem_free:
1064         hid_destroy_device(hid);
1065 
1066 err_irq:
1067         free_irq(ihid->irq, ihid);
1068 
1069 err_pm:
1070         pm_runtime_put_noidle(&client->dev);
1071         pm_runtime_disable(&client->dev);
1072 
1073 err:
1074         if (ihid->desc)
1075                 gpiod_put(ihid->desc);
1076 
1077         i2c_hid_free_buffers(ihid);
1078         kfree(ihid);
1079         return ret;
1080 }
1081 
1082 static int i2c_hid_remove(struct i2c_client *client)
1083 {
1084         struct i2c_hid *ihid = i2c_get_clientdata(client);
1085         struct hid_device *hid;
1086 
1087         pm_runtime_get_sync(&client->dev);
1088         pm_runtime_disable(&client->dev);
1089         pm_runtime_set_suspended(&client->dev);
1090         pm_runtime_put_noidle(&client->dev);
1091 
1092         hid = ihid->hid;
1093         hid_destroy_device(hid);
1094 
1095         free_irq(ihid->irq, ihid);
1096 
1097         if (ihid->bufsize)
1098                 i2c_hid_free_buffers(ihid);
1099 
1100         if (ihid->desc)
1101                 gpiod_put(ihid->desc);
1102 
1103         kfree(ihid);
1104 
1105         acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
1106 
1107         return 0;
1108 }
1109 
1110 static void i2c_hid_shutdown(struct i2c_client *client)
1111 {
1112         struct i2c_hid *ihid = i2c_get_clientdata(client);
1113 
1114         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1115         free_irq(client->irq, ihid);
1116 }
1117 
1118 #ifdef CONFIG_PM_SLEEP
1119 static int i2c_hid_suspend(struct device *dev)
1120 {
1121         struct i2c_client *client = to_i2c_client(dev);
1122         struct i2c_hid *ihid = i2c_get_clientdata(client);
1123         struct hid_device *hid = ihid->hid;
1124         int ret;
1125         int wake_status;
1126 
1127         if (hid->driver && hid->driver->suspend) {
1128                 /*
1129                  * Wake up the device so that IO issues in
1130                  * HID driver's suspend code can succeed.
1131                  */
1132                 ret = pm_runtime_resume(dev);
1133                 if (ret < 0)
1134                         return ret;
1135 
1136                 ret = hid->driver->suspend(hid, PMSG_SUSPEND);
1137                 if (ret < 0)
1138                         return ret;
1139         }
1140 
1141         if (!pm_runtime_suspended(dev)) {
1142                 /* Save some power */
1143                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1144 
1145                 disable_irq(ihid->irq);
1146         }
1147 
1148         if (device_may_wakeup(&client->dev)) {
1149                 wake_status = enable_irq_wake(ihid->irq);
1150                 if (!wake_status)
1151                         ihid->irq_wake_enabled = true;
1152                 else
1153                         hid_warn(hid, "Failed to enable irq wake: %d\n",
1154                                 wake_status);
1155         }
1156 
1157         return 0;
1158 }
1159 
1160 static int i2c_hid_resume(struct device *dev)
1161 {
1162         int ret;
1163         struct i2c_client *client = to_i2c_client(dev);
1164         struct i2c_hid *ihid = i2c_get_clientdata(client);
1165         struct hid_device *hid = ihid->hid;
1166         int wake_status;
1167 
1168         if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
1169                 wake_status = disable_irq_wake(ihid->irq);
1170                 if (!wake_status)
1171                         ihid->irq_wake_enabled = false;
1172                 else
1173                         hid_warn(hid, "Failed to disable irq wake: %d\n",
1174                                 wake_status);
1175         }
1176 
1177         /* We'll resume to full power */
1178         pm_runtime_disable(dev);
1179         pm_runtime_set_active(dev);
1180         pm_runtime_enable(dev);
1181 
1182         enable_irq(ihid->irq);
1183         ret = i2c_hid_hwreset(client);
1184         if (ret)
1185                 return ret;
1186 
1187         if (hid->driver && hid->driver->reset_resume) {
1188                 ret = hid->driver->reset_resume(hid);
1189                 return ret;
1190         }
1191 
1192         return 0;
1193 }
1194 #endif
1195 
1196 #ifdef CONFIG_PM
1197 static int i2c_hid_runtime_suspend(struct device *dev)
1198 {
1199         struct i2c_client *client = to_i2c_client(dev);
1200         struct i2c_hid *ihid = i2c_get_clientdata(client);
1201 
1202         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1203         disable_irq(ihid->irq);
1204         return 0;
1205 }
1206 
1207 static int i2c_hid_runtime_resume(struct device *dev)
1208 {
1209         struct i2c_client *client = to_i2c_client(dev);
1210         struct i2c_hid *ihid = i2c_get_clientdata(client);
1211 
1212         enable_irq(ihid->irq);
1213         i2c_hid_set_power(client, I2C_HID_PWR_ON);
1214         return 0;
1215 }
1216 #endif
1217 
1218 static const struct dev_pm_ops i2c_hid_pm = {
1219         SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_suspend, i2c_hid_resume)
1220         SET_RUNTIME_PM_OPS(i2c_hid_runtime_suspend, i2c_hid_runtime_resume,
1221                            NULL)
1222 };
1223 
1224 static const struct i2c_device_id i2c_hid_id_table[] = {
1225         { "hid", 0 },
1226         { "hid-over-i2c", 0 },
1227         { },
1228 };
1229 MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
1230 
1231 
1232 static struct i2c_driver i2c_hid_driver = {
1233         .driver = {
1234                 .name   = "i2c_hid",
1235                 .pm     = &i2c_hid_pm,
1236                 .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
1237                 .of_match_table = of_match_ptr(i2c_hid_of_match),
1238         },
1239 
1240         .probe          = i2c_hid_probe,
1241         .remove         = i2c_hid_remove,
1242         .shutdown       = i2c_hid_shutdown,
1243         .id_table       = i2c_hid_id_table,
1244 };
1245 
1246 module_i2c_driver(i2c_hid_driver);
1247 
1248 MODULE_DESCRIPTION("HID over I2C core driver");
1249 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1250 MODULE_LICENSE("GPL");
1251 

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