Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

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/device.h>
 29 #include <linux/wait.h>
 30 #include <linux/err.h>
 31 #include <linux/string.h>
 32 #include <linux/list.h>
 33 #include <linux/jiffies.h>
 34 #include <linux/kernel.h>
 35 #include <linux/hid.h>
 36 #include <linux/mutex.h>
 37 #include <linux/acpi.h>
 38 #include <linux/of.h>
 39 
 40 #include <linux/i2c/i2c-hid.h>
 41 
 42 /* flags */
 43 #define I2C_HID_STARTED         (1 << 0)
 44 #define I2C_HID_RESET_PENDING   (1 << 1)
 45 #define I2C_HID_READ_PENDING    (1 << 2)
 46 
 47 #define I2C_HID_PWR_ON          0x00
 48 #define I2C_HID_PWR_SLEEP       0x01
 49 
 50 /* debug option */
 51 static bool debug;
 52 module_param(debug, bool, 0444);
 53 MODULE_PARM_DESC(debug, "print a lot of debug information");
 54 
 55 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
 56 do {                                                                      \
 57         if (debug)                                                        \
 58                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
 59 } while (0)
 60 
 61 struct i2c_hid_desc {
 62         __le16 wHIDDescLength;
 63         __le16 bcdVersion;
 64         __le16 wReportDescLength;
 65         __le16 wReportDescRegister;
 66         __le16 wInputRegister;
 67         __le16 wMaxInputLength;
 68         __le16 wOutputRegister;
 69         __le16 wMaxOutputLength;
 70         __le16 wCommandRegister;
 71         __le16 wDataRegister;
 72         __le16 wVendorID;
 73         __le16 wProductID;
 74         __le16 wVersionID;
 75         __le32 reserved;
 76 } __packed;
 77 
 78 struct i2c_hid_cmd {
 79         unsigned int registerIndex;
 80         __u8 opcode;
 81         unsigned int length;
 82         bool wait;
 83 };
 84 
 85 union command {
 86         u8 data[0];
 87         struct cmd {
 88                 __le16 reg;
 89                 __u8 reportTypeID;
 90                 __u8 opcode;
 91         } __packed c;
 92 };
 93 
 94 #define I2C_HID_CMD(opcode_) \
 95         .opcode = opcode_, .length = 4, \
 96         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
 97 
 98 /* fetch HID descriptor */
 99 static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
100 /* fetch report descriptors */
101 static const struct i2c_hid_cmd hid_report_descr_cmd = {
102                 .registerIndex = offsetof(struct i2c_hid_desc,
103                         wReportDescRegister),
104                 .opcode = 0x00,
105                 .length = 2 };
106 /* commands */
107 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01),
108                                                           .wait = true };
109 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
110 static const struct i2c_hid_cmd hid_set_report_cmd =    { I2C_HID_CMD(0x03) };
111 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
112 static const struct i2c_hid_cmd hid_no_cmd =            { .length = 0 };
113 
114 /*
115  * These definitions are not used here, but are defined by the spec.
116  * Keeping them here for documentation purposes.
117  *
118  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
119  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
120  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
121  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
122  */
123 
124 static DEFINE_MUTEX(i2c_hid_open_mut);
125 
126 /* The main device structure */
127 struct i2c_hid {
128         struct i2c_client       *client;        /* i2c client */
129         struct hid_device       *hid;   /* pointer to corresponding HID dev */
130         union {
131                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
132                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
133         };
134         __le16                  wHIDDescRegister; /* location of the i2c
135                                                    * register of the HID
136                                                    * descriptor. */
137         unsigned int            bufsize;        /* i2c buffer size */
138         char                    *inbuf;         /* Input buffer */
139         char                    *cmdbuf;        /* Command buffer */
140         char                    *argsbuf;       /* Command arguments buffer */
141 
142         unsigned long           flags;          /* device flags */
143 
144         wait_queue_head_t       wait;           /* For waiting the interrupt */
145 
146         struct i2c_hid_platform_data pdata;
147 };
148 
149 static int __i2c_hid_command(struct i2c_client *client,
150                 const struct i2c_hid_cmd *command, u8 reportID,
151                 u8 reportType, u8 *args, int args_len,
152                 unsigned char *buf_recv, int data_len)
153 {
154         struct i2c_hid *ihid = i2c_get_clientdata(client);
155         union command *cmd = (union command *)ihid->cmdbuf;
156         int ret;
157         struct i2c_msg msg[2];
158         int msg_num = 1;
159 
160         int length = command->length;
161         bool wait = command->wait;
162         unsigned int registerIndex = command->registerIndex;
163 
164         /* special case for hid_descr_cmd */
165         if (command == &hid_descr_cmd) {
166                 cmd->c.reg = ihid->wHIDDescRegister;
167         } else {
168                 cmd->data[0] = ihid->hdesc_buffer[registerIndex];
169                 cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
170         }
171 
172         if (length > 2) {
173                 cmd->c.opcode = command->opcode;
174                 cmd->c.reportTypeID = reportID | reportType << 4;
175         }
176 
177         memcpy(cmd->data + length, args, args_len);
178         length += args_len;
179 
180         i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
181 
182         msg[0].addr = client->addr;
183         msg[0].flags = client->flags & I2C_M_TEN;
184         msg[0].len = length;
185         msg[0].buf = cmd->data;
186         if (data_len > 0) {
187                 msg[1].addr = client->addr;
188                 msg[1].flags = client->flags & I2C_M_TEN;
189                 msg[1].flags |= I2C_M_RD;
190                 msg[1].len = data_len;
191                 msg[1].buf = buf_recv;
192                 msg_num = 2;
193                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
194         }
195 
196         if (wait)
197                 set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
198 
199         ret = i2c_transfer(client->adapter, msg, msg_num);
200 
201         if (data_len > 0)
202                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
203 
204         if (ret != msg_num)
205                 return ret < 0 ? ret : -EIO;
206 
207         ret = 0;
208 
209         if (wait) {
210                 i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
211                 if (!wait_event_timeout(ihid->wait,
212                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
213                                 msecs_to_jiffies(5000)))
214                         ret = -ENODATA;
215                 i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
216         }
217 
218         return ret;
219 }
220 
221 static int i2c_hid_command(struct i2c_client *client,
222                 const struct i2c_hid_cmd *command,
223                 unsigned char *buf_recv, int data_len)
224 {
225         return __i2c_hid_command(client, command, 0, 0, NULL, 0,
226                                 buf_recv, data_len);
227 }
228 
229 static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
230                 u8 reportID, unsigned char *buf_recv, int data_len)
231 {
232         struct i2c_hid *ihid = i2c_get_clientdata(client);
233         u8 args[3];
234         int ret;
235         int args_len = 0;
236         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
237 
238         i2c_hid_dbg(ihid, "%s\n", __func__);
239 
240         if (reportID >= 0x0F) {
241                 args[args_len++] = reportID;
242                 reportID = 0x0F;
243         }
244 
245         args[args_len++] = readRegister & 0xFF;
246         args[args_len++] = readRegister >> 8;
247 
248         ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
249                 reportType, args, args_len, buf_recv, data_len);
250         if (ret) {
251                 dev_err(&client->dev,
252                         "failed to retrieve report from device.\n");
253                 return ret;
254         }
255 
256         return 0;
257 }
258 
259 static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
260                 u8 reportID, unsigned char *buf, size_t data_len)
261 {
262         struct i2c_hid *ihid = i2c_get_clientdata(client);
263         u8 *args = ihid->argsbuf;
264         const struct i2c_hid_cmd * hidcmd = &hid_set_report_cmd;
265         int ret;
266         u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
267         u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
268         u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
269 
270         /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
271         u16 size =      2                       /* size */ +
272                         (reportID ? 1 : 0)      /* reportID */ +
273                         data_len                /* buf */;
274         int args_len =  (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
275                         2                       /* dataRegister */ +
276                         size                    /* args */;
277         int index = 0;
278 
279         i2c_hid_dbg(ihid, "%s\n", __func__);
280 
281         if (reportID >= 0x0F) {
282                 args[index++] = reportID;
283                 reportID = 0x0F;
284         }
285 
286         /*
287          * use the data register for feature reports or if the device does not
288          * support the output register
289          */
290         if (reportType == 0x03 || maxOutputLength == 0) {
291                 args[index++] = dataRegister & 0xFF;
292                 args[index++] = dataRegister >> 8;
293         } else {
294                 args[index++] = outputRegister & 0xFF;
295                 args[index++] = outputRegister >> 8;
296                 hidcmd = &hid_no_cmd;
297         }
298 
299         args[index++] = size & 0xFF;
300         args[index++] = size >> 8;
301 
302         if (reportID)
303                 args[index++] = reportID;
304 
305         memcpy(&args[index], buf, data_len);
306 
307         ret = __i2c_hid_command(client, hidcmd, reportID,
308                 reportType, args, args_len, NULL, 0);
309         if (ret) {
310                 dev_err(&client->dev, "failed to set a report to device.\n");
311                 return ret;
312         }
313 
314         return data_len;
315 }
316 
317 static int i2c_hid_set_power(struct i2c_client *client, int power_state)
318 {
319         struct i2c_hid *ihid = i2c_get_clientdata(client);
320         int ret;
321 
322         i2c_hid_dbg(ihid, "%s\n", __func__);
323 
324         ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
325                 0, NULL, 0, NULL, 0);
326         if (ret)
327                 dev_err(&client->dev, "failed to change power setting.\n");
328 
329         return ret;
330 }
331 
332 static int i2c_hid_hwreset(struct i2c_client *client)
333 {
334         struct i2c_hid *ihid = i2c_get_clientdata(client);
335         int ret;
336 
337         i2c_hid_dbg(ihid, "%s\n", __func__);
338 
339         ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
340         if (ret)
341                 return ret;
342 
343         i2c_hid_dbg(ihid, "resetting...\n");
344 
345         ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
346         if (ret) {
347                 dev_err(&client->dev, "failed to reset device.\n");
348                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
349                 return ret;
350         }
351 
352         return 0;
353 }
354 
355 static void i2c_hid_get_input(struct i2c_hid *ihid)
356 {
357         int ret, ret_size;
358         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
359 
360         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
361         if (ret != size) {
362                 if (ret < 0)
363                         return;
364 
365                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
366                         __func__, ret, size);
367                 return;
368         }
369 
370         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
371 
372         if (!ret_size) {
373                 /* host or device initiated RESET completed */
374                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
375                         wake_up(&ihid->wait);
376                 return;
377         }
378 
379         if (ret_size > size) {
380                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
381                         __func__, size, ret_size);
382                 return;
383         }
384 
385         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
386 
387         if (test_bit(I2C_HID_STARTED, &ihid->flags))
388                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
389                                 ret_size - 2, 1);
390 
391         return;
392 }
393 
394 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
395 {
396         struct i2c_hid *ihid = dev_id;
397 
398         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
399                 return IRQ_HANDLED;
400 
401         i2c_hid_get_input(ihid);
402 
403         return IRQ_HANDLED;
404 }
405 
406 static int i2c_hid_get_report_length(struct hid_report *report)
407 {
408         return ((report->size - 1) >> 3) + 1 +
409                 report->device->report_enum[report->type].numbered + 2;
410 }
411 
412 static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
413         size_t bufsize)
414 {
415         struct hid_device *hid = report->device;
416         struct i2c_client *client = hid->driver_data;
417         struct i2c_hid *ihid = i2c_get_clientdata(client);
418         unsigned int size, ret_size;
419 
420         size = i2c_hid_get_report_length(report);
421         if (i2c_hid_get_report(client,
422                         report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
423                         report->id, buffer, size))
424                 return;
425 
426         i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
427 
428         ret_size = buffer[0] | (buffer[1] << 8);
429 
430         if (ret_size != size) {
431                 dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
432                         __func__, size, ret_size);
433                 return;
434         }
435 
436         /* hid->driver_lock is held as we are in probe function,
437          * we just need to setup the input fields, so using
438          * hid_report_raw_event is safe. */
439         hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
440 }
441 
442 /*
443  * Initialize all reports
444  */
445 static void i2c_hid_init_reports(struct hid_device *hid)
446 {
447         struct hid_report *report;
448         struct i2c_client *client = hid->driver_data;
449         struct i2c_hid *ihid = i2c_get_clientdata(client);
450         u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
451 
452         if (!inbuf) {
453                 dev_err(&client->dev, "can not retrieve initial reports\n");
454                 return;
455         }
456 
457         list_for_each_entry(report,
458                 &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
459                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
460 
461         kfree(inbuf);
462 }
463 
464 /*
465  * Traverse the supplied list of reports and find the longest
466  */
467 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
468                 unsigned int *max)
469 {
470         struct hid_report *report;
471         unsigned int size;
472 
473         /* We should not rely on wMaxInputLength, as some devices may set it to
474          * a wrong length. */
475         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
476                 size = i2c_hid_get_report_length(report);
477                 if (*max < size)
478                         *max = size;
479         }
480 }
481 
482 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
483 {
484         kfree(ihid->inbuf);
485         kfree(ihid->argsbuf);
486         kfree(ihid->cmdbuf);
487         ihid->inbuf = NULL;
488         ihid->cmdbuf = NULL;
489         ihid->argsbuf = NULL;
490         ihid->bufsize = 0;
491 }
492 
493 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
494 {
495         /* the worst case is computed from the set_report command with a
496          * reportID > 15 and the maximum report length */
497         int args_len = sizeof(__u8) + /* optional ReportID byte */
498                        sizeof(__u16) + /* data register */
499                        sizeof(__u16) + /* size of the report */
500                        report_size; /* report */
501 
502         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
503         ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
504         ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
505 
506         if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
507                 i2c_hid_free_buffers(ihid);
508                 return -ENOMEM;
509         }
510 
511         ihid->bufsize = report_size;
512 
513         return 0;
514 }
515 
516 static int i2c_hid_get_raw_report(struct hid_device *hid,
517                 unsigned char report_number, __u8 *buf, size_t count,
518                 unsigned char report_type)
519 {
520         struct i2c_client *client = hid->driver_data;
521         struct i2c_hid *ihid = i2c_get_clientdata(client);
522         size_t ret_count, ask_count;
523         int ret;
524 
525         if (report_type == HID_OUTPUT_REPORT)
526                 return -EINVAL;
527 
528         /* +2 bytes to include the size of the reply in the query buffer */
529         ask_count = min(count + 2, (size_t)ihid->bufsize);
530 
531         ret = i2c_hid_get_report(client,
532                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
533                         report_number, ihid->inbuf, ask_count);
534 
535         if (ret < 0)
536                 return ret;
537 
538         ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
539 
540         if (ret_count <= 2)
541                 return 0;
542 
543         ret_count = min(ret_count, ask_count);
544 
545         /* The query buffer contains the size, dropping it in the reply */
546         count = min(count, ret_count - 2);
547         memcpy(buf, ihid->inbuf + 2, count);
548 
549         return count;
550 }
551 
552 static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
553                 size_t count, unsigned char report_type)
554 {
555         struct i2c_client *client = hid->driver_data;
556         int report_id = buf[0];
557         int ret;
558 
559         if (report_type == HID_INPUT_REPORT)
560                 return -EINVAL;
561 
562         if (report_id) {
563                 buf++;
564                 count--;
565         }
566 
567         ret = i2c_hid_set_report(client,
568                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
569                                 report_id, buf, count);
570 
571         if (report_id && ret >= 0)
572                 ret++; /* add report_id to the number of transfered bytes */
573 
574         return ret;
575 }
576 
577 static void i2c_hid_request(struct hid_device *hid, struct hid_report *rep,
578                 int reqtype)
579 {
580         struct i2c_client *client = hid->driver_data;
581         char *buf;
582         int ret;
583         int len = i2c_hid_get_report_length(rep) - 2;
584 
585         buf = hid_alloc_report_buf(rep, GFP_KERNEL);
586         if (!buf)
587                 return;
588 
589         switch (reqtype) {
590         case HID_REQ_GET_REPORT:
591                 ret = i2c_hid_get_raw_report(hid, rep->id, buf, len, rep->type);
592                 if (ret < 0)
593                         dev_err(&client->dev, "%s: unable to get report: %d\n",
594                                 __func__, ret);
595                 else
596                         hid_input_report(hid, rep->type, buf, ret, 0);
597                 break;
598         case HID_REQ_SET_REPORT:
599                 hid_output_report(rep, buf);
600                 i2c_hid_output_raw_report(hid, buf, len, rep->type);
601                 break;
602         }
603 
604         kfree(buf);
605 }
606 
607 static int i2c_hid_parse(struct hid_device *hid)
608 {
609         struct i2c_client *client = hid->driver_data;
610         struct i2c_hid *ihid = i2c_get_clientdata(client);
611         struct i2c_hid_desc *hdesc = &ihid->hdesc;
612         unsigned int rsize;
613         char *rdesc;
614         int ret;
615         int tries = 3;
616 
617         i2c_hid_dbg(ihid, "entering %s\n", __func__);
618 
619         rsize = le16_to_cpu(hdesc->wReportDescLength);
620         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
621                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
622                 return -EINVAL;
623         }
624 
625         do {
626                 ret = i2c_hid_hwreset(client);
627                 if (ret)
628                         msleep(1000);
629         } while (tries-- > 0 && ret);
630 
631         if (ret)
632                 return ret;
633 
634         rdesc = kzalloc(rsize, GFP_KERNEL);
635 
636         if (!rdesc) {
637                 dbg_hid("couldn't allocate rdesc memory\n");
638                 return -ENOMEM;
639         }
640 
641         i2c_hid_dbg(ihid, "asking HID report descriptor\n");
642 
643         ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
644         if (ret) {
645                 hid_err(hid, "reading report descriptor failed\n");
646                 kfree(rdesc);
647                 return -EIO;
648         }
649 
650         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
651 
652         ret = hid_parse_report(hid, rdesc, rsize);
653         kfree(rdesc);
654         if (ret) {
655                 dbg_hid("parsing report descriptor failed\n");
656                 return ret;
657         }
658 
659         return 0;
660 }
661 
662 static int i2c_hid_start(struct hid_device *hid)
663 {
664         struct i2c_client *client = hid->driver_data;
665         struct i2c_hid *ihid = i2c_get_clientdata(client);
666         int ret;
667         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
668 
669         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
670         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
671         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
672 
673         if (bufsize > ihid->bufsize) {
674                 i2c_hid_free_buffers(ihid);
675 
676                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
677 
678                 if (ret)
679                         return ret;
680         }
681 
682         if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
683                 i2c_hid_init_reports(hid);
684 
685         return 0;
686 }
687 
688 static void i2c_hid_stop(struct hid_device *hid)
689 {
690         struct i2c_client *client = hid->driver_data;
691         struct i2c_hid *ihid = i2c_get_clientdata(client);
692 
693         hid->claimed = 0;
694 
695         i2c_hid_free_buffers(ihid);
696 }
697 
698 static int i2c_hid_open(struct hid_device *hid)
699 {
700         struct i2c_client *client = hid->driver_data;
701         struct i2c_hid *ihid = i2c_get_clientdata(client);
702         int ret = 0;
703 
704         mutex_lock(&i2c_hid_open_mut);
705         if (!hid->open++) {
706                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
707                 if (ret) {
708                         hid->open--;
709                         goto done;
710                 }
711                 set_bit(I2C_HID_STARTED, &ihid->flags);
712         }
713 done:
714         mutex_unlock(&i2c_hid_open_mut);
715         return ret;
716 }
717 
718 static void i2c_hid_close(struct hid_device *hid)
719 {
720         struct i2c_client *client = hid->driver_data;
721         struct i2c_hid *ihid = i2c_get_clientdata(client);
722 
723         /* protecting hid->open to make sure we don't restart
724          * data acquistion due to a resumption we no longer
725          * care about
726          */
727         mutex_lock(&i2c_hid_open_mut);
728         if (!--hid->open) {
729                 clear_bit(I2C_HID_STARTED, &ihid->flags);
730 
731                 /* Save some power */
732                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
733         }
734         mutex_unlock(&i2c_hid_open_mut);
735 }
736 
737 static int i2c_hid_power(struct hid_device *hid, int lvl)
738 {
739         struct i2c_client *client = hid->driver_data;
740         struct i2c_hid *ihid = i2c_get_clientdata(client);
741         int ret = 0;
742 
743         i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
744 
745         switch (lvl) {
746         case PM_HINT_FULLON:
747                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
748                 break;
749         case PM_HINT_NORMAL:
750                 ret = i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
751                 break;
752         }
753         return ret;
754 }
755 
756 static struct hid_ll_driver i2c_hid_ll_driver = {
757         .parse = i2c_hid_parse,
758         .start = i2c_hid_start,
759         .stop = i2c_hid_stop,
760         .open = i2c_hid_open,
761         .close = i2c_hid_close,
762         .power = i2c_hid_power,
763         .request = i2c_hid_request,
764 };
765 
766 static int i2c_hid_init_irq(struct i2c_client *client)
767 {
768         struct i2c_hid *ihid = i2c_get_clientdata(client);
769         int ret;
770 
771         dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
772 
773         ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
774                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
775                         client->name, ihid);
776         if (ret < 0) {
777                 dev_warn(&client->dev,
778                         "Could not register for %s interrupt, irq = %d,"
779                         " ret = %d\n",
780                         client->name, client->irq, ret);
781 
782                 return ret;
783         }
784 
785         return 0;
786 }
787 
788 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
789 {
790         struct i2c_client *client = ihid->client;
791         struct i2c_hid_desc *hdesc = &ihid->hdesc;
792         unsigned int dsize;
793         int ret;
794 
795         /* Fetch the length of HID description, retrieve the 4 first bytes:
796          * bytes 0-1 -> length
797          * bytes 2-3 -> bcdVersion (has to be 1.00) */
798         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
799 
800         i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %4ph\n", __func__,
801                         ihid->hdesc_buffer);
802 
803         if (ret) {
804                 dev_err(&client->dev,
805                         "unable to fetch the size of HID descriptor (ret=%d)\n",
806                         ret);
807                 return -ENODEV;
808         }
809 
810         dsize = le16_to_cpu(hdesc->wHIDDescLength);
811         /*
812          * the size of the HID descriptor should at least contain
813          * its size and the bcdVersion (4 bytes), and should not be greater
814          * than sizeof(struct i2c_hid_desc) as we directly fill this struct
815          * through i2c_hid_command.
816          */
817         if (dsize < 4 || dsize > sizeof(struct i2c_hid_desc)) {
818                 dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
819                         dsize);
820                 return -ENODEV;
821         }
822 
823         /* check bcdVersion == 1.0 */
824         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
825                 dev_err(&client->dev,
826                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
827                         le16_to_cpu(hdesc->bcdVersion));
828                 return -ENODEV;
829         }
830 
831         i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
832 
833         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
834                                 dsize);
835         if (ret) {
836                 dev_err(&client->dev, "hid_descr_cmd Fail\n");
837                 return -ENODEV;
838         }
839 
840         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
841 
842         return 0;
843 }
844 
845 #ifdef CONFIG_ACPI
846 static int i2c_hid_acpi_pdata(struct i2c_client *client,
847                 struct i2c_hid_platform_data *pdata)
848 {
849         static u8 i2c_hid_guid[] = {
850                 0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
851                 0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
852         };
853         union acpi_object *obj;
854         struct acpi_device *adev;
855         acpi_handle handle;
856 
857         handle = ACPI_HANDLE(&client->dev);
858         if (!handle || acpi_bus_get_device(handle, &adev))
859                 return -ENODEV;
860 
861         obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
862                                       ACPI_TYPE_INTEGER);
863         if (!obj) {
864                 dev_err(&client->dev, "device _DSM execution failed\n");
865                 return -ENODEV;
866         }
867 
868         pdata->hid_descriptor_address = obj->integer.value;
869         ACPI_FREE(obj);
870 
871         return 0;
872 }
873 
874 static const struct acpi_device_id i2c_hid_acpi_match[] = {
875         {"ACPI0C50", 0 },
876         {"PNP0C50", 0 },
877         { },
878 };
879 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
880 #else
881 static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
882                 struct i2c_hid_platform_data *pdata)
883 {
884         return -ENODEV;
885 }
886 #endif
887 
888 #ifdef CONFIG_OF
889 static int i2c_hid_of_probe(struct i2c_client *client,
890                 struct i2c_hid_platform_data *pdata)
891 {
892         struct device *dev = &client->dev;
893         u32 val;
894         int ret;
895 
896         ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
897         if (ret) {
898                 dev_err(&client->dev, "HID register address not provided\n");
899                 return -ENODEV;
900         }
901         if (val >> 16) {
902                 dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
903                         val);
904                 return -EINVAL;
905         }
906         pdata->hid_descriptor_address = val;
907 
908         return 0;
909 }
910 
911 static const struct of_device_id i2c_hid_of_match[] = {
912         { .compatible = "hid-over-i2c" },
913         {},
914 };
915 MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
916 #else
917 static inline int i2c_hid_of_probe(struct i2c_client *client,
918                 struct i2c_hid_platform_data *pdata)
919 {
920         return -ENODEV;
921 }
922 #endif
923 
924 static int i2c_hid_probe(struct i2c_client *client,
925                          const struct i2c_device_id *dev_id)
926 {
927         int ret;
928         struct i2c_hid *ihid;
929         struct hid_device *hid;
930         __u16 hidRegister;
931         struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
932 
933         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
934 
935         if (!client->irq) {
936                 dev_err(&client->dev,
937                         "HID over i2c has not been provided an Int IRQ\n");
938                 return -EINVAL;
939         }
940 
941         ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
942         if (!ihid)
943                 return -ENOMEM;
944 
945         if (client->dev.of_node) {
946                 ret = i2c_hid_of_probe(client, &ihid->pdata);
947                 if (ret)
948                         goto err;
949         } else if (!platform_data) {
950                 ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
951                 if (ret) {
952                         dev_err(&client->dev,
953                                 "HID register address not provided\n");
954                         goto err;
955                 }
956         } else {
957                 ihid->pdata = *platform_data;
958         }
959 
960         i2c_set_clientdata(client, ihid);
961 
962         ihid->client = client;
963 
964         hidRegister = ihid->pdata.hid_descriptor_address;
965         ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
966 
967         init_waitqueue_head(&ihid->wait);
968 
969         /* we need to allocate the command buffer without knowing the maximum
970          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
971          * real computation later. */
972         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
973         if (ret < 0)
974                 goto err;
975 
976         ret = i2c_hid_fetch_hid_descriptor(ihid);
977         if (ret < 0)
978                 goto err;
979 
980         ret = i2c_hid_init_irq(client);
981         if (ret < 0)
982                 goto err;
983 
984         hid = hid_allocate_device();
985         if (IS_ERR(hid)) {
986                 ret = PTR_ERR(hid);
987                 goto err_irq;
988         }
989 
990         ihid->hid = hid;
991 
992         hid->driver_data = client;
993         hid->ll_driver = &i2c_hid_ll_driver;
994         hid->hid_get_raw_report = i2c_hid_get_raw_report;
995         hid->hid_output_raw_report = i2c_hid_output_raw_report;
996         hid->dev.parent = &client->dev;
997         ACPI_COMPANION_SET(&hid->dev, ACPI_COMPANION(&client->dev));
998         hid->bus = BUS_I2C;
999         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1000         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1001         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1002 
1003         snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
1004                  client->name, hid->vendor, hid->product);
1005 
1006         ret = hid_add_device(hid);
1007         if (ret) {
1008                 if (ret != -ENODEV)
1009                         hid_err(client, "can't add hid device: %d\n", ret);
1010                 goto err_mem_free;
1011         }
1012 
1013         return 0;
1014 
1015 err_mem_free:
1016         hid_destroy_device(hid);
1017 
1018 err_irq:
1019         free_irq(client->irq, ihid);
1020 
1021 err:
1022         i2c_hid_free_buffers(ihid);
1023         kfree(ihid);
1024         return ret;
1025 }
1026 
1027 static int i2c_hid_remove(struct i2c_client *client)
1028 {
1029         struct i2c_hid *ihid = i2c_get_clientdata(client);
1030         struct hid_device *hid;
1031 
1032         hid = ihid->hid;
1033         hid_destroy_device(hid);
1034 
1035         free_irq(client->irq, ihid);
1036 
1037         if (ihid->bufsize)
1038                 i2c_hid_free_buffers(ihid);
1039 
1040         kfree(ihid);
1041 
1042         return 0;
1043 }
1044 
1045 #ifdef CONFIG_PM_SLEEP
1046 static int i2c_hid_suspend(struct device *dev)
1047 {
1048         struct i2c_client *client = to_i2c_client(dev);
1049 
1050         disable_irq(client->irq);
1051         if (device_may_wakeup(&client->dev))
1052                 enable_irq_wake(client->irq);
1053 
1054         /* Save some power */
1055         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1056 
1057         return 0;
1058 }
1059 
1060 static int i2c_hid_resume(struct device *dev)
1061 {
1062         int ret;
1063         struct i2c_client *client = to_i2c_client(dev);
1064 
1065         enable_irq(client->irq);
1066         ret = i2c_hid_hwreset(client);
1067         if (ret)
1068                 return ret;
1069 
1070         if (device_may_wakeup(&client->dev))
1071                 disable_irq_wake(client->irq);
1072 
1073         return 0;
1074 }
1075 #endif
1076 
1077 static SIMPLE_DEV_PM_OPS(i2c_hid_pm, i2c_hid_suspend, i2c_hid_resume);
1078 
1079 static const struct i2c_device_id i2c_hid_id_table[] = {
1080         { "hid", 0 },
1081         { },
1082 };
1083 MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
1084 
1085 
1086 static struct i2c_driver i2c_hid_driver = {
1087         .driver = {
1088                 .name   = "i2c_hid",
1089                 .owner  = THIS_MODULE,
1090                 .pm     = &i2c_hid_pm,
1091                 .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
1092                 .of_match_table = of_match_ptr(i2c_hid_of_match),
1093         },
1094 
1095         .probe          = i2c_hid_probe,
1096         .remove         = i2c_hid_remove,
1097 
1098         .id_table       = i2c_hid_id_table,
1099 };
1100 
1101 module_i2c_driver(i2c_hid_driver);
1102 
1103 MODULE_DESCRIPTION("HID over I2C core driver");
1104 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1105 MODULE_LICENSE("GPL");
1106 

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