Version:  2.0.40 2.2.26 2.4.37 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19

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

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