Version:  2.0.40 2.2.26 2.4.37 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 3.15 3.16

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

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