Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

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/irq.h>
 26 #include <linux/delay.h>
 27 #include <linux/slab.h>
 28 #include <linux/pm.h>
 29 #include <linux/pm_runtime.h>
 30 #include <linux/device.h>
 31 #include <linux/wait.h>
 32 #include <linux/err.h>
 33 #include <linux/string.h>
 34 #include <linux/list.h>
 35 #include <linux/jiffies.h>
 36 #include <linux/kernel.h>
 37 #include <linux/hid.h>
 38 #include <linux/mutex.h>
 39 #include <linux/acpi.h>
 40 #include <linux/of.h>
 41 #include <linux/regulator/consumer.h>
 42 
 43 #include <linux/i2c/i2c-hid.h>
 44 
 45 #include "../hid-ids.h"
 46 
 47 /* quirks to control the device */
 48 #define I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV        BIT(0)
 49 
 50 /* flags */
 51 #define I2C_HID_STARTED         0
 52 #define I2C_HID_RESET_PENDING   1
 53 #define I2C_HID_READ_PENDING    2
 54 
 55 #define I2C_HID_PWR_ON          0x00
 56 #define I2C_HID_PWR_SLEEP       0x01
 57 
 58 /* debug option */
 59 static bool debug;
 60 module_param(debug, bool, 0444);
 61 MODULE_PARM_DESC(debug, "print a lot of debug information");
 62 
 63 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
 64 do {                                                                      \
 65         if (debug)                                                        \
 66                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
 67 } while (0)
 68 
 69 struct i2c_hid_desc {
 70         __le16 wHIDDescLength;
 71         __le16 bcdVersion;
 72         __le16 wReportDescLength;
 73         __le16 wReportDescRegister;
 74         __le16 wInputRegister;
 75         __le16 wMaxInputLength;
 76         __le16 wOutputRegister;
 77         __le16 wMaxOutputLength;
 78         __le16 wCommandRegister;
 79         __le16 wDataRegister;
 80         __le16 wVendorID;
 81         __le16 wProductID;
 82         __le16 wVersionID;
 83         __le32 reserved;
 84 } __packed;
 85 
 86 struct i2c_hid_cmd {
 87         unsigned int registerIndex;
 88         __u8 opcode;
 89         unsigned int length;
 90         bool wait;
 91 };
 92 
 93 union command {
 94         u8 data[0];
 95         struct cmd {
 96                 __le16 reg;
 97                 __u8 reportTypeID;
 98                 __u8 opcode;
 99         } __packed c;
100 };
101 
102 #define I2C_HID_CMD(opcode_) \
103         .opcode = opcode_, .length = 4, \
104         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
105 
106 /* fetch HID descriptor */
107 static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
108 /* fetch report descriptors */
109 static const struct i2c_hid_cmd hid_report_descr_cmd = {
110                 .registerIndex = offsetof(struct i2c_hid_desc,
111                         wReportDescRegister),
112                 .opcode = 0x00,
113                 .length = 2 };
114 /* commands */
115 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01),
116                                                           .wait = true };
117 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
118 static const struct i2c_hid_cmd hid_set_report_cmd =    { I2C_HID_CMD(0x03) };
119 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
120 static const struct i2c_hid_cmd hid_no_cmd =            { .length = 0 };
121 
122 /*
123  * These definitions are not used here, but are defined by the spec.
124  * Keeping them here for documentation purposes.
125  *
126  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
127  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
128  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
129  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
130  */
131 
132 static DEFINE_MUTEX(i2c_hid_open_mut);
133 
134 /* The main device structure */
135 struct i2c_hid {
136         struct i2c_client       *client;        /* i2c client */
137         struct hid_device       *hid;   /* pointer to corresponding HID dev */
138         union {
139                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
140                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
141         };
142         __le16                  wHIDDescRegister; /* location of the i2c
143                                                    * register of the HID
144                                                    * descriptor. */
145         unsigned int            bufsize;        /* i2c buffer size */
146         char                    *inbuf;         /* Input buffer */
147         char                    *rawbuf;        /* Raw Input buffer */
148         char                    *cmdbuf;        /* Command buffer */
149         char                    *argsbuf;       /* Command arguments buffer */
150 
151         unsigned long           flags;          /* device flags */
152         unsigned long           quirks;         /* Various quirks */
153 
154         wait_queue_head_t       wait;           /* For waiting the interrupt */
155 
156         struct i2c_hid_platform_data pdata;
157 
158         bool                    irq_wake_enabled;
159         struct mutex            reset_lock;
160 };
161 
162 static const struct i2c_hid_quirks {
163         __u16 idVendor;
164         __u16 idProduct;
165         __u32 quirks;
166 } i2c_hid_quirks[] = {
167         { USB_VENDOR_ID_WEIDA, USB_DEVICE_ID_WEIDA_8752,
168                 I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
169         { USB_VENDOR_ID_WEIDA, USB_DEVICE_ID_WEIDA_8755,
170                 I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
171         { 0, 0 }
172 };
173 
174 /*
175  * i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
176  * @idVendor: the 16-bit vendor ID
177  * @idProduct: the 16-bit product ID
178  *
179  * Returns: a u32 quirks value.
180  */
181 static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
182 {
183         u32 quirks = 0;
184         int n;
185 
186         for (n = 0; i2c_hid_quirks[n].idVendor; n++)
187                 if (i2c_hid_quirks[n].idVendor == idVendor &&
188                     (i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
189                      i2c_hid_quirks[n].idProduct == idProduct))
190                         quirks = i2c_hid_quirks[n].quirks;
191 
192         return quirks;
193 }
194 
195 static int __i2c_hid_command(struct i2c_client *client,
196                 const struct i2c_hid_cmd *command, u8 reportID,
197                 u8 reportType, u8 *args, int args_len,
198                 unsigned char *buf_recv, int data_len)
199 {
200         struct i2c_hid *ihid = i2c_get_clientdata(client);
201         union command *cmd = (union command *)ihid->cmdbuf;
202         int ret;
203         struct i2c_msg msg[2];
204         int msg_num = 1;
205 
206         int length = command->length;
207         bool wait = command->wait;
208         unsigned int registerIndex = command->registerIndex;
209 
210         /* special case for hid_descr_cmd */
211         if (command == &hid_descr_cmd) {
212                 cmd->c.reg = ihid->wHIDDescRegister;
213         } else {
214                 cmd->data[0] = ihid->hdesc_buffer[registerIndex];
215                 cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
216         }
217 
218         if (length > 2) {
219                 cmd->c.opcode = command->opcode;
220                 cmd->c.reportTypeID = reportID | reportType << 4;
221         }
222 
223         memcpy(cmd->data + length, args, args_len);
224         length += args_len;
225 
226         i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
227 
228         msg[0].addr = client->addr;
229         msg[0].flags = client->flags & I2C_M_TEN;
230         msg[0].len = length;
231         msg[0].buf = cmd->data;
232         if (data_len > 0) {
233                 msg[1].addr = client->addr;
234                 msg[1].flags = client->flags & I2C_M_TEN;
235                 msg[1].flags |= I2C_M_RD;
236                 msg[1].len = data_len;
237                 msg[1].buf = buf_recv;
238                 msg_num = 2;
239                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
240         }
241 
242         if (wait)
243                 set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
244 
245         ret = i2c_transfer(client->adapter, msg, msg_num);
246 
247         if (data_len > 0)
248                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
249 
250         if (ret != msg_num)
251                 return ret < 0 ? ret : -EIO;
252 
253         ret = 0;
254 
255         if (wait) {
256                 i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
257                 if (!wait_event_timeout(ihid->wait,
258                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
259                                 msecs_to_jiffies(5000)))
260                         ret = -ENODATA;
261                 i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
262         }
263 
264         return ret;
265 }
266 
267 static int i2c_hid_command(struct i2c_client *client,
268                 const struct i2c_hid_cmd *command,
269                 unsigned char *buf_recv, int data_len)
270 {
271         return __i2c_hid_command(client, command, 0, 0, NULL, 0,
272                                 buf_recv, data_len);
273 }
274 
275 static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
276                 u8 reportID, unsigned char *buf_recv, int data_len)
277 {
278         struct i2c_hid *ihid = i2c_get_clientdata(client);
279         u8 args[3];
280         int ret;
281         int args_len = 0;
282         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
283 
284         i2c_hid_dbg(ihid, "%s\n", __func__);
285 
286         if (reportID >= 0x0F) {
287                 args[args_len++] = reportID;
288                 reportID = 0x0F;
289         }
290 
291         args[args_len++] = readRegister & 0xFF;
292         args[args_len++] = readRegister >> 8;
293 
294         ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
295                 reportType, args, args_len, buf_recv, data_len);
296         if (ret) {
297                 dev_err(&client->dev,
298                         "failed to retrieve report from device.\n");
299                 return ret;
300         }
301 
302         return 0;
303 }
304 
305 /**
306  * i2c_hid_set_or_send_report: forward an incoming report to the device
307  * @client: the i2c_client of the device
308  * @reportType: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
309  * @reportID: the report ID
310  * @buf: the actual data to transfer, without the report ID
311  * @len: size of buf
312  * @use_data: true: use SET_REPORT HID command, false: send plain OUTPUT report
313  */
314 static int i2c_hid_set_or_send_report(struct i2c_client *client, u8 reportType,
315                 u8 reportID, unsigned char *buf, size_t data_len, bool use_data)
316 {
317         struct i2c_hid *ihid = i2c_get_clientdata(client);
318         u8 *args = ihid->argsbuf;
319         const struct i2c_hid_cmd *hidcmd;
320         int ret;
321         u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
322         u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
323         u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
324         u16 size;
325         int args_len;
326         int index = 0;
327 
328         i2c_hid_dbg(ihid, "%s\n", __func__);
329 
330         if (data_len > ihid->bufsize)
331                 return -EINVAL;
332 
333         size =          2                       /* size */ +
334                         (reportID ? 1 : 0)      /* reportID */ +
335                         data_len                /* buf */;
336         args_len =      (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
337                         2                       /* dataRegister */ +
338                         size                    /* args */;
339 
340         if (!use_data && maxOutputLength == 0)
341                 return -ENOSYS;
342 
343         if (reportID >= 0x0F) {
344                 args[index++] = reportID;
345                 reportID = 0x0F;
346         }
347 
348         /*
349          * use the data register for feature reports or if the device does not
350          * support the output register
351          */
352         if (use_data) {
353                 args[index++] = dataRegister & 0xFF;
354                 args[index++] = dataRegister >> 8;
355                 hidcmd = &hid_set_report_cmd;
356         } else {
357                 args[index++] = outputRegister & 0xFF;
358                 args[index++] = outputRegister >> 8;
359                 hidcmd = &hid_no_cmd;
360         }
361 
362         args[index++] = size & 0xFF;
363         args[index++] = size >> 8;
364 
365         if (reportID)
366                 args[index++] = reportID;
367 
368         memcpy(&args[index], buf, data_len);
369 
370         ret = __i2c_hid_command(client, hidcmd, reportID,
371                 reportType, args, args_len, NULL, 0);
372         if (ret) {
373                 dev_err(&client->dev, "failed to set a report to device.\n");
374                 return ret;
375         }
376 
377         return data_len;
378 }
379 
380 static int i2c_hid_set_power(struct i2c_client *client, int power_state)
381 {
382         struct i2c_hid *ihid = i2c_get_clientdata(client);
383         int ret;
384 
385         i2c_hid_dbg(ihid, "%s\n", __func__);
386 
387         /*
388          * Some devices require to send a command to wakeup before power on.
389          * The call will get a return value (EREMOTEIO) but device will be
390          * triggered and activated. After that, it goes like a normal device.
391          */
392         if (power_state == I2C_HID_PWR_ON &&
393             ihid->quirks & I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV) {
394                 ret = i2c_hid_command(client, &hid_set_power_cmd, NULL, 0);
395 
396                 /* Device was already activated */
397                 if (!ret)
398                         goto set_pwr_exit;
399         }
400 
401         ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
402                 0, NULL, 0, NULL, 0);
403 
404         if (ret)
405                 dev_err(&client->dev, "failed to change power setting.\n");
406 
407 set_pwr_exit:
408         return ret;
409 }
410 
411 static int i2c_hid_hwreset(struct i2c_client *client)
412 {
413         struct i2c_hid *ihid = i2c_get_clientdata(client);
414         int ret;
415 
416         i2c_hid_dbg(ihid, "%s\n", __func__);
417 
418         /*
419          * This prevents sending feature reports while the device is
420          * being reset. Otherwise we may lose the reset complete
421          * interrupt.
422          */
423         mutex_lock(&ihid->reset_lock);
424 
425         ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
426         if (ret)
427                 goto out_unlock;
428 
429         /*
430          * The HID over I2C specification states that if a DEVICE needs time
431          * after the PWR_ON request, it should utilise CLOCK stretching.
432          * However, it has been observered that the Windows driver provides a
433          * 1ms sleep between the PWR_ON and RESET requests and that some devices
434          * rely on this.
435          */
436         usleep_range(1000, 5000);
437 
438         i2c_hid_dbg(ihid, "resetting...\n");
439 
440         ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
441         if (ret) {
442                 dev_err(&client->dev, "failed to reset device.\n");
443                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
444         }
445 
446 out_unlock:
447         mutex_unlock(&ihid->reset_lock);
448         return ret;
449 }
450 
451 static void i2c_hid_get_input(struct i2c_hid *ihid)
452 {
453         int ret, ret_size;
454         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
455 
456         if (size > ihid->bufsize)
457                 size = ihid->bufsize;
458 
459         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
460         if (ret != size) {
461                 if (ret < 0)
462                         return;
463 
464                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
465                         __func__, ret, size);
466                 return;
467         }
468 
469         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
470 
471         if (!ret_size) {
472                 /* host or device initiated RESET completed */
473                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
474                         wake_up(&ihid->wait);
475                 return;
476         }
477 
478         if (ret_size > size) {
479                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
480                         __func__, size, ret_size);
481                 return;
482         }
483 
484         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
485 
486         if (test_bit(I2C_HID_STARTED, &ihid->flags))
487                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
488                                 ret_size - 2, 1);
489 
490         return;
491 }
492 
493 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
494 {
495         struct i2c_hid *ihid = dev_id;
496 
497         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
498                 return IRQ_HANDLED;
499 
500         i2c_hid_get_input(ihid);
501 
502         return IRQ_HANDLED;
503 }
504 
505 static int i2c_hid_get_report_length(struct hid_report *report)
506 {
507         return ((report->size - 1) >> 3) + 1 +
508                 report->device->report_enum[report->type].numbered + 2;
509 }
510 
511 static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
512         size_t bufsize)
513 {
514         struct hid_device *hid = report->device;
515         struct i2c_client *client = hid->driver_data;
516         struct i2c_hid *ihid = i2c_get_clientdata(client);
517         unsigned int size, ret_size;
518 
519         size = i2c_hid_get_report_length(report);
520         if (i2c_hid_get_report(client,
521                         report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
522                         report->id, buffer, size))
523                 return;
524 
525         i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, buffer);
526 
527         ret_size = buffer[0] | (buffer[1] << 8);
528 
529         if (ret_size != size) {
530                 dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
531                         __func__, size, ret_size);
532                 return;
533         }
534 
535         /* hid->driver_lock is held as we are in probe function,
536          * we just need to setup the input fields, so using
537          * hid_report_raw_event is safe. */
538         hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
539 }
540 
541 /*
542  * Initialize all reports
543  */
544 static void i2c_hid_init_reports(struct hid_device *hid)
545 {
546         struct hid_report *report;
547         struct i2c_client *client = hid->driver_data;
548         struct i2c_hid *ihid = i2c_get_clientdata(client);
549         u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
550 
551         if (!inbuf) {
552                 dev_err(&client->dev, "can not retrieve initial reports\n");
553                 return;
554         }
555 
556         /*
557          * The device must be powered on while we fetch initial reports
558          * from it.
559          */
560         pm_runtime_get_sync(&client->dev);
561 
562         list_for_each_entry(report,
563                 &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
564                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
565 
566         pm_runtime_put(&client->dev);
567 
568         kfree(inbuf);
569 }
570 
571 /*
572  * Traverse the supplied list of reports and find the longest
573  */
574 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
575                 unsigned int *max)
576 {
577         struct hid_report *report;
578         unsigned int size;
579 
580         /* We should not rely on wMaxInputLength, as some devices may set it to
581          * a wrong length. */
582         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
583                 size = i2c_hid_get_report_length(report);
584                 if (*max < size)
585                         *max = size;
586         }
587 }
588 
589 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
590 {
591         kfree(ihid->inbuf);
592         kfree(ihid->rawbuf);
593         kfree(ihid->argsbuf);
594         kfree(ihid->cmdbuf);
595         ihid->inbuf = NULL;
596         ihid->rawbuf = NULL;
597         ihid->cmdbuf = NULL;
598         ihid->argsbuf = NULL;
599         ihid->bufsize = 0;
600 }
601 
602 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
603 {
604         /* the worst case is computed from the set_report command with a
605          * reportID > 15 and the maximum report length */
606         int args_len = sizeof(__u8) + /* optional ReportID byte */
607                        sizeof(__u16) + /* data register */
608                        sizeof(__u16) + /* size of the report */
609                        report_size; /* report */
610 
611         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
612         ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
613         ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
614         ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
615 
616         if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) {
617                 i2c_hid_free_buffers(ihid);
618                 return -ENOMEM;
619         }
620 
621         ihid->bufsize = report_size;
622 
623         return 0;
624 }
625 
626 static int i2c_hid_get_raw_report(struct hid_device *hid,
627                 unsigned char report_number, __u8 *buf, size_t count,
628                 unsigned char report_type)
629 {
630         struct i2c_client *client = hid->driver_data;
631         struct i2c_hid *ihid = i2c_get_clientdata(client);
632         size_t ret_count, ask_count;
633         int ret;
634 
635         if (report_type == HID_OUTPUT_REPORT)
636                 return -EINVAL;
637 
638         /* +2 bytes to include the size of the reply in the query buffer */
639         ask_count = min(count + 2, (size_t)ihid->bufsize);
640 
641         ret = i2c_hid_get_report(client,
642                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
643                         report_number, ihid->rawbuf, ask_count);
644 
645         if (ret < 0)
646                 return ret;
647 
648         ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
649 
650         if (ret_count <= 2)
651                 return 0;
652 
653         ret_count = min(ret_count, ask_count);
654 
655         /* The query buffer contains the size, dropping it in the reply */
656         count = min(count, ret_count - 2);
657         memcpy(buf, ihid->rawbuf + 2, count);
658 
659         return count;
660 }
661 
662 static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
663                 size_t count, unsigned char report_type, bool use_data)
664 {
665         struct i2c_client *client = hid->driver_data;
666         struct i2c_hid *ihid = i2c_get_clientdata(client);
667         int report_id = buf[0];
668         int ret;
669 
670         if (report_type == HID_INPUT_REPORT)
671                 return -EINVAL;
672 
673         mutex_lock(&ihid->reset_lock);
674 
675         if (report_id) {
676                 buf++;
677                 count--;
678         }
679 
680         ret = i2c_hid_set_or_send_report(client,
681                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
682                                 report_id, buf, count, use_data);
683 
684         if (report_id && ret >= 0)
685                 ret++; /* add report_id to the number of transfered bytes */
686 
687         mutex_unlock(&ihid->reset_lock);
688 
689         return ret;
690 }
691 
692 static int i2c_hid_output_report(struct hid_device *hid, __u8 *buf,
693                 size_t count)
694 {
695         return i2c_hid_output_raw_report(hid, buf, count, HID_OUTPUT_REPORT,
696                         false);
697 }
698 
699 static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
700                                __u8 *buf, size_t len, unsigned char rtype,
701                                int reqtype)
702 {
703         switch (reqtype) {
704         case HID_REQ_GET_REPORT:
705                 return i2c_hid_get_raw_report(hid, reportnum, buf, len, rtype);
706         case HID_REQ_SET_REPORT:
707                 if (buf[0] != reportnum)
708                         return -EINVAL;
709                 return i2c_hid_output_raw_report(hid, buf, len, rtype, true);
710         default:
711                 return -EIO;
712         }
713 }
714 
715 static int i2c_hid_parse(struct hid_device *hid)
716 {
717         struct i2c_client *client = hid->driver_data;
718         struct i2c_hid *ihid = i2c_get_clientdata(client);
719         struct i2c_hid_desc *hdesc = &ihid->hdesc;
720         unsigned int rsize;
721         char *rdesc;
722         int ret;
723         int tries = 3;
724 
725         i2c_hid_dbg(ihid, "entering %s\n", __func__);
726 
727         rsize = le16_to_cpu(hdesc->wReportDescLength);
728         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
729                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
730                 return -EINVAL;
731         }
732 
733         do {
734                 ret = i2c_hid_hwreset(client);
735                 if (ret)
736                         msleep(1000);
737         } while (tries-- > 0 && ret);
738 
739         if (ret)
740                 return ret;
741 
742         rdesc = kzalloc(rsize, GFP_KERNEL);
743 
744         if (!rdesc) {
745                 dbg_hid("couldn't allocate rdesc memory\n");
746                 return -ENOMEM;
747         }
748 
749         i2c_hid_dbg(ihid, "asking HID report descriptor\n");
750 
751         ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
752         if (ret) {
753                 hid_err(hid, "reading report descriptor failed\n");
754                 kfree(rdesc);
755                 return -EIO;
756         }
757 
758         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
759 
760         ret = hid_parse_report(hid, rdesc, rsize);
761         kfree(rdesc);
762         if (ret) {
763                 dbg_hid("parsing report descriptor failed\n");
764                 return ret;
765         }
766 
767         return 0;
768 }
769 
770 static int i2c_hid_start(struct hid_device *hid)
771 {
772         struct i2c_client *client = hid->driver_data;
773         struct i2c_hid *ihid = i2c_get_clientdata(client);
774         int ret;
775         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
776 
777         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
778         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
779         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
780 
781         if (bufsize > ihid->bufsize) {
782                 disable_irq(client->irq);
783                 i2c_hid_free_buffers(ihid);
784 
785                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
786                 enable_irq(client->irq);
787 
788                 if (ret)
789                         return ret;
790         }
791 
792         if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
793                 i2c_hid_init_reports(hid);
794 
795         return 0;
796 }
797 
798 static void i2c_hid_stop(struct hid_device *hid)
799 {
800         hid->claimed = 0;
801 }
802 
803 static int i2c_hid_open(struct hid_device *hid)
804 {
805         struct i2c_client *client = hid->driver_data;
806         struct i2c_hid *ihid = i2c_get_clientdata(client);
807         int ret = 0;
808 
809         mutex_lock(&i2c_hid_open_mut);
810         if (!hid->open++) {
811                 ret = pm_runtime_get_sync(&client->dev);
812                 if (ret < 0) {
813                         hid->open--;
814                         goto done;
815                 }
816                 set_bit(I2C_HID_STARTED, &ihid->flags);
817         }
818 done:
819         mutex_unlock(&i2c_hid_open_mut);
820         return ret < 0 ? ret : 0;
821 }
822 
823 static void i2c_hid_close(struct hid_device *hid)
824 {
825         struct i2c_client *client = hid->driver_data;
826         struct i2c_hid *ihid = i2c_get_clientdata(client);
827 
828         /* protecting hid->open to make sure we don't restart
829          * data acquistion due to a resumption we no longer
830          * care about
831          */
832         mutex_lock(&i2c_hid_open_mut);
833         if (!--hid->open) {
834                 clear_bit(I2C_HID_STARTED, &ihid->flags);
835 
836                 /* Save some power */
837                 pm_runtime_put(&client->dev);
838         }
839         mutex_unlock(&i2c_hid_open_mut);
840 }
841 
842 static int i2c_hid_power(struct hid_device *hid, int lvl)
843 {
844         struct i2c_client *client = hid->driver_data;
845         struct i2c_hid *ihid = i2c_get_clientdata(client);
846 
847         i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
848 
849         switch (lvl) {
850         case PM_HINT_FULLON:
851                 pm_runtime_get_sync(&client->dev);
852                 break;
853         case PM_HINT_NORMAL:
854                 pm_runtime_put(&client->dev);
855                 break;
856         }
857         return 0;
858 }
859 
860 static struct hid_ll_driver i2c_hid_ll_driver = {
861         .parse = i2c_hid_parse,
862         .start = i2c_hid_start,
863         .stop = i2c_hid_stop,
864         .open = i2c_hid_open,
865         .close = i2c_hid_close,
866         .power = i2c_hid_power,
867         .output_report = i2c_hid_output_report,
868         .raw_request = i2c_hid_raw_request,
869 };
870 
871 static int i2c_hid_init_irq(struct i2c_client *client)
872 {
873         struct i2c_hid *ihid = i2c_get_clientdata(client);
874         unsigned long irqflags = 0;
875         int ret;
876 
877         dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
878 
879         if (!irq_get_trigger_type(client->irq))
880                 irqflags = IRQF_TRIGGER_LOW;
881 
882         ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
883                                    irqflags | IRQF_ONESHOT, client->name, ihid);
884         if (ret < 0) {
885                 dev_warn(&client->dev,
886                         "Could not register for %s interrupt, irq = %d,"
887                         " ret = %d\n",
888                         client->name, client->irq, ret);
889 
890                 return ret;
891         }
892 
893         return 0;
894 }
895 
896 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
897 {
898         struct i2c_client *client = ihid->client;
899         struct i2c_hid_desc *hdesc = &ihid->hdesc;
900         unsigned int dsize;
901         int ret;
902 
903         /* i2c hid fetch using a fixed descriptor size (30 bytes) */
904         i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
905         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
906                                 sizeof(struct i2c_hid_desc));
907         if (ret) {
908                 dev_err(&client->dev, "hid_descr_cmd failed\n");
909                 return -ENODEV;
910         }
911 
912         /* Validate the length of HID descriptor, the 4 first bytes:
913          * bytes 0-1 -> length
914          * bytes 2-3 -> bcdVersion (has to be 1.00) */
915         /* check bcdVersion == 1.0 */
916         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
917                 dev_err(&client->dev,
918                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
919                         le16_to_cpu(hdesc->bcdVersion));
920                 return -ENODEV;
921         }
922 
923         /* Descriptor length should be 30 bytes as per the specification */
924         dsize = le16_to_cpu(hdesc->wHIDDescLength);
925         if (dsize != sizeof(struct i2c_hid_desc)) {
926                 dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
927                         dsize);
928                 return -ENODEV;
929         }
930         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
931         return 0;
932 }
933 
934 #ifdef CONFIG_ACPI
935 static int i2c_hid_acpi_pdata(struct i2c_client *client,
936                 struct i2c_hid_platform_data *pdata)
937 {
938         static u8 i2c_hid_guid[] = {
939                 0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
940                 0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
941         };
942         union acpi_object *obj;
943         struct acpi_device *adev;
944         acpi_handle handle;
945 
946         handle = ACPI_HANDLE(&client->dev);
947         if (!handle || acpi_bus_get_device(handle, &adev))
948                 return -ENODEV;
949 
950         obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
951                                       ACPI_TYPE_INTEGER);
952         if (!obj) {
953                 dev_err(&client->dev, "device _DSM execution failed\n");
954                 return -ENODEV;
955         }
956 
957         pdata->hid_descriptor_address = obj->integer.value;
958         ACPI_FREE(obj);
959 
960         return 0;
961 }
962 
963 static const struct acpi_device_id i2c_hid_acpi_match[] = {
964         {"ACPI0C50", 0 },
965         {"PNP0C50", 0 },
966         { },
967 };
968 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
969 #else
970 static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
971                 struct i2c_hid_platform_data *pdata)
972 {
973         return -ENODEV;
974 }
975 #endif
976 
977 #ifdef CONFIG_OF
978 static int i2c_hid_of_probe(struct i2c_client *client,
979                 struct i2c_hid_platform_data *pdata)
980 {
981         struct device *dev = &client->dev;
982         u32 val;
983         int ret;
984 
985         ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
986         if (ret) {
987                 dev_err(&client->dev, "HID register address not provided\n");
988                 return -ENODEV;
989         }
990         if (val >> 16) {
991                 dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
992                         val);
993                 return -EINVAL;
994         }
995         pdata->hid_descriptor_address = val;
996 
997         return 0;
998 }
999 
1000 static const struct of_device_id i2c_hid_of_match[] = {
1001         { .compatible = "hid-over-i2c" },
1002         {},
1003 };
1004 MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
1005 #else
1006 static inline int i2c_hid_of_probe(struct i2c_client *client,
1007                 struct i2c_hid_platform_data *pdata)
1008 {
1009         return -ENODEV;
1010 }
1011 #endif
1012 
1013 static int i2c_hid_probe(struct i2c_client *client,
1014                          const struct i2c_device_id *dev_id)
1015 {
1016         int ret;
1017         struct i2c_hid *ihid;
1018         struct hid_device *hid;
1019         __u16 hidRegister;
1020         struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
1021 
1022         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
1023 
1024         if (!client->irq) {
1025                 dev_err(&client->dev,
1026                         "HID over i2c has not been provided an Int IRQ\n");
1027                 return -EINVAL;
1028         }
1029 
1030         if (client->irq < 0) {
1031                 if (client->irq != -EPROBE_DEFER)
1032                         dev_err(&client->dev,
1033                                 "HID over i2c doesn't have a valid IRQ\n");
1034                 return client->irq;
1035         }
1036 
1037         ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
1038         if (!ihid)
1039                 return -ENOMEM;
1040 
1041         if (client->dev.of_node) {
1042                 ret = i2c_hid_of_probe(client, &ihid->pdata);
1043                 if (ret)
1044                         goto err;
1045         } else if (!platform_data) {
1046                 ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
1047                 if (ret) {
1048                         dev_err(&client->dev,
1049                                 "HID register address not provided\n");
1050                         goto err;
1051                 }
1052         } else {
1053                 ihid->pdata = *platform_data;
1054         }
1055 
1056         i2c_set_clientdata(client, ihid);
1057 
1058         ihid->client = client;
1059 
1060         hidRegister = ihid->pdata.hid_descriptor_address;
1061         ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
1062 
1063         init_waitqueue_head(&ihid->wait);
1064         mutex_init(&ihid->reset_lock);
1065 
1066         /* we need to allocate the command buffer without knowing the maximum
1067          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
1068          * real computation later. */
1069         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
1070         if (ret < 0)
1071                 goto err;
1072 
1073         pm_runtime_get_noresume(&client->dev);
1074         pm_runtime_set_active(&client->dev);
1075         pm_runtime_enable(&client->dev);
1076         device_enable_async_suspend(&client->dev);
1077 
1078         ret = i2c_hid_fetch_hid_descriptor(ihid);
1079         if (ret < 0)
1080                 goto err_pm;
1081 
1082         ret = i2c_hid_init_irq(client);
1083         if (ret < 0)
1084                 goto err_pm;
1085 
1086         hid = hid_allocate_device();
1087         if (IS_ERR(hid)) {
1088                 ret = PTR_ERR(hid);
1089                 goto err_irq;
1090         }
1091 
1092         ihid->hid = hid;
1093 
1094         hid->driver_data = client;
1095         hid->ll_driver = &i2c_hid_ll_driver;
1096         hid->dev.parent = &client->dev;
1097         hid->bus = BUS_I2C;
1098         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1099         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1100         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1101 
1102         snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
1103                  client->name, hid->vendor, hid->product);
1104         strlcpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1105 
1106         ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
1107 
1108         ret = hid_add_device(hid);
1109         if (ret) {
1110                 if (ret != -ENODEV)
1111                         hid_err(client, "can't add hid device: %d\n", ret);
1112                 goto err_mem_free;
1113         }
1114 
1115         pm_runtime_put(&client->dev);
1116         return 0;
1117 
1118 err_mem_free:
1119         hid_destroy_device(hid);
1120 
1121 err_irq:
1122         free_irq(client->irq, ihid);
1123 
1124 err_pm:
1125         pm_runtime_put_noidle(&client->dev);
1126         pm_runtime_disable(&client->dev);
1127 
1128 err:
1129         i2c_hid_free_buffers(ihid);
1130         kfree(ihid);
1131         return ret;
1132 }
1133 
1134 static int i2c_hid_remove(struct i2c_client *client)
1135 {
1136         struct i2c_hid *ihid = i2c_get_clientdata(client);
1137         struct hid_device *hid;
1138 
1139         pm_runtime_get_sync(&client->dev);
1140         pm_runtime_disable(&client->dev);
1141         pm_runtime_set_suspended(&client->dev);
1142         pm_runtime_put_noidle(&client->dev);
1143 
1144         hid = ihid->hid;
1145         hid_destroy_device(hid);
1146 
1147         free_irq(client->irq, ihid);
1148 
1149         if (ihid->bufsize)
1150                 i2c_hid_free_buffers(ihid);
1151 
1152         kfree(ihid);
1153 
1154         return 0;
1155 }
1156 
1157 static void i2c_hid_shutdown(struct i2c_client *client)
1158 {
1159         struct i2c_hid *ihid = i2c_get_clientdata(client);
1160 
1161         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1162         free_irq(client->irq, ihid);
1163 }
1164 
1165 #ifdef CONFIG_PM_SLEEP
1166 static int i2c_hid_suspend(struct device *dev)
1167 {
1168         struct i2c_client *client = to_i2c_client(dev);
1169         struct i2c_hid *ihid = i2c_get_clientdata(client);
1170         struct hid_device *hid = ihid->hid;
1171         int ret;
1172         int wake_status;
1173 
1174         if (hid->driver && hid->driver->suspend) {
1175                 /*
1176                  * Wake up the device so that IO issues in
1177                  * HID driver's suspend code can succeed.
1178                  */
1179                 ret = pm_runtime_resume(dev);
1180                 if (ret < 0)
1181                         return ret;
1182 
1183                 ret = hid->driver->suspend(hid, PMSG_SUSPEND);
1184                 if (ret < 0)
1185                         return ret;
1186         }
1187 
1188         if (!pm_runtime_suspended(dev)) {
1189                 /* Save some power */
1190                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1191 
1192                 disable_irq(client->irq);
1193         }
1194 
1195         if (device_may_wakeup(&client->dev)) {
1196                 wake_status = enable_irq_wake(client->irq);
1197                 if (!wake_status)
1198                         ihid->irq_wake_enabled = true;
1199                 else
1200                         hid_warn(hid, "Failed to enable irq wake: %d\n",
1201                                 wake_status);
1202         }
1203 
1204         return 0;
1205 }
1206 
1207 static int i2c_hid_resume(struct device *dev)
1208 {
1209         int ret;
1210         struct i2c_client *client = to_i2c_client(dev);
1211         struct i2c_hid *ihid = i2c_get_clientdata(client);
1212         struct hid_device *hid = ihid->hid;
1213         int wake_status;
1214 
1215         if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
1216                 wake_status = disable_irq_wake(client->irq);
1217                 if (!wake_status)
1218                         ihid->irq_wake_enabled = false;
1219                 else
1220                         hid_warn(hid, "Failed to disable irq wake: %d\n",
1221                                 wake_status);
1222         }
1223 
1224         /* We'll resume to full power */
1225         pm_runtime_disable(dev);
1226         pm_runtime_set_active(dev);
1227         pm_runtime_enable(dev);
1228 
1229         enable_irq(client->irq);
1230         ret = i2c_hid_hwreset(client);
1231         if (ret)
1232                 return ret;
1233 
1234         if (hid->driver && hid->driver->reset_resume) {
1235                 ret = hid->driver->reset_resume(hid);
1236                 return ret;
1237         }
1238 
1239         return 0;
1240 }
1241 #endif
1242 
1243 #ifdef CONFIG_PM
1244 static int i2c_hid_runtime_suspend(struct device *dev)
1245 {
1246         struct i2c_client *client = to_i2c_client(dev);
1247 
1248         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1249         disable_irq(client->irq);
1250         return 0;
1251 }
1252 
1253 static int i2c_hid_runtime_resume(struct device *dev)
1254 {
1255         struct i2c_client *client = to_i2c_client(dev);
1256 
1257         enable_irq(client->irq);
1258         i2c_hid_set_power(client, I2C_HID_PWR_ON);
1259         return 0;
1260 }
1261 #endif
1262 
1263 static const struct dev_pm_ops i2c_hid_pm = {
1264         SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_suspend, i2c_hid_resume)
1265         SET_RUNTIME_PM_OPS(i2c_hid_runtime_suspend, i2c_hid_runtime_resume,
1266                            NULL)
1267 };
1268 
1269 static const struct i2c_device_id i2c_hid_id_table[] = {
1270         { "hid", 0 },
1271         { "hid-over-i2c", 0 },
1272         { },
1273 };
1274 MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
1275 
1276 
1277 static struct i2c_driver i2c_hid_driver = {
1278         .driver = {
1279                 .name   = "i2c_hid",
1280                 .pm     = &i2c_hid_pm,
1281                 .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
1282                 .of_match_table = of_match_ptr(i2c_hid_of_match),
1283         },
1284 
1285         .probe          = i2c_hid_probe,
1286         .remove         = i2c_hid_remove,
1287         .shutdown       = i2c_hid_shutdown,
1288         .id_table       = i2c_hid_id_table,
1289 };
1290 
1291 module_i2c_driver(i2c_hid_driver);
1292 
1293 MODULE_DESCRIPTION("HID over I2C core driver");
1294 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1295 MODULE_LICENSE("GPL");
1296 

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