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radio-keene.c
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1 /*
2  * Copyright (c) 2012 Hans Verkuil <[email protected]>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18 
19 /* kernel includes */
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/input.h>
25 #include <linux/videodev2.h>
26 #include <media/v4l2-device.h>
27 #include <media/v4l2-ioctl.h>
28 #include <media/v4l2-ctrls.h>
29 #include <media/v4l2-event.h>
30 #include <linux/usb.h>
31 #include <linux/mutex.h>
32 
33 /* driver and module definitions */
34 MODULE_AUTHOR("Hans Verkuil <[email protected]>");
35 MODULE_DESCRIPTION("Keene FM Transmitter driver");
36 MODULE_LICENSE("GPL");
37 
38 /* Actually, it advertises itself as a Logitech */
39 #define USB_KEENE_VENDOR 0x046d
40 #define USB_KEENE_PRODUCT 0x0a0e
41 
42 /* Probably USB_TIMEOUT should be modified in module parameter */
43 #define BUFFER_LENGTH 8
44 #define USB_TIMEOUT 500
45 
46 /* Frequency limits in MHz */
47 #define FREQ_MIN 76U
48 #define FREQ_MAX 108U
49 #define FREQ_MUL 16000U
50 
51 /* USB Device ID List */
52 static struct usb_device_id usb_keene_device_table[] = {
53  {USB_DEVICE_AND_INTERFACE_INFO(USB_KEENE_VENDOR, USB_KEENE_PRODUCT,
54  USB_CLASS_HID, 0, 0) },
55  { } /* Terminating entry */
56 };
57 
58 MODULE_DEVICE_TABLE(usb, usb_keene_device_table);
59 
60 struct keene_device {
61  struct usb_device *usbdev;
66  struct mutex lock;
67 
69  unsigned curfreq;
70  u8 tx;
71  u8 pa;
72  bool stereo;
73  bool muted;
75 };
76 
77 static inline struct keene_device *to_keene_dev(struct v4l2_device *v4l2_dev)
78 {
79  return container_of(v4l2_dev, struct keene_device, v4l2_dev);
80 }
81 
82 /* Set frequency (if non-0), PA, mute and turn on/off the FM transmitter. */
83 static int keene_cmd_main(struct keene_device *radio, unsigned freq, bool play)
84 {
85  unsigned short freq_send = freq ? (freq - 76 * 16000) / 800 : 0;
86  int ret;
87 
88  radio->buffer[0] = 0x00;
89  radio->buffer[1] = 0x50;
90  radio->buffer[2] = (freq_send >> 8) & 0xff;
91  radio->buffer[3] = freq_send & 0xff;
92  radio->buffer[4] = radio->pa;
93  /* If bit 4 is set, then tune to the frequency.
94  If bit 3 is set, then unmute; if bit 2 is set, then mute.
95  If bit 1 is set, then enter idle mode; if bit 0 is set,
96  then enter transit mode.
97  */
98  radio->buffer[5] = (radio->muted ? 4 : 8) | (play ? 1 : 2) |
99  (freq ? 0x10 : 0);
100  radio->buffer[6] = 0x00;
101  radio->buffer[7] = 0x00;
102 
103  ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
104  9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
105 
106  if (ret < 0) {
107  dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
108  return ret;
109  }
110  if (freq)
111  radio->curfreq = freq;
112  return 0;
113 }
114 
115 /* Set TX, stereo and preemphasis mode (50 us vs 75 us). */
116 static int keene_cmd_set(struct keene_device *radio)
117 {
118  int ret;
119 
120  radio->buffer[0] = 0x00;
121  radio->buffer[1] = 0x51;
122  radio->buffer[2] = radio->tx;
123  /* If bit 0 is set, then transmit mono, otherwise stereo.
124  If bit 2 is set, then enable 75 us preemphasis, otherwise
125  it is 50 us. */
126  radio->buffer[3] = (!radio->stereo) | (radio->preemph_75_us ? 4 : 0);
127  radio->buffer[4] = 0x00;
128  radio->buffer[5] = 0x00;
129  radio->buffer[6] = 0x00;
130  radio->buffer[7] = 0x00;
131 
132  ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
133  9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
134 
135  if (ret < 0) {
136  dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
137  return ret;
138  }
139  return 0;
140 }
141 
142 /* Handle unplugging the device.
143  * We call video_unregister_device in any case.
144  * The last function called in this procedure is
145  * usb_keene_device_release.
146  */
147 static void usb_keene_disconnect(struct usb_interface *intf)
148 {
149  struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
150 
151  mutex_lock(&radio->lock);
152  usb_set_intfdata(intf, NULL);
153  video_unregister_device(&radio->vdev);
155  mutex_unlock(&radio->lock);
156  v4l2_device_put(&radio->v4l2_dev);
157 }
158 
159 static int usb_keene_suspend(struct usb_interface *intf, pm_message_t message)
160 {
161  struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
162 
163  return keene_cmd_main(radio, 0, false);
164 }
165 
166 static int usb_keene_resume(struct usb_interface *intf)
167 {
168  struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
169 
170  mdelay(50);
171  keene_cmd_set(radio);
172  keene_cmd_main(radio, radio->curfreq, true);
173  return 0;
174 }
175 
176 static int vidioc_querycap(struct file *file, void *priv,
177  struct v4l2_capability *v)
178 {
179  struct keene_device *radio = video_drvdata(file);
180 
181  strlcpy(v->driver, "radio-keene", sizeof(v->driver));
182  strlcpy(v->card, "Keene FM Transmitter", sizeof(v->card));
183  usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
186  return 0;
187 }
188 
189 static int vidioc_g_modulator(struct file *file, void *priv,
190  struct v4l2_modulator *v)
191 {
192  struct keene_device *radio = video_drvdata(file);
193 
194  if (v->index > 0)
195  return -EINVAL;
196 
197  strlcpy(v->name, "FM", sizeof(v->name));
198  v->rangelow = FREQ_MIN * FREQ_MUL;
199  v->rangehigh = FREQ_MAX * FREQ_MUL;
202  return 0;
203 }
204 
205 static int vidioc_s_modulator(struct file *file, void *priv,
206  const struct v4l2_modulator *v)
207 {
208  struct keene_device *radio = video_drvdata(file);
209 
210  if (v->index > 0)
211  return -EINVAL;
212 
213  radio->stereo = (v->txsubchans == V4L2_TUNER_SUB_STEREO);
214  return keene_cmd_set(radio);
215 }
216 
217 static int vidioc_s_frequency(struct file *file, void *priv,
218  struct v4l2_frequency *f)
219 {
220  struct keene_device *radio = video_drvdata(file);
221 
222  if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
223  return -EINVAL;
224  f->frequency = clamp(f->frequency,
225  FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
226  return keene_cmd_main(radio, f->frequency, true);
227 }
228 
229 static int vidioc_g_frequency(struct file *file, void *priv,
230  struct v4l2_frequency *f)
231 {
232  struct keene_device *radio = video_drvdata(file);
233 
234  if (f->tuner != 0)
235  return -EINVAL;
236  f->type = V4L2_TUNER_RADIO;
237  f->frequency = radio->curfreq;
238  return 0;
239 }
240 
241 static int keene_s_ctrl(struct v4l2_ctrl *ctrl)
242 {
243  static const u8 db2tx[] = {
244  /* -15, -12, -9, -6, -3, 0 dB */
245  0x03, 0x13, 0x02, 0x12, 0x22, 0x32,
246  /* 3, 6, 9, 12, 15, 18 dB */
247  0x21, 0x31, 0x20, 0x30, 0x40, 0x50
248  };
249  struct keene_device *radio =
250  container_of(ctrl->handler, struct keene_device, hdl);
251 
252  switch (ctrl->id) {
253  case V4L2_CID_AUDIO_MUTE:
254  radio->muted = ctrl->val;
255  return keene_cmd_main(radio, 0, true);
256 
258  /* To go from dBuV to the register value we apply the
259  following formula: */
260  radio->pa = (ctrl->val - 71) * 100 / 62;
261  return keene_cmd_main(radio, 0, true);
262 
264  radio->preemph_75_us = ctrl->val == V4L2_PREEMPHASIS_75_uS;
265  return keene_cmd_set(radio);
266 
268  radio->tx = db2tx[(ctrl->val - ctrl->minimum) / ctrl->step];
269  return keene_cmd_set(radio);
270  }
271  return -EINVAL;
272 }
273 
274 /* File system interface */
275 static const struct v4l2_file_operations usb_keene_fops = {
276  .owner = THIS_MODULE,
277  .open = v4l2_fh_open,
278  .release = v4l2_fh_release,
279  .poll = v4l2_ctrl_poll,
280  .unlocked_ioctl = video_ioctl2,
281 };
282 
283 static const struct v4l2_ctrl_ops keene_ctrl_ops = {
284  .s_ctrl = keene_s_ctrl,
285 };
286 
287 static const struct v4l2_ioctl_ops usb_keene_ioctl_ops = {
288  .vidioc_querycap = vidioc_querycap,
289  .vidioc_g_modulator = vidioc_g_modulator,
290  .vidioc_s_modulator = vidioc_s_modulator,
291  .vidioc_g_frequency = vidioc_g_frequency,
292  .vidioc_s_frequency = vidioc_s_frequency,
293  .vidioc_log_status = v4l2_ctrl_log_status,
294  .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
295  .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
296 };
297 
298 static void usb_keene_video_device_release(struct v4l2_device *v4l2_dev)
299 {
300  struct keene_device *radio = to_keene_dev(v4l2_dev);
301 
302  /* free rest memory */
303  v4l2_ctrl_handler_free(&radio->hdl);
304  kfree(radio->buffer);
305  kfree(radio);
306 }
307 
308 /* check if the device is present and register with v4l and usb if it is */
309 static int usb_keene_probe(struct usb_interface *intf,
310  const struct usb_device_id *id)
311 {
312  struct usb_device *dev = interface_to_usbdev(intf);
313  struct keene_device *radio;
314  struct v4l2_ctrl_handler *hdl;
315  int retval = 0;
316 
317  /*
318  * The Keene FM transmitter USB device has the same USB ID as
319  * the Logitech AudioHub Speaker, but it should ignore the hid.
320  * Check if the name is that of the Keene device.
321  * If not, then someone connected the AudioHub and we shouldn't
322  * attempt to handle this driver.
323  * For reference: the product name of the AudioHub is
324  * "AudioHub Speaker".
325  */
326  if (dev->product && strcmp(dev->product, "B-LINK USB Audio "))
327  return -ENODEV;
328 
329  radio = kzalloc(sizeof(struct keene_device), GFP_KERNEL);
330  if (radio)
332 
333  if (!radio || !radio->buffer) {
334  dev_err(&intf->dev, "kmalloc for keene_device failed\n");
335  kfree(radio);
336  retval = -ENOMEM;
337  goto err;
338  }
339 
340  hdl = &radio->hdl;
341  v4l2_ctrl_handler_init(hdl, 4);
342  v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_MUTE,
343  0, 1, 1, 0);
346  v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_POWER_LEVEL,
347  84, 118, 1, 118);
349  -15, 18, 3, 0);
350  radio->pa = 118;
351  radio->tx = 0x32;
352  radio->stereo = true;
353  radio->curfreq = 95.16 * FREQ_MUL;
354  if (hdl->error) {
355  retval = hdl->error;
356 
358  goto err_v4l2;
359  }
360  retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
361  if (retval < 0) {
362  dev_err(&intf->dev, "couldn't register v4l2_device\n");
363  goto err_v4l2;
364  }
365 
366  mutex_init(&radio->lock);
367 
368  radio->v4l2_dev.ctrl_handler = hdl;
369  radio->v4l2_dev.release = usb_keene_video_device_release;
370  strlcpy(radio->vdev.name, radio->v4l2_dev.name,
371  sizeof(radio->vdev.name));
372  radio->vdev.v4l2_dev = &radio->v4l2_dev;
373  radio->vdev.fops = &usb_keene_fops;
374  radio->vdev.ioctl_ops = &usb_keene_ioctl_ops;
375  radio->vdev.lock = &radio->lock;
376  radio->vdev.release = video_device_release_empty;
377 
378  radio->usbdev = interface_to_usbdev(intf);
379  radio->intf = intf;
380  usb_set_intfdata(intf, &radio->v4l2_dev);
381 
382  video_set_drvdata(&radio->vdev, radio);
383  set_bit(V4L2_FL_USE_FH_PRIO, &radio->vdev.flags);
384 
385  retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
386  if (retval < 0) {
387  dev_err(&intf->dev, "could not register video device\n");
388  goto err_vdev;
389  }
391  dev_info(&intf->dev, "V4L2 device registered as %s\n",
392  video_device_node_name(&radio->vdev));
393  return 0;
394 
395 err_vdev:
397 err_v4l2:
398  kfree(radio->buffer);
399  kfree(radio);
400 err:
401  return retval;
402 }
403 
404 /* USB subsystem interface */
405 static struct usb_driver usb_keene_driver = {
406  .name = "radio-keene",
407  .probe = usb_keene_probe,
408  .disconnect = usb_keene_disconnect,
409  .id_table = usb_keene_device_table,
410  .suspend = usb_keene_suspend,
411  .resume = usb_keene_resume,
412  .reset_resume = usb_keene_resume,
413 };
414 
415 static int __init keene_init(void)
416 {
417  int retval = usb_register(&usb_keene_driver);
418 
419  if (retval)
420  pr_err(KBUILD_MODNAME
421  ": usb_register failed. Error number %d\n", retval);
422 
423  return retval;
424 }
425 
426 static void __exit keene_exit(void)
427 {
428  usb_deregister(&usb_keene_driver);
429 }
430 
431 module_init(keene_init);
432 module_exit(keene_exit);
433