1 /*
2  * Copyright (c) 2012 Hans Verkuil <hverkuil@xs4all.nl>
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 <hverkuil@xs4all.nl>");
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;
62 	struct usb_interface *intf;
63 	struct video_device vdev;
64 	struct v4l2_device v4l2_dev;
65 	struct v4l2_ctrl_handler hdl;
66 	struct mutex lock;
67 
68 	u8 *buffer;
69 	unsigned curfreq;
70 	u8 tx;
71 	u8 pa;
72 	bool stereo;
73 	bool muted;
74 	bool preemph_75_us;
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 transmit 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 ? 0 : 1) | (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);
154 	v4l2_device_disconnect(&radio->v4l2_dev);
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));
184 	v->device_caps = V4L2_CAP_RADIO | V4L2_CAP_MODULATOR;
185 	v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
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;
200 	v->txsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
201 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
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 				const struct v4l2_frequency *f)
219 {
220 	struct keene_device *radio = video_drvdata(file);
221 	unsigned freq = f->frequency;
222 
223 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
224 		return -EINVAL;
225 	freq = clamp(freq, FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
226 	return keene_cmd_main(radio, freq, 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 
257 	case V4L2_CID_TUNE_POWER_LEVEL:
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 
263 	case V4L2_CID_TUNE_PREEMPHASIS:
264 		radio->preemph_75_us = ctrl->val == V4L2_PREEMPHASIS_75_uS;
265 		return keene_cmd_set(radio);
266 
267 	case V4L2_CID_AUDIO_COMPRESSION_GAIN:
268 		radio->tx = db2tx[(ctrl->val - (s32)ctrl->minimum) / (s32)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)
331 		radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
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);
344 	v4l2_ctrl_new_std_menu(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_PREEMPHASIS,
345 			V4L2_PREEMPHASIS_75_uS, 1, V4L2_PREEMPHASIS_50_uS);
346 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_POWER_LEVEL,
347 			84, 118, 1, 118);
348 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_COMPRESSION_GAIN,
349 			-15, 18, 3, 0);
350 	radio->pa = 118;
351 	radio->tx = 0x32;
352 	radio->stereo = true;
353 	if (hdl->error) {
354 		retval = hdl->error;
355 
356 		v4l2_ctrl_handler_free(hdl);
357 		goto err_v4l2;
358 	}
359 	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
360 	if (retval < 0) {
361 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
362 		goto err_v4l2;
363 	}
364 
365 	mutex_init(&radio->lock);
366 
367 	radio->v4l2_dev.ctrl_handler = hdl;
368 	radio->v4l2_dev.release = usb_keene_video_device_release;
369 	strlcpy(radio->vdev.name, radio->v4l2_dev.name,
370 		sizeof(radio->vdev.name));
371 	radio->vdev.v4l2_dev = &radio->v4l2_dev;
372 	radio->vdev.fops = &usb_keene_fops;
373 	radio->vdev.ioctl_ops = &usb_keene_ioctl_ops;
374 	radio->vdev.lock = &radio->lock;
375 	radio->vdev.release = video_device_release_empty;
376 	radio->vdev.vfl_dir = VFL_DIR_TX;
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 
384 	/* at least 11ms is needed in order to settle hardware */
385 	msleep(20);
386 	keene_cmd_main(radio, 95.16 * FREQ_MUL, false);
387 
388 	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
389 	if (retval < 0) {
390 		dev_err(&intf->dev, "could not register video device\n");
391 		goto err_vdev;
392 	}
393 	v4l2_ctrl_handler_setup(hdl);
394 	dev_info(&intf->dev, "V4L2 device registered as %s\n",
395 			video_device_node_name(&radio->vdev));
396 	return 0;
397 
398 err_vdev:
399 	v4l2_device_unregister(&radio->v4l2_dev);
400 err_v4l2:
401 	kfree(radio->buffer);
402 	kfree(radio);
403 err:
404 	return retval;
405 }
406 
407 /* USB subsystem interface */
408 static struct usb_driver usb_keene_driver = {
409 	.name			= "radio-keene",
410 	.probe			= usb_keene_probe,
411 	.disconnect		= usb_keene_disconnect,
412 	.id_table		= usb_keene_device_table,
413 	.suspend		= usb_keene_suspend,
414 	.resume			= usb_keene_resume,
415 	.reset_resume		= usb_keene_resume,
416 };
417 
418 module_usb_driver(usb_keene_driver);
419 
420