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 
15 /* kernel includes */
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/input.h>
21 #include <linux/videodev2.h>
22 #include <media/v4l2-device.h>
23 #include <media/v4l2-ioctl.h>
24 #include <media/v4l2-ctrls.h>
25 #include <media/v4l2-event.h>
26 #include <linux/usb.h>
27 #include <linux/mutex.h>
28 
29 /* driver and module definitions */
30 MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
31 MODULE_DESCRIPTION("Keene FM Transmitter driver");
32 MODULE_LICENSE("GPL");
33 
34 /* Actually, it advertises itself as a Logitech */
35 #define USB_KEENE_VENDOR 0x046d
36 #define USB_KEENE_PRODUCT 0x0a0e
37 
38 /* Probably USB_TIMEOUT should be modified in module parameter */
39 #define BUFFER_LENGTH 8
40 #define USB_TIMEOUT 500
41 
42 /* Frequency limits in MHz */
43 #define FREQ_MIN  76U
44 #define FREQ_MAX 108U
45 #define FREQ_MUL 16000U
46 
47 /* USB Device ID List */
48 static const struct usb_device_id usb_keene_device_table[] = {
49 	{USB_DEVICE_AND_INTERFACE_INFO(USB_KEENE_VENDOR, USB_KEENE_PRODUCT,
50 							USB_CLASS_HID, 0, 0) },
51 	{ }						/* Terminating entry */
52 };
53 
54 MODULE_DEVICE_TABLE(usb, usb_keene_device_table);
55 
56 struct keene_device {
57 	struct usb_device *usbdev;
58 	struct usb_interface *intf;
59 	struct video_device vdev;
60 	struct v4l2_device v4l2_dev;
61 	struct v4l2_ctrl_handler hdl;
62 	struct mutex lock;
63 
64 	u8 *buffer;
65 	unsigned curfreq;
66 	u8 tx;
67 	u8 pa;
68 	bool stereo;
69 	bool muted;
70 	bool preemph_75_us;
71 };
72 
73 static inline struct keene_device *to_keene_dev(struct v4l2_device *v4l2_dev)
74 {
75 	return container_of(v4l2_dev, struct keene_device, v4l2_dev);
76 }
77 
78 /* Set frequency (if non-0), PA, mute and turn on/off the FM transmitter. */
79 static int keene_cmd_main(struct keene_device *radio, unsigned freq, bool play)
80 {
81 	unsigned short freq_send = freq ? (freq - 76 * 16000) / 800 : 0;
82 	int ret;
83 
84 	radio->buffer[0] = 0x00;
85 	radio->buffer[1] = 0x50;
86 	radio->buffer[2] = (freq_send >> 8) & 0xff;
87 	radio->buffer[3] = freq_send & 0xff;
88 	radio->buffer[4] = radio->pa;
89 	/* If bit 4 is set, then tune to the frequency.
90 	   If bit 3 is set, then unmute; if bit 2 is set, then mute.
91 	   If bit 1 is set, then enter idle mode; if bit 0 is set,
92 	   then enter transmit mode.
93 	 */
94 	radio->buffer[5] = (radio->muted ? 4 : 8) | (play ? 1 : 2) |
95 							(freq ? 0x10 : 0);
96 	radio->buffer[6] = 0x00;
97 	radio->buffer[7] = 0x00;
98 
99 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
100 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
101 
102 	if (ret < 0) {
103 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
104 		return ret;
105 	}
106 	if (freq)
107 		radio->curfreq = freq;
108 	return 0;
109 }
110 
111 /* Set TX, stereo and preemphasis mode (50 us vs 75 us). */
112 static int keene_cmd_set(struct keene_device *radio)
113 {
114 	int ret;
115 
116 	radio->buffer[0] = 0x00;
117 	radio->buffer[1] = 0x51;
118 	radio->buffer[2] = radio->tx;
119 	/* If bit 0 is set, then transmit mono, otherwise stereo.
120 	   If bit 2 is set, then enable 75 us preemphasis, otherwise
121 	   it is 50 us. */
122 	radio->buffer[3] = (radio->stereo ? 0 : 1) | (radio->preemph_75_us ? 4 : 0);
123 	radio->buffer[4] = 0x00;
124 	radio->buffer[5] = 0x00;
125 	radio->buffer[6] = 0x00;
126 	radio->buffer[7] = 0x00;
127 
128 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
129 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
130 
131 	if (ret < 0) {
132 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
133 		return ret;
134 	}
135 	return 0;
136 }
137 
138 /* Handle unplugging the device.
139  * We call video_unregister_device in any case.
140  * The last function called in this procedure is
141  * usb_keene_device_release.
142  */
143 static void usb_keene_disconnect(struct usb_interface *intf)
144 {
145 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
146 
147 	mutex_lock(&radio->lock);
148 	usb_set_intfdata(intf, NULL);
149 	video_unregister_device(&radio->vdev);
150 	v4l2_device_disconnect(&radio->v4l2_dev);
151 	mutex_unlock(&radio->lock);
152 	v4l2_device_put(&radio->v4l2_dev);
153 }
154 
155 static int usb_keene_suspend(struct usb_interface *intf, pm_message_t message)
156 {
157 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
158 
159 	return keene_cmd_main(radio, 0, false);
160 }
161 
162 static int usb_keene_resume(struct usb_interface *intf)
163 {
164 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
165 
166 	mdelay(50);
167 	keene_cmd_set(radio);
168 	keene_cmd_main(radio, radio->curfreq, true);
169 	return 0;
170 }
171 
172 static int vidioc_querycap(struct file *file, void *priv,
173 					struct v4l2_capability *v)
174 {
175 	struct keene_device *radio = video_drvdata(file);
176 
177 	strscpy(v->driver, "radio-keene", sizeof(v->driver));
178 	strscpy(v->card, "Keene FM Transmitter", sizeof(v->card));
179 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
180 	v->device_caps = V4L2_CAP_RADIO | V4L2_CAP_MODULATOR;
181 	v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
182 	return 0;
183 }
184 
185 static int vidioc_g_modulator(struct file *file, void *priv,
186 				struct v4l2_modulator *v)
187 {
188 	struct keene_device *radio = video_drvdata(file);
189 
190 	if (v->index > 0)
191 		return -EINVAL;
192 
193 	strscpy(v->name, "FM", sizeof(v->name));
194 	v->rangelow = FREQ_MIN * FREQ_MUL;
195 	v->rangehigh = FREQ_MAX * FREQ_MUL;
196 	v->txsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
197 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
198 	return 0;
199 }
200 
201 static int vidioc_s_modulator(struct file *file, void *priv,
202 				const struct v4l2_modulator *v)
203 {
204 	struct keene_device *radio = video_drvdata(file);
205 
206 	if (v->index > 0)
207 		return -EINVAL;
208 
209 	radio->stereo = (v->txsubchans == V4L2_TUNER_SUB_STEREO);
210 	return keene_cmd_set(radio);
211 }
212 
213 static int vidioc_s_frequency(struct file *file, void *priv,
214 				const struct v4l2_frequency *f)
215 {
216 	struct keene_device *radio = video_drvdata(file);
217 	unsigned freq = f->frequency;
218 
219 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
220 		return -EINVAL;
221 	freq = clamp(freq, FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
222 	return keene_cmd_main(radio, freq, true);
223 }
224 
225 static int vidioc_g_frequency(struct file *file, void *priv,
226 				struct v4l2_frequency *f)
227 {
228 	struct keene_device *radio = video_drvdata(file);
229 
230 	if (f->tuner != 0)
231 		return -EINVAL;
232 	f->type = V4L2_TUNER_RADIO;
233 	f->frequency = radio->curfreq;
234 	return 0;
235 }
236 
237 static int keene_s_ctrl(struct v4l2_ctrl *ctrl)
238 {
239 	static const u8 db2tx[] = {
240 	     /*	 -15,  -12,   -9,   -6,   -3,    0 dB */
241 		0x03, 0x13, 0x02, 0x12, 0x22, 0x32,
242 	     /*	   3,    6,    9,   12,   15,   18 dB */
243 		0x21, 0x31, 0x20, 0x30, 0x40, 0x50
244 	};
245 	struct keene_device *radio =
246 		container_of(ctrl->handler, struct keene_device, hdl);
247 
248 	switch (ctrl->id) {
249 	case V4L2_CID_AUDIO_MUTE:
250 		radio->muted = ctrl->val;
251 		return keene_cmd_main(radio, 0, true);
252 
253 	case V4L2_CID_TUNE_POWER_LEVEL:
254 		/* To go from dBuV to the register value we apply the
255 		   following formula: */
256 		radio->pa = (ctrl->val - 71) * 100 / 62;
257 		return keene_cmd_main(radio, 0, true);
258 
259 	case V4L2_CID_TUNE_PREEMPHASIS:
260 		radio->preemph_75_us = ctrl->val == V4L2_PREEMPHASIS_75_uS;
261 		return keene_cmd_set(radio);
262 
263 	case V4L2_CID_AUDIO_COMPRESSION_GAIN:
264 		radio->tx = db2tx[(ctrl->val - (s32)ctrl->minimum) / (s32)ctrl->step];
265 		return keene_cmd_set(radio);
266 	}
267 	return -EINVAL;
268 }
269 
270 /* File system interface */
271 static const struct v4l2_file_operations usb_keene_fops = {
272 	.owner		= THIS_MODULE,
273 	.open           = v4l2_fh_open,
274 	.release        = v4l2_fh_release,
275 	.poll		= v4l2_ctrl_poll,
276 	.unlocked_ioctl	= video_ioctl2,
277 };
278 
279 static const struct v4l2_ctrl_ops keene_ctrl_ops = {
280 	.s_ctrl = keene_s_ctrl,
281 };
282 
283 static const struct v4l2_ioctl_ops usb_keene_ioctl_ops = {
284 	.vidioc_querycap    = vidioc_querycap,
285 	.vidioc_g_modulator = vidioc_g_modulator,
286 	.vidioc_s_modulator = vidioc_s_modulator,
287 	.vidioc_g_frequency = vidioc_g_frequency,
288 	.vidioc_s_frequency = vidioc_s_frequency,
289 	.vidioc_log_status = v4l2_ctrl_log_status,
290 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
291 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
292 };
293 
294 static void usb_keene_video_device_release(struct v4l2_device *v4l2_dev)
295 {
296 	struct keene_device *radio = to_keene_dev(v4l2_dev);
297 
298 	/* free rest memory */
299 	v4l2_ctrl_handler_free(&radio->hdl);
300 	kfree(radio->buffer);
301 	kfree(radio);
302 }
303 
304 /* check if the device is present and register with v4l and usb if it is */
305 static int usb_keene_probe(struct usb_interface *intf,
306 				const struct usb_device_id *id)
307 {
308 	struct usb_device *dev = interface_to_usbdev(intf);
309 	struct keene_device *radio;
310 	struct v4l2_ctrl_handler *hdl;
311 	int retval = 0;
312 
313 	/*
314 	 * The Keene FM transmitter USB device has the same USB ID as
315 	 * the Logitech AudioHub Speaker, but it should ignore the hid.
316 	 * Check if the name is that of the Keene device.
317 	 * If not, then someone connected the AudioHub and we shouldn't
318 	 * attempt to handle this driver.
319 	 * For reference: the product name of the AudioHub is
320 	 * "AudioHub Speaker".
321 	 */
322 	if (dev->product && strcmp(dev->product, "B-LINK USB Audio  "))
323 		return -ENODEV;
324 
325 	radio = kzalloc(sizeof(struct keene_device), GFP_KERNEL);
326 	if (radio)
327 		radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
328 
329 	if (!radio || !radio->buffer) {
330 		dev_err(&intf->dev, "kmalloc for keene_device failed\n");
331 		kfree(radio);
332 		retval = -ENOMEM;
333 		goto err;
334 	}
335 
336 	hdl = &radio->hdl;
337 	v4l2_ctrl_handler_init(hdl, 4);
338 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_MUTE,
339 			0, 1, 1, 0);
340 	v4l2_ctrl_new_std_menu(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_PREEMPHASIS,
341 			V4L2_PREEMPHASIS_75_uS, 1, V4L2_PREEMPHASIS_50_uS);
342 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_POWER_LEVEL,
343 			84, 118, 1, 118);
344 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_COMPRESSION_GAIN,
345 			-15, 18, 3, 0);
346 	radio->pa = 118;
347 	radio->tx = 0x32;
348 	radio->stereo = true;
349 	if (hdl->error) {
350 		retval = hdl->error;
351 
352 		v4l2_ctrl_handler_free(hdl);
353 		goto err_v4l2;
354 	}
355 	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
356 	if (retval < 0) {
357 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
358 		goto err_v4l2;
359 	}
360 
361 	mutex_init(&radio->lock);
362 
363 	radio->v4l2_dev.ctrl_handler = hdl;
364 	radio->v4l2_dev.release = usb_keene_video_device_release;
365 	strscpy(radio->vdev.name, radio->v4l2_dev.name,
366 		sizeof(radio->vdev.name));
367 	radio->vdev.v4l2_dev = &radio->v4l2_dev;
368 	radio->vdev.fops = &usb_keene_fops;
369 	radio->vdev.ioctl_ops = &usb_keene_ioctl_ops;
370 	radio->vdev.lock = &radio->lock;
371 	radio->vdev.release = video_device_release_empty;
372 	radio->vdev.vfl_dir = VFL_DIR_TX;
373 
374 	radio->usbdev = interface_to_usbdev(intf);
375 	radio->intf = intf;
376 	usb_set_intfdata(intf, &radio->v4l2_dev);
377 
378 	video_set_drvdata(&radio->vdev, radio);
379 
380 	/* at least 11ms is needed in order to settle hardware */
381 	msleep(20);
382 	keene_cmd_main(radio, 95.16 * FREQ_MUL, false);
383 
384 	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
385 	if (retval < 0) {
386 		dev_err(&intf->dev, "could not register video device\n");
387 		goto err_vdev;
388 	}
389 	v4l2_ctrl_handler_setup(hdl);
390 	dev_info(&intf->dev, "V4L2 device registered as %s\n",
391 			video_device_node_name(&radio->vdev));
392 	return 0;
393 
394 err_vdev:
395 	v4l2_device_unregister(&radio->v4l2_dev);
396 err_v4l2:
397 	kfree(radio->buffer);
398 	kfree(radio);
399 err:
400 	return retval;
401 }
402 
403 /* USB subsystem interface */
404 static struct usb_driver usb_keene_driver = {
405 	.name			= "radio-keene",
406 	.probe			= usb_keene_probe,
407 	.disconnect		= usb_keene_disconnect,
408 	.id_table		= usb_keene_device_table,
409 	.suspend		= usb_keene_suspend,
410 	.resume			= usb_keene_resume,
411 	.reset_resume		= usb_keene_resume,
412 };
413 
414 module_usb_driver(usb_keene_driver);
415 
416