1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2012 Hans Verkuil <hverkuil@xs4all.nl>
4  */
5 
6 /* kernel includes */
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/input.h>
12 #include <linux/videodev2.h>
13 #include <media/v4l2-device.h>
14 #include <media/v4l2-ioctl.h>
15 #include <media/v4l2-ctrls.h>
16 #include <media/v4l2-event.h>
17 #include <linux/usb.h>
18 #include <linux/mutex.h>
19 
20 /* driver and module definitions */
21 MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
22 MODULE_DESCRIPTION("Keene FM Transmitter driver");
23 MODULE_LICENSE("GPL");
24 
25 /* Actually, it advertises itself as a Logitech */
26 #define USB_KEENE_VENDOR 0x046d
27 #define USB_KEENE_PRODUCT 0x0a0e
28 
29 /* Probably USB_TIMEOUT should be modified in module parameter */
30 #define BUFFER_LENGTH 8
31 #define USB_TIMEOUT 500
32 
33 /* Frequency limits in MHz */
34 #define FREQ_MIN  76U
35 #define FREQ_MAX 108U
36 #define FREQ_MUL 16000U
37 
38 /* USB Device ID List */
39 static const struct usb_device_id usb_keene_device_table[] = {
40 	{USB_DEVICE_AND_INTERFACE_INFO(USB_KEENE_VENDOR, USB_KEENE_PRODUCT,
41 							USB_CLASS_HID, 0, 0) },
42 	{ }						/* Terminating entry */
43 };
44 
45 MODULE_DEVICE_TABLE(usb, usb_keene_device_table);
46 
47 struct keene_device {
48 	struct usb_device *usbdev;
49 	struct usb_interface *intf;
50 	struct video_device vdev;
51 	struct v4l2_device v4l2_dev;
52 	struct v4l2_ctrl_handler hdl;
53 	struct mutex lock;
54 
55 	u8 *buffer;
56 	unsigned curfreq;
57 	u8 tx;
58 	u8 pa;
59 	bool stereo;
60 	bool muted;
61 	bool preemph_75_us;
62 };
63 
64 static inline struct keene_device *to_keene_dev(struct v4l2_device *v4l2_dev)
65 {
66 	return container_of(v4l2_dev, struct keene_device, v4l2_dev);
67 }
68 
69 /* Set frequency (if non-0), PA, mute and turn on/off the FM transmitter. */
70 static int keene_cmd_main(struct keene_device *radio, unsigned freq, bool play)
71 {
72 	unsigned short freq_send = freq ? (freq - 76 * 16000) / 800 : 0;
73 	int ret;
74 
75 	radio->buffer[0] = 0x00;
76 	radio->buffer[1] = 0x50;
77 	radio->buffer[2] = (freq_send >> 8) & 0xff;
78 	radio->buffer[3] = freq_send & 0xff;
79 	radio->buffer[4] = radio->pa;
80 	/* If bit 4 is set, then tune to the frequency.
81 	   If bit 3 is set, then unmute; if bit 2 is set, then mute.
82 	   If bit 1 is set, then enter idle mode; if bit 0 is set,
83 	   then enter transmit mode.
84 	 */
85 	radio->buffer[5] = (radio->muted ? 4 : 8) | (play ? 1 : 2) |
86 							(freq ? 0x10 : 0);
87 	radio->buffer[6] = 0x00;
88 	radio->buffer[7] = 0x00;
89 
90 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
91 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
92 
93 	if (ret < 0) {
94 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
95 		return ret;
96 	}
97 	if (freq)
98 		radio->curfreq = freq;
99 	return 0;
100 }
101 
102 /* Set TX, stereo and preemphasis mode (50 us vs 75 us). */
103 static int keene_cmd_set(struct keene_device *radio)
104 {
105 	int ret;
106 
107 	radio->buffer[0] = 0x00;
108 	radio->buffer[1] = 0x51;
109 	radio->buffer[2] = radio->tx;
110 	/* If bit 0 is set, then transmit mono, otherwise stereo.
111 	   If bit 2 is set, then enable 75 us preemphasis, otherwise
112 	   it is 50 us. */
113 	radio->buffer[3] = (radio->stereo ? 0 : 1) | (radio->preemph_75_us ? 4 : 0);
114 	radio->buffer[4] = 0x00;
115 	radio->buffer[5] = 0x00;
116 	radio->buffer[6] = 0x00;
117 	radio->buffer[7] = 0x00;
118 
119 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
120 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
121 
122 	if (ret < 0) {
123 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
124 		return ret;
125 	}
126 	return 0;
127 }
128 
129 /* Handle unplugging the device.
130  * We call video_unregister_device in any case.
131  * The last function called in this procedure is
132  * usb_keene_device_release.
133  */
134 static void usb_keene_disconnect(struct usb_interface *intf)
135 {
136 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
137 
138 	mutex_lock(&radio->lock);
139 	usb_set_intfdata(intf, NULL);
140 	video_unregister_device(&radio->vdev);
141 	v4l2_device_disconnect(&radio->v4l2_dev);
142 	mutex_unlock(&radio->lock);
143 	v4l2_device_put(&radio->v4l2_dev);
144 }
145 
146 static int usb_keene_suspend(struct usb_interface *intf, pm_message_t message)
147 {
148 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
149 
150 	return keene_cmd_main(radio, 0, false);
151 }
152 
153 static int usb_keene_resume(struct usb_interface *intf)
154 {
155 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
156 
157 	mdelay(50);
158 	keene_cmd_set(radio);
159 	keene_cmd_main(radio, radio->curfreq, true);
160 	return 0;
161 }
162 
163 static int vidioc_querycap(struct file *file, void *priv,
164 					struct v4l2_capability *v)
165 {
166 	struct keene_device *radio = video_drvdata(file);
167 
168 	strscpy(v->driver, "radio-keene", sizeof(v->driver));
169 	strscpy(v->card, "Keene FM Transmitter", sizeof(v->card));
170 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
171 	return 0;
172 }
173 
174 static int vidioc_g_modulator(struct file *file, void *priv,
175 				struct v4l2_modulator *v)
176 {
177 	struct keene_device *radio = video_drvdata(file);
178 
179 	if (v->index > 0)
180 		return -EINVAL;
181 
182 	strscpy(v->name, "FM", sizeof(v->name));
183 	v->rangelow = FREQ_MIN * FREQ_MUL;
184 	v->rangehigh = FREQ_MAX * FREQ_MUL;
185 	v->txsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
186 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
187 	return 0;
188 }
189 
190 static int vidioc_s_modulator(struct file *file, void *priv,
191 				const struct v4l2_modulator *v)
192 {
193 	struct keene_device *radio = video_drvdata(file);
194 
195 	if (v->index > 0)
196 		return -EINVAL;
197 
198 	radio->stereo = (v->txsubchans == V4L2_TUNER_SUB_STEREO);
199 	return keene_cmd_set(radio);
200 }
201 
202 static int vidioc_s_frequency(struct file *file, void *priv,
203 				const struct v4l2_frequency *f)
204 {
205 	struct keene_device *radio = video_drvdata(file);
206 	unsigned freq = f->frequency;
207 
208 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
209 		return -EINVAL;
210 	freq = clamp(freq, FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
211 	return keene_cmd_main(radio, freq, true);
212 }
213 
214 static int vidioc_g_frequency(struct file *file, void *priv,
215 				struct v4l2_frequency *f)
216 {
217 	struct keene_device *radio = video_drvdata(file);
218 
219 	if (f->tuner != 0)
220 		return -EINVAL;
221 	f->type = V4L2_TUNER_RADIO;
222 	f->frequency = radio->curfreq;
223 	return 0;
224 }
225 
226 static int keene_s_ctrl(struct v4l2_ctrl *ctrl)
227 {
228 	static const u8 db2tx[] = {
229 	     /*	 -15,  -12,   -9,   -6,   -3,    0 dB */
230 		0x03, 0x13, 0x02, 0x12, 0x22, 0x32,
231 	     /*	   3,    6,    9,   12,   15,   18 dB */
232 		0x21, 0x31, 0x20, 0x30, 0x40, 0x50
233 	};
234 	struct keene_device *radio =
235 		container_of(ctrl->handler, struct keene_device, hdl);
236 
237 	switch (ctrl->id) {
238 	case V4L2_CID_AUDIO_MUTE:
239 		radio->muted = ctrl->val;
240 		return keene_cmd_main(radio, 0, true);
241 
242 	case V4L2_CID_TUNE_POWER_LEVEL:
243 		/* To go from dBuV to the register value we apply the
244 		   following formula: */
245 		radio->pa = (ctrl->val - 71) * 100 / 62;
246 		return keene_cmd_main(radio, 0, true);
247 
248 	case V4L2_CID_TUNE_PREEMPHASIS:
249 		radio->preemph_75_us = ctrl->val == V4L2_PREEMPHASIS_75_uS;
250 		return keene_cmd_set(radio);
251 
252 	case V4L2_CID_AUDIO_COMPRESSION_GAIN:
253 		radio->tx = db2tx[(ctrl->val - (s32)ctrl->minimum) / (s32)ctrl->step];
254 		return keene_cmd_set(radio);
255 	}
256 	return -EINVAL;
257 }
258 
259 /* File system interface */
260 static const struct v4l2_file_operations usb_keene_fops = {
261 	.owner		= THIS_MODULE,
262 	.open           = v4l2_fh_open,
263 	.release        = v4l2_fh_release,
264 	.poll		= v4l2_ctrl_poll,
265 	.unlocked_ioctl	= video_ioctl2,
266 };
267 
268 static const struct v4l2_ctrl_ops keene_ctrl_ops = {
269 	.s_ctrl = keene_s_ctrl,
270 };
271 
272 static const struct v4l2_ioctl_ops usb_keene_ioctl_ops = {
273 	.vidioc_querycap    = vidioc_querycap,
274 	.vidioc_g_modulator = vidioc_g_modulator,
275 	.vidioc_s_modulator = vidioc_s_modulator,
276 	.vidioc_g_frequency = vidioc_g_frequency,
277 	.vidioc_s_frequency = vidioc_s_frequency,
278 	.vidioc_log_status = v4l2_ctrl_log_status,
279 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
280 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
281 };
282 
283 static void usb_keene_video_device_release(struct v4l2_device *v4l2_dev)
284 {
285 	struct keene_device *radio = to_keene_dev(v4l2_dev);
286 
287 	/* free rest memory */
288 	v4l2_ctrl_handler_free(&radio->hdl);
289 	kfree(radio->buffer);
290 	kfree(radio);
291 }
292 
293 /* check if the device is present and register with v4l and usb if it is */
294 static int usb_keene_probe(struct usb_interface *intf,
295 				const struct usb_device_id *id)
296 {
297 	struct usb_device *dev = interface_to_usbdev(intf);
298 	struct keene_device *radio;
299 	struct v4l2_ctrl_handler *hdl;
300 	int retval = 0;
301 
302 	/*
303 	 * The Keene FM transmitter USB device has the same USB ID as
304 	 * the Logitech AudioHub Speaker, but it should ignore the hid.
305 	 * Check if the name is that of the Keene device.
306 	 * If not, then someone connected the AudioHub and we shouldn't
307 	 * attempt to handle this driver.
308 	 * For reference: the product name of the AudioHub is
309 	 * "AudioHub Speaker".
310 	 */
311 	if (dev->product && strcmp(dev->product, "B-LINK USB Audio  "))
312 		return -ENODEV;
313 
314 	radio = kzalloc(sizeof(struct keene_device), GFP_KERNEL);
315 	if (radio)
316 		radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
317 
318 	if (!radio || !radio->buffer) {
319 		dev_err(&intf->dev, "kmalloc for keene_device failed\n");
320 		kfree(radio);
321 		retval = -ENOMEM;
322 		goto err;
323 	}
324 
325 	hdl = &radio->hdl;
326 	v4l2_ctrl_handler_init(hdl, 4);
327 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_MUTE,
328 			0, 1, 1, 0);
329 	v4l2_ctrl_new_std_menu(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_PREEMPHASIS,
330 			V4L2_PREEMPHASIS_75_uS, 1, V4L2_PREEMPHASIS_50_uS);
331 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_POWER_LEVEL,
332 			84, 118, 1, 118);
333 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_COMPRESSION_GAIN,
334 			-15, 18, 3, 0);
335 	radio->pa = 118;
336 	radio->tx = 0x32;
337 	radio->stereo = true;
338 	if (hdl->error) {
339 		retval = hdl->error;
340 
341 		v4l2_ctrl_handler_free(hdl);
342 		goto err_v4l2;
343 	}
344 	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
345 	if (retval < 0) {
346 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
347 		goto err_v4l2;
348 	}
349 
350 	mutex_init(&radio->lock);
351 
352 	radio->v4l2_dev.ctrl_handler = hdl;
353 	radio->v4l2_dev.release = usb_keene_video_device_release;
354 	strscpy(radio->vdev.name, radio->v4l2_dev.name,
355 		sizeof(radio->vdev.name));
356 	radio->vdev.v4l2_dev = &radio->v4l2_dev;
357 	radio->vdev.fops = &usb_keene_fops;
358 	radio->vdev.ioctl_ops = &usb_keene_ioctl_ops;
359 	radio->vdev.lock = &radio->lock;
360 	radio->vdev.release = video_device_release_empty;
361 	radio->vdev.vfl_dir = VFL_DIR_TX;
362 	radio->vdev.device_caps = V4L2_CAP_RADIO | V4L2_CAP_MODULATOR;
363 
364 	radio->usbdev = interface_to_usbdev(intf);
365 	radio->intf = intf;
366 	usb_set_intfdata(intf, &radio->v4l2_dev);
367 
368 	video_set_drvdata(&radio->vdev, radio);
369 
370 	/* at least 11ms is needed in order to settle hardware */
371 	msleep(20);
372 	keene_cmd_main(radio, 95.16 * FREQ_MUL, false);
373 
374 	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
375 	if (retval < 0) {
376 		dev_err(&intf->dev, "could not register video device\n");
377 		goto err_vdev;
378 	}
379 	v4l2_ctrl_handler_setup(hdl);
380 	dev_info(&intf->dev, "V4L2 device registered as %s\n",
381 			video_device_node_name(&radio->vdev));
382 	return 0;
383 
384 err_vdev:
385 	v4l2_device_unregister(&radio->v4l2_dev);
386 err_v4l2:
387 	kfree(radio->buffer);
388 	kfree(radio);
389 err:
390 	return retval;
391 }
392 
393 /* USB subsystem interface */
394 static struct usb_driver usb_keene_driver = {
395 	.name			= "radio-keene",
396 	.probe			= usb_keene_probe,
397 	.disconnect		= usb_keene_disconnect,
398 	.id_table		= usb_keene_device_table,
399 	.suspend		= usb_keene_suspend,
400 	.resume			= usb_keene_resume,
401 	.reset_resume		= usb_keene_resume,
402 };
403 
404 module_usb_driver(usb_keene_driver);
405 
406