1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * The Virtual DVB test driver serves as a reference DVB driver and helps
4 * validate the existing APIs in the media subsystem. It can also aid
5 * developers working on userspace applications.
6 *
7 * The vidtv tuner should support common TV standards such as
8 * DVB-T/T2/S/S2, ISDB-T and ATSC when completed.
9 *
10 * Copyright (C) 2020 Daniel W. S. Almeida
11 */
12
13 #include <linux/errno.h>
14 #include <linux/i2c.h>
15 #include <linux/module.h>
16 #include <linux/printk.h>
17 #include <linux/ratelimit.h>
18 #include <linux/slab.h>
19 #include <linux/types.h>
20
21 #include <media/dvb_frontend.h>
22
23 #include "vidtv_tuner.h"
24
25 struct vidtv_tuner_cnr_to_qual_s {
26 /* attempt to use the same values as libdvbv5 */
27 u32 modulation;
28 u32 fec;
29 u32 cnr_ok;
30 u32 cnr_good;
31 };
32
33 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_c_cnr_2_qual[] = {
34 /* from libdvbv5 source code, in milli db */
35 { QAM_256, FEC_NONE, 34000, 38000},
36 { QAM_64, FEC_NONE, 30000, 34000},
37 };
38
39 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_s_cnr_2_qual[] = {
40 /* from libdvbv5 source code, in milli db */
41 { QPSK, FEC_1_2, 7000, 10000},
42 { QPSK, FEC_2_3, 9000, 12000},
43 { QPSK, FEC_3_4, 10000, 13000},
44 { QPSK, FEC_5_6, 11000, 14000},
45 { QPSK, FEC_7_8, 12000, 15000},
46 };
47
48 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_s2_cnr_2_qual[] = {
49 /* from libdvbv5 source code, in milli db */
50 { QPSK, FEC_1_2, 9000, 12000},
51 { QPSK, FEC_2_3, 11000, 14000},
52 { QPSK, FEC_3_4, 12000, 15000},
53 { QPSK, FEC_5_6, 12000, 15000},
54 { QPSK, FEC_8_9, 13000, 16000},
55 { QPSK, FEC_9_10, 13500, 16500},
56 { PSK_8, FEC_2_3, 14500, 17500},
57 { PSK_8, FEC_3_4, 16000, 19000},
58 { PSK_8, FEC_5_6, 17500, 20500},
59 { PSK_8, FEC_8_9, 19000, 22000},
60 };
61
62 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_t_cnr_2_qual[] = {
63 /* from libdvbv5 source code, in milli db*/
64 { QPSK, FEC_1_2, 4100, 5900},
65 { QPSK, FEC_2_3, 6100, 9600},
66 { QPSK, FEC_3_4, 7200, 12400},
67 { QPSK, FEC_5_6, 8500, 15600},
68 { QPSK, FEC_7_8, 9200, 17500},
69 { QAM_16, FEC_1_2, 9800, 11800},
70 { QAM_16, FEC_2_3, 12100, 15300},
71 { QAM_16, FEC_3_4, 13400, 18100},
72 { QAM_16, FEC_5_6, 14800, 21300},
73 { QAM_16, FEC_7_8, 15700, 23600},
74 { QAM_64, FEC_1_2, 14000, 16000},
75 { QAM_64, FEC_2_3, 19900, 25400},
76 { QAM_64, FEC_3_4, 24900, 27900},
77 { QAM_64, FEC_5_6, 21300, 23300},
78 { QAM_64, FEC_7_8, 22000, 24000},
79 };
80
81 /**
82 * struct vidtv_tuner_hardware_state - Simulate the tuner hardware status
83 * @asleep: whether the tuner is asleep, i.e whether _sleep() or _suspend() was
84 * called.
85 * @lock_status: Whether the tuner has managed to lock on the requested
86 * frequency.
87 * @if_frequency: The tuner's intermediate frequency. Hardcoded for the purposes
88 * of simulation.
89 * @tuned_frequency: The actual tuned frequency.
90 * @bandwidth: The actual bandwidth.
91 *
92 * This structure is meant to simulate the status of the tuner hardware, as if
93 * we had a physical tuner hardware.
94 */
95 struct vidtv_tuner_hardware_state {
96 bool asleep;
97 u32 lock_status;
98 u32 if_frequency;
99 u32 tuned_frequency;
100 u32 bandwidth;
101 };
102
103 /**
104 * struct vidtv_tuner_dev - The tuner struct
105 * @fe: A pointer to the dvb_frontend structure allocated by vidtv_demod
106 * @hw_state: A struct to simulate the tuner's hardware state as if we had a
107 * physical tuner hardware.
108 * @config: The configuration used to start the tuner module, usually filled
109 * by a bridge driver. For vidtv, this is filled by vidtv_bridge before the
110 * tuner module is probed.
111 */
112 struct vidtv_tuner_dev {
113 struct dvb_frontend *fe;
114 struct vidtv_tuner_hardware_state hw_state;
115 struct vidtv_tuner_config config;
116 };
117
118 static struct vidtv_tuner_dev*
vidtv_tuner_get_dev(struct dvb_frontend * fe)119 vidtv_tuner_get_dev(struct dvb_frontend *fe)
120 {
121 return i2c_get_clientdata(fe->tuner_priv);
122 }
123
vidtv_tuner_check_frequency_shift(struct dvb_frontend * fe)124 static int vidtv_tuner_check_frequency_shift(struct dvb_frontend *fe)
125 {
126 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
127 struct dtv_frontend_properties *c = &fe->dtv_property_cache;
128 struct vidtv_tuner_config config = tuner_dev->config;
129 u32 *valid_freqs = NULL;
130 u32 array_sz = 0;
131 u32 i;
132 u32 shift;
133
134 switch (c->delivery_system) {
135 case SYS_DVBT:
136 case SYS_DVBT2:
137 valid_freqs = config.vidtv_valid_dvb_t_freqs;
138 array_sz = ARRAY_SIZE(config.vidtv_valid_dvb_t_freqs);
139 break;
140 case SYS_DVBS:
141 case SYS_DVBS2:
142 valid_freqs = config.vidtv_valid_dvb_s_freqs;
143 array_sz = ARRAY_SIZE(config.vidtv_valid_dvb_s_freqs);
144 break;
145 case SYS_DVBC_ANNEX_A:
146 valid_freqs = config.vidtv_valid_dvb_c_freqs;
147 array_sz = ARRAY_SIZE(config.vidtv_valid_dvb_c_freqs);
148 break;
149
150 default:
151 dev_warn(fe->dvb->device,
152 "%s: unsupported delivery system: %u\n",
153 __func__,
154 c->delivery_system);
155
156 return -EINVAL;
157 }
158
159 for (i = 0; i < array_sz; i++) {
160 if (!valid_freqs[i])
161 break;
162 shift = abs(c->frequency - valid_freqs[i]);
163
164 if (!shift)
165 return 0;
166
167 /*
168 * This will provide a value from 0 to 100 that would
169 * indicate how far is the tuned frequency from the
170 * right one.
171 */
172 if (shift < config.max_frequency_shift_hz)
173 return shift * 100 / config.max_frequency_shift_hz;
174 }
175
176 return -EINVAL;
177 }
178
179 static int
vidtv_tuner_get_signal_strength(struct dvb_frontend * fe,u16 * strength)180 vidtv_tuner_get_signal_strength(struct dvb_frontend *fe, u16 *strength)
181 {
182 struct dtv_frontend_properties *c = &fe->dtv_property_cache;
183 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
184 const struct vidtv_tuner_cnr_to_qual_s *cnr2qual = NULL;
185 struct device *dev = fe->dvb->device;
186 u32 array_size = 0;
187 s32 shift;
188 u32 i;
189
190 shift = vidtv_tuner_check_frequency_shift(fe);
191 if (shift < 0) {
192 tuner_dev->hw_state.lock_status = 0;
193 *strength = 0;
194 return 0;
195 }
196
197 switch (c->delivery_system) {
198 case SYS_DVBT:
199 case SYS_DVBT2:
200 cnr2qual = vidtv_tuner_t_cnr_2_qual;
201 array_size = ARRAY_SIZE(vidtv_tuner_t_cnr_2_qual);
202 break;
203
204 case SYS_DVBS:
205 cnr2qual = vidtv_tuner_s_cnr_2_qual;
206 array_size = ARRAY_SIZE(vidtv_tuner_s_cnr_2_qual);
207 break;
208
209 case SYS_DVBS2:
210 cnr2qual = vidtv_tuner_s2_cnr_2_qual;
211 array_size = ARRAY_SIZE(vidtv_tuner_s2_cnr_2_qual);
212 break;
213
214 case SYS_DVBC_ANNEX_A:
215 cnr2qual = vidtv_tuner_c_cnr_2_qual;
216 array_size = ARRAY_SIZE(vidtv_tuner_c_cnr_2_qual);
217 break;
218
219 default:
220 dev_warn_ratelimited(dev,
221 "%s: unsupported delivery system: %u\n",
222 __func__,
223 c->delivery_system);
224 return -EINVAL;
225 }
226
227 for (i = 0; i < array_size; i++) {
228 if (cnr2qual[i].modulation != c->modulation ||
229 cnr2qual[i].fec != c->fec_inner)
230 continue;
231
232 if (!shift) {
233 *strength = cnr2qual[i].cnr_good;
234 return 0;
235 }
236 /*
237 * Channel tuned at wrong frequency. Simulate that the
238 * Carrier S/N ratio is not too good.
239 */
240
241 *strength = cnr2qual[i].cnr_ok -
242 (cnr2qual[i].cnr_good - cnr2qual[i].cnr_ok);
243 return 0;
244 }
245
246 /*
247 * do a linear interpolation between 34dB and 10dB if we can't
248 * match against the table
249 */
250 *strength = 34000 - 24000 * shift / 100;
251 return 0;
252 }
253
vidtv_tuner_init(struct dvb_frontend * fe)254 static int vidtv_tuner_init(struct dvb_frontend *fe)
255 {
256 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
257 struct vidtv_tuner_config config = tuner_dev->config;
258
259 msleep_interruptible(config.mock_power_up_delay_msec);
260
261 tuner_dev->hw_state.asleep = false;
262 tuner_dev->hw_state.if_frequency = 5000;
263
264 return 0;
265 }
266
vidtv_tuner_sleep(struct dvb_frontend * fe)267 static int vidtv_tuner_sleep(struct dvb_frontend *fe)
268 {
269 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
270
271 tuner_dev->hw_state.asleep = true;
272 return 0;
273 }
274
vidtv_tuner_suspend(struct dvb_frontend * fe)275 static int vidtv_tuner_suspend(struct dvb_frontend *fe)
276 {
277 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
278
279 tuner_dev->hw_state.asleep = true;
280 return 0;
281 }
282
vidtv_tuner_resume(struct dvb_frontend * fe)283 static int vidtv_tuner_resume(struct dvb_frontend *fe)
284 {
285 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
286
287 tuner_dev->hw_state.asleep = false;
288 return 0;
289 }
290
vidtv_tuner_set_params(struct dvb_frontend * fe)291 static int vidtv_tuner_set_params(struct dvb_frontend *fe)
292 {
293 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
294 struct vidtv_tuner_config config = tuner_dev->config;
295 struct dtv_frontend_properties *c = &fe->dtv_property_cache;
296 s32 shift;
297
298 u32 min_freq = fe->ops.tuner_ops.info.frequency_min_hz;
299 u32 max_freq = fe->ops.tuner_ops.info.frequency_max_hz;
300 u32 min_bw = fe->ops.tuner_ops.info.bandwidth_min;
301 u32 max_bw = fe->ops.tuner_ops.info.bandwidth_max;
302
303 if (c->frequency < min_freq || c->frequency > max_freq ||
304 c->bandwidth_hz < min_bw || c->bandwidth_hz > max_bw) {
305 tuner_dev->hw_state.lock_status = 0;
306 return -EINVAL;
307 }
308
309 tuner_dev->hw_state.tuned_frequency = c->frequency;
310 tuner_dev->hw_state.bandwidth = c->bandwidth_hz;
311 tuner_dev->hw_state.lock_status = TUNER_STATUS_LOCKED;
312
313 msleep_interruptible(config.mock_tune_delay_msec);
314
315 shift = vidtv_tuner_check_frequency_shift(fe);
316 if (shift < 0) {
317 tuner_dev->hw_state.lock_status = 0;
318 return shift;
319 }
320
321 return 0;
322 }
323
vidtv_tuner_set_config(struct dvb_frontend * fe,void * priv_cfg)324 static int vidtv_tuner_set_config(struct dvb_frontend *fe,
325 void *priv_cfg)
326 {
327 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
328
329 memcpy(&tuner_dev->config, priv_cfg, sizeof(tuner_dev->config));
330
331 return 0;
332 }
333
vidtv_tuner_get_frequency(struct dvb_frontend * fe,u32 * frequency)334 static int vidtv_tuner_get_frequency(struct dvb_frontend *fe,
335 u32 *frequency)
336 {
337 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
338
339 *frequency = tuner_dev->hw_state.tuned_frequency;
340
341 return 0;
342 }
343
vidtv_tuner_get_bandwidth(struct dvb_frontend * fe,u32 * bandwidth)344 static int vidtv_tuner_get_bandwidth(struct dvb_frontend *fe,
345 u32 *bandwidth)
346 {
347 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
348
349 *bandwidth = tuner_dev->hw_state.bandwidth;
350
351 return 0;
352 }
353
vidtv_tuner_get_if_frequency(struct dvb_frontend * fe,u32 * frequency)354 static int vidtv_tuner_get_if_frequency(struct dvb_frontend *fe,
355 u32 *frequency)
356 {
357 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
358
359 *frequency = tuner_dev->hw_state.if_frequency;
360
361 return 0;
362 }
363
vidtv_tuner_get_status(struct dvb_frontend * fe,u32 * status)364 static int vidtv_tuner_get_status(struct dvb_frontend *fe, u32 *status)
365 {
366 struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
367
368 *status = tuner_dev->hw_state.lock_status;
369
370 return 0;
371 }
372
373 static const struct dvb_tuner_ops vidtv_tuner_ops = {
374 .init = vidtv_tuner_init,
375 .sleep = vidtv_tuner_sleep,
376 .suspend = vidtv_tuner_suspend,
377 .resume = vidtv_tuner_resume,
378 .set_params = vidtv_tuner_set_params,
379 .set_config = vidtv_tuner_set_config,
380 .get_bandwidth = vidtv_tuner_get_bandwidth,
381 .get_frequency = vidtv_tuner_get_frequency,
382 .get_if_frequency = vidtv_tuner_get_if_frequency,
383 .get_status = vidtv_tuner_get_status,
384 .get_rf_strength = vidtv_tuner_get_signal_strength
385 };
386
387 static const struct i2c_device_id vidtv_tuner_i2c_id_table[] = {
388 { "dvb_vidtv_tuner" },
389 {}
390 };
391 MODULE_DEVICE_TABLE(i2c, vidtv_tuner_i2c_id_table);
392
vidtv_tuner_i2c_probe(struct i2c_client * client)393 static int vidtv_tuner_i2c_probe(struct i2c_client *client)
394 {
395 struct vidtv_tuner_config *config = client->dev.platform_data;
396 struct dvb_frontend *fe = config->fe;
397 struct vidtv_tuner_dev *tuner_dev = NULL;
398
399 tuner_dev = kzalloc(sizeof(*tuner_dev), GFP_KERNEL);
400 if (!tuner_dev)
401 return -ENOMEM;
402
403 tuner_dev->fe = config->fe;
404 i2c_set_clientdata(client, tuner_dev);
405
406 memcpy(&fe->ops.tuner_ops,
407 &vidtv_tuner_ops,
408 sizeof(struct dvb_tuner_ops));
409
410 memcpy(&tuner_dev->config, config, sizeof(tuner_dev->config));
411 fe->tuner_priv = client;
412
413 return 0;
414 }
415
vidtv_tuner_i2c_remove(struct i2c_client * client)416 static void vidtv_tuner_i2c_remove(struct i2c_client *client)
417 {
418 struct vidtv_tuner_dev *tuner_dev = i2c_get_clientdata(client);
419
420 kfree(tuner_dev);
421 }
422
423 static struct i2c_driver vidtv_tuner_i2c_driver = {
424 .driver = {
425 .name = "dvb_vidtv_tuner",
426 .suppress_bind_attrs = true,
427 },
428 .probe = vidtv_tuner_i2c_probe,
429 .remove = vidtv_tuner_i2c_remove,
430 .id_table = vidtv_tuner_i2c_id_table,
431 };
432 module_i2c_driver(vidtv_tuner_i2c_driver);
433
434 MODULE_DESCRIPTION("Virtual DVB Tuner");
435 MODULE_AUTHOR("Daniel W. S. Almeida");
436 MODULE_LICENSE("GPL");
437