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
25struct 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
33static 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
39static 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
48static 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
62static 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 */
95struct 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 */
112struct vidtv_tuner_dev {
113	struct dvb_frontend *fe;
114	struct vidtv_tuner_hardware_state hw_state;
115	struct vidtv_tuner_config config;
116};
117
118static struct vidtv_tuner_dev*
119vidtv_tuner_get_dev(struct dvb_frontend *fe)
120{
121	return i2c_get_clientdata(fe->tuner_priv);
122}
123
124static 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
179static int
180vidtv_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
254static 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
267static 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
275static 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
283static 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
291static 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
324static 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
334static 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
344static 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
354static 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
364static 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
373static 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
387static const struct i2c_device_id vidtv_tuner_i2c_id_table[] = {
388	{"dvb_vidtv_tuner", 0},
389	{}
390};
391MODULE_DEVICE_TABLE(i2c, vidtv_tuner_i2c_id_table);
392
393static 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
416static 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
423static 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};
432module_i2c_driver(vidtv_tuner_i2c_driver);
433
434MODULE_DESCRIPTION("Virtual DVB Tuner");
435MODULE_AUTHOR("Daniel W. S. Almeida");
436MODULE_LICENSE("GPL");
437