test-drivers/vidtv/vidtv_tuner.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * The Virtual DVB test driver serves as a reference DVB driver and helps
0004  * validate the existing APIs in the media subsystem. It can also aid
0005  * developers working on userspace applications.
0006  *
0007  * The vidtv tuner should support common TV standards such as
0008  * DVB-T/T2/S/S2, ISDB-T and ATSC when completed.
0009  *
0010  * Copyright (C) 2020 Daniel W. S. Almeida
0011  */
0012
0013 #include <linux/errno.h>
0014 #include <linux/i2c.h>
0015 #include <linux/module.h>
0016 #include <linux/printk.h>
0017 #include <linux/ratelimit.h>
0018 #include <linux/slab.h>
0019 #include <linux/types.h>
0020
0021 #include <media/dvb_frontend.h>
0022
0023 #include "vidtv_tuner.h"
0024
0025 struct vidtv_tuner_cnr_to_qual_s {
0026     /* attempt to use the same values as libdvbv5 */
0027     u32 modulation;
0028     u32 fec;
0029     u32 cnr_ok;
0030     u32 cnr_good;
0031 };
0032
0033 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_c_cnr_2_qual[] = {
0034     /* from libdvbv5 source code, in milli db */
0035     { QAM_256, FEC_NONE,  34000, 38000},
0036     { QAM_64,  FEC_NONE,  30000, 34000},
0037 };
0038
0039 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_s_cnr_2_qual[] = {
0040     /* from libdvbv5 source code, in milli db */
0041     { QPSK, FEC_1_2,  7000, 10000},
0042     { QPSK, FEC_2_3,  9000, 12000},
0043     { QPSK, FEC_3_4, 10000, 13000},
0044     { QPSK, FEC_5_6, 11000, 14000},
0045     { QPSK, FEC_7_8, 12000, 15000},
0046 };
0047
0048 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_s2_cnr_2_qual[] = {
0049     /* from libdvbv5 source code, in milli db */
0050     { QPSK,  FEC_1_2,   9000,  12000},
0051     { QPSK,  FEC_2_3,  11000,  14000},
0052     { QPSK,  FEC_3_4,  12000,  15000},
0053     { QPSK,  FEC_5_6,  12000,  15000},
0054     { QPSK,  FEC_8_9,  13000,  16000},
0055     { QPSK,  FEC_9_10, 13500,  16500},
0056     { PSK_8, FEC_2_3,  14500,  17500},
0057     { PSK_8, FEC_3_4,  16000,  19000},
0058     { PSK_8, FEC_5_6,  17500,  20500},
0059     { PSK_8, FEC_8_9,  19000,  22000},
0060 };
0061
0062 static const struct vidtv_tuner_cnr_to_qual_s vidtv_tuner_t_cnr_2_qual[] = {
0063     /* from libdvbv5 source code, in milli db*/
0064     {   QPSK, FEC_1_2,  4100,  5900},
0065     {   QPSK, FEC_2_3,  6100,  9600},
0066     {   QPSK, FEC_3_4,  7200, 12400},
0067     {   QPSK, FEC_5_6,  8500, 15600},
0068     {   QPSK, FEC_7_8,  9200, 17500},
0069     { QAM_16, FEC_1_2,  9800, 11800},
0070     { QAM_16, FEC_2_3, 12100, 15300},
0071     { QAM_16, FEC_3_4, 13400, 18100},
0072     { QAM_16, FEC_5_6, 14800, 21300},
0073     { QAM_16, FEC_7_8, 15700, 23600},
0074     { QAM_64, FEC_1_2, 14000, 16000},
0075     { QAM_64, FEC_2_3, 19900, 25400},
0076     { QAM_64, FEC_3_4, 24900, 27900},
0077     { QAM_64, FEC_5_6, 21300, 23300},
0078     { QAM_64, FEC_7_8, 22000, 24000},
0079 };
0080
0081 /**
0082  * struct vidtv_tuner_hardware_state - Simulate the tuner hardware status
0083  * @asleep: whether the tuner is asleep, i.e whether _sleep() or _suspend() was
0084  * called.
0085  * @lock_status: Whether the tuner has managed to lock on the requested
0086  * frequency.
0087  * @if_frequency: The tuner's intermediate frequency. Hardcoded for the purposes
0088  * of simulation.
0089  * @tuned_frequency: The actual tuned frequency.
0090  * @bandwidth: The actual bandwidth.
0091  *
0092  * This structure is meant to simulate the status of the tuner hardware, as if
0093  * we had a physical tuner hardware.
0094  */
0095 struct vidtv_tuner_hardware_state {
0096     bool asleep;
0097     u32 lock_status;
0098     u32 if_frequency;
0099     u32 tuned_frequency;
0100     u32 bandwidth;
0101 };
0102
0103 /**
0104  * struct vidtv_tuner_dev - The tuner struct
0105  * @fe: A pointer to the dvb_frontend structure allocated by vidtv_demod
0106  * @hw_state: A struct to simulate the tuner's hardware state as if we had a
0107  * physical tuner hardware.
0108  * @config: The configuration used to start the tuner module, usually filled
0109  * by a bridge driver. For vidtv, this is filled by vidtv_bridge before the
0110  * tuner module is probed.
0111  */
0112 struct vidtv_tuner_dev {
0113     struct dvb_frontend *fe;
0114     struct vidtv_tuner_hardware_state hw_state;
0115     struct vidtv_tuner_config config;
0116 };
0117
0118 static struct vidtv_tuner_dev*
0119 vidtv_tuner_get_dev(struct dvb_frontend *fe)
0120 {
0121     return i2c_get_clientdata(fe->tuner_priv);
0122 }
0123
0124 static int vidtv_tuner_check_frequency_shift(struct dvb_frontend *fe)
0125 {
0126     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0127     struct dtv_frontend_properties *c = &fe->dtv_property_cache;
0128     struct vidtv_tuner_config config  = tuner_dev->config;
0129     u32 *valid_freqs = NULL;
0130     u32 array_sz = 0;
0131     u32 i;
0132     u32 shift;
0133
0134     switch (c->delivery_system) {
0135     case SYS_DVBT:
0136     case SYS_DVBT2:
0137         valid_freqs = config.vidtv_valid_dvb_t_freqs;
0138         array_sz    = ARRAY_SIZE(config.vidtv_valid_dvb_t_freqs);
0139         break;
0140     case SYS_DVBS:
0141     case SYS_DVBS2:
0142         valid_freqs = config.vidtv_valid_dvb_s_freqs;
0143         array_sz    = ARRAY_SIZE(config.vidtv_valid_dvb_s_freqs);
0144         break;
0145     case SYS_DVBC_ANNEX_A:
0146         valid_freqs = config.vidtv_valid_dvb_c_freqs;
0147         array_sz    = ARRAY_SIZE(config.vidtv_valid_dvb_c_freqs);
0148         break;
0149
0150     default:
0151         dev_warn(fe->dvb->device,
0152              "%s: unsupported delivery system: %u\n",
0153              __func__,
0154              c->delivery_system);
0155
0156         return -EINVAL;
0157     }
0158
0159     for (i = 0; i < array_sz; i++) {
0160         if (!valid_freqs[i])
0161             break;
0162         shift = abs(c->frequency - valid_freqs[i]);
0163
0164         if (!shift)
0165             return 0;
0166
0167         /*
0168          * This will provide a value from 0 to 100 that would
0169          * indicate how far is the tuned frequency from the
0170          * right one.
0171          */
0172         if (shift < config.max_frequency_shift_hz)
0173             return shift * 100 / config.max_frequency_shift_hz;
0174     }
0175
0176     return -EINVAL;
0177 }
0178
0179 static int
0180 vidtv_tuner_get_signal_strength(struct dvb_frontend *fe, u16 *strength)
0181 {
0182     struct dtv_frontend_properties *c = &fe->dtv_property_cache;
0183     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0184     const struct vidtv_tuner_cnr_to_qual_s *cnr2qual = NULL;
0185     struct device *dev = fe->dvb->device;
0186     u32 array_size = 0;
0187     s32 shift;
0188     u32 i;
0189
0190     shift = vidtv_tuner_check_frequency_shift(fe);
0191     if (shift < 0) {
0192         tuner_dev->hw_state.lock_status = 0;
0193         *strength = 0;
0194         return 0;
0195     }
0196
0197     switch (c->delivery_system) {
0198     case SYS_DVBT:
0199     case SYS_DVBT2:
0200         cnr2qual   = vidtv_tuner_t_cnr_2_qual;
0201         array_size = ARRAY_SIZE(vidtv_tuner_t_cnr_2_qual);
0202         break;
0203
0204     case SYS_DVBS:
0205         cnr2qual   = vidtv_tuner_s_cnr_2_qual;
0206         array_size = ARRAY_SIZE(vidtv_tuner_s_cnr_2_qual);
0207         break;
0208
0209     case SYS_DVBS2:
0210         cnr2qual   = vidtv_tuner_s2_cnr_2_qual;
0211         array_size = ARRAY_SIZE(vidtv_tuner_s2_cnr_2_qual);
0212         break;
0213
0214     case SYS_DVBC_ANNEX_A:
0215         cnr2qual   = vidtv_tuner_c_cnr_2_qual;
0216         array_size = ARRAY_SIZE(vidtv_tuner_c_cnr_2_qual);
0217         break;
0218
0219     default:
0220         dev_warn_ratelimited(dev,
0221                      "%s: unsupported delivery system: %u\n",
0222                      __func__,
0223                      c->delivery_system);
0224         return -EINVAL;
0225     }
0226
0227     for (i = 0; i < array_size; i++) {
0228         if (cnr2qual[i].modulation != c->modulation ||
0229             cnr2qual[i].fec != c->fec_inner)
0230             continue;
0231
0232         if (!shift) {
0233             *strength = cnr2qual[i].cnr_good;
0234             return 0;
0235         }
0236         /*
0237          * Channel tuned at wrong frequency. Simulate that the
0238          * Carrier S/N ratio is not too good.
0239          */
0240
0241         *strength = cnr2qual[i].cnr_ok -
0242                 (cnr2qual[i].cnr_good - cnr2qual[i].cnr_ok);
0243         return 0;
0244     }
0245
0246     /*
0247      * do a linear interpolation between 34dB and 10dB if we can't
0248      * match against the table
0249      */
0250     *strength = 34000 - 24000 * shift / 100;
0251     return 0;
0252 }
0253
0254 static int vidtv_tuner_init(struct dvb_frontend *fe)
0255 {
0256     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0257     struct vidtv_tuner_config config  = tuner_dev->config;
0258
0259     msleep_interruptible(config.mock_power_up_delay_msec);
0260
0261     tuner_dev->hw_state.asleep = false;
0262     tuner_dev->hw_state.if_frequency = 5000;
0263
0264     return 0;
0265 }
0266
0267 static int vidtv_tuner_sleep(struct dvb_frontend *fe)
0268 {
0269     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0270
0271     tuner_dev->hw_state.asleep = true;
0272     return 0;
0273 }
0274
0275 static int vidtv_tuner_suspend(struct dvb_frontend *fe)
0276 {
0277     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0278
0279     tuner_dev->hw_state.asleep = true;
0280     return 0;
0281 }
0282
0283 static int vidtv_tuner_resume(struct dvb_frontend *fe)
0284 {
0285     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0286
0287     tuner_dev->hw_state.asleep = false;
0288     return 0;
0289 }
0290
0291 static int vidtv_tuner_set_params(struct dvb_frontend *fe)
0292 {
0293     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0294     struct vidtv_tuner_config config  = tuner_dev->config;
0295     struct dtv_frontend_properties *c = &fe->dtv_property_cache;
0296     s32 shift;
0297
0298     u32 min_freq = fe->ops.tuner_ops.info.frequency_min_hz;
0299     u32 max_freq = fe->ops.tuner_ops.info.frequency_max_hz;
0300     u32 min_bw = fe->ops.tuner_ops.info.bandwidth_min;
0301     u32 max_bw = fe->ops.tuner_ops.info.bandwidth_max;
0302
0303     if (c->frequency < min_freq  || c->frequency > max_freq  ||
0304         c->bandwidth_hz < min_bw || c->bandwidth_hz > max_bw) {
0305         tuner_dev->hw_state.lock_status = 0;
0306         return -EINVAL;
0307     }
0308
0309     tuner_dev->hw_state.tuned_frequency = c->frequency;
0310     tuner_dev->hw_state.bandwidth = c->bandwidth_hz;
0311     tuner_dev->hw_state.lock_status = TUNER_STATUS_LOCKED;
0312
0313     msleep_interruptible(config.mock_tune_delay_msec);
0314
0315     shift = vidtv_tuner_check_frequency_shift(fe);
0316     if (shift < 0) {
0317         tuner_dev->hw_state.lock_status = 0;
0318         return shift;
0319     }
0320
0321     return 0;
0322 }
0323
0324 static int vidtv_tuner_set_config(struct dvb_frontend *fe,
0325                   void *priv_cfg)
0326 {
0327     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0328
0329     memcpy(&tuner_dev->config, priv_cfg, sizeof(tuner_dev->config));
0330
0331     return 0;
0332 }
0333
0334 static int vidtv_tuner_get_frequency(struct dvb_frontend *fe,
0335                      u32 *frequency)
0336 {
0337     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0338
0339     *frequency = tuner_dev->hw_state.tuned_frequency;
0340
0341     return 0;
0342 }
0343
0344 static int vidtv_tuner_get_bandwidth(struct dvb_frontend *fe,
0345                      u32 *bandwidth)
0346 {
0347     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0348
0349     *bandwidth = tuner_dev->hw_state.bandwidth;
0350
0351     return 0;
0352 }
0353
0354 static int vidtv_tuner_get_if_frequency(struct dvb_frontend *fe,
0355                     u32 *frequency)
0356 {
0357     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0358
0359     *frequency = tuner_dev->hw_state.if_frequency;
0360
0361     return 0;
0362 }
0363
0364 static int vidtv_tuner_get_status(struct dvb_frontend *fe, u32 *status)
0365 {
0366     struct vidtv_tuner_dev *tuner_dev = vidtv_tuner_get_dev(fe);
0367
0368     *status = tuner_dev->hw_state.lock_status;
0369
0370     return 0;
0371 }
0372
0373 static const struct dvb_tuner_ops vidtv_tuner_ops = {
0374     .init             = vidtv_tuner_init,
0375     .sleep            = vidtv_tuner_sleep,
0376     .suspend          = vidtv_tuner_suspend,
0377     .resume           = vidtv_tuner_resume,
0378     .set_params       = vidtv_tuner_set_params,
0379     .set_config       = vidtv_tuner_set_config,
0380     .get_bandwidth    = vidtv_tuner_get_bandwidth,
0381     .get_frequency    = vidtv_tuner_get_frequency,
0382     .get_if_frequency = vidtv_tuner_get_if_frequency,
0383     .get_status       = vidtv_tuner_get_status,
0384     .get_rf_strength  = vidtv_tuner_get_signal_strength
0385 };
0386
0387 static const struct i2c_device_id vidtv_tuner_i2c_id_table[] = {
0388     {"dvb_vidtv_tuner", 0},
0389     {}
0390 };
0391 MODULE_DEVICE_TABLE(i2c, vidtv_tuner_i2c_id_table);
0392
0393 static int vidtv_tuner_i2c_probe(struct i2c_client *client,
0394                  const struct i2c_device_id *id)
0395 {
0396     struct vidtv_tuner_config *config = client->dev.platform_data;
0397     struct dvb_frontend *fe           = config->fe;
0398     struct vidtv_tuner_dev *tuner_dev = NULL;
0399
0400     tuner_dev = kzalloc(sizeof(*tuner_dev), GFP_KERNEL);
0401     if (!tuner_dev)
0402         return -ENOMEM;
0403
0404     tuner_dev->fe = config->fe;
0405     i2c_set_clientdata(client, tuner_dev);
0406
0407     memcpy(&fe->ops.tuner_ops,
0408            &vidtv_tuner_ops,
0409            sizeof(struct dvb_tuner_ops));
0410
0411     memcpy(&tuner_dev->config, config, sizeof(tuner_dev->config));
0412     fe->tuner_priv = client;
0413
0414     return 0;
0415 }
0416
0417 static int vidtv_tuner_i2c_remove(struct i2c_client *client)
0418 {
0419     struct vidtv_tuner_dev *tuner_dev = i2c_get_clientdata(client);
0420
0421     kfree(tuner_dev);
0422
0423     return 0;
0424 }
0425
0426 static struct i2c_driver vidtv_tuner_i2c_driver = {
0427     .driver = {
0428         .name                = "dvb_vidtv_tuner",
0429         .suppress_bind_attrs = true,
0430     },
0431     .probe    = vidtv_tuner_i2c_probe,
0432     .remove   = vidtv_tuner_i2c_remove,
0433     .id_table = vidtv_tuner_i2c_id_table,
0434 };
0435 module_i2c_driver(vidtv_tuner_i2c_driver);
0436
0437 MODULE_DESCRIPTION("Virtual DVB Tuner");
0438 MODULE_AUTHOR("Daniel W. S. Almeida");
0439 MODULE_LICENSE("GPL");