[Linux-kernel-mentees] [RFC, WIP, v2 1/3] media: dvb_dummy_tuner: implement driver skeleton
Sean Young
sean at mess.org
Sun Mar 29 10:09:33 UTC 2020
Hi Daniel,
On Mon, Mar 23, 2020 at 09:57:30AM -0300, Daniel W. S. Almeida wrote:
> From: "Daniel W. S. Almeida" <dwlsalmeida at gmail.com>
>
> The virtual DVB test driver serves as a reference DVB driver and helps
> validate the existing APIs in the media subsystem. It can also aid developers
> working on userspace applications.
>
> This dummy tuner should support common TV standards such as DVB-T/T2/S/S2,
> ISDB-T and ATSC when completed.
>
> Signed-off-by: Daniel W. S. Almeida <dwlsalmeida at gmail.com>
> ---
> drivers/media/tuners/Kconfig | 9 +
> drivers/media/tuners/Makefile | 1 +
> drivers/media/tuners/dvb_dummy_tuner.c | 419 +++++++++++++++++++++++++
> 3 files changed, 429 insertions(+)
> create mode 100644 drivers/media/tuners/dvb_dummy_tuner.c
>
> diff --git a/drivers/media/tuners/Kconfig b/drivers/media/tuners/Kconfig
> index e104bb7766e1..8ad54339ceee 100644
> --- a/drivers/media/tuners/Kconfig
> +++ b/drivers/media/tuners/Kconfig
> @@ -296,4 +296,13 @@ config MEDIA_TUNER_QM1D1B0004
> default m if !MEDIA_SUBDRV_AUTOSELECT
> help
> Sharp QM1D1B0004 ISDB-S tuner driver.
> +
> +config MEDIA_TUNER_DVB_DUMMY_TUNER
> + tristate "Dummy DVB Media Tuner"
> + depends on MEDIA_SUPPORT && I2C
> + help
> + Dummy DVB media tuner driver
> + The virtual DVB test driver serves as a reference DVB driver and helps
> + validate the existing APIs in the media subsystem. It can also aid
> + developers working on userspace applications.
> endmenu
> diff --git a/drivers/media/tuners/Makefile b/drivers/media/tuners/Makefile
> index 7b4f8423501e..f98de1cf2e19 100644
> --- a/drivers/media/tuners/Makefile
> +++ b/drivers/media/tuners/Makefile
> @@ -44,5 +44,6 @@ obj-$(CONFIG_MEDIA_TUNER_QM1D1C0042) += qm1d1c0042.o
> obj-$(CONFIG_MEDIA_TUNER_QM1D1B0004) += qm1d1b0004.o
> obj-$(CONFIG_MEDIA_TUNER_M88RS6000T) += m88rs6000t.o
> obj-$(CONFIG_MEDIA_TUNER_TDA18250) += tda18250.o
> +obj-$(CONFIG_MEDIA_TUNER_DVB_DUMMY_TUNER) += dvb_dummy_tuner.o
>
> ccflags-y += -I$(srctree)/drivers/media/dvb-frontends
> diff --git a/drivers/media/tuners/dvb_dummy_tuner.c b/drivers/media/tuners/dvb_dummy_tuner.c
> new file mode 100644
> index 000000000000..f0e1f60918f0
> --- /dev/null
> +++ b/drivers/media/tuners/dvb_dummy_tuner.c
> @@ -0,0 +1,419 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020 Daniel W. S. Almeida <dwlsalmeida at gmail.com>
> + *
> + * The virtual DVB test driver serves as a reference DVB driver and helps
> + * validate the existing APIs in the media subsystem. It can also aid
> + * developers working on userspace applications.
> + *
> + * This dummy tuner should support common TV standards such as
> + * DVB-T/T2/S/S2, ISDB-T and ATSC when completed.
> + *
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <media/dvb_frontend.h>
> +
> +struct dvb_dummy_tuner_config {
> + struct dvb_frontend *fe;
> + u32 mock_power_up_delay_msec;
> + u32 mock_tune_delay_msec;
> + u32 mock_sleep_delay_msec;
> + u32 mock_resume_delay_msec;
> + u32 dummy_valid_dvb_t_freqs[8];
> + u32 dummy_valid_dvb_c_freqs[8];
> + u32 dummy_valid_dvb_s_freqs[8];
> + u8 max_frequency_shift_hz;
> +};
> +
> +struct dvb_dummy_tuner_cnr_to_qual_s {
> + /* attempt to use the same values as libdvbv5 */
> + u32 modulation;
> + u32 fec;
> + u32 cnr_ok, cnr_good;
> +};
> +
> +struct dvb_dummy_tuner_cnr_to_qual_s dvb_dummy_tuner_c_cnr_2_qual[] = {
> + /* from libdvbv5 source code, in milli db */
> + { QAM_256, FEC_NONE, 34000, 38000},
> + { QAM_64, FEC_NONE, 30000, 34000},
> +};
> +
> +struct dvb_dummy_tuner_cnr_to_qual_s dvb_dummy_tuner_s_cnr_2_qual[] = {
> + /* from libdvbv5 source code, in milli db */
> + { QPSK, FEC_1_2, 7000, 10000},
> +
> + { QPSK, FEC_2_3, 9000, 12000},
> + { QPSK, FEC_3_4, 10000, 13000},
> + { QPSK, FEC_5_6, 11000, 14000},
> +
> + { QPSK, FEC_7_8, 12000, 15000},
> +};
> +
> +struct dvb_dummy_tuner_cnr_to_qual_s dvb_dummy_tuner_s2_cnr_2_qual[] = {
> + /* from libdvbv5 source code, in milli db */
> + { QPSK, FEC_1_2, 9000, 12000},
> + { QPSK, FEC_2_3, 11000, 14000},
> + { QPSK, FEC_3_4, 12000, 15000},
> + { QPSK, FEC_5_6, 12000, 15000},
> + { QPSK, FEC_8_9, 13000, 16000},
> + { QPSK, FEC_9_10, 13500, 16500},
> + { PSK_8, FEC_2_3, 14500, 17500},
> + { PSK_8, FEC_3_4, 16000, 19000},
> + { PSK_8, FEC_5_6, 17500, 20500},
> + { PSK_8, FEC_8_9, 19000, 22000},
> +};
> +
> +static struct dvb_dummy_tuner_cnr_to_qual_s dvb_dummy_tuner_t_cnr_2_qual[] = {
> + /* from libdvbv5 source code, in milli db*/
> + { QPSK, FEC_1_2, 4100, 5900},
> + { QPSK, FEC_2_3, 6100, 9600},
> + { QPSK, FEC_3_4, 7200, 12400},
> + { QPSK, FEC_5_6, 8500, 15600},
> + { QPSK, FEC_7_8, 9200, 17500},
> +
> + { QAM_16, FEC_1_2, 9800, 11800},
> + { QAM_16, FEC_2_3, 12100, 15300},
> + { QAM_16, FEC_3_4, 13400, 18100},
> + { QAM_16, FEC_5_6, 14800, 21300},
> + { QAM_16, FEC_7_8, 15700, 23600},
> +
> + { QAM_64, FEC_1_2, 14000, 16000},
> + { QAM_64, FEC_2_3, 19900, 25400},
> + { QAM_64, FEC_3_4, 24900, 27900},
> + { QAM_64, FEC_5_6, 21300, 23300},
> + { QAM_64, FEC_7_8, 22000, 24000},
> +};
> +
> +enum dvb_dummy_tuner_lock_status {
> + STATUS_NO_LOCK = 0,
> + STATUS_LOCKED = TUNER_STATUS_LOCKED,
> +};
This enum is a little odd. In dvb-core tuner status is represented as a u32,
with two bitfields. TUNER_STATUS_LOCKED and TUNER_STATUS_STEREO. There
is no STATUS_NO_LOCK; the bitfield is simply 0.
Just use a u32 like the rest of dvb core, I would suggest.
> +
> +enum dvb_dummy_tuner_power_status {
> + STATUS_UNKNOWN,
> + STATUS_ASLEEP,
> + STATUS_ACTIVE
> +};
I'm guessing that STATUS_UNKNOWN won't be used, so this enum can be replaced
with a "boolean asleep".
> +struct dvb_dummy_tuner_hardware_state {
> + enum dvb_dummy_tuner_power_status power_status;
> + enum dvb_dummy_tuner_lock_status lock_status;
> + u32 if_frequency;
> + u32 tuned_frequency;
> + u32 bandwidth;
> +};
> +
> +struct dvb_dummy_tuner_dev {
> + struct dvb_frontend *fe;
> + struct dvb_dummy_tuner_hardware_state hw_state;
> + struct dvb_dummy_tuner_config config;
> +};
> +
> +static struct dvb_dummy_tuner_dev*
> +dvb_dummy_tuner_get_dev(struct dvb_frontend *fe)
> +{
> + struct i2c_client *client = fe->tuner_priv;
> +
> + return (struct dvb_dummy_tuner_dev *)i2c_get_clientdata(client);
i2c_get_clientdata() returns void* so need for the cast. C allows void *
to be cast to any pointer type without a cast.
Thanks
Sean
> +}
> +
> +static s32 dvb_dummy_tuner_check_frequency_shift(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> + struct dtv_frontend_properties *c = &fe->dtv_property_cache;
> + struct dvb_dummy_tuner_config config = tuner_dev->config;
> + u32 *valid_freqs = NULL;
> + u32 array_sz = 0;
> + u32 i;
> +
> + switch (c->delivery_system) {
> + case SYS_DVBT:
> + case SYS_DVBT2:
> + valid_freqs =
> + config.dummy_valid_dvb_t_freqs;
> + array_sz = ARRAY_SIZE(config.dummy_valid_dvb_t_freqs);
> + break;
> + case SYS_DVBS:
> + case SYS_DVBS2:
> + valid_freqs =
> + config.dummy_valid_dvb_s_freqs;
> + array_sz = ARRAY_SIZE(config.dummy_valid_dvb_s_freqs);
> + break;
> + case SYS_DVBC_ANNEX_A:
> + valid_freqs =
> + config.dummy_valid_dvb_c_freqs;
> + array_sz = ARRAY_SIZE(config.dummy_valid_dvb_c_freqs);
> + break;
> +
> + default:
> + pr_warn("%s: unsupported delivery system: %u\n",
> + __func__,
> + c->delivery_system);
> + break;
> + }
> +
> + for (i = 0; i < array_sz; i++) {
> + if (c->frequency == valid_freqs[i])
> + return 0;
> + else if (c->frequency >= valid_freqs[i] -
> + config.max_frequency_shift_hz &&
> + c->frequency <= valid_freqs[i] +
> + config.max_frequency_shift_hz)
> + /* This will provide a value from 0 to 100 that would
> + * indicate how far is the tuned frequency from the
> + * right one.
> + */
> + return abs((c->frequency - valid_freqs[i]) *
> + 100 / config.max_frequency_shift_hz);
> + }
> +
> + return -1;
> +}
> +
> +static int
> +dvb_dummy_tuner_get_signal_strength(struct dvb_frontend *fe, u16 *strength)
> +{
> + struct dtv_frontend_properties *c = &fe->dtv_property_cache;
> + struct dvb_dummy_tuner_cnr_to_qual_s *cnr2qual = NULL;
> + u32 array_size = 0;
> + s32 shift;
> + u32 i;
> +
> + shift = dvb_dummy_tuner_check_frequency_shift(fe);
> +
> + switch (c->delivery_system) {
> + case SYS_DVBT:
> + case SYS_DVBT2:
> + cnr2qual = dvb_dummy_tuner_t_cnr_2_qual;
> + array_size = ARRAY_SIZE(dvb_dummy_tuner_t_cnr_2_qual);
> + break;
> +
> + case SYS_DVBS:
> + cnr2qual = dvb_dummy_tuner_s_cnr_2_qual;
> + array_size = ARRAY_SIZE(dvb_dummy_tuner_s_cnr_2_qual);
> + break;
> +
> + case SYS_DVBS2:
> + cnr2qual = dvb_dummy_tuner_s2_cnr_2_qual;
> + array_size = ARRAY_SIZE(dvb_dummy_tuner_s2_cnr_2_qual);
> + break;
> +
> + case SYS_DVBC_ANNEX_A:
> + cnr2qual = dvb_dummy_tuner_c_cnr_2_qual;
> + array_size = ARRAY_SIZE(dvb_dummy_tuner_c_cnr_2_qual);
> + break;
> +
> + default:
> + pr_warn("%s: unsupported delivery system: %u\n",
> + __func__,
> + c->delivery_system);
> + return -EINVAL;
> + }
> +
> + for (i = 0; i <= array_size; i++) {
> + if (cnr2qual[i].modulation == c->modulation &&
> + cnr2qual[i].fec == c->fec_inner) {
> + *strength = (shift == 0) ?
> + cnr2qual[i].cnr_good :
> + (shift > 0) ?
> + cnr2qual[i].cnr_ok :
> + cnr2qual[i].cnr_ok -
> + (cnr2qual[i].cnr_good - cnr2qual[i].cnr_ok);
> + return 0;
> + }
> + }
> +
> + /* do a linear interpolation between 34dB and 10dB if we can't
> + * match against the table
> + */
> + *strength = 34 - 24 * shift / 100;
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_init(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> + struct dvb_dummy_tuner_config config = tuner_dev->config;
> +
> + msleep_interruptible(config.mock_power_up_delay_msec);
> +
> + tuner_dev->hw_state.power_status = STATUS_ACTIVE;
> + tuner_dev->hw_state.if_frequency = 5000;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_sleep(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> + struct dvb_dummy_tuner_config config = tuner_dev->config;
> +
> + msleep_interruptible(config.mock_sleep_delay_msec);
> + tuner_dev->hw_state.power_status = STATUS_ASLEEP;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_suspend(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + tuner_dev->hw_state.power_status = STATUS_ASLEEP;
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_resume(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + tuner_dev->hw_state.power_status = STATUS_ACTIVE;
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_set_params(struct dvb_frontend *fe)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> + struct dvb_dummy_tuner_config config = tuner_dev->config;
> + struct dtv_frontend_properties *c = &fe->dtv_property_cache;
> + u32 min_freq = fe->ops.tuner_ops.info.frequency_min_hz;
> + u32 max_freq = fe->ops.tuner_ops.info.frequency_max_hz;
> + u32 min_bw = fe->ops.tuner_ops.info.bandwidth_min;
> + u32 max_bw = fe->ops.tuner_ops.info.bandwidth_max;
> +
> + if (c->frequency < min_freq || c->frequency > max_freq ||
> + c->bandwidth_hz < min_bw || c->bandwidth_hz > max_bw) {
> + tuner_dev->hw_state.lock_status = STATUS_NO_LOCK;
> + return -EINVAL;
> + }
> +
> + tuner_dev->hw_state.tuned_frequency = c->frequency;
> + tuner_dev->hw_state.bandwidth = c->bandwidth_hz;
> + tuner_dev->hw_state.lock_status = STATUS_LOCKED;
> +
> + msleep_interruptible(config.mock_tune_delay_msec);
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_set_config(struct dvb_frontend *fe,
> + void *priv_cfg)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + memcpy(&tuner_dev->config, priv_cfg, sizeof(tuner_dev->config));
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_get_frequency(struct dvb_frontend *fe,
> + u32 *frequency)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + *frequency = tuner_dev->hw_state.tuned_frequency;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_get_bandwidth(struct dvb_frontend *fe,
> + u32 *bandwidth)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + *bandwidth = tuner_dev->hw_state.bandwidth;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_get_if_frequency(struct dvb_frontend *fe,
> + u32 *frequency)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + *frequency = tuner_dev->hw_state.if_frequency;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_get_status(struct dvb_frontend *fe, u32 *status)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = dvb_dummy_tuner_get_dev(fe);
> +
> + *status = tuner_dev->hw_state.lock_status;
> +
> + return 0;
> +}
> +
> +static const struct dvb_tuner_ops dvb_dummy_tuner_ops = {
> + .init = dvb_dummy_tuner_init,
> + .sleep = dvb_dummy_tuner_sleep,
> + .suspend = dvb_dummy_tuner_suspend,
> + .resume = dvb_dummy_tuner_resume,
> + .set_params = dvb_dummy_tuner_set_params,
> + .set_config = dvb_dummy_tuner_set_config,
> + .get_bandwidth = dvb_dummy_tuner_get_bandwidth,
> + .get_frequency = dvb_dummy_tuner_get_frequency,
> + .get_if_frequency = dvb_dummy_tuner_get_if_frequency,
> + .get_status = dvb_dummy_tuner_get_status,
> + .get_rf_strength = dvb_dummy_tuner_get_signal_strength
> +};
> +
> +static const struct i2c_device_id dvb_dummy_tuner_i2c_id_table[] = {
> + {"dvb_dummy_tuner", 0},
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, dvb_dummy_tuner_i2c_id_table);
> +
> +static int dvb_dummy_tuner_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct dvb_dummy_tuner_config *config = client->dev.platform_data;
> + struct dvb_frontend *fe = config->fe;
> + struct dvb_dummy_tuner_dev *tuner_dev = NULL;
> +
> + tuner_dev = kzalloc(sizeof(*tuner_dev), GFP_KERNEL);
> + if (!tuner_dev)
> + return -ENOMEM;
> +
> + tuner_dev->fe = config->fe;
> + i2c_set_clientdata(client, tuner_dev);
> +
> + memcpy(&fe->ops.tuner_ops,
> + &dvb_dummy_tuner_ops,
> + sizeof(struct dvb_tuner_ops));
> +
> + fe->tuner_priv = client;
> +
> + return 0;
> +}
> +
> +static int dvb_dummy_tuner_i2c_remove(struct i2c_client *client)
> +{
> + struct dvb_dummy_tuner_dev *tuner_dev = i2c_get_clientdata(client);
> + struct dvb_frontend *fe = tuner_dev->fe;
> +
> + memset(&fe->ops.tuner_ops, 0, sizeof(struct dvb_tuner_ops));
> + fe->tuner_priv = NULL;
> + kfree(tuner_dev);
> +
> + return 0;
> +}
> +
> +static struct i2c_driver dvb_dummy_tuner_i2c_driver = {
> + .driver = {
> + .name = "dvb_dummy_tuner",
> + .suppress_bind_attrs = true,
> + },
> + .probe = dvb_dummy_tuner_i2c_probe,
> + .remove = dvb_dummy_tuner_i2c_remove,
> + .id_table = dvb_dummy_tuner_i2c_id_table,
> +};
> +module_i2c_driver(dvb_dummy_tuner_i2c_driver);
> +
> +MODULE_DESCRIPTION("DVB Dummy Tuner");
> +MODULE_AUTHOR("Daniel W. S. Almeida");
> +MODULE_LICENSE("GPL");
> --
> 2.25.2
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