-Driver for I2C radios for the Silicon Labs Si4713 FM Radio Transmitters
+.. include:: <isonum.txt>
+
+The Silicon Labs Si4713 FM Radio Transmitter Driver
+===================================================
+
+Copyright |copy| 2009 Nokia Corporation
-Copyright (c) 2009 Nokia Corporation
Contact: Eduardo Valentin <eduardo.valentin@nokia.com>
Information about the Device
-============================
+----------------------------
+
This chip is a Silicon Labs product. It is a I2C device, currently on 0x63 address.
Basically, it has transmission and signal noise level measurement features.
Users must comply with local regulations on radio frequency (RF) transmission.
Device driver description
-=========================
+-------------------------
+
There are two modules to handle this device. One is a I2C device driver
and the other is a platform driver.
When the v4l2 mute property is set to 1 (true), the driver will turn the chip off.
Properties description
-======================
+----------------------
The properties can be accessed using v4l2 extended controls.
Here is an output from v4l2-ctl util:
-/ # v4l2-ctl -d /dev/radio0 --all -L
-Driver Info:
- Driver name : radio-si4713
- Card type : Silicon Labs Si4713 Modulator
- Bus info :
- Driver version: 0
- Capabilities : 0x00080800
- RDS Output
- Modulator
-Audio output: 0 (FM Modulator Audio Out)
-Frequency: 1408000 (88.000000 MHz)
-Video Standard = 0x00000000
-Modulator:
- Name : FM Modulator
- Capabilities : 62.5 Hz stereo rds
- Frequency range : 76.0 MHz - 108.0 MHz
- Subchannel modulation: stereo+rds
-
-User Controls
-
- mute (bool) : default=1 value=0
-
-FM Radio Modulator Controls
-
- rds_signal_deviation (int) : min=0 max=90000 step=10 default=200 value=200 flags=slider
- rds_program_id (int) : min=0 max=65535 step=1 default=0 value=0
- rds_program_type (int) : min=0 max=31 step=1 default=0 value=0
- rds_ps_name (str) : min=0 max=96 step=8 value='si4713 '
- rds_radio_text (str) : min=0 max=384 step=32 value=''
- audio_limiter_feature_enabled (bool) : default=1 value=1
- audio_limiter_release_time (int) : min=250 max=102390 step=50 default=5010 value=5010 flags=slider
- audio_limiter_deviation (int) : min=0 max=90000 step=10 default=66250 value=66250 flags=slider
-audio_compression_feature_enabl (bool) : default=1 value=1
- audio_compression_gain (int) : min=0 max=20 step=1 default=15 value=15 flags=slider
- audio_compression_threshold (int) : min=-40 max=0 step=1 default=-40 value=-40 flags=slider
- audio_compression_attack_time (int) : min=0 max=5000 step=500 default=0 value=0 flags=slider
- audio_compression_release_time (int) : min=100000 max=1000000 step=100000 default=1000000 value=1000000 flags=slider
- pilot_tone_feature_enabled (bool) : default=1 value=1
- pilot_tone_deviation (int) : min=0 max=90000 step=10 default=6750 value=6750 flags=slider
- pilot_tone_frequency (int) : min=0 max=19000 step=1 default=19000 value=19000 flags=slider
- pre_emphasis_settings (menu) : min=0 max=2 default=1 value=1
- tune_power_level (int) : min=0 max=120 step=1 default=88 value=88 flags=slider
- tune_antenna_capacitor (int) : min=0 max=191 step=1 default=0 value=110 flags=slider
-/ #
+
+.. code-block:: none
+
+ / # v4l2-ctl -d /dev/radio0 --all -L
+ Driver Info:
+ Driver name : radio-si4713
+ Card type : Silicon Labs Si4713 Modulator
+ Bus info :
+ Driver version: 0
+ Capabilities : 0x00080800
+ RDS Output
+ Modulator
+ Audio output: 0 (FM Modulator Audio Out)
+ Frequency: 1408000 (88.000000 MHz)
+ Video Standard = 0x00000000
+ Modulator:
+ Name : FM Modulator
+ Capabilities : 62.5 Hz stereo rds
+ Frequency range : 76.0 MHz - 108.0 MHz
+ Subchannel modulation: stereo+rds
+
+ User Controls
+
+ mute (bool) : default=1 value=0
+
+ FM Radio Modulator Controls
+
+ rds_signal_deviation (int) : min=0 max=90000 step=10 default=200 value=200 flags=slider
+ rds_program_id (int) : min=0 max=65535 step=1 default=0 value=0
+ rds_program_type (int) : min=0 max=31 step=1 default=0 value=0
+ rds_ps_name (str) : min=0 max=96 step=8 value='si4713 '
+ rds_radio_text (str) : min=0 max=384 step=32 value=''
+ audio_limiter_feature_enabled (bool) : default=1 value=1
+ audio_limiter_release_time (int) : min=250 max=102390 step=50 default=5010 value=5010 flags=slider
+ audio_limiter_deviation (int) : min=0 max=90000 step=10 default=66250 value=66250 flags=slider
+ audio_compression_feature_enabl (bool) : default=1 value=1
+ audio_compression_gain (int) : min=0 max=20 step=1 default=15 value=15 flags=slider
+ audio_compression_threshold (int) : min=-40 max=0 step=1 default=-40 value=-40 flags=slider
+ audio_compression_attack_time (int) : min=0 max=5000 step=500 default=0 value=0 flags=slider
+ audio_compression_release_time (int) : min=100000 max=1000000 step=100000 default=1000000 value=1000000 flags=slider
+ pilot_tone_feature_enabled (bool) : default=1 value=1
+ pilot_tone_deviation (int) : min=0 max=90000 step=10 default=6750 value=6750 flags=slider
+ pilot_tone_frequency (int) : min=0 max=19000 step=1 default=19000 value=19000 flags=slider
+ pre_emphasis_settings (menu) : min=0 max=2 default=1 value=1
+ tune_power_level (int) : min=0 max=120 step=1 default=88 value=88 flags=slider
+ tune_antenna_capacitor (int) : min=0 max=191 step=1 default=0 value=110 flags=slider
Here is a summary of them:
* Pilot is an audible tone sent by the device.
-pilot_frequency - Configures the frequency of the stereo pilot tone.
-pilot_deviation - Configures pilot tone frequency deviation level.
-pilot_enabled - Enables or disables the pilot tone feature.
+- pilot_frequency - Configures the frequency of the stereo pilot tone.
+- pilot_deviation - Configures pilot tone frequency deviation level.
+- pilot_enabled - Enables or disables the pilot tone feature.
-* The si4713 device is capable of applying audio compression to the transmitted signal.
+* The si4713 device is capable of applying audio compression to the
+ transmitted signal.
-acomp_enabled - Enables or disables the audio dynamic range control feature.
-acomp_gain - Sets the gain for audio dynamic range control.
-acomp_threshold - Sets the threshold level for audio dynamic range control.
-acomp_attack_time - Sets the attack time for audio dynamic range control.
-acomp_release_time - Sets the release time for audio dynamic range control.
+- acomp_enabled - Enables or disables the audio dynamic range control feature.
+- acomp_gain - Sets the gain for audio dynamic range control.
+- acomp_threshold - Sets the threshold level for audio dynamic range control.
+- acomp_attack_time - Sets the attack time for audio dynamic range control.
+- acomp_release_time - Sets the release time for audio dynamic range control.
* Limiter setups audio deviation limiter feature. Once a over deviation occurs,
-it is possible to adjust the front-end gain of the audio input and always
-prevent over deviation.
+ it is possible to adjust the front-end gain of the audio input and always
+ prevent over deviation.
-limiter_enabled - Enables or disables the limiter feature.
-limiter_deviation - Configures audio frequency deviation level.
-limiter_release_time - Sets the limiter release time.
+- limiter_enabled - Enables or disables the limiter feature.
+- limiter_deviation - Configures audio frequency deviation level.
+- limiter_release_time - Sets the limiter release time.
* Tuning power
-power_level - Sets the output power level for signal transmission.
-antenna_capacitor - This selects the value of antenna tuning capacitor manually
-or automatically if set to zero.
+- power_level - Sets the output power level for signal transmission.
+ antenna_capacitor - This selects the value of antenna tuning capacitor
+ manually or automatically if set to zero.
* RDS related
-rds_ps_name - Sets the RDS ps name field for transmission.
-rds_radio_text - Sets the RDS radio text for transmission.
-rds_pi - Sets the RDS PI field for transmission.
-rds_pty - Sets the RDS PTY field for transmission.
+- rds_ps_name - Sets the RDS ps name field for transmission.
+- rds_radio_text - Sets the RDS radio text for transmission.
+- rds_pi - Sets the RDS PI field for transmission.
+- rds_pty - Sets the RDS PTY field for transmission.
* Region related
-preemphasis - sets the preemphasis to be applied for transmission.
+- preemphasis - sets the preemphasis to be applied for transmission.
RNL
-===
+---
This device also has an interface to measure received noise level. To do that, you should
ioctl the device node. Here is an code of example:
-int main (int argc, char *argv[])
-{
- struct si4713_rnl rnl;
- int fd = open("/dev/radio0", O_RDWR);
- int rval;
+.. code-block:: none
+
+ int main (int argc, char *argv[])
+ {
+ struct si4713_rnl rnl;
+ int fd = open("/dev/radio0", O_RDWR);
+ int rval;
- if (argc < 2)
- return -EINVAL;
+ if (argc < 2)
+ return -EINVAL;
- if (fd < 0)
- return fd;
+ if (fd < 0)
+ return fd;
- sscanf(argv[1], "%d", &rnl.frequency);
+ sscanf(argv[1], "%d", &rnl.frequency);
- rval = ioctl(fd, SI4713_IOC_MEASURE_RNL, &rnl);
- if (rval < 0)
- return rval;
+ rval = ioctl(fd, SI4713_IOC_MEASURE_RNL, &rnl);
+ if (rval < 0)
+ return rval;
- printf("received noise level: %d\n", rnl.rnl);
+ printf("received noise level: %d\n", rnl.rnl);
- close(fd);
-}
+ close(fd);
+ }
The struct si4713_rnl and SI4713_IOC_MEASURE_RNL are defined under
include/linux/platform_data/media/si4713.h.
Stereo/Mono and RDS subchannels
-===============================
+-------------------------------
The device can also be configured using the available sub channels for
transmission. To do that use S/G_MODULATOR ioctl and configure txsubchans properly.
Refer to the V4L2 API specification for proper use of this ioctl.
Testing
-=======
+-------
Testing is usually done with v4l2-ctl utility for managing FM tuner cards.
The tool can be found in v4l-dvb repository under v4l2-apps/util directory.
Example for setting rds ps name:
-# v4l2-ctl -d /dev/radio0 --set-ctrl=rds_ps_name="Dummy"
+
+.. code-block:: none
+
+ # v4l2-ctl -d /dev/radio0 --set-ctrl=rds_ps_name="Dummy"
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