1 .. SPDX-License-Identifier: GPL-2.0
2
3 .. include:: <isonum.txt>
4
5 The Silicon Labs Si4713 FM Radio Transmitter D
6 ==============================================
7
8 Copyright |copy| 2009 Nokia Corporation
9
10 Contact: Eduardo Valentin <eduardo.valentin@nok
11
12
13 Information about the Device
14 ----------------------------
15
16 This chip is a Silicon Labs product. It is a I
17 Basically, it has transmission and signal nois
18
19 The Si4713 integrates transmit functions for F
20 The chip also allows integrated receive power
21 power FM channels.
22
23 The chip is programmed using commands and resp
24 properties which can change the behavior of th
25
26 Users must comply with local regulations on ra
27
28 Device driver description
29 -------------------------
30
31 There are two modules to handle this device. O
32 and the other is a platform driver.
33
34 The I2C device driver exports a v4l2-subdev in
35 All properties can also be accessed by v4l2 ex
36 using the v4l2-subdev calls (g_ext_ctrls, s_ex
37
38 The platform device driver exports a v4l2 radi
39 So, it uses the I2C device driver as a sub dev
40 commands to the actual device. Basically it is
41
42 Applications can use v4l2 radio API to specify
43 etc. But mostly of its properties will be pres
44
45 When the v4l2 mute property is set to 1 (true)
46
47 Properties description
48 ----------------------
49
50 The properties can be accessed using v4l2 exte
51 Here is an output from v4l2-ctl util:
52
53 .. code-block:: none
54
55 / # v4l2-ctl -d /dev/radio0 --all -L
56 Driver Info:
57 Driver name : radio-si4713
58 Card type : Silicon Labs S
59 Bus info :
60 Driver version: 0
61 Capabilities : 0x00080800
62 RDS Output
63 Modulator
64 Audio output: 0 (FM Modulator Audio Ou
65 Frequency: 1408000 (88.000000 MHz)
66 Video Standard = 0x00000000
67 Modulator:
68 Name : FM Modu
69 Capabilities : 62.5 Hz
70 Frequency range : 76.0 MH
71 Subchannel modulation: stereo+
72
73 User Controls
74
75 mute (bool) :
76
77 FM Radio Modulator Controls
78
79 rds_signal_deviation (int) :
80 rds_program_id (int)
81 rds_program_type (int) : min=
82 rds_ps_name (str) : m
83 rds_radio_text (str)
84 audio_limiter_feature_enabled (bool) :
85 audio_limiter_release_time (int) : mi
86 audio_limiter_deviation (int)
87 audio_compression_feature_enabl (bool)
88 audio_compression_gain (int)
89 audio_compression_threshold (int) : m
90 audio_compression_attack_time (int) :
91 audio_compression_release_time (int)
92 pilot_tone_feature_enabled (bool) : de
93 pilot_tone_deviation (int) :
94 pilot_tone_frequency (int) :
95 pre_emphasis_settings (menu) :
96 tune_power_level (int) : min=
97 tune_antenna_capacitor (int)
98
99 Here is a summary of them:
100
101 * Pilot is an audible tone sent by the device.
102
103 - pilot_frequency - Configures the frequency o
104 - pilot_deviation - Configures pilot tone freq
105 - pilot_enabled - Enables or disables the pilo
106
107 * The si4713 device is capable of applying aud
108 transmitted signal.
109
110 - acomp_enabled - Enables or disables the audi
111 - acomp_gain - Sets the gain for audio dynamic
112 - acomp_threshold - Sets the threshold level f
113 - acomp_attack_time - Sets the attack time for
114 - acomp_release_time - Sets the release time f
115
116 * Limiter setups audio deviation limiter featu
117 it is possible to adjust the front-end gain
118 prevent over deviation.
119
120 - limiter_enabled - Enables or disables the li
121 - limiter_deviation - Configures audio frequen
122 - limiter_release_time - Sets the limiter rele
123
124 * Tuning power
125
126 - power_level - Sets the output power level fo
127 antenna_capacitor - This selects the value o
128 manually or automatically if set to zero.
129
130 * RDS related
131
132 - rds_ps_name - Sets the RDS ps name field for
133 - rds_radio_text - Sets the RDS radio text for
134 - rds_pi - Sets the RDS PI field for transmiss
135 - rds_pty - Sets the RDS PTY field for transmi
136
137 * Region related
138
139 - preemphasis - sets the preemphasis to be app
140
141 RNL
142 ---
143
144 This device also has an interface to measure r
145 ioctl the device node. Here is an code of exam
146
147 .. code-block:: none
148
149 int main (int argc, char *argv[])
150 {
151 struct si4713_rnl rnl;
152 int fd = open("/dev/radio0", O
153 int rval;
154
155 if (argc < 2)
156 return -EINVAL;
157
158 if (fd < 0)
159 return fd;
160
161 sscanf(argv[1], "%d", &rnl.fre
162
163 rval = ioctl(fd, SI4713_IOC_ME
164 if (rval < 0)
165 return rval;
166
167 printf("received noise level:
168
169 close(fd);
170 }
171
172 The struct si4713_rnl and SI4713_IOC_MEASURE_R
173 include/linux/platform_data/media/si4713.h.
174
175 Stereo/Mono and RDS subchannels
176 -------------------------------
177
178 The device can also be configured using the av
179 transmission. To do that use S/G_MODULATOR ioc
180 Refer to the V4L2 API specification for proper
181
182 Testing
183 -------
184 Testing is usually done with v4l2-ctl utility
185 The tool can be found in v4l-dvb repository un
186
187 Example for setting rds ps name:
188
189 .. code-block:: none
190
191 # v4l2-ctl -d /dev/radio0 --set-ctrl=r
192
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