1 Renesas R-Car sound
2
3 =============================================
4 * Modules
5 =============================================
6
7 Renesas R-Car and RZ/G sound is constructed from below modules
8 (for Gen2 or later)
9
10 SCU : Sampling Rate Converter Unit
11 - SRC : Sampling Rate Converter
12 - CMD
13 - CTU : Channel Transfer Unit
14 - MIX : Mixer
15 - DVC : Digital Volume and Mute Function
16 SSIU : Serial Sound Interface Unit
17 SSI : Serial Sound Interface
18
19 See detail of each module's channels, connection, limitation on datasheet
20
21 =============================================
22 * Multi channel
23 =============================================
24
25 Multi channel is supported by Multi-SSI, or TDM-SSI.
26
27 Multi-SSI : 6ch case, you can use stereo x 3 SSI
28 TDM-SSI : 6ch case, you can use TDM
29
30 =============================================
31 * Enable/Disable each modules
32 =============================================
33
34 See datasheet to check SRC/CTU/MIX/DVC connect-limitation.
35 DT controls enabling/disabling module.
36 ${LINUX}/arch/arm/boot/dts/r8a7790-lager.dts can be good example.
37 This is example of
38
39 Playback: [MEM] -> [SRC2] -> [DVC0] -> [SSIU0/SSI0] -> [codec]
40 Capture: [MEM] <- [DVC1] <- [SRC3] <- [SSIU1/SSI1] <- [codec]
41
42 see "Example: simple sound card"
43
44 You can use below.
45 ${LINUX}/arch/arm/boot/dts/r8a7790.dts can be good example.
46
47 &src0 &ctu00 &mix0 &dvc0 &ssi0
48 &src1 &ctu01 &mix1 &dvc1 &ssi1
49 &src2 &ctu02 &ssi2
50 &src3 &ctu03 &ssi3
51 &src4 &ssi4
52 &src5 &ctu10 &ssi5
53 &src6 &ctu11 &ssi6
54 &src7 &ctu12 &ssi7
55 &src8 &ctu13 &ssi8
56 &src9 &ssi9
57
58 =============================================
59 * SRC (Sampling Rate Converter)
60 =============================================
61
62 [xx]Hz [yy]Hz
63 ------> [SRC] ------>
64
65 SRC can convert [xx]Hz to [yy]Hz. Then, it has below 2 modes
66
67 Asynchronous mode: input data / output data are based on different clocks.
68 you can use this mode on Playback / Capture
69 Synchronous mode: input data / output data are based on same clocks.
70 This mode will be used if system doesn't have its input clock,
71 for example digital TV case.
72 you can use this mode on Playback
73
74 ------------------
75 ** Asynchronous mode
76 ------------------
77
78 You need to use "simple-scu-audio-card" or "audio-graph-scu-card" for it.
79 see "Example: simple sound card for Asynchronous mode"
80
81 ------------------
82 ** Synchronous mode
83 ------------------
84
85 > amixer set "SRC Out Rate" on
86 > aplay xxxx.wav
87 > amixer set "SRC Out Rate" 48000
88 > amixer set "SRC Out Rate" 44100
89
90 =============================================
91 * CTU (Channel Transfer Unit)
92 =============================================
93
94 [xx]ch [yy]ch
95 ------> [CTU] -------->
96
97 CTU can convert [xx]ch to [yy]ch, or exchange outputted channel.
98 CTU conversion needs matrix settings.
99 For more detail information, see below
100
101 Renesas R-Car datasheet
102 - Sampling Rate Converter Unit (SCU)
103 - SCU Operation
104 - CMD Block
105 - Functional Blocks in CMD
106
107 Renesas R-Car datasheet
108 - Sampling Rate Converter Unit (SCU)
109 - Register Description
110 - CTUn Scale Value exx Register (CTUn_SVxxR)
111
112 ${LINUX}/sound/soc/sh/rcar/ctu.c
113 - comment of header
114
115 You need to use "simple-scu-audio-card" or "audio-graph-scu-card" for it.
116 see "Example: simple sound card for channel convert"
117
118 Ex) Exchange output channel
119 Input -> Output
120 1ch -> 0ch
121 0ch -> 1ch
122
123 example of using matrix
124 output 0ch = (input 0ch x 0) + (input 1ch x 1)
125 output 1ch = (input 0ch x 1) + (input 1ch x 0)
126
127 amixer set "CTU Reset" on
128 amixer set "CTU Pass" 9,10
129 amixer set "CTU SV0" 0,4194304
130 amixer set "CTU SV1" 4194304,0
131
132 example of changing connection
133 amixer set "CTU Reset" on
134 amixer set "CTU Pass" 2,1
135
136 =============================================
137 * MIX (Mixer)
138 =============================================
139
140 MIX merges 2 sounds path. You can see 2 sound interface on system,
141 and these sounds will be merged by MIX.
142
143 aplay -D plughw:0,0 xxxx.wav &
144 aplay -D plughw:0,1 yyyy.wav
145
146 You need to use "simple-scu-audio-card" or "audio-graph-scu-card" for it.
147 Ex)
148 [MEM] -> [SRC1] -> [CTU02] -+-> [MIX0] -> [DVC0] -> [SSI0]
149 |
150 [MEM] -> [SRC2] -> [CTU03] -+
151
152 see "Example: simple sound card for MIXer"
153
154 =============================================
155 * DVC (Digital Volume and Mute Function)
156 =============================================
157
158 DVC controls Playback/Capture volume.
159
160 Playback Volume
161 amixer set "DVC Out" 100%
162
163 Capture Volume
164 amixer set "DVC In" 100%
165
166 Playback Mute
167 amixer set "DVC Out Mute" on
168
169 Capture Mute
170 amixer set "DVC In Mute" on
171
172 Volume Ramp
173 amixer set "DVC Out Ramp Up Rate" "0.125 dB/64 steps"
174 amixer set "DVC Out Ramp Down Rate" "0.125 dB/512 steps"
175 amixer set "DVC Out Ramp" on
176 aplay xxx.wav &
177 amixer set "DVC Out" 80% // Volume Down
178 amixer set "DVC Out" 100% // Volume Up
179
180 =============================================
181 * SSIU (Serial Sound Interface Unit)
182 =============================================
183
184 SSIU can avoid some under/over run error, because it has some buffer.
185 But you can't use it if SSI was PIO mode.
186 In DMA mode, you can select not to use SSIU by using "no-busif" via SSI.
187
188 SSIU handles BUSIF which will be used for TDM Split mode.
189 This driver is assuming that audio-graph card will be used.
190
191 TDM Split mode merges 4 sounds. You can see 4 sound interface on system,
192 and these sounds will be merged SSIU/SSI.
193
194 aplay -D plughw:0,0 xxxx.wav &
195 aplay -D plughw:0,1 xxxx.wav &
196 aplay -D plughw:0,2 xxxx.wav &
197 aplay -D plughw:0,3 xxxx.wav
198
199 2ch 8ch
200 [MEM] -> [SSIU 30] -+-> [SSIU 3] --> [Codec]
201 2ch |
202 [MEM] -> [SSIU 31] -+
203 2ch |
204 [MEM] -> [SSIU 32] -+
205 2ch |
206 [MEM] -> [SSIU 33] -+
207
208 see "Example: simple sound card for TDM Split"
209
210 =============================================
211 * SSI (Serial Sound Interface)
212 =============================================
213
214 ** PIO mode
215
216 You can use PIO mode which is for connection check by using.
217 Note: The system will drop non-SSI modules in PIO mode
218 even though if DT is selecting other modules.
219
220 &ssi0 {
221 pio-transfer
222 };
223
224 ** DMA mode without SSIU
225
226 You can use DMA without SSIU.
227 Note: under/over run, or noise are likely to occur
228
229 &ssi0 {
230 no-busif;
231 };
232
233 ** PIN sharing
234
235 Each SSI can share WS pin. It is based on platform.
236 This is example if SSI1 want to share WS pin with SSI0
237
238 &ssi1 {
239 shared-pin;
240 };
241
242 ** Multi-SSI
243
244 You can use Multi-SSI.
245 This is example of SSI0/SSI1/SSI2 (= for 6ch)
246
247 see "Example: simple sound card for Multi channel"
248
249 ** TDM-SSI
250
251 You can use TDM with SSI.
252 This is example of TDM 6ch.
253 Driver can automatically switches TDM <-> stereo mode in this case.
254
255 see "Example: simple sound card for TDM"
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