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-rw-r--r--Documentation/sound/alsa/ALSA-Configuration.txt6
-rw-r--r--Documentation/sound/alsa/Audiophile-Usb.txt2
-rw-r--r--Documentation/sound/alsa/CMIPCI.txt2
-rw-r--r--Documentation/sound/alsa/HD-Audio-Models.txt58
-rw-r--r--Documentation/sound/alsa/HD-Audio.txt2
-rw-r--r--Documentation/sound/alsa/README.maya442
-rw-r--r--Documentation/sound/alsa/compress_offload.txt10
-rw-r--r--Documentation/sound/alsa/soc/DPCM.txt380
-rw-r--r--Documentation/sound/alsa/soc/codec.txt46
-rw-r--r--Documentation/sound/alsa/soc/dapm.txt73
-rw-r--r--Documentation/sound/alsa/soc/machine.txt6
-rw-r--r--Documentation/sound/alsa/soc/overview.txt27
-rw-r--r--Documentation/sound/alsa/soc/platform.txt19
-rw-r--r--Documentation/sound/oss/vwsnd293
14 files changed, 525 insertions, 401 deletions
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 95731a08f25..7ccf933bfbe 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -616,7 +616,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
As default, snd-dummy drivers doesn't allocate the real buffers
but either ignores read/write or mmap a single dummy page to all
- buffer pages, in order to save the resouces. If your apps need
+ buffer pages, in order to save the resources. If your apps need
the read/ written buffer data to be consistent, pass fake_buffer=0
option.
@@ -948,7 +948,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
avoided as much as possible...
MORE NOTES ON "azx_get_response timeout" PROBLEMS:
- On some hardwares, you may need to add a proper probe_mask option
+ On some hardware, you may need to add a proper probe_mask option
to avoid the "azx_get_response timeout" problem above, instead.
This occurs when the access to non-existing or non-working codec slot
(likely a modem one) causes a stall of the communication via HD-audio
@@ -1124,7 +1124,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
buggy_irq - Enable workaround for buggy interrupts on some
motherboards (default yes on nForce chips,
otherwise off)
- buggy_semaphore - Enable workaround for hardwares with buggy
+ buggy_semaphore - Enable workaround for hardware with buggy
semaphores (e.g. on some ASUS laptops)
(default off)
spdif_aclink - Use S/PDIF over AC-link instead of direct connection
diff --git a/Documentation/sound/alsa/Audiophile-Usb.txt b/Documentation/sound/alsa/Audiophile-Usb.txt
index 654dd3b694a..e7a5ed4dcae 100644
--- a/Documentation/sound/alsa/Audiophile-Usb.txt
+++ b/Documentation/sound/alsa/Audiophile-Usb.txt
@@ -232,7 +232,7 @@ The parameter can be given:
# modprobe snd-usb-audio index=1 device_setup=0x09
* Or while configuring the modules options in your modules configuration file
- (tipically a .conf file in /etc/modprobe.d/ directory:
+ (typically a .conf file in /etc/modprobe.d/ directory:
alias snd-card-1 snd-usb-audio
options snd-usb-audio index=1 device_setup=0x09
diff --git a/Documentation/sound/alsa/CMIPCI.txt b/Documentation/sound/alsa/CMIPCI.txt
index 16935c8561f..4e36e6e809c 100644
--- a/Documentation/sound/alsa/CMIPCI.txt
+++ b/Documentation/sound/alsa/CMIPCI.txt
@@ -87,7 +87,7 @@ with 4 channels,
and use the interleaved 4 channel data.
-There are some control switchs affecting to the speaker connections:
+There are some control switches affecting to the speaker connections:
"Line-In Mode" - an enum control to change the behavior of line-in
jack. Either "Line-In", "Rear Output" or "Bass Output" can
diff --git a/Documentation/sound/alsa/HD-Audio-Models.txt b/Documentation/sound/alsa/HD-Audio-Models.txt
index bb8b0dc532b..d1ab5e17eb1 100644
--- a/Documentation/sound/alsa/HD-Audio-Models.txt
+++ b/Documentation/sound/alsa/HD-Audio-Models.txt
@@ -21,38 +21,42 @@ ALC267/268
==========
inv-dmic Inverted internal mic workaround
-ALC269/270/275/276/280/282
+ALC269/270/275/276/28x/29x
======
- laptop-amic Laptops with analog-mic input
- laptop-dmic Laptops with digital-mic input
- alc269-dmic Enable ALC269(VA) digital mic workaround
- alc271-dmic Enable ALC271X digital mic workaround
- inv-dmic Inverted internal mic workaround
- lenovo-dock Enables docking station I/O for some Lenovos
-
-ALC662/663/272
+ laptop-amic Laptops with analog-mic input
+ laptop-dmic Laptops with digital-mic input
+ alc269-dmic Enable ALC269(VA) digital mic workaround
+ alc271-dmic Enable ALC271X digital mic workaround
+ inv-dmic Inverted internal mic workaround
+ headset-mic Indicates a combined headset (headphone+mic) jack
+ lenovo-dock Enables docking station I/O for some Lenovos
+ dell-headset-multi Headset jack, which can also be used as mic-in
+ dell-headset-dock Headset jack (without mic-in), and also dock I/O
+
+ALC66x/67x/892
==============
- mario Chromebook mario model fixup
- asus-mode1 ASUS
- asus-mode2 ASUS
- asus-mode3 ASUS
- asus-mode4 ASUS
- asus-mode5 ASUS
- asus-mode6 ASUS
- asus-mode7 ASUS
- asus-mode8 ASUS
- inv-dmic Inverted internal mic workaround
+ mario Chromebook mario model fixup
+ asus-mode1 ASUS
+ asus-mode2 ASUS
+ asus-mode3 ASUS
+ asus-mode4 ASUS
+ asus-mode5 ASUS
+ asus-mode6 ASUS
+ asus-mode7 ASUS
+ asus-mode8 ASUS
+ inv-dmic Inverted internal mic workaround
+ dell-headset-multi Headset jack, which can also be used as mic-in
ALC680
======
N/A
-ALC882/883/885/888/889
+ALC88x/898/1150
======================
acer-aspire-4930g Acer Aspire 4930G/5930G/6530G/6930G/7730G
acer-aspire-8930g Acer Aspire 8330G/6935G
acer-aspire Acer Aspire others
- inv-dmic Inverted internal mic workaround
+ inv-dmic Inverted internal mic workaround
no-primary-hp VAIO Z/VGC-LN51JGB workaround (for fixed speaker DAC)
ALC861/660
@@ -241,6 +245,7 @@ STAC9227/9228/9229/927x
5stack-no-fp D965 5stack without front panel
dell-3stack Dell Dimension E520
dell-bios Fixes with Dell BIOS setup
+ dell-bios-amic Fixes with Dell BIOS setup including analog mic
volknob Fixes with volume-knob widget 0x24
auto BIOS setup (default)
@@ -281,6 +286,11 @@ STAC92HD83*
hp-inv-led HP with broken BIOS for inverted mute LED
auto BIOS setup (default)
+STAC92HD95
+==========
+ hp-led LED support for HP laptops
+ hp-bass Bass HPF setup for HP Spectre 13
+
STAC9872
========
vaio VAIO laptop without SPDIF
@@ -292,6 +302,12 @@ Cirrus Logic CS4206/4207
imac27 IMac 27 Inch
auto BIOS setup (default)
+Cirrus Logic CS4208
+===================
+ mba6 MacBook Air 6,1 and 6,2
+ gpio0 Enable GPIO 0 amp
+ auto BIOS setup (default)
+
VIA VT17xx/VT18xx/VT20xx
========================
auto BIOS setup (default)
diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt
index c3c912d023c..42a0a39b77e 100644
--- a/Documentation/sound/alsa/HD-Audio.txt
+++ b/Documentation/sound/alsa/HD-Audio.txt
@@ -454,6 +454,8 @@ The generic parser supports the following hints:
- need_dac_fix (bool): limits the DACs depending on the channel count
- primary_hp (bool): probe headphone jacks as the primary outputs;
default true
+- multi_io (bool): try probing multi-I/O config (e.g. shared
+ line-in/surround, mic/clfe jacks)
- multi_cap_vol (bool): provide multiple capture volumes
- inv_dmic_split (bool): provide split internal mic volume/switch for
phase-inverted digital mics
diff --git a/Documentation/sound/alsa/README.maya44 b/Documentation/sound/alsa/README.maya44
index 0e41576fa13..67b2ea1cc31 100644
--- a/Documentation/sound/alsa/README.maya44
+++ b/Documentation/sound/alsa/README.maya44
@@ -120,7 +120,7 @@ Mic Phantom+48V: switch for +48V phantom power for electrostatic microphones on
Make sure this is not turned on while any other source is connected to input 1/2.
It might damage the source and/or the maya44 card.
-Mic/Line input: if switch is is on, input jack 1/2 is microphone input (mono), otherwise line input (stereo).
+Mic/Line input: if switch is on, input jack 1/2 is microphone input (mono), otherwise line input (stereo).
Bypass: analogue bypass from ADC input to output for channel 1+2. Same as "Monitor" in the windows driver.
Bypass 1: same for channel 3+4.
diff --git a/Documentation/sound/alsa/compress_offload.txt b/Documentation/sound/alsa/compress_offload.txt
index 0bcc5515591..630c492c3dc 100644
--- a/Documentation/sound/alsa/compress_offload.txt
+++ b/Documentation/sound/alsa/compress_offload.txt
@@ -73,7 +73,7 @@ The main requirements are:
Design
-The new API shares a number of concepts with with the PCM API for flow
+The new API shares a number of concepts with the PCM API for flow
control. Start, pause, resume, drain and stop commands have the same
semantics no matter what the content is.
@@ -130,7 +130,7 @@ the settings should remain the exception.
The timestamp becomes a multiple field structure. It lists the number
of bytes transferred, the number of samples processed and the number
of samples rendered/grabbed. All these values can be used to determine
-the avarage bitrate, figure out if the ring buffer needs to be
+the average bitrate, figure out if the ring buffer needs to be
refilled or the delay due to decoding/encoding/io on the DSP.
Note that the list of codecs/profiles/modes was derived from the
@@ -217,12 +217,12 @@ Not supported:
would be enabled with ALSA kcontrols.
- Audio policy/resource management. This API does not provide any
- hooks to query the utilization of the audio DSP, nor any premption
+ hooks to query the utilization of the audio DSP, nor any preemption
mechanisms.
-- No notion of underun/overrun. Since the bytes written are compressed
+- No notion of underrun/overrun. Since the bytes written are compressed
in nature and data written/read doesn't translate directly to
- rendered output in time, this does not deal with underrun/overun and
+ rendered output in time, this does not deal with underrun/overrun and
maybe dealt in user-library
Credits:
diff --git a/Documentation/sound/alsa/soc/DPCM.txt b/Documentation/sound/alsa/soc/DPCM.txt
new file mode 100644
index 00000000000..0110180b7ac
--- /dev/null
+++ b/Documentation/sound/alsa/soc/DPCM.txt
@@ -0,0 +1,380 @@
+Dynamic PCM
+===========
+
+1. Description
+==============
+
+Dynamic PCM allows an ALSA PCM device to digitally route its PCM audio to
+various digital endpoints during the PCM stream runtime. e.g. PCM0 can route
+digital audio to I2S DAI0, I2S DAI1 or PDM DAI2. This is useful for on SoC DSP
+drivers that expose several ALSA PCMs and can route to multiple DAIs.
+
+The DPCM runtime routing is determined by the ALSA mixer settings in the same
+way as the analog signal is routed in an ASoC codec driver. DPCM uses a DAPM
+graph representing the DSP internal audio paths and uses the mixer settings to
+determine the patch used by each ALSA PCM.
+
+DPCM re-uses all the existing component codec, platform and DAI drivers without
+any modifications.
+
+
+Phone Audio System with SoC based DSP
+-------------------------------------
+
+Consider the following phone audio subsystem. This will be used in this
+document for all examples :-
+
+| Front End PCMs | SoC DSP | Back End DAIs | Audio devices |
+
+ *************
+PCM0 <------------> * * <----DAI0-----> Codec Headset
+ * *
+PCM1 <------------> * * <----DAI1-----> Codec Speakers
+ * DSP *
+PCM2 <------------> * * <----DAI2-----> MODEM
+ * *
+PCM3 <------------> * * <----DAI3-----> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+This diagram shows a simple smart phone audio subsystem. It supports Bluetooth,
+FM digital radio, Speakers, Headset Jack, digital microphones and cellular
+modem. This sound card exposes 4 DSP front end (FE) ALSA PCM devices and
+supports 6 back end (BE) DAIs. Each FE PCM can digitally route audio data to any
+of the BE DAIs. The FE PCM devices can also route audio to more than 1 BE DAI.
+
+
+
+Example - DPCM Switching playback from DAI0 to DAI1
+---------------------------------------------------
+
+Audio is being played to the Headset. After a while the user removes the headset
+and audio continues playing on the speakers.
+
+Playback on PCM0 to Headset would look like :-
+
+ *************
+PCM0 <============> * * <====DAI0=====> Codec Headset
+ * *
+PCM1 <------------> * * <----DAI1-----> Codec Speakers
+ * DSP *
+PCM2 <------------> * * <----DAI2-----> MODEM
+ * *
+PCM3 <------------> * * <----DAI3-----> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+The headset is removed from the jack by user so the speakers must now be used :-
+
+ *************
+PCM0 <============> * * <----DAI0-----> Codec Headset
+ * *
+PCM1 <------------> * * <====DAI1=====> Codec Speakers
+ * DSP *
+PCM2 <------------> * * <----DAI2-----> MODEM
+ * *
+PCM3 <------------> * * <----DAI3-----> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+The audio driver processes this as follows :-
+
+ 1) Machine driver receives Jack removal event.
+
+ 2) Machine driver OR audio HAL disables the Headset path.
+
+ 3) DPCM runs the PCM trigger(stop), hw_free(), shutdown() operations on DAI0
+ for headset since the path is now disabled.
+
+ 4) Machine driver or audio HAL enables the speaker path.
+
+ 5) DPCM runs the PCM ops for startup(), hw_params(), prepapre() and
+ trigger(start) for DAI1 Speakers since the path is enabled.
+
+In this example, the machine driver or userspace audio HAL can alter the routing
+and then DPCM will take care of managing the DAI PCM operations to either bring
+the link up or down. Audio playback does not stop during this transition.
+
+
+
+DPCM machine driver
+===================
+
+The DPCM enabled ASoC machine driver is similar to normal machine drivers
+except that we also have to :-
+
+ 1) Define the FE and BE DAI links.
+
+ 2) Define any FE/BE PCM operations.
+
+ 3) Define widget graph connections.
+
+
+1 FE and BE DAI links
+---------------------
+
+| Front End PCMs | SoC DSP | Back End DAIs | Audio devices |
+
+ *************
+PCM0 <------------> * * <----DAI0-----> Codec Headset
+ * *
+PCM1 <------------> * * <----DAI1-----> Codec Speakers
+ * DSP *
+PCM2 <------------> * * <----DAI2-----> MODEM
+ * *
+PCM3 <------------> * * <----DAI3-----> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+For the example above we have to define 4 FE DAI links and 6 BE DAI links. The
+FE DAI links are defined as follows :-
+
+static struct snd_soc_dai_link machine_dais[] = {
+ {
+ .name = "PCM0 System",
+ .stream_name = "System Playback",
+ .cpu_dai_name = "System Pin",
+ .platform_name = "dsp-audio",
+ .codec_name = "snd-soc-dummy",
+ .codec_dai_name = "snd-soc-dummy-dai",
+ .dynamic = 1,
+ .trigger = {SND_SOC_DPCM_TRIGGER_POST, SND_SOC_DPCM_TRIGGER_POST},
+ .dpcm_playback = 1,
+ },
+ .....< other FE and BE DAI links here >
+};
+
+This FE DAI link is pretty similar to a regular DAI link except that we also
+set the DAI link to a DPCM FE with the "dynamic = 1". The supported FE stream
+directions should also be set with the "dpcm_playback" and "dpcm_capture"
+flags. There is also an option to specify the ordering of the trigger call for
+each FE. This allows the ASoC core to trigger the DSP before or after the other
+components (as some DSPs have strong requirements for the ordering DAI/DSP
+start and stop sequences).
+
+The FE DAI above sets the codec and code DAIs to dummy devices since the BE is
+dynamic and will change depending on runtime config.
+
+The BE DAIs are configured as follows :-
+
+static struct snd_soc_dai_link machine_dais[] = {
+ .....< FE DAI links here >
+ {
+ .name = "Codec Headset",
+ .cpu_dai_name = "ssp-dai.0",
+ .platform_name = "snd-soc-dummy",
+ .no_pcm = 1,
+ .codec_name = "rt5640.0-001c",
+ .codec_dai_name = "rt5640-aif1",
+ .ignore_suspend = 1,
+ .ignore_pmdown_time = 1,
+ .be_hw_params_fixup = hswult_ssp0_fixup,
+ .ops = &haswell_ops,
+ .dpcm_playback = 1,
+ .dpcm_capture = 1,
+ },
+ .....< other BE DAI links here >
+};
+
+This BE DAI link connects DAI0 to the codec (in this case RT5460 AIF1). It sets
+the "no_pcm" flag to mark it has a BE and sets flags for supported stream
+directions using "dpcm_playback" and "dpcm_capture" above.
+
+The BE has also flags set for ignoring suspend and PM down time. This allows
+the BE to work in a hostless mode where the host CPU is not transferring data
+like a BT phone call :-
+
+ *************
+PCM0 <------------> * * <----DAI0-----> Codec Headset
+ * *
+PCM1 <------------> * * <----DAI1-----> Codec Speakers
+ * DSP *
+PCM2 <------------> * * <====DAI2=====> MODEM
+ * *
+PCM3 <------------> * * <====DAI3=====> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+This allows the host CPU to sleep whilst the DSP, MODEM DAI and the BT DAI are
+still in operation.
+
+A BE DAI link can also set the codec to a dummy device if the code is a device
+that is managed externally.
+
+Likewise a BE DAI can also set a dummy cpu DAI if the CPU DAI is managed by the
+DSP firmware.
+
+
+2 FE/BE PCM operations
+----------------------
+
+The BE above also exports some PCM operations and a "fixup" callback. The fixup
+callback is used by the machine driver to (re)configure the DAI based upon the
+FE hw params. i.e. the DSP may perform SRC or ASRC from the FE to BE.
+
+e.g. DSP converts all FE hw params to run at fixed rate of 48k, 16bit, stereo for
+DAI0. This means all FE hw_params have to be fixed in the machine driver for
+DAI0 so that the DAI is running at desired configuration regardless of the FE
+configuration.
+
+static int dai0_fixup(struct snd_soc_pcm_runtime *rtd,
+ struct snd_pcm_hw_params *params)
+{
+ struct snd_interval *rate = hw_param_interval(params,
+ SNDRV_PCM_HW_PARAM_RATE);
+ struct snd_interval *channels = hw_param_interval(params,
+ SNDRV_PCM_HW_PARAM_CHANNELS);
+
+ /* The DSP will covert the FE rate to 48k, stereo */
+ rate->min = rate->max = 48000;
+ channels->min = channels->max = 2;
+
+ /* set DAI0 to 16 bit */
+ snd_mask_set(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT -
+ SNDRV_PCM_HW_PARAM_FIRST_MASK],
+ SNDRV_PCM_FORMAT_S16_LE);
+ return 0;
+}
+
+The other PCM operation are the same as for regular DAI links. Use as necessary.
+
+
+3 Widget graph connections
+--------------------------
+
+The BE DAI links will normally be connected to the graph at initialisation time
+by the ASoC DAPM core. However, if the BE codec or BE DAI is a dummy then this
+has to be set explicitly in the driver :-
+
+/* BE for codec Headset - DAI0 is dummy and managed by DSP FW */
+{"DAI0 CODEC IN", NULL, "AIF1 Capture"},
+{"AIF1 Playback", NULL, "DAI0 CODEC OUT"},
+
+
+Writing a DPCM DSP driver
+=========================
+
+The DPCM DSP driver looks much like a standard platform class ASoC driver
+combined with elements from a codec class driver. A DSP platform driver must
+implement :-
+
+ 1) Front End PCM DAIs - i.e. struct snd_soc_dai_driver.
+
+ 2) DAPM graph showing DSP audio routing from FE DAIs to BEs.
+
+ 3) DAPM widgets from DSP graph.
+
+ 4) Mixers for gains, routing, etc.
+
+ 5) DMA configuration.
+
+ 6) BE AIF widgets.
+
+Items 6 is important for routing the audio outside of the DSP. AIF need to be
+defined for each BE and each stream direction. e.g for BE DAI0 above we would
+have :-
+
+SND_SOC_DAPM_AIF_IN("DAI0 RX", NULL, 0, SND_SOC_NOPM, 0, 0),
+SND_SOC_DAPM_AIF_OUT("DAI0 TX", NULL, 0, SND_SOC_NOPM, 0, 0),
+
+The BE AIF are used to connect the DSP graph to the graphs for the other
+component drivers (e.g. codec graph).
+
+
+Hostless PCM streams
+====================
+
+A hostless PCM stream is a stream that is not routed through the host CPU. An
+example of this would be a phone call from handset to modem.
+
+
+ *************
+PCM0 <------------> * * <----DAI0-----> Codec Headset
+ * *
+PCM1 <------------> * * <====DAI1=====> Codec Speakers/Mic
+ * DSP *
+PCM2 <------------> * * <====DAI2=====> MODEM
+ * *
+PCM3 <------------> * * <----DAI3-----> BT
+ * *
+ * * <----DAI4-----> DMIC
+ * *
+ * * <----DAI5-----> FM
+ *************
+
+In this case the PCM data is routed via the DSP. The host CPU in this use case
+is only used for control and can sleep during the runtime of the stream.
+
+The host can control the hostless link either by :-
+
+ 1) Configuring the link as a CODEC <-> CODEC style link. In this case the link
+ is enabled or disabled by the state of the DAPM graph. This usually means
+ there is a mixer control that can be used to connect or disconnect the path
+ between both DAIs.
+
+ 2) Hostless FE. This FE has a virtual connection to the BE DAI links on the DAPM
+ graph. Control is then carried out by the FE as regular PCM operations.
+ This method gives more control over the DAI links, but requires much more
+ userspace code to control the link. Its recommended to use CODEC<->CODEC
+ unless your HW needs more fine grained sequencing of the PCM ops.
+
+
+CODEC <-> CODEC link
+--------------------
+
+This DAI link is enabled when DAPM detects a valid path within the DAPM graph.
+The machine driver sets some additional parameters to the DAI link i.e.
+
+static const struct snd_soc_pcm_stream dai_params = {
+ .formats = SNDRV_PCM_FMTBIT_S32_LE,
+ .rate_min = 8000,
+ .rate_max = 8000,
+ .channels_min = 2,
+ .channels_max = 2,
+};
+
+static struct snd_soc_dai_link dais[] = {
+ < ... more DAI links above ... >
+ {
+ .name = "MODEM",
+ .stream_name = "MODEM",
+ .cpu_dai_name = "dai2",
+ .codec_dai_name = "modem-aif1",
+ .codec_name = "modem",
+ .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF
+ | SND_SOC_DAIFMT_CBM_CFM,
+ .params = &dai_params,
+ }
+ < ... more DAI links here ... >
+
+These parameters are used to configure the DAI hw_params() when DAPM detects a
+valid path and then calls the PCM operations to start the link. DAPM will also
+call the appropriate PCM operations to disable the DAI when the path is no
+longer valid.
+
+
+Hostless FE
+-----------
+
+The DAI link(s) are enabled by a FE that does not read or write any PCM data.
+This means creating a new FE that is connected with a virtual path to both
+DAI links. The DAI links will be started when the FE PCM is started and stopped
+when the FE PCM is stopped. Note that the FE PCM cannot read or write data in
+this configuration.
+
+
diff --git a/Documentation/sound/alsa/soc/codec.txt b/Documentation/sound/alsa/soc/codec.txt
index bce23a4a787..db5f9c9ae14 100644
--- a/Documentation/sound/alsa/soc/codec.txt
+++ b/Documentation/sound/alsa/soc/codec.txt
@@ -1,22 +1,23 @@
-ASoC Codec Driver
-=================
+ASoC Codec Class Driver
+=======================
-The codec driver is generic and hardware independent code that configures the
-codec to provide audio capture and playback. It should contain no code that is
-specific to the target platform or machine. All platform and machine specific
-code should be added to the platform and machine drivers respectively.
+The codec class driver is generic and hardware independent code that configures
+the codec, FM, MODEM, BT or external DSP to provide audio capture and playback.
+It should contain no code that is specific to the target platform or machine.
+All platform and machine specific code should be added to the platform and
+machine drivers respectively.
-Each codec driver *must* provide the following features:-
+Each codec class driver *must* provide the following features:-
1) Codec DAI and PCM configuration
- 2) Codec control IO - using I2C, 3 Wire(SPI) or both APIs
+ 2) Codec control IO - using RegMap API
3) Mixers and audio controls
4) Codec audio operations
+ 5) DAPM description.
+ 6) DAPM event handler.
Optionally, codec drivers can also provide:-
- 5) DAPM description.
- 6) DAPM event handler.
7) DAC Digital mute control.
Its probably best to use this guide in conjunction with the existing codec
@@ -64,26 +65,9 @@ struct snd_soc_dai_driver wm8731_dai = {
2 - Codec control IO
--------------------
The codec can usually be controlled via an I2C or SPI style interface
-(AC97 combines control with data in the DAI). The codec drivers provide
-functions to read and write the codec registers along with supplying a
-register cache:-
-
- /* IO control data and register cache */
- void *control_data; /* codec control (i2c/3wire) data */
- void *reg_cache;
-
-Codec read/write should do any data formatting and call the hardware
-read write below to perform the IO. These functions are called by the
-core and ALSA when performing DAPM or changing the mixer:-
-
- unsigned int (*read)(struct snd_soc_codec *, unsigned int);
- int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
-
-Codec hardware IO functions - usually points to either the I2C, SPI or AC97
-read/write:-
-
- hw_write_t hw_write;
- hw_read_t hw_read;
+(AC97 combines control with data in the DAI). The codec driver should use the
+Regmap API for all codec IO. Please see include/linux/regmap.h and existing
+codec drivers for example regmap usage.
3 - Mixers and audio controls
@@ -127,7 +111,7 @@ Defines a stereo enumerated control
4 - Codec Audio Operations
--------------------------
-The codec driver also supports the following ALSA operations:-
+The codec driver also supports the following ALSA PCM operations:-
/* SoC audio ops */
struct snd_soc_ops {
diff --git a/Documentation/sound/alsa/soc/dapm.txt b/Documentation/sound/alsa/soc/dapm.txt
index 05bf5a0eee4..6faab488000 100644
--- a/Documentation/sound/alsa/soc/dapm.txt
+++ b/Documentation/sound/alsa/soc/dapm.txt
@@ -21,7 +21,7 @@ level power systems.
There are 4 power domains within DAPM
- 1. Codec domain - VREF, VMID (core codec and audio power)
+ 1. Codec bias domain - VREF, VMID (core codec and audio power)
Usually controlled at codec probe/remove and suspend/resume, although
can be set at stream time if power is not needed for sidetone, etc.
@@ -30,7 +30,7 @@ There are 4 power domains within DAPM
machine driver and responds to asynchronous events e.g when HP
are inserted
- 3. Path domain - audio susbsystem signal paths
+ 3. Path domain - audio subsystem signal paths
Automatically set when mixer and mux settings are changed by the user.
e.g. alsamixer, amixer.
@@ -63,14 +63,22 @@ Audio DAPM widgets fall into a number of types:-
o Line - Line Input/Output (and optional Jack)
o Speaker - Speaker
o Supply - Power or clock supply widget used by other widgets.
+ o Regulator - External regulator that supplies power to audio components.
+ o Clock - External clock that supplies clock to audio components.
+ o AIF IN - Audio Interface Input (with TDM slot mask).
+ o AIF OUT - Audio Interface Output (with TDM slot mask).
+ o Siggen - Signal Generator.
+ o DAI IN - Digital Audio Interface Input.
+ o DAI OUT - Digital Audio Interface Output.
+ o DAI Link - DAI Link between two DAI structures */
o Pre - Special PRE widget (exec before all others)
o Post - Special POST widget (exec after all others)
(Widgets are defined in include/sound/soc-dapm.h)
-Widgets are usually added in the codec driver and the machine driver. There are
-convenience macros defined in soc-dapm.h that can be used to quickly build a
-list of widgets of the codecs and machines DAPM widgets.
+Widgets can be added to the sound card by any of the component driver types.
+There are convenience macros defined in soc-dapm.h that can be used to quickly
+build a list of widgets of the codecs and machines DAPM widgets.
Most widgets have a name, register, shift and invert. Some widgets have extra
parameters for stream name and kcontrols.
@@ -80,11 +88,13 @@ parameters for stream name and kcontrols.
-------------------------
Stream Widgets relate to the stream power domain and only consist of ADCs
-(analog to digital converters) and DACs (digital to analog converters).
+(analog to digital converters), DACs (digital to analog converters),
+AIF IN and AIF OUT.
Stream widgets have the following format:-
SND_SOC_DAPM_DAC(name, stream name, reg, shift, invert),
+SND_SOC_DAPM_AIF_IN(name, stream, slot, reg, shift, invert)
NOTE: the stream name must match the corresponding stream name in your codec
snd_soc_codec_dai.
@@ -94,6 +104,11 @@ e.g. stream widgets for HiFi playback and capture
SND_SOC_DAPM_DAC("HiFi DAC", "HiFi Playback", REG, 3, 1),
SND_SOC_DAPM_ADC("HiFi ADC", "HiFi Capture", REG, 2, 1),
+e.g. stream widgets for AIF
+
+SND_SOC_DAPM_AIF_IN("AIF1RX", "AIF1 Playback", 0, SND_SOC_NOPM, 0, 0),
+SND_SOC_DAPM_AIF_OUT("AIF1TX", "AIF1 Capture", 0, SND_SOC_NOPM, 0, 0),
+
2.2 Path Domain Widgets
-----------------------
@@ -121,12 +136,14 @@ If you dont want the mixer elements prefixed with the name of the mixer widget,
you can use SND_SOC_DAPM_MIXER_NAMED_CTL instead. the parameters are the same
as for SND_SOC_DAPM_MIXER.
-2.3 Platform/Machine domain Widgets
------------------------------------
+
+2.3 Machine domain Widgets
+--------------------------
Machine widgets are different from codec widgets in that they don't have a
codec register bit associated with them. A machine widget is assigned to each
-machine audio component (non codec) that can be independently powered. e.g.
+machine audio component (non codec or DSP) that can be independently
+powered. e.g.
o Speaker Amp
o Microphone Bias
@@ -146,12 +163,12 @@ static int spitz_mic_bias(struct snd_soc_dapm_widget* w, int event)
SND_SOC_DAPM_MIC("Mic Jack", spitz_mic_bias),
-2.4 Codec Domain
-----------------
+2.4 Codec (BIAS) Domain
+-----------------------
-The codec power domain has no widgets and is handled by the codecs DAPM event
-handler. This handler is called when the codec powerstate is changed wrt to any
-stream event or by kernel PM events.
+The codec bias power domain has no widgets and is handled by the codecs DAPM
+event handler. This handler is called when the codec powerstate is changed wrt
+to any stream event or by kernel PM events.
2.5 Virtual Widgets
@@ -169,15 +186,16 @@ After all the widgets have been defined, they can then be added to the DAPM
subsystem individually with a call to snd_soc_dapm_new_control().
-3. Codec Widget Interconnections
-================================
+3. Codec/DSP Widget Interconnections
+====================================
-Widgets are connected to each other within the codec and machine by audio paths
-(called interconnections). Each interconnection must be defined in order to
-create a map of all audio paths between widgets.
+Widgets are connected to each other within the codec, platform and machine by
+audio paths (called interconnections). Each interconnection must be defined in
+order to create a map of all audio paths between widgets.
-This is easiest with a diagram of the codec (and schematic of the machine audio
-system), as it requires joining widgets together via their audio signal paths.
+This is easiest with a diagram of the codec or DSP (and schematic of the machine
+audio system), as it requires joining widgets together via their audio signal
+paths.
e.g., from the WM8731 output mixer (wm8731.c)
@@ -247,16 +265,9 @@ machine and includes the codec. e.g.
o Mic Jack
o Codec Pins
-When a codec pin is NC it can be marked as not used with a call to
-
-snd_soc_dapm_set_endpoint(codec, "Widget Name", 0);
-
-The last argument is 0 for inactive and 1 for active. This way the pin and its
-input widget will never be powered up and consume power.
-
-This also applies to machine widgets. e.g. if a headphone is connected to a
-jack then the jack can be marked active. If the headphone is removed, then
-the headphone jack can be marked inactive.
+Endpoints are added to the DAPM graph so that their usage can be determined in
+order to save power. e.g. NC codecs pins will be switched OFF, unconnected
+jacks can also be switched OFF.
5 DAPM Widget Events
diff --git a/Documentation/sound/alsa/soc/machine.txt b/Documentation/sound/alsa/soc/machine.txt
index d50c14df341..74056dba52b 100644
--- a/Documentation/sound/alsa/soc/machine.txt
+++ b/Documentation/sound/alsa/soc/machine.txt
@@ -1,8 +1,10 @@
ASoC Machine Driver
===================
-The ASoC machine (or board) driver is the code that glues together the platform
-and codec drivers.
+The ASoC machine (or board) driver is the code that glues together all the
+component drivers (e.g. codecs, platforms and DAIs). It also describes the
+relationships between each componnent which include audio paths, GPIOs,
+interrupts, clocking, jacks and voltage regulators.
The machine driver can contain codec and platform specific code. It registers
the audio subsystem with the kernel as a platform device and is represented by
diff --git a/Documentation/sound/alsa/soc/overview.txt b/Documentation/sound/alsa/soc/overview.txt
index 138ac88c146..ff88f52eec9 100644
--- a/Documentation/sound/alsa/soc/overview.txt
+++ b/Documentation/sound/alsa/soc/overview.txt
@@ -49,18 +49,23 @@ features :-
* Machine specific controls: Allow machines to add controls to the sound card
(e.g. volume control for speaker amplifier).
-To achieve all this, ASoC basically splits an embedded audio system into 3
-components :-
+To achieve all this, ASoC basically splits an embedded audio system into
+multiple re-usable component drivers :-
- * Codec driver: The codec driver is platform independent and contains audio
- controls, audio interface capabilities, codec DAPM definition and codec IO
- functions.
+ * Codec class drivers: The codec class driver is platform independent and
+ contains audio controls, audio interface capabilities, codec DAPM
+ definition and codec IO functions. This class extends to BT, FM and MODEM
+ ICs if required. Codec class drivers should be generic code that can run
+ on any architecture and machine.
- * Platform driver: The platform driver contains the audio DMA engine and audio
- interface drivers (e.g. I2S, AC97, PCM) for that platform.
+ * Platform class drivers: The platform class driver includes the audio DMA
+ engine driver, digital audio interface (DAI) drivers (e.g. I2S, AC97, PCM)
+ and any audio DSP drivers for that platform.
- * Machine driver: The machine driver handles any machine specific controls and
- audio events (e.g. turning on an amp at start of playback).
+ * Machine class driver: The machine driver class acts as the glue that
+ decribes and binds the other component drivers together to form an ALSA
+ "sound card device". It handles any machine specific controls and
+ machine level audio events (e.g. turning on an amp at start of playback).
Documentation
@@ -84,3 +89,7 @@ machine.txt: Machine driver internals.
pop_clicks.txt: How to minimise audio artifacts.
clocking.txt: ASoC clocking for best power performance.
+
+jack.txt: ASoC jack detection.
+
+DPCM.txt: Dynamic PCM - Describes DPCM with DSP examples.
diff --git a/Documentation/sound/alsa/soc/platform.txt b/Documentation/sound/alsa/soc/platform.txt
index d57efad37e0..3a08a2c9150 100644
--- a/Documentation/sound/alsa/soc/platform.txt
+++ b/Documentation/sound/alsa/soc/platform.txt
@@ -1,9 +1,9 @@
ASoC Platform Driver
====================
-An ASoC platform driver can be divided into audio DMA and SoC DAI configuration
-and control. The platform drivers only target the SoC CPU and must have no board
-specific code.
+An ASoC platform driver class can be divided into audio DMA drivers, SoC DAI
+drivers and DSP drivers. The platform drivers only target the SoC CPU and must
+have no board specific code.
Audio DMA
=========
@@ -64,3 +64,16 @@ Each SoC DAI driver must provide the following features:-
5) Suspend and resume (optional)
Please see codec.txt for a description of items 1 - 4.
+
+
+SoC DSP Drivers
+===============
+
+Each SoC DSP driver usually supplies the following features :-
+
+ 1) DAPM graph
+ 2) Mixer controls
+ 3) DMA IO to/from DSP buffers (if applicable)
+ 4) Definition of DSP front end (FE) PCM devices.
+
+Please see DPCM.txt for a description of item 4.
diff --git a/Documentation/sound/oss/vwsnd b/Documentation/sound/oss/vwsnd
deleted file mode 100644
index 4c6cbdb3c54..00000000000
--- a/Documentation/sound/oss/vwsnd
+++ /dev/null
@@ -1,293 +0,0 @@
-vwsnd - Sound driver for the Silicon Graphics 320 and 540 Visual
-Workstations' onboard audio.
-
-Copyright 1999 Silicon Graphics, Inc. All rights reserved.
-
-
-At the time of this writing, March 1999, there are two models of
-Visual Workstation, the 320 and the 540. This document only describes
-those models. Future Visual Workstation models may have different
-sound capabilities, and this driver will probably not work on those
-boxes.
-
-The Visual Workstation has an Analog Devices AD1843 "SoundComm" audio
-codec chip. The AD1843 is accessed through the Cobalt I/O ASIC, also
-known as Lithium. This driver programs both chips.
-
-==============================================================================
-QUICK CONFIGURATION
-
- # insmod soundcore
- # insmod vwsnd
-
-==============================================================================
-I/O CONNECTIONS
-
-On the Visual Workstation, only three of the AD1843 inputs are hooked
-up. The analog line in jacks are connected to the AD1843's AUX1
-input. The CD audio lines are connected to the AD1843's AUX2 input.
-The microphone jack is connected to the AD1843's MIC input. The mic
-jack is mono, but the signal is delivered to both the left and right
-MIC inputs. You can record in stereo from the mic input, but you will
-get the same signal on both channels (within the limits of A/D
-accuracy). Full scale on the Line input is +/- 2.0 V. Full scale on
-the MIC input is 20 dB less, or +/- 0.2 V.
-
-The AD1843's LOUT1 outputs are connected to the Line Out jacks. The
-AD1843's HPOUT outputs are connected to the speaker/headphone jack.
-LOUT2 is not connected. Line out's maximum level is +/- 2.0 V peak to
-peak. The speaker/headphone out's maximum is +/- 4.0 V peak to peak.
-
-The AD1843's PCM input channel and one of its output channels (DAC1)
-are connected to Lithium. The other output channel (DAC2) is not
-connected.
-
-==============================================================================
-CAPABILITIES
-
-The AD1843 has PCM input and output (Pulse Code Modulation, also known
-as wavetable). PCM input and output can be mono or stereo in any of
-four formats. The formats are 16 bit signed and 8 bit unsigned,
-u-Law, and A-Law format. Any sample rate from 4 KHz to 49 KHz is
-available, in 1 Hz increments.
-
-The AD1843 includes an analog mixer that can mix all three input
-signals (line, mic and CD) into the analog outputs. The mixer has a
-separate gain control and mute switch for each input.
-
-There are two outputs, line out and speaker/headphone out. They
-always produce the same signal, and the speaker always has 3 dB more
-gain than the line out. The speaker/headphone output can be muted,
-but this driver does not export that function.
-
-The hardware can sync audio to the video clock, but this driver does
-not have a way to specify syncing to video.
-
-==============================================================================
-PROGRAMMING
-
-This section explains the API supported by the driver. Also see the
-Open Sound Programming Guide at http://www.opensound.com/pguide/ .
-This section assumes familiarity with that document.
-
-The driver has two interfaces, an I/O interface and a mixer interface.
-There is no MIDI or sequencer capability.
-
-==============================================================================
-PROGRAMMING PCM I/O
-
-The I/O interface is usually accessed as /dev/audio or /dev/dsp.
-Using the standard Open Sound System (OSS) ioctl calls, the sample
-rate, number of channels, and sample format may be set within the
-limitations described above. The driver supports triggering. It also
-supports getting the input and output pointers with one-sample
-accuracy.
-
-The SNDCTL_DSP_GETCAP ioctl returns these capabilities.
-
- DSP_CAP_DUPLEX - driver supports full duplex.
-
- DSP_CAP_TRIGGER - driver supports triggering.
-
- DSP_CAP_REALTIME - values returned by SNDCTL_DSP_GETIPTR
- and SNDCTL_DSP_GETOPTR are accurate to a few samples.
-
-Memory mapping (mmap) is not implemented.
-
-The driver permits subdivided fragment sizes from 64 to 4096 bytes.
-The number of fragments can be anything from 3 fragments to however
-many fragments fit into 124 kilobytes. It is up to the user to
-determine how few/small fragments can be used without introducing
-glitches with a given workload. Linux is not realtime, so we can't
-promise anything. (sigh...)
-
-When this driver is switched into or out of mu-Law or A-Law mode on
-output, it may produce an audible click. This is unavoidable. To
-prevent clicking, use signed 16-bit mode instead, and convert from
-mu-Law or A-Law format in software.
-
-==============================================================================
-PROGRAMMING THE MIXER INTERFACE
-
-The mixer interface is usually accessed as /dev/mixer. It is accessed
-through ioctls. The mixer allows the application to control gain or
-mute several audio signal paths, and also allows selection of the
-recording source.
-
-Each of the constants described here can be read using the
-MIXER_READ(SOUND_MIXER_xxx) ioctl. Those that are not read-only can
-also be written using the MIXER_WRITE(SOUND_MIXER_xxx) ioctl. In most
-cases, <sys/soundcard.h> defines constants SOUND_MIXER_READ_xxx and
-SOUND_MIXER_WRITE_xxx which work just as well.
-
-SOUND_MIXER_CAPS Read-only
-
-This is a mask of optional driver capabilities that are implemented.
-This driver's only capability is SOUND_CAP_EXCL_INPUT, which means
-that only one recording source can be active at a time.
-
-SOUND_MIXER_DEVMASK Read-only
-
-This is a mask of the sound channels. This driver's channels are PCM,
-LINE, MIC, CD, and RECLEV.
-
-SOUND_MIXER_STEREODEVS Read-only
-
-This is a mask of which sound channels are capable of stereo. All
-channels are capable of stereo. (But see caveat on MIC input in I/O
-CONNECTIONS section above).
-
-SOUND_MIXER_OUTMASK Read-only
-
-This is a mask of channels that route inputs through to outputs.
-Those are LINE, MIC, and CD.
-
-SOUND_MIXER_RECMASK Read-only
-
-This is a mask of channels that can be recording sources. Those are
-PCM, LINE, MIC, CD.
-
-SOUND_MIXER_PCM Default: 0x5757 (0 dB)
-
-This is the gain control for PCM output. The left and right channel
-gain are controlled independently. This gain control has 64 levels,
-which range from -82.5 dB to +12.0 dB in 1.5 dB steps. Those 64
-levels are mapped onto 100 levels at the ioctl, see below.
-
-SOUND_MIXER_LINE Default: 0x4a4a (0 dB)
-
-This is the gain control for mixing the Line In source into the
-outputs. The left and right channel gain are controlled
-independently. This gain control has 32 levels, which range from
--34.5 dB to +12.0 dB in 1.5 dB steps. Those 32 levels are mapped onto
-100 levels at the ioctl, see below.
-
-SOUND_MIXER_MIC Default: 0x4a4a (0 dB)
-
-This is the gain control for mixing the MIC source into the outputs.
-The left and right channel gain are controlled independently. This
-gain control has 32 levels, which range from -34.5 dB to +12.0 dB in
-1.5 dB steps. Those 32 levels are mapped onto 100 levels at the
-ioctl, see below.
-
-SOUND_MIXER_CD Default: 0x4a4a (0 dB)
-
-This is the gain control for mixing the CD audio source into the
-outputs. The left and right channel gain are controlled
-independently. This gain control has 32 levels, which range from
--34.5 dB to +12.0 dB in 1.5 dB steps. Those 32 levels are mapped onto
-100 levels at the ioctl, see below.
-
-SOUND_MIXER_RECLEV Default: 0 (0 dB)
-
-This is the gain control for PCM input (RECording LEVel). The left
-and right channel gain are controlled independently. This gain
-control has 16 levels, which range from 0 dB to +22.5 dB in 1.5 dB
-steps. Those 16 levels are mapped onto 100 levels at the ioctl, see
-below.
-
-SOUND_MIXER_RECSRC Default: SOUND_MASK_LINE
-
-This is a mask of currently selected PCM input sources (RECording
-SouRCes). Because the AD1843 can only have a single recording source
-at a time, only one bit at a time can be set in this mask. The
-allowable values are SOUND_MASK_PCM, SOUND_MASK_LINE, SOUND_MASK_MIC,
-or SOUND_MASK_CD. Selecting SOUND_MASK_PCM sets up internal
-resampling which is useful for loopback testing and for hardware
-sample rate conversion. But software sample rate conversion is
-probably faster, so I don't know how useful that is.
-
-SOUND_MIXER_OUTSRC DEFAULT: SOUND_MASK_LINE|SOUND_MASK_MIC|SOUND_MASK_CD
-
-This is a mask of sources that are currently passed through to the
-outputs. Those sources whose bits are not set are muted.
-
-==============================================================================
-GAIN CONTROL
-
-There are five gain controls listed above. Each has 16, 32, or 64
-steps. Each control has 1.5 dB of gain per step. Each control is
-stereo.
-
-The OSS defines the argument to a channel gain ioctl as having two
-components, left and right, each of which ranges from 0 to 100. The
-two components are packed into the same word, with the left side gain
-in the least significant byte, and the right side gain in the second
-least significant byte. In C, we would say this.
-
- #include <assert.h>
-
- ...
-
- assert(leftgain >= 0 && leftgain <= 100);
- assert(rightgain >= 0 && rightgain <= 100);
- arg = leftgain | rightgain << 8;
-
-So each OSS gain control has 101 steps. But the hardware has 16, 32,
-or 64 steps. The hardware steps are spread across the 101 OSS steps
-nearly evenly. The conversion formulas are like this, given N equals
-16, 32, or 64.
-
- int round = N/2 - 1;
- OSS_gain_steps = (hw_gain_steps * 100 + round) / (N - 1);
- hw_gain_steps = (OSS_gain_steps * (N - 1) + round) / 100;
-
-Here is a snippet of C code that will return the left and right gain
-of any channel in dB. Pass it one of the predefined gain_desc_t
-structures to access any of the five channels' gains.
-
- typedef struct gain_desc {
- float min_gain;
- float gain_step;
- int nbits;
- int chan;
- } gain_desc_t;
-
- const gain_desc_t gain_pcm = { -82.5, 1.5, 6, SOUND_MIXER_PCM };
- const gain_desc_t gain_line = { -34.5, 1.5, 5, SOUND_MIXER_LINE };
- const gain_desc_t gain_mic = { -34.5, 1.5, 5, SOUND_MIXER_MIC };
- const gain_desc_t gain_cd = { -34.5, 1.5, 5, SOUND_MIXER_CD };
- const gain_desc_t gain_reclev = { 0.0, 1.5, 4, SOUND_MIXER_RECLEV };
-
- int get_gain_dB(int fd, const gain_desc_t *gp,
- float *left, float *right)
- {
- int word;
- int lg, rg;
- int mask = (1 << gp->nbits) - 1;
-
- if (ioctl(fd, MIXER_READ(gp->chan), &word) != 0)
- return -1; /* fail */
- lg = word & 0xFF;
- rg = word >> 8 & 0xFF;
- lg = (lg * mask + mask / 2) / 100;
- rg = (rg * mask + mask / 2) / 100;
- *left = gp->min_gain + gp->gain_step * lg;
- *right = gp->min_gain + gp->gain_step * rg;
- return 0;
- }
-
-And here is the corresponding routine to set a channel's gain in dB.
-
- int set_gain_dB(int fd, const gain_desc_t *gp, float left, float right)
- {
- float max_gain =
- gp->min_gain + (1 << gp->nbits) * gp->gain_step;
- float round = gp->gain_step / 2;
- int mask = (1 << gp->nbits) - 1;
- int word;
- int lg, rg;
-
- if (left < gp->min_gain || right < gp->min_gain)
- return EINVAL;
- lg = (left - gp->min_gain + round) / gp->gain_step;
- rg = (right - gp->min_gain + round) / gp->gain_step;
- if (lg >= (1 << gp->nbits) || rg >= (1 << gp->nbits))
- return EINVAL;
- lg = (100 * lg + mask / 2) / mask;
- rg = (100 * rg + mask / 2) / mask;
- word = lg | rg << 8;
-
- return ioctl(fd, MIXER_WRITE(gp->chan), &word);
- }
-