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- From 3bb2e01fd397f375e54f6fe8a33af25aef1c981f Mon Sep 17 00:00:00 2001
- From: Digital Dreamtime <clive.messer@digitaldreamtime.co.uk>
- Date: Thu, 4 Feb 2016 14:14:44 +0000
- Subject: [PATCH 140/381] Allow up to 24dB digital gain to be applied when
- using IQAudIO DAC+
- 24db_digital_gain DT param can be used to specify that PCM512x
- codec "Digital" volume control should not be limited to 0dB gain,
- and if specified will allow the full 24dB gain.
- ---
- arch/arm/boot/dts/overlays/README | 17 +++++++++++++++--
- .../boot/dts/overlays/iqaudio-dacplus-overlay.dts | 6 +++++-
- sound/soc/bcm/iqaudio-dac.c | 20 ++++++++++++++------
- 3 files changed, 34 insertions(+), 9 deletions(-)
- --- a/arch/arm/boot/dts/overlays/README
- +++ b/arch/arm/boot/dts/overlays/README
- @@ -362,8 +362,21 @@ Params: <None>
-
- Name: iqaudio-dacplus
- Info: Configures the IQaudio DAC+ audio card
- -Load: dtoverlay=iqaudio-dacplus
- -Params: <None>
- +Load: dtoverlay=iqaudio-dacplus,<param>=<val>
- +Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
- + Digital volume control. Enable with
- + "dtoverlay=iqaudio-dacplus,24db_digital_gain"
- + (The default behaviour is that the Digital
- + volume control is limited to a maximum of
- + 0dB. ie. it can attenuate but not provide
- + gain. For most users, this will be desired
- + as it will prevent clipping. By appending
- + the 24db_digital_gain parameter, the Digital
- + volume control will allow up to 24dB of
- + gain. If this parameter is enabled, it is the
- + responsibility of the user to ensure that
- + the Digital volume control is set to a value
- + that does not result in clipping/distortion!)
-
-
- Name: lirc-rpi
- --- a/arch/arm/boot/dts/overlays/iqaudio-dacplus-overlay.dts
- +++ b/arch/arm/boot/dts/overlays/iqaudio-dacplus-overlay.dts
- @@ -7,7 +7,7 @@
-
- fragment@0 {
- target = <&sound>;
- - __overlay__ {
- + frag0: __overlay__ {
- compatible = "iqaudio,iqaudio-dac";
- i2s-controller = <&i2s>;
- status = "okay";
- @@ -36,4 +36,8 @@
- };
- };
- };
- +
- + __overrides__ {
- + 24db_digital_gain = <&frag0>,"iqaudio,24db_digital_gain?";
- + };
- };
- --- a/sound/soc/bcm/iqaudio-dac.c
- +++ b/sound/soc/bcm/iqaudio-dac.c
- @@ -23,14 +23,19 @@
- #include <sound/soc.h>
- #include <sound/jack.h>
-
- +static bool digital_gain_0db_limit = true;
- +
- static int snd_rpi_iqaudio_dac_init(struct snd_soc_pcm_runtime *rtd)
- {
- - int ret;
- - struct snd_soc_card *card = rtd->card;
- -
- - ret = snd_soc_limit_volume(card, "Digital Playback Volume", 207);
- - if (ret < 0)
- - dev_warn(card->dev, "Failed to set volume limit: %d\n", ret);
- + if (digital_gain_0db_limit)
- + {
- + int ret;
- + struct snd_soc_card *card = rtd->card;
- +
- + ret = snd_soc_limit_volume(card, "Digital Playback Volume", 207);
- + if (ret < 0)
- + dev_warn(card->dev, "Failed to set volume limit: %d\n", ret);
- + }
-
- return 0;
- }
- @@ -94,6 +99,9 @@ static int snd_rpi_iqaudio_dac_probe(str
- dai->platform_name = NULL;
- dai->platform_of_node = i2s_node;
- }
- +
- + digital_gain_0db_limit = !of_property_read_bool(pdev->dev.of_node,
- + "iqaudio,24db_digital_gain");
- }
-
- ret = snd_soc_register_card(&snd_rpi_iqaudio_dac);
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