100 lines
3.5 KiB
Diff
100 lines
3.5 KiB
Diff
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From e7fc348fed61518907205603a7d0d6038cecfa1f Mon Sep 17 00:00:00 2001
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From: Digital Dreamtime <clive.messer@digitaldreamtime.co.uk>
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Date: Thu, 4 Feb 2016 14:14:44 +0000
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Subject: [PATCH 143/156] Allow up to 24dB digital gain to be applied when
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using IQAudIO DAC+
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24db_digital_gain DT param can be used to specify that PCM512x
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codec "Digital" volume control should not be limited to 0dB gain,
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and if specified will allow the full 24dB gain.
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---
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arch/arm/boot/dts/overlays/README | 17 +++++++++++++++--
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.../boot/dts/overlays/iqaudio-dacplus-overlay.dts | 6 +++++-
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sound/soc/bcm/iqaudio-dac.c | 20 ++++++++++++++------
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3 files changed, 34 insertions(+), 9 deletions(-)
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--- a/arch/arm/boot/dts/overlays/README
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+++ b/arch/arm/boot/dts/overlays/README
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@@ -362,8 +362,21 @@ Params: <None>
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Name: iqaudio-dacplus
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Info: Configures the IQaudio DAC+ audio card
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-Load: dtoverlay=iqaudio-dacplus
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-Params: <None>
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+Load: dtoverlay=iqaudio-dacplus,<param>=<val>
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+Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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+ Digital volume control. Enable with
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+ "dtoverlay=iqaudio-dacplus,24db_digital_gain"
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+ (The default behaviour is that the Digital
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+ volume control is limited to a maximum of
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+ 0dB. ie. it can attenuate but not provide
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+ gain. For most users, this will be desired
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+ as it will prevent clipping. By appending
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+ the 24db_digital_gain parameter, the Digital
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+ volume control will allow up to 24dB of
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+ gain. If this parameter is enabled, it is the
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+ responsibility of the user to ensure that
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+ the Digital volume control is set to a value
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+ that does not result in clipping/distortion!)
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Name: lirc-rpi
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--- a/arch/arm/boot/dts/overlays/iqaudio-dacplus-overlay.dts
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+++ b/arch/arm/boot/dts/overlays/iqaudio-dacplus-overlay.dts
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@@ -7,7 +7,7 @@
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fragment@0 {
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target = <&sound>;
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- __overlay__ {
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+ frag0: __overlay__ {
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compatible = "iqaudio,iqaudio-dac";
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i2s-controller = <&i2s>;
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status = "okay";
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@@ -36,4 +36,8 @@
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};
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};
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};
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+
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+ __overrides__ {
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+ 24db_digital_gain = <&frag0>,"iqaudio,24db_digital_gain?";
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+ };
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};
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--- a/sound/soc/bcm/iqaudio-dac.c
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+++ b/sound/soc/bcm/iqaudio-dac.c
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@@ -23,14 +23,19 @@
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#include <sound/soc.h>
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#include <sound/jack.h>
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+static bool digital_gain_0db_limit = true;
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+
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static int snd_rpi_iqaudio_dac_init(struct snd_soc_pcm_runtime *rtd)
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{
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- int ret;
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- struct snd_soc_card *card = rtd->card;
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-
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- ret = snd_soc_limit_volume(card, "Digital Playback Volume", 207);
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- if (ret < 0)
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- dev_warn(card->dev, "Failed to set volume limit: %d\n", ret);
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+ if (digital_gain_0db_limit)
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+ {
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+ int ret;
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+ struct snd_soc_card *card = rtd->card;
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+
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+ ret = snd_soc_limit_volume(card, "Digital Playback Volume", 207);
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+ if (ret < 0)
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+ dev_warn(card->dev, "Failed to set volume limit: %d\n", ret);
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+ }
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return 0;
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}
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@@ -94,6 +99,9 @@ static int snd_rpi_iqaudio_dac_probe(str
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dai->platform_name = NULL;
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dai->platform_of_node = i2s_node;
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}
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+
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+ digital_gain_0db_limit = !of_property_read_bool(pdev->dev.of_node,
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+ "iqaudio,24db_digital_gain");
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}
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ret = snd_soc_register_card(&snd_rpi_iqaudio_dac);
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