diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0323-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0323-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0323-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch b/target/linux/brcm2708/patches-4.4/0323-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch new file mode 100644 index 0000000000..3278745176 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0323-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch @@ -0,0 +1,60 @@ +From 691922255a15630c6f726c4c871ce2475d4fec72 Mon Sep 17 00:00:00 2001 +From: DigitalDreamtime <clive.messer@digitaldreamtime.co.uk> +Date: Fri, 6 May 2016 09:42:55 +0100 +Subject: [PATCH] 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. + +Signed-off-by: DigitalDreamtime <clive.messer@digitaldreamtime.co.uk> +--- + arch/arm/boot/dts/overlays/README | 17 +++++++++++++++-- + arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts | 6 +++++- + 2 files changed, 20 insertions(+), 3 deletions(-) + +--- a/arch/arm/boot/dts/overlays/README ++++ b/arch/arm/boot/dts/overlays/README +@@ -490,8 +490,21 @@ Params: <None> + + Name: iqaudio-dac + Info: Configures the IQaudio DAC audio card +-Load: dtoverlay=iqaudio-dac +-Params: <None> ++Load: dtoverlay=iqaudio-dac,<param> ++Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec ++ Digital volume control. Enable with ++ "dtoverlay=iqaudio-dac,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: iqaudio-dacplus +--- a/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts ++++ b/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts +@@ -30,10 +30,14 @@ + + fragment@2 { + target = <&sound>; +- __overlay__ { ++ frag2: __overlay__ { + compatible = "iqaudio,iqaudio-dac"; + i2s-controller = <&i2s>; + status = "okay"; + }; + }; ++ ++ __overrides__ { ++ 24db_digital_gain = <&frag2>,"iqaudio,24db_digital_gain?"; ++ }; + }; |