diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0143-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0143-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0143-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch b/target/linux/brcm2708/patches-4.4/0143-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch new file mode 100644 index 0000000000..258210bd42 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0143-Allow-up-to-24dB-digital-gain-to-be-applied-when-usi.patch @@ -0,0 +1,99 @@ +From e7fc348fed61518907205603a7d0d6038cecfa1f 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 143/156] 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); |