99 lines
3.6 KiB
Diff
99 lines
3.6 KiB
Diff
|
From 9084d0c769be7aaf552eeaa27eac948226bc10cc Mon Sep 17 00:00:00 2001
|
||
|
|
From: Digital Dreamtime <clive.messer@digitaldreamtime.co.uk>
|
||
|
|
Date: Thu, 4 Feb 2016 20:04:00 +0000
|
||
|
|
Subject: [PATCH 144/156] Limit PCM512x "Digital" gain to 0dB by default with
|
||
|
|
HiFiBerry 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 +++++++++++++++--
|
||
|
|
.../arm/boot/dts/overlays/hifiberry-dacplus-overlay.dts | 6 +++++-
|
||
|
|
sound/soc/bcm/hifiberry_dacplus.c | 14 ++++++++++++++
|
||
|
|
3 files changed, 34 insertions(+), 3 deletions(-)
|
||
|
|
|
||
|
|
--- a/arch/arm/boot/dts/overlays/README
|
||
|
|
+++ b/arch/arm/boot/dts/overlays/README
|
||
|
|
@@ -273,8 +273,21 @@ Params: <None>
|
||
|
|
|
||
|
|
Name: hifiberry-dacplus
|
||
|
|
Info: Configures the HifiBerry DAC+ audio card
|
||
|
|
-Load: dtoverlay=hifiberry-dacplus
|
||
|
|
-Params: <None>
|
||
|
|
+Load: dtoverlay=hifiberry-dacplus,<param>=<val>
|
||
|
|
+Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
|
||
|
|
+ Digital volume control. Enable with
|
||
|
|
+ "dtoverlay=hifiberry-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: hifiberry-digi
|
||
|
|
--- a/arch/arm/boot/dts/overlays/hifiberry-dacplus-overlay.dts
|
||
|
|
+++ b/arch/arm/boot/dts/overlays/hifiberry-dacplus-overlay.dts
|
||
|
|
@@ -17,7 +17,7 @@
|
||
|
|
|
||
|
|
fragment@1 {
|
||
|
|
target = <&sound>;
|
||
|
|
- __overlay__ {
|
||
|
|
+ frag1: __overlay__ {
|
||
|
|
compatible = "hifiberry,hifiberry-dacplus";
|
||
|
|
i2s-controller = <&i2s>;
|
||
|
|
status = "okay";
|
||
|
|
@@ -47,4 +47,8 @@
|
||
|
|
};
|
||
|
|
};
|
||
|
|
};
|
||
|
|
+
|
||
|
|
+ __overrides__ {
|
||
|
|
+ 24db_digital_gain = <&frag1>,"hifiberry,24db_digital_gain?";
|
||
|
|
+ };
|
||
|
|
};
|
||
|
|
--- a/sound/soc/bcm/hifiberry_dacplus.c
|
||
|
|
+++ b/sound/soc/bcm/hifiberry_dacplus.c
|
||
|
|
@@ -48,6 +48,7 @@ struct pcm512x_priv {
|
||
|
|
#define CLK_48EN_RATE 24576000UL
|
||
|
|
|
||
|
|
static bool snd_rpi_hifiberry_is_dacpro;
|
||
|
|
+static bool digital_gain_0db_limit = true;
|
||
|
|
|
||
|
|
static void snd_rpi_hifiberry_dacplus_select_clk(struct snd_soc_codec *codec,
|
||
|
|
int clk_id)
|
||
|
|
@@ -167,6 +168,16 @@ static int snd_rpi_hifiberry_dacplus_ini
|
||
|
|
snd_soc_update_bits(codec, PCM512x_GPIO_OUTPUT_4, 0x0f, 0x02);
|
||
|
|
snd_soc_update_bits(codec, PCM512x_GPIO_CONTROL_1, 0x08, 0x08);
|
||
|
|
|
||
|
|
+ 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;
|
||
|
|
}
|
||
|
|
|
||
|
|
@@ -299,6 +310,9 @@ static int snd_rpi_hifiberry_dacplus_pro
|
||
|
|
dai->platform_name = NULL;
|
||
|
|
dai->platform_of_node = i2s_node;
|
||
|
|
}
|
||
|
|
+
|
||
|
|
+ digital_gain_0db_limit = !of_property_read_bool(
|
||
|
|
+ pdev->dev.of_node, "hifiberry,24db_digital_gain");
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = snd_soc_register_card(&snd_rpi_hifiberry_dacplus);
|