From ae776ef7eb34d99945aadbaa607e1aec66fd04d0 Mon Sep 17 00:00:00 2001
From: Matt Flax <flatmax@flatmax.org>
Date: Mon, 16 May 2016 21:36:31 +1000
Subject: [PATCH] New AudioInjector.net Pi soundcard with low jitter audio in
 and out.

Contains the sound/soc/bcm ALSA machine driver and necessary alterations to the Kconfig and Makefile.
Adds the dts overlay and updates the Makefile and README.
Updates the relevant defconfig files to enable building for the Raspberry Pi.
Thanks to Phil Elwell (pelwell) for the review, simple-card concepts and discussion. Thanks to Clive Messer for overlay naming suggestions.
---
 arch/arm/boot/dts/overlays/Makefile                |   1 +
 arch/arm/boot/dts/overlays/README                  |   6 +
 .../audioinjector-wm8731-audio-overlay.dts         |  39 ++++++
 arch/arm/configs/bcm2709_defconfig                 |   1 +
 arch/arm/configs/bcmrpi_defconfig                  |   1 +
 sound/soc/bcm/Kconfig                              |   7 +
 sound/soc/bcm/Makefile                             |   3 +
 sound/soc/bcm/audioinjector-pi-soundcard.c         | 142 +++++++++++++++++++++
 8 files changed, 200 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/audioinjector-wm8731-audio-overlay.dts
 create mode 100644 sound/soc/bcm/audioinjector-pi-soundcard.c

--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -16,6 +16,7 @@ dtbo-$(RPI_DT_OVERLAYS) += adau1977-adc.
 dtbo-$(RPI_DT_OVERLAYS) += ads7846.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += akkordion-iqdacplus.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += at86rf233.dtbo
+dtbo-$(RPI_DT_OVERLAYS) += audioinjector-wm8731-audio.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += bmp085_i2c-sensor.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += boomberry-dac.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += boomberry-digi.dtbo
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -225,6 +225,12 @@ Params: interrupt               GPIO use
                                 arrays (0=+0pF, 15=+4.5pF, default 15)
 
 
+Name:   audioinjector-wm8731-audio
+Info:   Configures the audioinjector.net audio add on soundcard
+Load:   dtoverlay=audioinjector-wm8731-audio
+Params: <None>
+
+
 Name:   bmp085_i2c-sensor
 Info:   Configures the BMP085/BMP180 digital barometric pressure and temperature
         sensors from Bosch Sensortec
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/audioinjector-wm8731-audio-overlay.dts
@@ -0,0 +1,39 @@
+// Definitions for audioinjector.net audio add on soundcard
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2708";
+
+	fragment@0 {
+		target = <&i2s>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target = <&i2c1>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "okay";
+
+			wm8731@1a {
+				#sound-dai-cells = <0>;
+				compatible = "wlf,wm8731";
+				reg = <0x1a>;
+				status = "okay";
+			};
+		};
+	};
+
+	fragment@2 {
+		target = <&sound>;
+		__overlay__ {
+			compatible = "ai,audioinjector-pi-soundcard";
+			i2s-controller = <&i2s>;
+			status = "okay";
+		};
+	};
+};
--- a/arch/arm/configs/bcm2709_defconfig
+++ b/arch/arm/configs/bcm2709_defconfig
@@ -863,6 +863,7 @@ CONFIG_SND_BCM2708_SOC_BOOMBERRY_DAC=m
 CONFIG_SND_BCM2708_SOC_BOOMBERRY_DIGI=m
 CONFIG_SND_BCM2708_SOC_IQAUDIO_DAC=m
 CONFIG_SND_BCM2708_SOC_RASPIDAC3=m
+CONFIG_SND_AUDIOINJECTOR_PI_SOUNDCARD=m
 CONFIG_SND_BCM2708_SOC_ADAU1977_ADC=m
 CONFIG_SND_SOC_ADAU1701=m
 CONFIG_SND_SOC_WM8804_I2C=m
--- a/arch/arm/configs/bcmrpi_defconfig
+++ b/arch/arm/configs/bcmrpi_defconfig
@@ -855,6 +855,7 @@ CONFIG_SND_BCM2708_SOC_BOOMBERRY_DAC=m
 CONFIG_SND_BCM2708_SOC_BOOMBERRY_DIGI=m
 CONFIG_SND_BCM2708_SOC_IQAUDIO_DAC=m
 CONFIG_SND_BCM2708_SOC_RASPIDAC3=m
+CONFIG_SND_AUDIOINJECTOR_PI_SOUNDCARD=m
 CONFIG_SND_BCM2708_SOC_ADAU1977_ADC=m
 CONFIG_SND_SOC_ADAU1701=m
 CONFIG_SND_SOC_WM8804_I2C=m
--- a/sound/soc/bcm/Kconfig
+++ b/sound/soc/bcm/Kconfig
@@ -85,3 +85,10 @@ config SND_BCM2708_SOC_ADAU1977_ADC
 	select SND_SOC_ADAU1977_I2C
 	help
 	  Say Y or M if you want to add support for ADAU1977 ADC.
+
+config SND_AUDIOINJECTOR_PI_SOUNDCARD
+	tristate "Support for audioinjector.net Pi add on soundcard"
+	depends on SND_BCM2708_SOC_I2S || SND_BCM2835_SOC_I2S
+	select SND_SOC_WM8731
+	help
+	  Say Y or M if you want to add support for audioinjector.net Pi Hat
--- a/sound/soc/bcm/Makefile
+++ b/sound/soc/bcm/Makefile
@@ -15,6 +15,7 @@ snd-soc-rpi-dac-objs := rpi-dac.o
 snd-soc-rpi-proto-objs := rpi-proto.o
 snd-soc-iqaudio-dac-objs := iqaudio-dac.o
 snd-soc-raspidac3-objs := raspidac3.o
+snd-soc-audioinjector-pi-soundcard-objs := audioinjector-pi-soundcard.o
 
 obj-$(CONFIG_SND_BCM2708_SOC_ADAU1977_ADC) += snd-soc-adau1977-adc.o
 obj-$(CONFIG_SND_BCM2708_SOC_HIFIBERRY_DAC) += snd-soc-hifiberry-dac.o
@@ -27,3 +28,5 @@ obj-$(CONFIG_SND_BCM2708_SOC_RPI_DAC) +=
 obj-$(CONFIG_SND_BCM2708_SOC_RPI_PROTO) += snd-soc-rpi-proto.o
 obj-$(CONFIG_SND_BCM2708_SOC_IQAUDIO_DAC) += snd-soc-iqaudio-dac.o
 obj-$(CONFIG_SND_BCM2708_SOC_RASPIDAC3) += snd-soc-raspidac3.o
+obj-$(CONFIG_SND_AUDIOINJECTOR_PI_SOUNDCARD) += snd-soc-audioinjector-pi-soundcard.o
+
--- /dev/null
+++ b/sound/soc/bcm/audioinjector-pi-soundcard.c
@@ -0,0 +1,142 @@
+/*
+ * ASoC Driver for AudioInjector Pi add on soundcard
+ *
+ *  Created on: 13-May-2016
+ *      Author: flatmax@flatmax.org
+ *              based on code by  Cliff Cai <Cliff.Cai@analog.com> for the ssm2602 machine blackfin.
+ *              with help from Lars-Peter Clausen for simplifying the original code to use the dai_fmt field.
+ *		i2s_node code taken from the other sound/soc/bcm machine drivers.
+ *
+ * Copyright (C) 2016 Flatmax Pty. Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <sound/core.h>
+#include <sound/soc.h>
+#include <sound/pcm_params.h>
+#include <sound/control.h>
+
+#include "../codecs/wm8731.h"
+
+static int audioinjector_pi_soundcard_dai_init(struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_soc_dapm_context *dapm = &rtd->card->dapm;
+
+	// not connected
+	snd_soc_dapm_nc_pin(dapm, "Mic Bias");
+	snd_soc_dapm_nc_pin(dapm, "MICIN");
+	snd_soc_dapm_nc_pin(dapm, "RHPOUT");
+	snd_soc_dapm_nc_pin(dapm, "LHPOUT");
+
+	return snd_soc_dai_set_sysclk(rtd->codec_dai, WM8731_SYSCLK_XTAL, 12000000, SND_SOC_CLOCK_IN);
+}
+
+static struct snd_soc_dai_link audioinjector_pi_soundcard_dai[] = {
+	{
+		.name = "AudioInjector audio",
+		.stream_name = "AudioInjector audio",
+		.cpu_dai_name	= "bcm2708-i2s.0",
+		.codec_dai_name = "wm8731-hifi",
+		.platform_name	= "bcm2835-i2s.0",
+		.codec_name = "wm8731.1-001a",
+		.init = audioinjector_pi_soundcard_dai_init,
+		.dai_fmt = SND_SOC_DAIFMT_CBM_CFM|SND_SOC_DAIFMT_I2S|SND_SOC_DAIFMT_NB_NF,
+	},
+};
+
+static const struct snd_soc_dapm_widget wm8731_dapm_widgets[] = {
+	SND_SOC_DAPM_SPK("Ext Spk", NULL),
+	SND_SOC_DAPM_LINE("Line In Jacks", NULL),
+};
+
+/* Corgi machine connections to the codec pins */
+static const struct snd_soc_dapm_route audioinjector_audio_map[] = {
+	/* speaker connected to LOUT, ROUT */
+	{"Ext Spk", NULL, "ROUT"},
+	{"Ext Spk", NULL, "LOUT"},
+
+	/* line inputs */
+	{"Line In Jacks", NULL, "Line Input"},
+};
+
+static struct snd_soc_card snd_soc_audioinjector = {
+	.name = "audioinjector-pi-soundcard",
+	.dai_link = audioinjector_pi_soundcard_dai,
+	.num_links = 1,
+
+	.dapm_widgets = wm8731_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(wm8731_dapm_widgets),
+	.dapm_routes = audioinjector_audio_map,
+	.num_dapm_routes = ARRAY_SIZE(audioinjector_audio_map),
+};
+
+static int audioinjector_pi_soundcard_probe(struct platform_device *pdev)
+{
+	struct snd_soc_card *card = &snd_soc_audioinjector;
+	int ret;
+	
+	card->dev = &pdev->dev;
+
+	if (pdev->dev.of_node) {
+		struct snd_soc_dai_link *dai = &audioinjector_pi_soundcard_dai[0];
+		struct device_node *i2s_node = of_parse_phandle(pdev->dev.of_node,
+								"i2s-controller", 0);
+
+		if (i2s_node) {
+			dai->cpu_dai_name = NULL;
+			dai->cpu_of_node = i2s_node;
+			dai->platform_name = NULL;
+			dai->platform_of_node = i2s_node;
+		} else
+			if (!dai->cpu_of_node) {
+				dev_err(&pdev->dev, "Property 'i2s-controller' missing or invalid\n");
+				return -EINVAL;
+			}
+	}
+
+	if ((ret = snd_soc_register_card(card))) {
+		dev_err(&pdev->dev, "snd_soc_register_card failed (%d)\n", ret);
+	}
+	return ret;
+}
+
+static int audioinjector_pi_soundcard_remove(struct platform_device *pdev)
+{
+	struct snd_soc_card *card = platform_get_drvdata(pdev);
+	return snd_soc_unregister_card(card);
+
+}
+
+static const struct of_device_id audioinjector_pi_soundcard_of_match[] = {
+	{ .compatible = "ai,audioinjector-pi-soundcard", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, audioinjector_pi_soundcard_of_match);
+
+static struct platform_driver audioinjector_pi_soundcard_driver = {
+       .driver         = {
+		.name   = "audioinjector-audio",
+		.owner  = THIS_MODULE,
+		.of_match_table = audioinjector_pi_soundcard_of_match,
+       },
+       .probe          = audioinjector_pi_soundcard_probe,
+       .remove         = audioinjector_pi_soundcard_remove,
+};
+
+module_platform_driver(audioinjector_pi_soundcard_driver);
+MODULE_AUTHOR("Matt Flax <flatmax@flatmax.org>");
+MODULE_DESCRIPTION("AudioInjector.net Pi Soundcard");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:audioinjector-pi-soundcard");
+
