ASoC: Intel: avs: Add I2S-test machine board

Allow for testing audio streaming over I2S interface through SSP
loopback. No actual codec is needed here as board is intended for SSP
loopback scenarios only. One playback and one capture endpoint is
exposed per SSP port.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220511162403.3987658-6-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/avs/boards/Kconfig

@@ -20,4 +20,10 @@ config SND_SOC_INTEL_AVS_MACH_HDAUDIO
 	  Say Y or m if you have such a device. This is a recommended option.
 	  If unsure select "N".
 
+config SND_SOC_INTEL_AVS_MACH_I2S_TEST
+	tristate "I2S test board"
+	help
+	   This adds support for I2S test-board which can be used to verify
+	   transfer over I2S interface with SSP loopback scenarios.
+
 endmenu

sound/soc/intel/avs/boards/Makefile

@@ -2,6 +2,8 @@
 
 snd-soc-avs-dmic-objs := dmic.o
 snd-soc-avs-hdaudio-objs := hdaudio.o
+snd-soc-avs-i2s-test-objs := i2s_test.o
 
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_DMIC) += snd-soc-avs-dmic.o
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_HDAUDIO) += snd-soc-avs-hdaudio.o
+obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_i2s_TEST) += snd-soc-avs-i2s-test.o

sound/soc/intel/avs/boards/i2s_test.c

@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright(c) 2021-2022 Intel Corporation. All rights reserved.
+//
+// Authors: Cezary Rojewski <cezary.rojewski@intel.com>
+//          Amadeusz Slawinski <amadeuszx.slawinski@linux.intel.com>
+//
+
+#include <linux/module.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-acpi.h>
+#include <sound/soc-dapm.h>
+
+static int avs_create_dai_link(struct device *dev, const char *platform_name, int ssp_port,
+			       struct snd_soc_dai_link **dai_link)
+{
+	struct snd_soc_dai_link_component *platform;
+	struct snd_soc_dai_link *dl;
+
+	dl = devm_kzalloc(dev, sizeof(*dl), GFP_KERNEL);
+	platform = devm_kzalloc(dev, sizeof(*platform), GFP_KERNEL);
+	if (!dl || !platform)
+		return -ENOMEM;
+
+	platform->name = platform_name;
+
+	dl->name = devm_kasprintf(dev, GFP_KERNEL, "SSP%d-Codec", ssp_port);
+	dl->cpus = devm_kzalloc(dev, sizeof(*dl->cpus), GFP_KERNEL);
+	dl->codecs = devm_kzalloc(dev, sizeof(*dl->codecs), GFP_KERNEL);
+	if (!dl->name || !dl->cpus || !dl->codecs)
+		return -ENOMEM;
+
+	dl->cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL, "SSP%d Pin", ssp_port);
+	dl->codecs->name = devm_kasprintf(dev, GFP_KERNEL, "snd-soc-dummy");
+	dl->codecs->dai_name = devm_kasprintf(dev, GFP_KERNEL, "snd-soc-dummy-dai");
+	if (!dl->cpus->dai_name || !dl->codecs->name || !dl->codecs->dai_name)
+		return -ENOMEM;
+
+	dl->num_cpus = 1;
+	dl->num_codecs = 1;
+	dl->platforms = platform;
+	dl->num_platforms = 1;
+	dl->id = 0;
+	dl->nonatomic = 1;
+	dl->no_pcm = 1;
+	dl->dpcm_capture = 1;
+	dl->dpcm_playback = 1;
+
+	*dai_link = dl;
+
+	return 0;
+}
+
+static int avs_create_dapm_routes(struct device *dev, int ssp_port,
+				  struct snd_soc_dapm_route **routes, int *num_routes)
+{
+	struct snd_soc_dapm_route *dr;
+	const int num_dr = 2;
+
+	dr = devm_kcalloc(dev, num_dr, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	dr[0].sink = devm_kasprintf(dev, GFP_KERNEL, "ssp%dpb", ssp_port);
+	dr[0].source = devm_kasprintf(dev, GFP_KERNEL, "ssp%d Tx", ssp_port);
+	if (!dr[0].sink || !dr[0].source)
+		return -ENOMEM;
+
+	dr[1].sink = devm_kasprintf(dev, GFP_KERNEL, "ssp%d Rx", ssp_port);
+	dr[1].source = devm_kasprintf(dev, GFP_KERNEL, "ssp%dcp", ssp_port);
+	if (!dr[1].sink || !dr[1].source)
+		return -ENOMEM;
+
+	*routes = dr;
+	*num_routes = num_dr;
+
+	return 0;
+}
+
+static int avs_create_dapm_widgets(struct device *dev, int ssp_port,
+				   struct snd_soc_dapm_widget **widgets, int *num_widgets)
+{
+	struct snd_soc_dapm_widget *dw;
+	const int num_dw = 2;
+
+	dw = devm_kcalloc(dev, num_dw, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	dw[0].id = snd_soc_dapm_hp;
+	dw[0].reg = SND_SOC_NOPM;
+	dw[0].name = devm_kasprintf(dev, GFP_KERNEL, "ssp%dpb", ssp_port);
+	if (!dw[0].name)
+		return -ENOMEM;
+
+	dw[1].id = snd_soc_dapm_mic;
+	dw[1].reg = SND_SOC_NOPM;
+	dw[1].name = devm_kasprintf(dev, GFP_KERNEL, "ssp%dcp", ssp_port);
+	if (!dw[1].name)
+		return -ENOMEM;
+
+	*widgets = dw;
+	*num_widgets = num_dw;
+
+	return 0;
+}
+
+static int avs_i2s_test_probe(struct platform_device *pdev)
+{
+	struct snd_soc_dapm_widget *widgets;
+	struct snd_soc_dapm_route *routes;
+	struct snd_soc_dai_link *dai_link;
+	struct snd_soc_acpi_mach *mach;
+	struct snd_soc_card *card;
+	struct device *dev = &pdev->dev;
+	const char *pname;
+	int num_routes, num_widgets;
+	int ssp_port, ret;
+
+	mach = dev_get_platdata(dev);
+	pname = mach->mach_params.platform;
+	ssp_port = __ffs(mach->mach_params.i2s_link_mask);
+
+	card = devm_kzalloc(dev, sizeof(*card), GFP_KERNEL);
+	if (!card)
+		return -ENOMEM;
+
+	card->name = devm_kasprintf(dev, GFP_KERNEL, "ssp%ld-loopback", ssp_port);
+	if (!card->name)
+		return -ENOMEM;
+
+	ret = avs_create_dai_link(dev, pname, ssp_port, &dai_link);
+	if (ret) {
+		dev_err(dev, "Failed to create dai link: %d\n", ret);
+		return ret;
+	}
+
+	ret = avs_create_dapm_routes(dev, ssp_port, &routes, &num_routes);
+	if (ret) {
+		dev_err(dev, "Failed to create dapm routes: %d\n", ret);
+		return ret;
+	}
+
+	ret = avs_create_dapm_widgets(dev, ssp_port, &widgets, &num_widgets);
+	if (ret) {
+		dev_err(dev, "Failed to create dapm widgets: %d\n", ret);
+		return ret;
+	}
+
+	card->dev = dev;
+	card->owner = THIS_MODULE;
+	card->dai_link = dai_link;
+	card->num_links = 1;
+	card->dapm_routes = routes;
+	card->num_dapm_routes = num_routes;
+	card->dapm_widgets = widgets;
+	card->num_dapm_widgets = num_widgets;
+	card->fully_routed = true;
+
+	ret = snd_soc_fixup_dai_links_platform_name(card, pname);
+	if (ret)
+		return ret;
+
+	return devm_snd_soc_register_card(dev, card);
+}
+
+static struct platform_driver avs_i2s_test_driver = {
+	.probe = avs_i2s_test_probe,
+	.driver = {
+		.name = "avs_i2s_test",
+		.pm = &snd_soc_pm_ops,
+	},
+};
+
+module_platform_driver(avs_i2s_test_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:avs_i2s_test");