ASoC: rsrc-card: add Renesas sampling rate convert sound card support

Renesas sound card has "sampling rate convert" feature which
should be implemented via DPCM.
But, sound card driver point of view, it is difficult to add
this DPCM feature on simple-card driver. Especially, DT binding
support is very difficult.

This patch implements DPCM feature on DT as Renesas specific sound card.
This new driver is copied from current simple-card driver.
Main difference between simple-card and this driver are...
 1. removed unused feature from simple-card
 2. removed driver named prefix from DT property
 3. CPU will be FE, CODEC will be BE with snd-soc-dummy
 4. it supports sampling rate convert via .be_hw_params_fixup
 5. board specific routing is implemented in driver
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/renesas,rsrc-card.txt

+Renesas Sampling Rate Convert Sound Card:
+
+Renesas Sampling Rate Convert Sound Card specifies audio DAI connections of SoC <-> codec.
+
+Required properties:
+
+- compatible				: "renesas,rsrc-card,<board>"
+					  Examples with soctypes are:
+					    - "renesas,rsrc-card,lager"
+					    - "renesas,rsrc-card,koelsch"
+Optional properties:
+
+- card_name				: User specified audio sound card name, one string
+					  property.
+- cpu					: CPU   sub-node
+- codec					: CODEC sub-node
+
+Optional subnode properties:
+
+- format				: CPU/CODEC common audio format.
+					  "i2s", "right_j", "left_j" , "dsp_a"
+					  "dsp_b", "ac97", "pdm", "msb", "lsb"
+- frame-master				: Indicates dai-link frame master.
+					  phandle to a cpu or codec subnode.
+- bitclock-master			: Indicates dai-link bit clock master.
+					  phandle to a cpu or codec subnode.
+- bitclock-inversion			: bool property. Add this if the
+					  dai-link uses bit clock inversion.
+- frame-inversion			: bool property. Add this if the
+					  dai-link uses frame clock inversion.
+
+Required CPU/CODEC subnodes properties:
+
+- sound-dai				: phandle and port of CPU/CODEC
+
+Optional CPU/CODEC subnodes properties:
+
+- clocks / system-clock-frequency	: specify subnode's clock if needed.
+					  it can be specified via "clocks" if system has
+					  clock node (= common clock), or "system-clock-frequency"
+					  (if system doens't support common clock)
+					  If a clock is specified, it is
+					  enabled with clk_prepare_enable()
+					  in dai startup() and disabled with
+					  clk_disable_unprepare() in dai
+					  shutdown().
+
+Example
+
+sound {
+	compatible = "renesas,rsrc-card,lager";
+
+	card-name = "rsnd-ak4643";
+	format = "left_j";
+	bitclock-master = <&sndcodec>;
+	frame-master = <&sndcodec>;
+
+	sndcpu: cpu {
+		sound-dai = <&rcar_sound>;
+	};
+
+	sndcodec: codec {
+		sound-dai = <&ak4643>;
+		system-clock-frequency = <11289600>;
+	};
+};

sound/soc/sh/Kconfig

@@ -41,6 +41,11 @@ config SND_SOC_RCAR
 	help
 	  This option enables R-Car SUR/SCU/SSIU/SSI sound support
 
+config SND_SOC_RSRC_CARD
+	tristate "Renesas Sampling Rate Convert Sound Card"
+	help
+	  This option enables simple sound if you need sampling rate convert
+
 ##
 ## Boards
 ##

sound/soc/sh/rcar/Makefile

 snd-soc-rcar-objs	:= core.o gen.o dma.o src.o adg.o ssi.o dvc.o
-obj-$(CONFIG_SND_SOC_RCAR)	+= snd-soc-rcar.o
\ No newline at end of file
+obj-$(CONFIG_SND_SOC_RCAR)	+= snd-soc-rcar.o
+
+snd-soc-rsrc-card-objs	:= rsrc-card.o
+obj-$(CONFIG_SND_SOC_RSRC_CARD)	+= snd-soc-rsrc-card.o

sound/soc/sh/rcar/rsrc-card.c

+/*
+ * Renesas Sampling Rate Convert Sound Card for DPCM
+ *
+ * Copyright (C) 2015 Renesas Solutions Corp.
+ * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ *
+ * based on ${LINUX}/sound/soc/generic/simple-card.c
+ *
+ * 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.
+ */
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <sound/jack.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+struct rsrc_card_of_data {
+	const char *prefix;
+	const struct snd_soc_dapm_route *routes;
+	int num_routes;
+};
+
+static const struct snd_soc_dapm_route routes_ssi0_ak4642[] = {
+	{"ak4642 Playback", NULL, "DAI0 Playback"},
+	{"DAI0 Capture", NULL, "ak4642 Capture"},
+};
+
+static const struct rsrc_card_of_data routes_of_ssi0_ak4642 = {
+	.prefix		= "ak4642",
+	.routes		= routes_ssi0_ak4642,
+	.num_routes	= ARRAY_SIZE(routes_ssi0_ak4642),
+};
+
+static const struct of_device_id rsrc_card_of_match[] = {
+	{ .compatible = "renesas,rsrc-card,lager",	.data = &routes_of_ssi0_ak4642 },
+	{ .compatible = "renesas,rsrc-card,koelsch",	.data = &routes_of_ssi0_ak4642 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rsrc_card_of_match);
+
+struct rsrc_card_dai {
+	const char *name;
+	unsigned int fmt;
+	unsigned int sysclk;
+	struct clk *clk;
+};
+
+#define RSRC_FB_NUM	2 /* FE/BE */
+#define IDX_CPU		0
+#define IDX_CODEC	1
+struct rsrc_card_priv {
+	struct snd_soc_card snd_card;
+	struct rsrc_card_dai_props {
+		struct rsrc_card_dai cpu_dai;
+		struct rsrc_card_dai codec_dai;
+	} dai_props[RSRC_FB_NUM];
+	struct snd_soc_codec_conf codec_conf;
+	struct snd_soc_dai_link dai_link[RSRC_FB_NUM];
+};
+
+#define rsrc_priv_to_dev(priv) ((priv)->snd_card.dev)
+#define rsrc_priv_to_link(priv, i) ((priv)->snd_card.dai_link + i)
+#define rsrc_priv_to_props(priv, i) ((priv)->dai_props + i)
+#define rsrc_dev_to_of_data(dev) (of_match_device(rsrc_card_of_match, (dev))->data)
+
+static int rsrc_card_startup(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct rsrc_card_priv *priv =	snd_soc_card_get_drvdata(rtd->card);
+	struct rsrc_card_dai_props *dai_props =
+		&priv->dai_props[rtd - rtd->card->rtd];
+	int ret;
+
+	ret = clk_prepare_enable(dai_props->cpu_dai.clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(dai_props->codec_dai.clk);
+	if (ret)
+		clk_disable_unprepare(dai_props->cpu_dai.clk);
+
+	return ret;
+}
+
+static void rsrc_card_shutdown(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct rsrc_card_priv *priv =	snd_soc_card_get_drvdata(rtd->card);
+	struct rsrc_card_dai_props *dai_props =
+		&priv->dai_props[rtd - rtd->card->rtd];
+
+	clk_disable_unprepare(dai_props->cpu_dai.clk);
+
+	clk_disable_unprepare(dai_props->codec_dai.clk);
+}
+
+static struct snd_soc_ops rsrc_card_ops = {
+	.startup = rsrc_card_startup,
+	.shutdown = rsrc_card_shutdown,
+};
+
+static int __rsrc_card_dai_init(struct snd_soc_dai *dai,
+				struct rsrc_card_dai *set)
+{
+	int ret;
+
+	if (set->fmt) {
+		ret = snd_soc_dai_set_fmt(dai, set->fmt);
+		if (ret && ret != -ENOTSUPP) {
+			dev_err(dai->dev, "set_fmt error\n");
+			goto err;
+		}
+	}
+
+	if (set->sysclk) {
+		ret = snd_soc_dai_set_sysclk(dai, 0, set->sysclk, 0);
+		if (ret && ret != -ENOTSUPP) {
+			dev_err(dai->dev, "set_sysclk error\n");
+			goto err;
+		}
+	}
+
+	ret = 0;
+
+err:
+	return ret;
+}
+
+static int rsrc_card_dai_init(struct snd_soc_pcm_runtime *rtd)
+{
+	struct rsrc_card_priv *priv =	snd_soc_card_get_drvdata(rtd->card);
+	struct snd_soc_dai *codec = rtd->codec_dai;
+	struct snd_soc_dai *cpu = rtd->cpu_dai;
+	struct rsrc_card_dai_props *dai_props;
+	int num, ret;
+
+	num = rtd - rtd->card->rtd;
+	dai_props = &priv->dai_props[num];
+	ret = __rsrc_card_dai_init(codec, &dai_props->codec_dai);
+	if (ret < 0)
+		return ret;
+
+	ret = __rsrc_card_dai_init(cpu, &dai_props->cpu_dai);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int
+rsrc_card_sub_parse_of(struct rsrc_card_priv *priv,
+		       struct device_node *np,
+		       struct rsrc_card_dai *dai,
+		       struct snd_soc_dai_link *dai_link,
+		       int *args_count)
+{
+	struct device *dev = rsrc_priv_to_dev(priv);
+	const struct rsrc_card_of_data *of_data = rsrc_dev_to_of_data(dev);
+	struct of_phandle_args args;
+	struct device_node **p_node;
+	struct clk *clk;
+	const char **dai_name;
+	const char **name;
+	u32 val;
+	int ret;
+
+	if (args_count) {
+		p_node		= &dai_link->cpu_of_node;
+		dai_name	= &dai_link->cpu_dai_name;
+		name		= &dai_link->cpu_name;
+	} else {
+		p_node		= &dai_link->codec_of_node;
+		dai_name	= &dai_link->codec_dai_name;
+		name		= &dai_link->codec_name;
+	}
+
+	if (!np) {
+		/* use snd-soc-dummy */
+		*p_node		= NULL;
+		*dai_name	= "snd-soc-dummy-dai";
+		*name		= "snd-soc-dummy";
+		return 0;
+	}
+
+	/*
+	 * Get node via "sound-dai = <&phandle port>"
+	 * it will be used as xxx_of_node on soc_bind_dai_link()
+	 */
+	ret = of_parse_phandle_with_args(np, "sound-dai",
+					 "#sound-dai-cells", 0, &args);
+	if (ret)
+		return ret;
+
+	*p_node = args.np;
+
+	/* Get dai->name */
+	ret = snd_soc_of_get_dai_name(np, dai_name);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * FIXME
+	 *
+	 * rsrc assumes DPCM playback/capture
+	 */
+	dai_link->dpcm_playback = 1;
+	dai_link->dpcm_capture = 1;
+
+	if (args_count) {
+		*args_count = args.args_count;
+		dai_link->dynamic = 1;
+	} else {
+		dai_link->no_pcm = 1;
+		priv->codec_conf.of_node = (*p_node);
+		priv->codec_conf.name_prefix = of_data->prefix;
+	}
+
+	/*
+	 * Parse dai->sysclk come from "clocks = <&xxx>"
+	 * (if system has common clock)
+	 *  or "system-clock-frequency = <xxx>"
+	 *  or device's module clock.
+	 */
+	if (of_property_read_bool(np, "clocks")) {
+		clk = of_clk_get(np, 0);
+		if (IS_ERR(clk)) {
+			ret = PTR_ERR(clk);
+			return ret;
+		}
+
+		dai->sysclk = clk_get_rate(clk);
+		dai->clk = clk;
+	} else if (!of_property_read_u32(np, "system-clock-frequency", &val)) {
+		dai->sysclk = val;
+	} else {
+		clk = of_clk_get(args.np, 0);
+		if (!IS_ERR(clk))
+			dai->sysclk = clk_get_rate(clk);
+	}
+
+	return 0;
+}
+
+static int rsrc_card_parse_daifmt(struct device_node *node,
+				  struct rsrc_card_priv *priv,
+				  struct device_node *codec,
+				  int idx)
+{
+	struct device_node *bitclkmaster = NULL;
+	struct device_node *framemaster = NULL;
+	struct rsrc_card_dai_props *dai_props = rsrc_priv_to_props(priv, idx);
+	struct rsrc_card_dai *cpu_dai = &dai_props->cpu_dai;
+	struct rsrc_card_dai *codec_dai = &dai_props->codec_dai;
+	unsigned int daifmt;
+
+	daifmt = snd_soc_of_parse_daifmt(node, NULL,
+					 &bitclkmaster, &framemaster);
+	daifmt &= ~SND_SOC_DAIFMT_MASTER_MASK;
+
+	if (!bitclkmaster && !framemaster)
+		return -EINVAL;
+
+	if (codec == bitclkmaster)
+		daifmt |= (codec == framemaster) ?
+			SND_SOC_DAIFMT_CBM_CFM : SND_SOC_DAIFMT_CBM_CFS;
+	else
+		daifmt |= (codec == framemaster) ?
+			SND_SOC_DAIFMT_CBS_CFM : SND_SOC_DAIFMT_CBS_CFS;
+
+	cpu_dai->fmt	= daifmt;
+	codec_dai->fmt	= daifmt;
+
+	of_node_put(bitclkmaster);
+	of_node_put(framemaster);
+
+	return 0;
+}
+
+static int rsrc_card_dai_link_of(struct device_node *node,
+				 struct rsrc_card_priv *priv,
+				 int idx)
+{
+	struct device *dev = rsrc_priv_to_dev(priv);
+	struct snd_soc_dai_link *dai_link = rsrc_priv_to_link(priv, idx);
+	struct rsrc_card_dai_props *dai_props = rsrc_priv_to_props(priv, idx);
+	struct device_node *cpu = NULL;
+	struct device_node *codec = NULL;
+	char *name;
+	char prop[128];
+	int ret, cpu_args;
+
+	cpu = of_get_child_by_name(node, "cpu");
+	codec = of_get_child_by_name(node, "codec");
+
+	if (!cpu || !codec) {
+		ret = -EINVAL;
+		dev_err(dev, "%s: Can't find %s DT node\n", __func__, prop);
+		goto dai_link_of_err;
+	}
+
+	ret = rsrc_card_parse_daifmt(node, priv, codec, idx);
+	if (ret < 0)
+		goto dai_link_of_err;
+
+	ret = rsrc_card_sub_parse_of(priv, (idx == IDX_CPU) ? cpu : NULL,
+				     &dai_props->cpu_dai,
+				     dai_link,
+				     &cpu_args);
+	if (ret < 0)
+		goto dai_link_of_err;
+
+	ret = rsrc_card_sub_parse_of(priv, (idx == IDX_CODEC) ? codec : NULL,
+				     &dai_props->codec_dai,
+				     dai_link,
+				     NULL);
+	if (ret < 0)
+		goto dai_link_of_err;
+
+	if (!dai_link->cpu_dai_name || !dai_link->codec_dai_name) {
+		ret = -EINVAL;
+		goto dai_link_of_err;
+	}
+
+	/* Simple Card assumes platform == cpu */
+	dai_link->platform_of_node = dai_link->cpu_of_node;
+
+	/* DAI link name is created from CPU/CODEC dai name */
+	name = devm_kzalloc(dev,
+			    strlen(dai_link->cpu_dai_name)   +
+			    strlen(dai_link->codec_dai_name) + 2,
+			    GFP_KERNEL);
+	if (!name) {
+		ret = -ENOMEM;
+		goto dai_link_of_err;
+	}
+
+	sprintf(name, "%s-%s", dai_link->cpu_dai_name,
+		dai_link->codec_dai_name);
+	dai_link->name = dai_link->stream_name = name;
+	dai_link->ops = &rsrc_card_ops;
+	dai_link->init = rsrc_card_dai_init;
+
+	dev_dbg(dev, "\tname : %s\n", dai_link->stream_name);
+	dev_dbg(dev, "\tcpu : %s / %04x / %d\n",
+		dai_link->cpu_dai_name,
+		dai_props->cpu_dai.fmt,
+		dai_props->cpu_dai.sysclk);
+	dev_dbg(dev, "\tcodec : %s / %04x / %d\n",
+		dai_link->codec_dai_name,
+		dai_props->codec_dai.fmt,
+		dai_props->codec_dai.sysclk);
+
+	/*
+	 * In soc_bind_dai_link() will check cpu name after
+	 * of_node matching if dai_link has cpu_dai_name.
+	 * but, it will never match if name was created by
+	 * fmt_single_name() remove cpu_dai_name if cpu_args
+	 * was 0. See:
+	 *	fmt_single_name()
+	 *	fmt_multiple_name()
+	 */
+	if (!cpu_args)
+		dai_link->cpu_dai_name = NULL;
+
+dai_link_of_err:
+	of_node_put(cpu);
+	of_node_put(codec);
+
+	return ret;
+}
+
+static int rsrc_card_parse_of(struct device_node *node,
+			      struct rsrc_card_priv *priv)
+{
+	struct device *dev = rsrc_priv_to_dev(priv);
+	const struct rsrc_card_of_data *of_data = rsrc_dev_to_of_data(dev);
+	int ret;
+	int i;
+
+	if (!node)
+		return -EINVAL;
+
+	/* Parse the card name from DT */
+	snd_soc_of_parse_card_name(&priv->snd_card, "card-name");
+
+	/* DAPM routes */
+	priv->snd_card.of_dapm_routes		= of_data->routes;
+	priv->snd_card.num_of_dapm_routes	= of_data->num_routes;
+
+	dev_dbg(dev, "New rsrc-audio-card: %s\n", priv->snd_card.name ?
+		priv->snd_card.name : "");
+
+	/* FE/BE */
+	for (i = 0; i < RSRC_FB_NUM; i++) {
+		ret = rsrc_card_dai_link_of(node, priv, i);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (!priv->snd_card.name)
+		priv->snd_card.name = priv->snd_card.dai_link->name;
+
+	return 0;
+}
+
+/* Decrease the reference count of the device nodes */
+static int rsrc_card_unref(struct snd_soc_card *card)
+{
+	struct snd_soc_dai_link *dai_link;
+	int num_links;
+
+	for (num_links = 0, dai_link = card->dai_link;
+	     num_links < card->num_links;
+	     num_links++, dai_link++) {
+		of_node_put(dai_link->cpu_of_node);
+		of_node_put(dai_link->codec_of_node);
+	}
+	return 0;
+}
+
+static int rsrc_card_probe(struct platform_device *pdev)
+{
+	struct rsrc_card_priv *priv;
+	struct snd_soc_dai_link *dai_link;
+	struct device_node *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	/* Allocate the private data */
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* Init snd_soc_card */
+	priv->snd_card.owner = THIS_MODULE;
+	priv->snd_card.dev = dev;
+	dai_link = priv->dai_link;
+	priv->snd_card.dai_link = dai_link;
+	priv->snd_card.num_links = RSRC_FB_NUM;
+	priv->snd_card.codec_conf = &priv->codec_conf;
+	priv->snd_card.num_configs = 1;
+
+	ret = rsrc_card_parse_of(np, priv);
+	if (ret < 0) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "parse error %d\n", ret);
+		goto err;
+	}
+
+	snd_soc_card_set_drvdata(&priv->snd_card, priv);
+
+	ret = devm_snd_soc_register_card(&pdev->dev, &priv->snd_card);
+	if (ret >= 0)
+		return ret;
+err:
+	rsrc_card_unref(&priv->snd_card);
+
+	return ret;
+}
+
+static int rsrc_card_remove(struct platform_device *pdev)
+{
+	struct snd_soc_card *card = platform_get_drvdata(pdev);
+
+	return rsrc_card_unref(card);
+}
+
+static struct platform_driver rsrc_card = {
+	.driver = {
+		.name = "renesas-src-audio-card",
+		.of_match_table = rsrc_card_of_match,
+	},
+	.probe = rsrc_card_probe,
+	.remove = rsrc_card_remove,
+};
+
+module_platform_driver(rsrc_card);
+
+MODULE_ALIAS("platform:renesas-src-audio-card");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Renesas Sampling Rate Convert Sound Card");
+MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");