[RFC,01/14] ASoC: Add SOC USB APIs for adding an USB backend

Commit Message

Wesley Cheng Dec. 23, 2022, 11:31 p.m. UTC

Some platforms may want to register its USB port to be handled by the ASoC
framework.  Audio playback/capture support is also handled entirely by the
vendor ASoC drivers.

Signed-off-by: Wesley Cheng <[e-mail]>
---
 include/sound/soc-usb.h | 31 +++++++++++++++++++
 sound/soc/Makefile      |  2 +-
 sound/soc/soc-usb.c     | 66 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 include/sound/soc-usb.h
 create mode 100644 sound/soc/soc-usb.c

Comments

Greg KH Dec. 24, 2022, 6:48 a.m. UTC | #1

On Fri, Dec 23, 2022 at 03:31:47PM -0800, Wesley Cheng wrote:
> diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c
> new file mode 100644
> index 000000000000..c6c376960e4d
> --- /dev/null
> +++ b/sound/soc/soc-usb.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +#include <linux/usb.h>
> +#include <sound/soc.h>
> +#include <sound/soc-usb.h>
> +#include "../usb/card.h"
> +
> +struct snd_soc_usb *ctx;

Note, this will not work.  You can not only have "one" state for a
system like this.  That just broke any system with more than one
controller, of which we have millions.

This has to be dynamic for any number of controllers in the system, like
the sound and USB core can handle.  Any requirement of "there can be
only one!" will obviously never be acceptable as that is not how Linux
works.

thanks,

greg k-h

Patch

diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h
new file mode 100644
index 000000000000..7d52e5d2371c
--- /dev/null
+++ b/include/sound/soc-usb.h
@@ -0,0 +1,31 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef __LINUX_SND_SOC_USB_H
+#define __LINUX_SND_SOC_USB_H
+
+/**
+ * struct snd_soc_usb
+ * @component - Reference to DAPM component
+ * @connection_status_cb - callback to notify connection events
+ * @priv_data - vendor data
+ **/
+struct snd_soc_usb {
+	struct snd_soc_component *component;
+	int (*connection_status_cb)(struct snd_soc_usb *usb, int card_idx,
+				int connected);
+	void *priv_data;
+};
+
+int snd_soc_usb_connect(int card_idx);
+int snd_soc_usb_disconnect(void);
+void snd_soc_usb_set_priv_data(void *priv);
+void *snd_soc_usb_get_priv_data(void);
+
+struct snd_soc_usb *snd_soc_usb_add_port(struct device *dev,
+			int (*connection_cb)(struct snd_soc_usb *usb, int card_idx,
+			int connected));
+int snd_soc_usb_remove_port(void);
+#endif
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index 507eaed1d6a1..3305ceb59d84 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -1,5 +1,5 @@ 
 # SPDX-License-Identifier: GPL-2.0
-snd-soc-core-objs := soc-core.o soc-dapm.o soc-jack.o soc-utils.o soc-dai.o soc-component.o
+snd-soc-core-objs := soc-core.o soc-dapm.o soc-jack.o soc-usb.o soc-utils.o soc-dai.o soc-component.o
 snd-soc-core-objs += soc-pcm.o soc-devres.o soc-ops.o soc-link.o soc-card.o
 snd-soc-core-$(CONFIG_SND_SOC_COMPRESS) += soc-compress.o
 
diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c
new file mode 100644
index 000000000000..c6c376960e4d
--- /dev/null
+++ b/sound/soc/soc-usb.c
@@ -0,0 +1,66 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#include <linux/usb.h>
+#include <sound/soc.h>
+#include <sound/soc-usb.h>
+#include "../usb/card.h"
+
+struct snd_soc_usb *ctx;
+
+void *snd_soc_usb_get_priv_data(void)
+{
+	if (ctx)
+		return ctx->priv_data;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_get_priv_data);
+
+void snd_soc_usb_set_priv_data(void *priv)
+{
+	if (ctx)
+		ctx->priv_data = priv;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_set_priv_data);
+
+struct snd_soc_usb *snd_soc_usb_add_port(struct device *dev,
+			int (*connection_cb)(struct snd_soc_usb *usb, int card_idx,
+			int connected))
+{
+	struct snd_soc_usb *usb;
+
+	usb = devm_kzalloc(dev, sizeof(*usb), GFP_KERNEL);
+	if (!usb)
+		return ERR_PTR(-ENOMEM);
+
+	usb->connection_status_cb = connection_cb;
+	ctx = usb;
+
+	return usb;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_add_port);
+
+int snd_soc_usb_remove_port(void)
+{
+	ctx = NULL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_remove_port);
+
+int snd_soc_usb_connect(int card_idx)
+{
+	if (ctx && ctx->connection_status_cb)
+		ctx->connection_status_cb(ctx, card_idx, 1);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_connect);
+
+int snd_soc_usb_disconnect(void)
+{
+	if (ctx && ctx->connection_status_cb)
+		ctx->connection_status_cb(ctx, -1, 0);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_disconnect);