usb:gadget:audio_source: Move to USB_FUNCTION API

This patch adds support to use audio_source
gadget function through DECLARE_USB_FUNCTION_INIT
interface.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Change-Id: I1fc6c9ea07105ae4eb785eebd3bb925bfdd8bc6b

3 files changed, 239 insertions, 7 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 6977b224218c..f550989173bf 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -203,6 +203,9 @@ config USB_F_MTP
 	tristate
 
 config USB_F_PTP
+        tristate
+
+config USB_F_AUDIO_SRC
 	tristate
 
 choice
@@ -391,6 +394,13 @@ config USB_CONFIGFS_F_PTP
 	help
 	  USB gadget PTP support
 
+config USB_CONFIGFS_F_AUDIO_SRC
+	boolean "Audio Source gadget"
+	depends on USB_CONFIGFS
+	select USB_F_AUDIO_SRC
+	help
+	  USB gadget Audio Source support
+
 config USB_CONFIGFS_UEVENT
 	boolean "Uevent notification of Gadget state"
 	depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 502c379cce80..386ed6343e33 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -15,3 +15,5 @@ usb_f_mtp-y			:= f_mtp.o
 obj-$(CONFIG_USB_F_MTP)		+= usb_f_mtp.o
 usb_f_ptp-y			:= f_ptp.o
 obj-$(CONFIG_USB_F_PTP)		+= usb_f_ptp.o
+usb_f_audio_source-y		:= f_audio_source.o
+obj-$(CONFIG_USB_F_AUDIO_SRC)	+= usb_f_audio_source.o
diff --git a/drivers/usb/gadget/f_audio_source.c b/drivers/usb/gadget/f_audio_source.c
index 4b9786b48950..39645be93502 100644
--- a/drivers/usb/gadget/f_audio_source.c
+++ b/drivers/usb/gadget/f_audio_source.c
@@ -21,6 +21,13 @@
 #include <sound/initval.h>
 #include <sound/pcm.h>
 
+#include <linux/usb.h>
+#include <linux/usb_usual.h>
+#include <linux/usb/ch9.h>
+#include <linux/configfs.h>
+#include <linux/usb/composite.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
 #define SAMPLE_RATE 44100
 #define FRAMES_PER_MSEC (SAMPLE_RATE / 1000)
 
@@ -32,6 +39,7 @@
 #define AUDIO_AC_INTERFACE	0
 #define AUDIO_AS_INTERFACE	1
 #define AUDIO_NUM_INTERFACES	2
+#define MAX_INST_NAME_LEN     40
 
 /* B.3.1  Standard AC Interface Descriptor */
 static struct usb_interface_descriptor ac_interface_desc = {
@@ -259,6 +267,7 @@ struct audio_dev {
 	ktime_t				start_time;
 	/* number of frames sent since start_time */
 	s64				frames_sent;
+	struct audio_source_config	*config;
 };
 
 static inline struct audio_dev *func_to_audio(struct usb_function *f)
@@ -268,6 +277,36 @@ static inline struct audio_dev *func_to_audio(struct usb_function *f)
 
 /*-------------------------------------------------------------------------*/
 
+struct audio_source_instance {
+	struct usb_function_instance func_inst;
+	const char *name;
+	struct audio_source_config *config;
+	struct device *audio_device;
+};
+
+static void audio_source_attr_release(struct config_item *item);
+
+static struct configfs_item_operations audio_source_item_ops = {
+	.release        = audio_source_attr_release,
+};
+
+static struct config_item_type audio_source_func_type = {
+	.ct_item_ops    = &audio_source_item_ops,
+	.ct_owner       = THIS_MODULE,
+};
+
+static ssize_t audio_source_pcm_show(struct device *dev,
+		struct device_attribute *attr, char *buf);
+
+static DEVICE_ATTR(pcm, S_IRUGO, audio_source_pcm_show, NULL);
+
+static struct device_attribute *audio_source_function_attributes[] = {
+	&dev_attr_pcm,
+	NULL
+};
+
+/*--------------------------------------------------------------------------*/
+
 static struct usb_request *audio_request_new(struct usb_ep *ep, int buffer_size)
 {
 	struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
@@ -561,6 +600,13 @@ static void audio_build_desc(struct audio_dev *audio)
 	memcpy(sam_freq, &rate, 3);
 }
 
+
+static int snd_card_setup(struct usb_configuration *c,
+	struct audio_source_config *config);
+static struct audio_source_instance *to_fi_audio_source(
+	const struct usb_function_instance *fi);
+
+
 /* audio function driver setup/binding */
 static int
 audio_bind(struct usb_configuration *c, struct usb_function *f)
@@ -571,6 +617,18 @@ audio_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_ep *ep;
 	struct usb_request *req;
 	int i;
+	int err;
+
+	if (IS_ENABLED(CONFIG_USB_CONFIGFS)) {
+		struct audio_source_instance *fi_audio =
+				to_fi_audio_source(f->fi);
+		struct audio_source_config *config =
+				fi_audio->config;
+
+		err = snd_card_setup(c, config);
+		if (err)
+			return err;
+	}
 
 	audio_build_desc(audio);
 
@@ -636,6 +694,16 @@ audio_unbind(struct usb_configuration *c, struct usb_function *f)
 	audio->pcm = NULL;
 	audio->substream = NULL;
 	audio->in_ep = NULL;
+
+	if (IS_ENABLED(CONFIG_USB_CONFIGFS)) {
+		struct audio_source_instance *fi_audio =
+				to_fi_audio_source(f->fi);
+		struct audio_source_config *config =
+				fi_audio->config;
+
+		config->card = -1;
+		config->device = -1;
+	}
 }
 
 static void audio_pcm_playback_start(struct audio_dev *audio)
@@ -779,8 +847,6 @@ int audio_source_bind_config(struct usb_configuration *c,
 		struct audio_source_config *config)
 {
 	struct audio_dev *audio;
-	struct snd_card *card;
-	struct snd_pcm *pcm;
 	int err;
 
 	config->card = -1;
@@ -788,6 +854,31 @@ int audio_source_bind_config(struct usb_configuration *c,
 
 	audio = &_audio_dev;
 
+	err = snd_card_setup(c, config);
+	if (err)
+		return err;
+
+	err = usb_add_function(c, &audio->func);
+	if (err)
+		goto add_fail;
+
+	return 0;
+
+add_fail:
+	snd_card_free(audio->card);
+	return err;
+}
+
+static int snd_card_setup(struct usb_configuration *c,
+		struct audio_source_config *config)
+{
+	struct audio_dev *audio;
+	struct snd_card *card;
+	struct snd_pcm *pcm;
+	int err;
+
+	audio = &_audio_dev;
+
 	err = snd_card_new(&c->cdev->gadget->dev,
 			SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
 			THIS_MODULE, 0, &card);
@@ -817,18 +908,147 @@ int audio_source_bind_config(struct usb_configuration *c,
 	if (err)
 		goto register_fail;
 
-	err = usb_add_function(c, &audio->func);
-	if (err)
-		goto add_fail;
-
 	config->card = pcm->card->number;
 	config->device = pcm->device;
 	audio->card = card;
 	return 0;
 
-add_fail:
 register_fail:
 pcm_fail:
 	snd_card_free(audio->card);
 	return err;
 }
+
+static struct audio_source_instance *to_audio_source_instance(
+					struct config_item *item)
+{
+	return container_of(to_config_group(item), struct audio_source_instance,
+		func_inst.group);
+}
+
+static struct audio_source_instance *to_fi_audio_source(
+					const struct usb_function_instance *fi)
+{
+	return container_of(fi, struct audio_source_instance, func_inst);
+}
+
+static void audio_source_attr_release(struct config_item *item)
+{
+	struct audio_source_instance *fi_audio = to_audio_source_instance(item);
+
+	usb_put_function_instance(&fi_audio->func_inst);
+}
+
+static int audio_source_set_inst_name(struct usb_function_instance *fi,
+					const char *name)
+{
+	struct audio_source_instance *fi_audio;
+	char *ptr;
+	int name_len;
+
+	name_len = strlen(name) + 1;
+	if (name_len > MAX_INST_NAME_LEN)
+		return -ENAMETOOLONG;
+
+	ptr = kstrndup(name, name_len, GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	fi_audio = to_fi_audio_source(fi);
+	fi_audio->name = ptr;
+
+	return 0;
+}
+
+static void audio_source_free_inst(struct usb_function_instance *fi)
+{
+	struct audio_source_instance *fi_audio;
+
+	fi_audio = to_fi_audio_source(fi);
+	device_destroy(fi_audio->audio_device->class,
+			fi_audio->audio_device->devt);
+	kfree(fi_audio->name);
+	kfree(fi_audio->config);
+}
+
+static ssize_t audio_source_pcm_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct audio_source_instance *fi_audio = dev_get_drvdata(dev);
+	struct audio_source_config *config = fi_audio->config;
+
+	/* print PCM card and device numbers */
+	return sprintf(buf, "%d %d\n", config->card, config->device);
+}
+
+struct device *create_function_device(char *name);
+
+static struct usb_function_instance *audio_source_alloc_inst(void)
+{
+	struct audio_source_instance *fi_audio;
+	struct device_attribute **attrs;
+	struct device_attribute *attr;
+	struct device *dev;
+	void *err_ptr;
+	int err = 0;
+
+	fi_audio = kzalloc(sizeof(*fi_audio), GFP_KERNEL);
+	if (!fi_audio)
+		return ERR_PTR(-ENOMEM);
+
+	fi_audio->func_inst.set_inst_name = audio_source_set_inst_name;
+	fi_audio->func_inst.free_func_inst = audio_source_free_inst;
+
+	fi_audio->config = kzalloc(sizeof(struct audio_source_config),
+							GFP_KERNEL);
+	if (!fi_audio->config) {
+		err_ptr = ERR_PTR(-ENOMEM);
+		goto fail_audio;
+	}
+
+	config_group_init_type_name(&fi_audio->func_inst.group, "",
+						&audio_source_func_type);
+	dev = create_function_device("f_audio_source");
+
+	if (IS_ERR(dev)) {
+		err_ptr = dev;
+		goto fail_audio_config;
+	}
+
+	fi_audio->config->card = -1;
+	fi_audio->config->device = -1;
+	fi_audio->audio_device = dev;
+
+	attrs = audio_source_function_attributes;
+	if (attrs) {
+		while ((attr = *attrs++) && !err)
+			err = device_create_file(dev, attr);
+		if (err) {
+			err_ptr = ERR_PTR(-EINVAL);
+			goto fail_device;
+		}
+	}
+
+	dev_set_drvdata(dev, fi_audio);
+	_audio_dev.config = fi_audio->config;
+
+	return  &fi_audio->func_inst;
+
+fail_device:
+	device_destroy(dev->class, dev->devt);
+fail_audio_config:
+	kfree(fi_audio->config);
+fail_audio:
+	kfree(fi_audio);
+	return err_ptr;
+
+}
+
+static struct usb_function *audio_source_alloc(struct usb_function_instance *fi)
+{
+	return &_audio_dev.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(audio_source, audio_source_alloc_inst,
+			audio_source_alloc);
+MODULE_LICENSE("GPL");