USB: gadget: f_audio_source: New gadget driver for audio output
This driver presents a standard USB audio class interface to the host
and an ALSA PCM device to userspace
Signed-off-by: Mike Lockwood <lockwood@google.com>
Change-Id: Ie20264ac86d21a1b1366491273034b755366d3c3
diff --git a/drivers/usb/gadget/android.c b/drivers/usb/gadget/android.c
index f728295..64f4657 100644
--- a/drivers/usb/gadget/android.c
+++ b/drivers/usb/gadget/android.c
@@ -50,6 +50,7 @@
#include "f_rmnet_sdio.c"
#include "f_rmnet_smd_sdio.c"
#include "f_rmnet.c"
+#include "f_audio_source.c"
#include "f_mass_storage.c"
#include "u_serial.c"
#include "u_sdio.c"
@@ -1602,6 +1603,68 @@
.ctrlrequest = accessory_function_ctrlrequest,
};
+static int audio_source_function_init(struct android_usb_function *f,
+ struct usb_composite_dev *cdev)
+{
+ struct audio_source_config *config;
+
+ config = kzalloc(sizeof(struct audio_source_config), GFP_KERNEL);
+ if (!config)
+ return -ENOMEM;
+ config->card = -1;
+ config->device = -1;
+ f->config = config;
+ return 0;
+}
+
+static void audio_source_function_cleanup(struct android_usb_function *f)
+{
+ kfree(f->config);
+}
+
+static int audio_source_function_bind_config(struct android_usb_function *f,
+ struct usb_configuration *c)
+{
+ struct audio_source_config *config = f->config;
+
+ return audio_source_bind_config(c, config);
+}
+
+static void audio_source_function_unbind_config(struct android_usb_function *f,
+ struct usb_configuration *c)
+{
+ struct audio_source_config *config = f->config;
+
+ config->card = -1;
+ config->device = -1;
+}
+
+static ssize_t audio_source_pcm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct android_usb_function *f = dev_get_drvdata(dev);
+ struct audio_source_config *config = f->config;
+
+ /* print PCM card and device numbers */
+ return sprintf(buf, "%d %d\n", config->card, config->device);
+}
+
+static DEVICE_ATTR(pcm, S_IRUGO | S_IWUSR, audio_source_pcm_show, NULL);
+
+static struct device_attribute *audio_source_function_attributes[] = {
+ &dev_attr_pcm,
+ NULL
+};
+
+static struct android_usb_function audio_source_function = {
+ .name = "audio_source",
+ .init = audio_source_function_init,
+ .cleanup = audio_source_function_cleanup,
+ .bind_config = audio_source_function_bind_config,
+ .unbind_config = audio_source_function_unbind_config,
+ .attributes = audio_source_function_attributes,
+};
+
static int android_uasp_connect_cb(bool connect)
{
/*
@@ -1671,6 +1734,7 @@
&rndis_qc_function,
&mass_storage_function,
&accessory_function,
+ &audio_source_function,
&uasp_function,
NULL
};