[RFC PATCH 3/5] usb: gadget: f_uac1: drop volume/mute functionality

[Ruslan Bilovol <ruslan.bilovol@gmail.com>]

The volume/mute feature unit was dummy implementation
since this driver creation (2009) and never had
real volume control or mute functionality.
Since it was never implemented, drop it and
increase maintainability of the driver.
Those who want real volume/mute support may
revert this patch and add needed handlers

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac1.c | 182 +----------------------------------
 1 file changed, 5 insertions(+), 177 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index f2ac0cb..ba498af 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -17,9 +17,6 @@
 
 #include "u_uac1.h"
 
-static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
-static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);
-
 /*
  * DESCRIPTORS ... most are static, but strings and full
  * configuration descriptors are built on demand.
@@ -49,9 +46,9 @@ static struct usb_interface_descriptor ac_interface_desc = {
 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
 
 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
-/* 1 input terminal, 1 output terminal and 1 feature unit */
+/* 1 input terminal and 1 output terminal */
 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
-	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
+	+ UAC_DT_OUTPUT_TERMINAL_SIZE)
 /* B.3.2  Class-Specific AC Interface Descriptor */
 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
@@ -77,54 +74,15 @@ static struct uac_input_terminal_descriptor input_terminal_desc = {
 	.wChannelConfig =	0x3,
 };
 
-DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
-
-#define FEATURE_UNIT_ID		2
-static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
-	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
-	.bDescriptorType	= USB_DT_CS_INTERFACE,
-	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
-	.bUnitID		= FEATURE_UNIT_ID,
-	.bSourceID		= INPUT_TERMINAL_ID,
-	.bControlSize		= 2,
-	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
-};
-
-static struct usb_audio_control mute_control = {
-	.list = LIST_HEAD_INIT(mute_control.list),
-	.name = "Mute Control",
-	.type = UAC_FU_MUTE,
-	/* Todo: add real Mute control code */
-	.set = generic_set_cmd,
-	.get = generic_get_cmd,
-};
-
-static struct usb_audio_control volume_control = {
-	.list = LIST_HEAD_INIT(volume_control.list),
-	.name = "Volume Control",
-	.type = UAC_FU_VOLUME,
-	/* Todo: add real Volume control code */
-	.set = generic_set_cmd,
-	.get = generic_get_cmd,
-};
-
-static struct usb_audio_control_selector feature_unit = {
-	.list = LIST_HEAD_INIT(feature_unit.list),
-	.id = FEATURE_UNIT_ID,
-	.name = "Mute & Volume Control",
-	.type = UAC_FEATURE_UNIT,
-	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
-};
-
-#define OUTPUT_TERMINAL_ID	3
+#define OUTPUT_TERMINAL_ID	2
 static struct uac1_output_terminal_descriptor output_terminal_desc = {
 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
 	.bDescriptorType	= USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
 	.bTerminalID		= OUTPUT_TERMINAL_ID,
 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
-	.bAssocTerminal		= FEATURE_UNIT_ID,
-	.bSourceID		= FEATURE_UNIT_ID,
+	.bAssocTerminal		= 0,
+	.bSourceID		= INPUT_TERMINAL_ID,
 };
 
 /* B.4.1  Standard AS Interface Descriptor */
@@ -195,7 +153,6 @@ static struct usb_descriptor_header *f_audio_desc[] = {
 
 	(struct usb_descriptor_header *)&input_terminal_desc,
 	(struct usb_descriptor_header *)&output_terminal_desc,
-	(struct usb_descriptor_header *)&feature_unit_desc,
 
 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
@@ -212,7 +169,6 @@ enum {
 	STR_AC_IF,
 	STR_INPUT_TERMINAL,
 	STR_INPUT_TERMINAL_CH_NAMES,
-	STR_FEAT_DESC_0,
 	STR_OUTPUT_TERMINAL,
 	STR_AS_IF_ALT0,
 	STR_AS_IF_ALT1,
@@ -222,7 +178,6 @@ static struct usb_string strings_uac1[] = {
 	[STR_AC_IF].s = "AC Interface",
 	[STR_INPUT_TERMINAL].s = "Input terminal",
 	[STR_INPUT_TERMINAL_CH_NAMES].s = "Channels",
-	[STR_FEAT_DESC_0].s = "Volume control & mute",
 	[STR_OUTPUT_TERMINAL].s = "Output terminal",
 	[STR_AS_IF_ALT0].s = "AS Interface",
 	[STR_AS_IF_ALT1].s = "AS Interface",
@@ -284,11 +239,6 @@ struct f_audio {
 	struct f_audio_buf *copy_buf;
 	struct work_struct playback_work;
 	struct list_head play_queue;
-
-	/* Control Set command */
-	struct list_head cs;
-	u8 set_cmd;
-	struct usb_audio_control *set_con;
 };
 
 static inline struct f_audio *func_to_audio(struct usb_function *f)
@@ -359,7 +309,6 @@ static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_audio *audio = req->context;
 	int status = req->status;
-	u32 data = 0;
 	struct usb_ep *out_ep = audio->out_ep;
 
 	switch (status) {
@@ -367,92 +316,12 @@ static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
 	case 0:				/* normal completion? */
 		if (ep == out_ep)
 			f_audio_out_ep_complete(ep, req);
-		else if (audio->set_con) {
-			memcpy(&data, req->buf, req->length);
-			audio->set_con->set(audio->set_con, audio->set_cmd,
-					le16_to_cpu(data));
-			audio->set_con = NULL;
-		}
 		break;
 	default:
 		break;
 	}
 }
 
-static int audio_set_intf_req(struct usb_function *f,
-		const struct usb_ctrlrequest *ctrl)
-{
-	struct f_audio		*audio = func_to_audio(f);
-	struct usb_composite_dev *cdev = f->config->cdev;
-	struct usb_request	*req = cdev->req;
-	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
-	u16			len = le16_to_cpu(ctrl->wLength);
-	u16			w_value = le16_to_cpu(ctrl->wValue);
-	u8			con_sel = (w_value >> 8) & 0xFF;
-	u8			cmd = (ctrl->bRequest & 0x0F);
-	struct usb_audio_control_selector *cs;
-	struct usb_audio_control *con;
-
-	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
-			ctrl->bRequest, w_value, len, id);
-
-	list_for_each_entry(cs, &audio->cs, list) {
-		if (cs->id == id) {
-			list_for_each_entry(con, &cs->control, list) {
-				if (con->type == con_sel) {
-					audio->set_con = con;
-					break;
-				}
-			}
-			break;
-		}
-	}
-
-	audio->set_cmd = cmd;
-	req->context = audio;
-	req->complete = f_audio_complete;
-
-	return len;
-}
-
-static int audio_get_intf_req(struct usb_function *f,
-		const struct usb_ctrlrequest *ctrl)
-{
-	struct f_audio		*audio = func_to_audio(f);
-	struct usb_composite_dev *cdev = f->config->cdev;
-	struct usb_request	*req = cdev->req;
-	int			value = -EOPNOTSUPP;
-	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
-	u16			len = le16_to_cpu(ctrl->wLength);
-	u16			w_value = le16_to_cpu(ctrl->wValue);
-	u8			con_sel = (w_value >> 8) & 0xFF;
-	u8			cmd = (ctrl->bRequest & 0x0F);
-	struct usb_audio_control_selector *cs;
-	struct usb_audio_control *con;
-
-	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
-			ctrl->bRequest, w_value, len, id);
-
-	list_for_each_entry(cs, &audio->cs, list) {
-		if (cs->id == id) {
-			list_for_each_entry(con, &cs->control, list) {
-				if (con->type == con_sel && con->get) {
-					value = con->get(con, cmd);
-					break;
-				}
-			}
-			break;
-		}
-	}
-
-	req->context = audio;
-	req->complete = f_audio_complete;
-	len = min_t(size_t, sizeof(value), len);
-	memcpy(req->buf, &value, len);
-
-	return len;
-}
-
 static int audio_set_endpoint_req(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
@@ -531,14 +400,6 @@ f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 	 * activation uses set_alt().
 	 */
 	switch (ctrl->bRequestType) {
-	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
-		value = audio_set_intf_req(f, ctrl);
-		break;
-
-	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
-		value = audio_get_intf_req(f, ctrl);
-		break;
-
 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
 		value = audio_set_endpoint_req(f, ctrl);
 		break;
@@ -689,7 +550,6 @@ f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
 	input_terminal_desc.iTerminal = us[STR_INPUT_TERMINAL].id;
 	input_terminal_desc.iChannelNames = us[STR_INPUT_TERMINAL_CH_NAMES].id;
-	feature_unit_desc.iFeature = us[STR_FEAT_DESC_0].id;
 	output_terminal_desc.iTerminal = us[STR_OUTPUT_TERMINAL].id;
 	as_interface_alt_0_desc.iInterface = us[STR_AS_IF_ALT0].id;
 	as_interface_alt_1_desc.iInterface = us[STR_AS_IF_ALT1].id;
@@ -734,36 +594,6 @@ fail:
 
 /*-------------------------------------------------------------------------*/
 
-static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
-{
-	con->data[cmd] = value;
-
-	return 0;
-}
-
-static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
-{
-	return con->data[cmd];
-}
-
-/* Todo: add more control selecotor dynamically */
-static int control_selector_init(struct f_audio *audio)
-{
-	INIT_LIST_HEAD(&audio->cs);
-	list_add(&feature_unit.list, &audio->cs);
-
-	INIT_LIST_HEAD(&feature_unit.control);
-	list_add(&mute_control.list, &feature_unit.control);
-	list_add(&volume_control.list, &feature_unit.control);
-
-	volume_control.data[UAC__CUR] = 0xffc0;
-	volume_control.data[UAC__MIN] = 0xe3a0;
-	volume_control.data[UAC__MAX] = 0xfff0;
-	volume_control.data[UAC__RES] = 0x0030;
-
-	return 0;
-}
-
 static inline struct f_uac1_opts *to_f_uac1_opts(struct config_item *item)
 {
 	return container_of(to_config_group(item), struct f_uac1_opts,
@@ -970,8 +800,6 @@ static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
 	audio->card.func.disable = f_audio_disable;
 	audio->card.func.free_func = f_audio_free;
 
-	control_selector_init(audio);
-
 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
 
 	return &audio->card.func;
-- 
1.9.1