usb: gadget: f_uac1: Expose all string descriptors through configfs.

This makes all string descriptors configurable for the UAC1 gadget
so the user can configure names of terminals/controls/alt modes.

Signed-off-by: Chris Wulff <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/configfs-usb-gadget-uac1

···
 		req_number		the number of pre-allocated requests
 					for both capture and playback
 		function_name		name of the interface
+		p_it_name		playback input terminal name
+		p_it_ch_name		playback channels name
+		p_ot_name		playback output terminal name
+		p_fu_name		playback functional unit name
+		p_alt0_name		playback alt mode 0 name
+		p_alt1_name		playback alt mode 1 name
+		c_it_name		capture input terminal name
+		c_it_ch_name		capture channels name
+		c_ot_name		capture output terminal name
+		c_fu_name		capture functional unit name
+		c_alt0_name		capture alt mode 0 name
+		c_alt1_name		capture alt mode 1 name
 		=====================	=======================================

Documentation/usb/gadget-testing.rst

···
 	req_number       the number of pre-allocated requests for both capture
 	                 and playback
 	function_name    name of the interface
+	p_it_name        playback input terminal name
+	p_it_ch_name     playback channels name
+	p_ot_name        playback output terminal name
+	p_fu_name        playback functional unit name
+	p_alt0_name      playback alt mode 0 name
+	p_alt1_name      playback alt mode 1 name
+	c_it_name        capture input terminal name
+	c_it_ch_name     capture channels name
+	c_ot_name        capture output terminal name
+	c_fu_name        capture functional unit name
+	c_alt0_name      capture alt mode 0 name
+	c_alt1_name      capture alt mode 1 name
 	================ ====================================================
 
 The attributes have sane default values.

drivers/usb/gadget/function/f_uac1.c

···
 	STR_AS_OUT_IF_ALT1,
 	STR_AS_IN_IF_ALT0,
 	STR_AS_IN_IF_ALT1,
+	NUM_STR_DESCRIPTORS,
 };
 
-static struct usb_string strings_uac1[] = {
-	/* [STR_AC_IF].s = DYNAMIC, */
-	[STR_USB_OUT_IT].s = "Playback Input terminal",
-	[STR_USB_OUT_IT_CH_NAMES].s = "Playback Channels",
-	[STR_IO_OUT_OT].s = "Playback Output terminal",
-	[STR_IO_IN_IT].s = "Capture Input terminal",
-	[STR_IO_IN_IT_CH_NAMES].s = "Capture Channels",
-	[STR_USB_IN_OT].s = "Capture Output terminal",
-	[STR_FU_IN].s = "Capture Volume",
-	[STR_FU_OUT].s = "Playback Volume",
-	[STR_AS_OUT_IF_ALT0].s = "Playback Inactive",
-	[STR_AS_OUT_IF_ALT1].s = "Playback Active",
-	[STR_AS_IN_IF_ALT0].s = "Capture Inactive",
-	[STR_AS_IN_IF_ALT1].s = "Capture Active",
-	{ },
-};
+static struct usb_string strings_uac1[NUM_STR_DESCRIPTORS + 1] = {};
 
 static struct usb_gadget_strings str_uac1 = {
 	.language = 0x0409,	/* en-us */
···
 
 	strings_uac1[STR_AC_IF].s = audio_opts->function_name;
 
+	strings_uac1[STR_USB_OUT_IT].s = audio_opts->p_it_name;
+	strings_uac1[STR_USB_OUT_IT_CH_NAMES].s = audio_opts->p_it_ch_name;
+	strings_uac1[STR_IO_OUT_OT].s = audio_opts->p_ot_name;
+	strings_uac1[STR_FU_OUT].s = audio_opts->p_fu_name;
+	strings_uac1[STR_AS_OUT_IF_ALT0].s = audio_opts->p_alt0_name;
+	strings_uac1[STR_AS_OUT_IF_ALT1].s = audio_opts->p_alt1_name;
+
+	strings_uac1[STR_IO_IN_IT].s = audio_opts->c_it_name;
+	strings_uac1[STR_IO_IN_IT_CH_NAMES].s = audio_opts->c_it_ch_name;
+	strings_uac1[STR_USB_IN_OT].s = audio_opts->c_ot_name;
+	strings_uac1[STR_FU_IN].s = audio_opts->c_fu_name;
+	strings_uac1[STR_AS_IN_IF_ALT0].s = audio_opts->c_alt0_name;
+	strings_uac1[STR_AS_IN_IF_ALT1].s = audio_opts->c_alt1_name;
+
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
 	if (IS_ERR(us))
 		return PTR_ERR(us);
···
 UAC1_ATTRIBUTE(s16, c_volume_min);
 UAC1_ATTRIBUTE(s16, c_volume_max);
 UAC1_ATTRIBUTE(s16, c_volume_res);
+
 UAC1_ATTRIBUTE_STRING(function_name);
+
+UAC1_ATTRIBUTE_STRING(p_it_name);
+UAC1_ATTRIBUTE_STRING(p_it_ch_name);
+UAC1_ATTRIBUTE_STRING(p_ot_name);
+UAC1_ATTRIBUTE_STRING(p_fu_name);
+UAC1_ATTRIBUTE_STRING(p_alt0_name);
+UAC1_ATTRIBUTE_STRING(p_alt1_name);
+
+UAC1_ATTRIBUTE_STRING(c_it_name);
+UAC1_ATTRIBUTE_STRING(c_it_ch_name);
+UAC1_ATTRIBUTE_STRING(c_ot_name);
+UAC1_ATTRIBUTE_STRING(c_fu_name);
+UAC1_ATTRIBUTE_STRING(c_alt0_name);
+UAC1_ATTRIBUTE_STRING(c_alt1_name);
 
 static struct configfs_attribute *f_uac1_attrs[] = {
 	&f_uac1_opts_attr_c_chmask,
···
 	&f_uac1_opts_attr_c_volume_res,
 
 	&f_uac1_opts_attr_function_name,
+
+	&f_uac1_opts_attr_p_it_name,
+	&f_uac1_opts_attr_p_it_ch_name,
+	&f_uac1_opts_attr_p_ot_name,
+	&f_uac1_opts_attr_p_fu_name,
+	&f_uac1_opts_attr_p_alt0_name,
+	&f_uac1_opts_attr_p_alt1_name,
+
+	&f_uac1_opts_attr_c_it_name,
+	&f_uac1_opts_attr_c_it_ch_name,
+	&f_uac1_opts_attr_c_ot_name,
+	&f_uac1_opts_attr_c_fu_name,
+	&f_uac1_opts_attr_c_alt0_name,
+	&f_uac1_opts_attr_c_alt1_name,
 
 	NULL,
 };
···
 	opts->req_number = UAC1_DEF_REQ_NUM;
 
 	scnprintf(opts->function_name, sizeof(opts->function_name), "AC Interface");
+
+	scnprintf(opts->p_it_name, sizeof(opts->p_it_name), "Playback Input terminal");
+	scnprintf(opts->p_it_ch_name, sizeof(opts->p_it_ch_name), "Playback Channels");
+	scnprintf(opts->p_ot_name, sizeof(opts->p_ot_name), "Playback Output terminal");
+	scnprintf(opts->p_fu_name, sizeof(opts->p_fu_name), "Playback Volume");
+	scnprintf(opts->p_alt0_name, sizeof(opts->p_alt0_name), "Playback Inactive");
+	scnprintf(opts->p_alt1_name, sizeof(opts->p_alt1_name), "Playback Active");
+
+	scnprintf(opts->c_it_name, sizeof(opts->c_it_name), "Capture Input terminal");
+	scnprintf(opts->c_it_ch_name, sizeof(opts->c_it_ch_name), "Capture Channels");
+	scnprintf(opts->c_ot_name, sizeof(opts->c_ot_name), "Capture Output terminal");
+	scnprintf(opts->c_fu_name, sizeof(opts->c_fu_name), "Capture Volume");
+	scnprintf(opts->c_alt0_name, sizeof(opts->c_alt0_name), "Capture Inactive");
+	scnprintf(opts->c_alt1_name, sizeof(opts->c_alt1_name), "Capture Active");
 
 	return &opts->func_inst;
 }

drivers/usb/gadget/function/u_uac1.h

···
 	int				req_number;
 	unsigned			bound:1;
 
-	char			function_name[32];
+	char			function_name[USB_MAX_STRING_LEN];
+
+	char			p_it_name[USB_MAX_STRING_LEN];
+	char			p_it_ch_name[USB_MAX_STRING_LEN];
+	char			p_ot_name[USB_MAX_STRING_LEN];
+	char			p_fu_name[USB_MAX_STRING_LEN];
+	char			p_alt0_name[USB_MAX_STRING_LEN];
+	char			p_alt1_name[USB_MAX_STRING_LEN];
+
+	char			c_it_name[USB_MAX_STRING_LEN];
+	char			c_it_ch_name[USB_MAX_STRING_LEN];
+	char			c_ot_name[USB_MAX_STRING_LEN];
+	char			c_fu_name[USB_MAX_STRING_LEN];
+	char			c_alt0_name[USB_MAX_STRING_LEN];
+	char			c_alt1_name[USB_MAX_STRING_LEN];
 
 	struct mutex			lock;
 	int				refcnt;