usb: gadget: f_uac2: Expose all string descriptors through configfs.

This makes all string descriptors configurable for the UAC2 gadget
so the user can configure names of terminals and controls. Alt mode
names are not included for now and will be in future work related
to adding alternate settings.

discussion thread for api changes for alt mode settings:
https://lore.kernel.org/linux-usb/35be4668-58d3-894a-72cf-de1afaacae45@ivitera.com/T/

Signed-off-by: Chris Wulff <chris.wulff@biamp.com>
Link: https://lore.kernel.org/r/20240804001923.3279431-2-crwulff@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 77 insertions, 18 deletions

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 2d6d3286ffde..1cdda44455b3 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -95,7 +95,9 @@ enum {
 	STR_CLKSRC_IN,
 	STR_CLKSRC_OUT,
 	STR_USB_IT,
+	STR_USB_IT_CH,
 	STR_IO_IT,
+	STR_IO_IT_CH,
 	STR_USB_OT,
 	STR_IO_OT,
 	STR_FU_IN,
@@ -104,25 +106,10 @@ enum {
 	STR_AS_OUT_ALT1,
 	STR_AS_IN_ALT0,
 	STR_AS_IN_ALT1,
+	NUM_STR_DESCRIPTORS,
 };
 
-static struct usb_string strings_fn[] = {
-	/* [STR_ASSOC].s = DYNAMIC, */
-	[STR_IF_CTRL].s = "Topology Control",
-	[STR_CLKSRC_IN].s = "Input Clock",
-	[STR_CLKSRC_OUT].s = "Output Clock",
-	[STR_USB_IT].s = "USBH Out",
-	[STR_IO_IT].s = "USBD Out",
-	[STR_USB_OT].s = "USBH In",
-	[STR_IO_OT].s = "USBD In",
-	[STR_FU_IN].s = "Capture Volume",
-	[STR_FU_OUT].s = "Playback Volume",
-	[STR_AS_OUT_ALT0].s = "Playback Inactive",
-	[STR_AS_OUT_ALT1].s = "Playback Active",
-	[STR_AS_IN_ALT0].s = "Capture Inactive",
-	[STR_AS_IN_ALT1].s = "Capture Active",
-	{ },
-};
+static struct usb_string strings_fn[NUM_STR_DESCRIPTORS + 1] = {};
 
 static const char *const speed_names[] = {
 	[USB_SPEED_UNKNOWN] = "UNKNOWN",
@@ -1049,6 +1036,23 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 		return ret;
 
 	strings_fn[STR_ASSOC].s = uac2_opts->function_name;
+	strings_fn[STR_IF_CTRL].s = uac2_opts->if_ctrl_name;
+	strings_fn[STR_CLKSRC_IN].s = uac2_opts->clksrc_in_name;
+	strings_fn[STR_CLKSRC_OUT].s = uac2_opts->clksrc_out_name;
+
+	strings_fn[STR_USB_IT].s = uac2_opts->c_it_name;
+	strings_fn[STR_USB_IT_CH].s = uac2_opts->c_it_ch_name;
+	strings_fn[STR_IO_OT].s = uac2_opts->c_ot_name;
+	strings_fn[STR_FU_OUT].s = uac2_opts->c_fu_vol_name;
+	strings_fn[STR_AS_OUT_ALT0].s = "Playback Inactive";
+	strings_fn[STR_AS_OUT_ALT1].s = "Playback Active";
+
+	strings_fn[STR_IO_IT].s = uac2_opts->p_it_name;
+	strings_fn[STR_IO_IT_CH].s = uac2_opts->p_it_ch_name;
+	strings_fn[STR_USB_OT].s = uac2_opts->p_ot_name;
+	strings_fn[STR_FU_IN].s = uac2_opts->p_fu_vol_name;
+	strings_fn[STR_AS_IN_ALT0].s = "Capture Inactive";
+	strings_fn[STR_AS_IN_ALT1].s = "Capture Active";
 
 	us = usb_gstrings_attach(cdev, fn_strings, ARRAY_SIZE(strings_fn));
 	if (IS_ERR(us))
@@ -1072,7 +1076,9 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 	in_clk_src_desc.iClockSource = us[STR_CLKSRC_IN].id;
 	out_clk_src_desc.iClockSource = us[STR_CLKSRC_OUT].id;
 	usb_out_it_desc.iTerminal = us[STR_USB_IT].id;
+	usb_out_it_desc.iChannelNames = us[STR_USB_IT_CH].id;
 	io_in_it_desc.iTerminal = us[STR_IO_IT].id;
+	io_in_it_desc.iChannelNames = us[STR_IO_IT_CH].id;
 	usb_in_ot_desc.iTerminal = us[STR_USB_OT].id;
 	io_out_ot_desc.iTerminal = us[STR_IO_OT].id;
 	std_as_out_if0_desc.iInterface = us[STR_AS_OUT_ALT0].id;
@@ -2100,10 +2106,24 @@ UAC2_ATTRIBUTE(s16, c_volume_max);
 UAC2_ATTRIBUTE(s16, c_volume_res);
 UAC2_ATTRIBUTE(u32, fb_max);
 UAC2_ATTRIBUTE_STRING(function_name);
+UAC2_ATTRIBUTE_STRING(if_ctrl_name);
+UAC2_ATTRIBUTE_STRING(clksrc_in_name);
+UAC2_ATTRIBUTE_STRING(clksrc_out_name);
+
+UAC2_ATTRIBUTE_STRING(p_it_name);
+UAC2_ATTRIBUTE_STRING(p_it_ch_name);
+UAC2_ATTRIBUTE_STRING(p_ot_name);
+UAC2_ATTRIBUTE_STRING(p_fu_vol_name);
+
+UAC2_ATTRIBUTE_STRING(c_it_name);
+UAC2_ATTRIBUTE_STRING(c_it_ch_name);
+UAC2_ATTRIBUTE_STRING(c_ot_name);
+UAC2_ATTRIBUTE_STRING(c_fu_vol_name);
 
 UAC2_ATTRIBUTE(s16, p_terminal_type);
 UAC2_ATTRIBUTE(s16, c_terminal_type);
 
+
 static struct configfs_attribute *f_uac2_attrs[] = {
 	&f_uac2_opts_attr_p_chmask,
 	&f_uac2_opts_attr_p_srate,
@@ -2130,6 +2150,19 @@ static struct configfs_attribute *f_uac2_attrs[] = {
 	&f_uac2_opts_attr_c_volume_res,
 
 	&f_uac2_opts_attr_function_name,
+	&f_uac2_opts_attr_if_ctrl_name,
+	&f_uac2_opts_attr_clksrc_in_name,
+	&f_uac2_opts_attr_clksrc_out_name,
+
+	&f_uac2_opts_attr_p_it_name,
+	&f_uac2_opts_attr_p_it_ch_name,
+	&f_uac2_opts_attr_p_ot_name,
+	&f_uac2_opts_attr_p_fu_vol_name,
+
+	&f_uac2_opts_attr_c_it_name,
+	&f_uac2_opts_attr_c_it_ch_name,
+	&f_uac2_opts_attr_c_ot_name,
+	&f_uac2_opts_attr_c_fu_vol_name,
 
 	&f_uac2_opts_attr_p_terminal_type,
 	&f_uac2_opts_attr_c_terminal_type,
@@ -2191,6 +2224,19 @@ static struct usb_function_instance *afunc_alloc_inst(void)
 	opts->fb_max = FBACK_FAST_MAX;
 
 	scnprintf(opts->function_name, sizeof(opts->function_name), "Source/Sink");
+	scnprintf(opts->if_ctrl_name, sizeof(opts->if_ctrl_name), "Topology Control");
+	scnprintf(opts->clksrc_in_name, sizeof(opts->clksrc_in_name), "Input Clock");
+	scnprintf(opts->clksrc_out_name, sizeof(opts->clksrc_out_name), "Output Clock");
+
+	scnprintf(opts->p_it_name, sizeof(opts->p_it_name), "USBD Out");
+	scnprintf(opts->p_it_ch_name, sizeof(opts->p_it_ch_name), "Capture Channels");
+	scnprintf(opts->p_ot_name, sizeof(opts->p_ot_name), "USBH In");
+	scnprintf(opts->p_fu_vol_name, sizeof(opts->p_fu_vol_name), "Capture Volume");
+
+	scnprintf(opts->c_it_name, sizeof(opts->c_it_name), "USBH Out");
+	scnprintf(opts->c_it_ch_name, sizeof(opts->c_it_ch_name), "Playback Channels");
+	scnprintf(opts->c_ot_name, sizeof(opts->c_ot_name), "USBD In");
+	scnprintf(opts->c_fu_vol_name, sizeof(opts->c_fu_vol_name), "Playback Volume");
 
 	opts->p_terminal_type = UAC2_DEF_P_TERM_TYPE;
 	opts->c_terminal_type = UAC2_DEF_C_TERM_TYPE;
diff --git a/drivers/usb/gadget/function/u_uac2.h b/drivers/usb/gadget/function/u_uac2.h
index 5e81bdd6c5fb..0df808289ded 100644
--- a/drivers/usb/gadget/function/u_uac2.h
+++ b/drivers/usb/gadget/function/u_uac2.h
@@ -68,7 +68,20 @@ struct f_uac2_opts {
 	int				fb_max;
 	bool			bound;
 
-	char			function_name[32];
+	char			function_name[USB_MAX_STRING_LEN];
+	char			if_ctrl_name[USB_MAX_STRING_LEN];
+	char			clksrc_in_name[USB_MAX_STRING_LEN];
+	char			clksrc_out_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_vol_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_vol_name[USB_MAX_STRING_LEN];
 
 	s16				p_terminal_type;
 	s16				c_terminal_type;