[PATCH v2] usb: gadget: f_uac1: Expose all string descriptors through configfs.

From: Chris Wulff
Date: Tue Apr 23 2024 - 10:09:58 EST


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 <chris.wulff@xxxxxxxxx>
---
v2: Improved naming of parameters to be mode user friendly. Added documentation.
v1: https://lore.kernel.org/linux-usb/CO1PR17MB54198F836C3ED1B4FA5F14A9E10D2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

.../ABI/testing/configfs-usb-gadget-uac1 | 12 +++
Documentation/usb/gadget-testing.rst | 12 +++
drivers/usb/gadget/function/f_uac1.c | 75 +++++++++++++++----
drivers/usb/gadget/function/u_uac1.h | 16 +++-
4 files changed, 98 insertions(+), 17 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac1 b/Documentation/ABI/testing/configfs-usb-gadget-uac1
index c4ba92f004c3..cf93b98b274d 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uac1
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uac1
@@ -30,4 +30,16 @@ Description:
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
===================== =======================================
diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst
index b086c7ab72f0..a89b49e639c3 100644
--- a/Documentation/usb/gadget-testing.rst
+++ b/Documentation/usb/gadget-testing.rst
@@ -957,6 +957,18 @@ The uac1 function provides these attributes in its function directory:
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.
diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index 7de74a3dd392..f7dd6a2466b0 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -377,24 +377,10 @@ enum {
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 */
@@ -1265,6 +1251,20 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)

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);
@@ -1681,8 +1681,23 @@ UAC1_ATTRIBUTE(bool, c_volume_present);
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_srate,
@@ -1706,6 +1721,20 @@ static struct configfs_attribute *f_uac1_attrs[] = {

&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,
};

@@ -1760,6 +1789,20 @@ static struct usb_function_instance *f_audio_alloc_inst(void)

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;
}

diff --git a/drivers/usb/gadget/function/u_uac1.h b/drivers/usb/gadget/function/u_uac1.h
index f7a616760e31..67784de9782b 100644
--- a/drivers/usb/gadget/function/u_uac1.h
+++ b/drivers/usb/gadget/function/u_uac1.h
@@ -52,7 +52,21 @@ struct f_uac1_opts {
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;
--
2.34.1