usb: gadget: the start of the configfs interface
|# modprobe dummy_hcd num=2
|# modprobe libcomposite
|# lsmod
|Module Size Used by
|libcomposite 31648 0
|dummy_hcd 19871 0
|# mkdir /sys/kernel/config/usb_gadget/oha
|# cd /sys/kernel/config/usb_gadget/oha
|# mkdir configs/def.1
|# mkdir configs/def.2
|# mkdir functions/acm.ttyS1
|# mkdir strings/0x1
|mkdir: cannot create directory `strings/0x1': Invalid argument
|# mkdir strings/0x409
|# mkdir strings/1033
|mkdir: cannot create directory `strings/1033': File exists
|# mkdir strings/1032
|# mkdir configs/def.1/strings/0x409
|# mkdir configs/def.2/strings/0x409
|#find . -ls
| 975 0 drwxr-xr-x 5 root root 0 Dec 23 17:40 .
| 978 0 drwxr-xr-x 4 root root 0 Dec 23 17:43 ./strings
| 4100 0 drwxr-xr-x 2 root root 0 Dec 23 17:43 ./strings/1032
| 995 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/1032/serialnumber
| 996 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/1032/product
| 997 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/1032/manufacturer
| 2002 0 drwxr-xr-x 2 root root 0 Dec 23 17:41 ./strings/0x409
| 998 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/0x409/serialnumber
| 999 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/0x409/product
| 1000 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./strings/0x409/manufacturer
| 977 0 drwxr-xr-x 4 root root 0 Dec 23 17:41 ./configs
| 4081 0 drwxr-xr-x 3 root root 0 Dec 23 17:41 ./configs/def.2
| 4082 0 drwxr-xr-x 3 root root 0 Dec 23 17:42 ./configs/def.2/strings
| 2016 0 drwxr-xr-x 2 root root 0 Dec 23 17:42 ./configs/def.2/strings/0x409
| 1001 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.2/strings/0x409/configuration
| 1002 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.2/bmAttributes
| 1003 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.2/MaxPower
| 979 0 drwxr-xr-x 3 root root 0 Dec 23 17:42 ./configs/def.1
| 980 0 drwxr-xr-x 3 root root 0 Dec 23 17:42 ./configs/def.1/strings
| 5122 0 drwxr-xr-x 2 root root 0 Dec 23 17:42 ./configs/def.1/strings/0x409
| 1004 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.1/strings/0x409/configuration
| 1005 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.1/bmAttributes
| 1006 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./configs/def.1/MaxPower
| 976 0 drwxr-xr-x 3 root root 0 Dec 23 17:41 ./functions
| 981 0 drwxr-xr-x 2 root root 0 Dec 23 17:41 ./functions/acm.ttyS1
| 1007 0 -r--r--r-- 1 root root 4096 Dec 23 17:43 ./functions/acm.ttyS1/port_num
| 1008 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./UDC
| 1009 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bcdUSB
| 1010 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bcdDevice
| 1011 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./idProduct
| 1012 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./idVendor
| 1013 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bMaxPacketSize0
| 1014 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bDeviceProtocol
| 1015 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bDeviceSubClass
| 1016 0 -rw-r--r-- 1 root root 4096 Dec 23 17:43 ./bDeviceClass
|# cat functions/acm.ttyS1/port_num
|0
|# ls -lah /dev/ttyGS*
|crw-rw---T 1 root dialout 252, 0 Dec 23 17:41 /dev/ttyGS0
|
|# echo 0x1234 > idProduct
|# echo 0xabcd > idVendor
|# echo 1122 > strings/0x409/serialnumber
|# echo "The manufacturer" > strings/0x409/manufacturer
|# echo 1 > strings/1032/manufacturer
|# echo 1sa > strings/1032/product
|# echo tada > strings/1032/serialnumber
|echo "Primary configuration" > configs/def.1/strings/0x409/configuration
|# echo "Secondary configuration" > configs/def.2/strings/0x409/configuration
|# ln -s functions/acm.ttyS1 configs/def.1/
|# ln -s functions/acm.ttyS1 configs/def.2/
|find configs/def.1/ -ls
| 979 0 drwxr-xr-x 3 root root 0 Dec 23 17:49 configs/def.1/
| 6264 0 lrwxrwxrwx 1 root root 0 Dec 23 17:48 configs/def.1/acm.ttyS1 -> ../../../../usb_gadget/oha/functions/acm.ttyS1
| 980 0 drwxr-xr-x 3 root root 0 Dec 23 17:42 configs/def.1/strings
| 5122 0 drwxr-xr-x 2 root root 0 Dec 23 17:49 configs/def.1/strings/0x409
| 6284 0 -rw-r--r-- 1 root root 4096 Dec 23 17:47 configs/def.1/strings/0x409/configuration
| 6285 0 -rw-r--r-- 1 root root 4096 Dec 23 17:49 configs/def.1/bmAttributes
| 6286 0 -rw-r--r-- 1 root root 4096 Dec 23 17:49 configs/def.1/MaxPower
|
|echo 120 > configs/def.1/MaxPower
|
|# ls -lh /sys/class/udc/
|total 0
|lrwxrwxrwx 1 root root 0 Dec 23 17:50 dummy_udc.0 -> ../../devices/platform/dummy_udc.0/udc/dummy_udc.0
|lrwxrwxrwx 1 root root 0 Dec 23 17:50 dummy_udc.1 -> ../../devices/platform/dummy_udc.1/udc/dummy_udc.1
|# echo dummy_udc.0 > UDC
|# lsusb
|Bus 001 Device 002: ID abcd:1234 Unknown
|
|lsusb -d abcd:1234 -v
|Device Descriptor:
…
| idVendor 0xabcd Unknown
| idProduct 0x1234
| bcdDevice 3.06
| iManufacturer 1 The manufacturer
| iProduct 2
| iSerial 3 1122
| bNumConfigurations 2
…
|echo "" > UDC
v5…v6
- wired up strings with usb_gstrings_attach()
- add UDC attribe. Write "udc-name" will bind the gadget. Write an empty
string (it should contain \n since 0 bytes write get optimzed away)
will unbind the UDC from the gadget. The name of available UDCs can be
obtained from /sys/class/udc/
v4…v5
- string rework. This will add a strings folder incl. language code like
strings/409/manufacturer
as suggested by Alan.
- rebased ontop reworked functions.c which has usb_function_instance
which is used prior after "mkdir acm.instance" and can be directly
used for configuration via configfs.
v3…v4
- moved functions from the root folde down to the gadget as suggested
by Michał
- configs have now their own configs folder as suggested by Michał.
The folder is still name.bConfigurationValue where name becomes the
sConfiguration. Is this usefull should we just stilc
configs/bConfigurationValue/ ?
- added configfs support to the ACM function. The port_num attribute is
exported by f_acm. An argument has been added to the USB alloc
function to distinguish between "old" (use facm_configure() to
configure and configfs interface (expose a config_node).
The port_num is currently a dumb counter. It will
require some function re-work to make it work.
scheduled for v5:
- sym linking function into config.
v2…v3
- replaced one ifndef by ifdef as suggested by Micahał
- strstr()/strchr() function_make as suggested by Micahł
- replace [iSerialNumber|iProduct|iManufacturer] with
[sSerialNumber|sProduct|sManufacturer] as suggested by Alan
- added creation of config descriptors
v1…v2
- moved gadgets from configfs' root directory into /udcs/ within our
"usb_gadget" folder. Requested by Andrzej & Michał
- use a dot as a delimiter between function's name and its instance's name
as suggested by Michał
- renamed all config_item_type, configfs_group_operations, make_group,
drop_item as suggested by suggested by Andrzej to remain consisten
within this file and within other configfs users
- Since configfs.c and functions.c are now part of the udc-core module,
the module itself is now called udc. Also added a tiny ifdef around
init code becuase udc-core is subsys init and this is too early for
configfs in the built-in case. In the module case, we can only have
one init function.
Signed-off-by: 
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>