Make the hid function available for gadgets composed with configfs.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
---
Documentation/ABI/testing/configfs-usb-gadget-hid | 11 ++
Documentation/usb/gadget_hid.txt | 7 ++
drivers/usb/gadget/Kconfig | 10 ++
drivers/usb/gadget/function/f_hid.c | 144 +++++++++++++++++++++-
drivers/usb/gadget/function/u_hid.h | 7 ++
5 files changed, 178 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-hid
diff --git a/Documentation/ABI/testing/configfs-usb-gadget-hid b/Documentation/ABI/testing/configfs-usb-gadget-hid
new file mode 100644
index 0000000..f12e00e
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-hid
@@ -0,0 +1,11 @@
+What: /config/usb-gadget/gadget/functions/hid.name
+Date: Nov 2014
+KernelVersion: 3.19
+Description:
+ The attributes:
+
+ protocol - HID protocol to use
+ report_desc - blob corresponding to HID report descriptors
+ except the data passed through /dev/hidg<N>
+ report_length - HID report length
+ subclass - HID device subclass to use
diff --git a/Documentation/usb/gadget_hid.txt b/Documentation/usb/gadget_hid.txt
index 12696c2..7a0fb8e 100644
--- a/Documentation/usb/gadget_hid.txt
+++ b/Documentation/usb/gadget_hid.txt
@@ -74,6 +74,13 @@ static struct platform_device my_hid = {
You can add as many HID functions as you want, only limited by
the amount of interrupt endpoints your gadget driver supports.
+Configuration with configfs
+
+ Instead of adding fake platform devices and drivers in order to pass
+ some data to the kernel, if HID is a part of a gadget composed with
+ configfs the hidg_func_descriptor.report_desc is passed to the kernel
+ by writing the appropriate stream of bytes to a configfs attribute.
+
Send and receive HID reports
HID reports can be sent/received using read/write on the
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index e48f7c0..2f9a1bc 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -365,6 +365,16 @@ config USB_CONFIGFS_F_FS
implemented in kernel space (for instance Ethernet, serial or
mass storage) and other are implemented in user space.
+config USB_CONFIGFS_F_HID
+ boolean "HID function"
+ select USB_LIBCOMPOSITE
+ select USB_F_HID
+ help
+ The HID function driver provides generic emulation of USB
+ Human Interface Devices (HID).
+
+ For more information, see Documentation/usb/gadget_hid.txt.
+
source "drivers/usb/gadget/legacy/Kconfig"
endchoice
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 8c0096f..5821ad7 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -689,6 +689,136 @@ static inline int hidg_get_minor(void)
return ret;
}
+static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct f_hid_opts,
+ func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_hid_opts);
+CONFIGFS_ATTR_OPS(f_hid_opts);
+
+static void hid_attr_release(struct config_item *item)
+{
+ struct f_hid_opts *opts = to_f_hid_opts(item);
+
+ usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations hidg_item_ops = {
+ .release = hid_attr_release,
+ .show_attribute = f_hid_opts_attr_show,
+ .store_attribute = f_hid_opts_attr_store,
+};
+
+#define F_HID_OPT(name, prec, limit) \
+static ssize_t f_hid_opts_##name##_show(struct f_hid_opts *opts, char *page)\
+{ \
+ int result; \
+ \
+ mutex_lock(&opts->lock); \
+ result = sprintf(page, "%d\n", opts->name); \
+ mutex_unlock(&opts->lock); \
+ \
+ return result; \
+} \
+ \
+static ssize_t f_hid_opts_##name##_store(struct f_hid_opts *opts, \
+ const char *page, size_t len) \
+{ \
+ int ret; \
+ u##prec num; \
+ \
+ mutex_lock(&opts->lock); \
+ if (opts->refcnt) { \
+ ret = -EBUSY; \
+ goto end; \
+ } \
+ \
+ ret = kstrtou##prec(page, 0, &num); \
+ if (ret) \
+ goto end; \
+ \
+ if (num > limit) { \
+ ret = -EINVAL; \
+ goto end; \
+ } \
+ opts->name = num; \
+ ret = len; \
+ \
+end: \
+ mutex_unlock(&opts->lock); \
+ return ret; \
+} \
+ \
+static struct f_hid_opts_attribute f_hid_opts_##name = \
+ __CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_hid_opts_##name##_show,\
+ f_hid_opts_##name##_store)
+
+F_HID_OPT(subclass, 8, 255);
+F_HID_OPT(protocol, 8, 255);
+F_HID_OPT(report_length, 16, 65536);
+
+static ssize_t f_hid_opts_report_desc_show(struct f_hid_opts *opts, char *page)
+{
+ int result;
+
+ mutex_lock(&opts->lock);
+ result = opts->report_desc_length;
+ memcpy(page, opts->report_desc, opts->report_desc_length);
+ mutex_unlock(&opts->lock);
+
+ return result;
+}
+
+static ssize_t f_hid_opts_report_desc_store(struct f_hid_opts *opts,
+ const char *page, size_t len)
+{
+ int ret = -EBUSY;
+ char *d;
+
+ mutex_lock(&opts->lock);
+
+ if (opts->refcnt)
+ goto end;
+ if (len > PAGE_SIZE) {
+ ret = -ENOSPC;
+ goto end;
+ }
+ d = kmemdup(page, len, GFP_KERNEL);
+ if (!d) {
+ ret = -ENOMEM;
+ goto end;
+ }
+ kfree(opts->report_desc);
+ opts->report_desc = d;
+ opts->report_desc_length = len;
+ opts->report_desc_alloc = true;
+ ret = len;
+end:
+ mutex_unlock(&opts->lock);
+ return ret;
+}
+
+static struct f_hid_opts_attribute f_hid_opts_report_desc =
+ __CONFIGFS_ATTR(report_desc, S_IRUGO | S_IWUSR,
+ f_hid_opts_report_desc_show,
+ f_hid_opts_report_desc_store);
+
+static struct configfs_attribute *hid_attrs[] = {
+ &f_hid_opts_subclass.attr,
+ &f_hid_opts_protocol.attr,
+ &f_hid_opts_report_length.attr,
+ &f_hid_opts_report_desc.attr,
+ NULL,
+};
+
+static struct config_item_type hid_func_type = {
+ .ct_item_ops = &hidg_item_ops,
+ .ct_attrs = hid_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
static inline void hidg_put_minor(int minor)
{
ida_simple_remove(&hidg_ida, minor);
@@ -723,7 +853,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);
-
+ mutex_init(&opts->lock);
opts->func_inst.free_func_inst = hidg_free_inst;
ret = &opts->func_inst;
@@ -745,6 +875,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
if (idr_is_empty(&hidg_ida.idr))
ghid_cleanup();
}
+ config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
unlock:
mutex_unlock(&hidg_ida_lock);
@@ -754,10 +885,15 @@ unlock:
static void hidg_free(struct usb_function *f)
{
struct f_hidg *hidg;
+ struct f_hid_opts *opts;
hidg = func_to_hidg(f);
+ opts = container_of(f->fi, struct f_hid_opts, func_inst);
kfree(hidg->report_desc);
kfree(hidg);
+ mutex_lock(&opts->lock);
+ --opts->refcnt;
+ mutex_unlock(&opts->lock);
}
static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
@@ -788,6 +924,9 @@ struct usb_function *hidg_alloc(struct usb_function_instance *fi)
opts = container_of(fi, struct f_hid_opts, func_inst);
+ mutex_lock(&opts->lock);
+ ++opts->refcnt;
+
hidg->minor = opts->minor;
hidg->bInterfaceSubClass = opts->subclass;
hidg->bInterfaceProtocol = opts->protocol;
@@ -799,10 +938,13 @@ struct usb_function *hidg_alloc(struct usb_function_instance *fi)
GFP_KERNEL);
if (!hidg->report_desc) {
kfree(hidg);
+ mutex_unlock(&opts->lock);
return ERR_PTR(-ENOMEM);
}
}
+ mutex_unlock(&opts->lock);
+
hidg->func.name = "hid";
hidg->func.bind = hidg_bind;
hidg->func.unbind = hidg_unbind;
diff --git a/drivers/usb/gadget/function/u_hid.h b/drivers/usb/gadget/function/u_hid.h
index 3edfc95..aaa0e36 100644
--- a/drivers/usb/gadget/function/u_hid.h
+++ b/drivers/usb/gadget/function/u_hid.h
@@ -27,6 +27,13 @@ struct f_hid_opts {
unsigned short report_desc_length;
unsigned char *report_desc;
bool report_desc_alloc;
+
+ /*
+ * Protect the data form concurrent access by read/write
+ * and create symlink/remove symlink.
+ */
+ struct mutex lock;
+ int refcnt;
};
int ghid_setup(struct usb_gadget *g, int count);
--
1.9.1
--
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