usb: gadget: hid: add configfs support
Make the hid function available for gadgets composed with configfs. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
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11
Documentation/ABI/testing/configfs-usb-gadget-hid
Normal file
11
Documentation/ABI/testing/configfs-usb-gadget-hid
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@ -0,0 +1,11 @@
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What: /config/usb-gadget/gadget/functions/hid.name
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Date: Nov 2014
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KernelVersion: 3.19
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Description:
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The attributes:
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protocol - HID protocol to use
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report_desc - blob corresponding to HID report descriptors
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except the data passed through /dev/hidg<N>
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report_length - HID report length
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subclass - HID device subclass to use
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@ -74,6 +74,13 @@ static struct platform_device my_hid = {
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You can add as many HID functions as you want, only limited by
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You can add as many HID functions as you want, only limited by
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the amount of interrupt endpoints your gadget driver supports.
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the amount of interrupt endpoints your gadget driver supports.
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Configuration with configfs
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Instead of adding fake platform devices and drivers in order to pass
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some data to the kernel, if HID is a part of a gadget composed with
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configfs the hidg_func_descriptor.report_desc is passed to the kernel
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by writing the appropriate stream of bytes to a configfs attribute.
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Send and receive HID reports
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Send and receive HID reports
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HID reports can be sent/received using read/write on the
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HID reports can be sent/received using read/write on the
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@ -413,6 +413,16 @@ config USB_CONFIGFS_F_MIDI
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connections can then be made on the gadget system, using
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connections can then be made on the gadget system, using
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ALSA's aconnect utility etc.
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ALSA's aconnect utility etc.
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config USB_CONFIGFS_F_HID
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boolean "HID function"
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depends on USB_CONFIGFS
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select USB_F_HID
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help
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The HID function driver provides generic emulation of USB
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Human Interface Devices (HID).
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For more information, see Documentation/usb/gadget_hid.txt.
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source "drivers/usb/gadget/legacy/Kconfig"
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source "drivers/usb/gadget/legacy/Kconfig"
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endchoice
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endchoice
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@ -690,6 +690,136 @@ static inline int hidg_get_minor(void)
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return ret;
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return ret;
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}
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}
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static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
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{
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return container_of(to_config_group(item), struct f_hid_opts,
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func_inst.group);
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}
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CONFIGFS_ATTR_STRUCT(f_hid_opts);
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CONFIGFS_ATTR_OPS(f_hid_opts);
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static void hid_attr_release(struct config_item *item)
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{
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struct f_hid_opts *opts = to_f_hid_opts(item);
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usb_put_function_instance(&opts->func_inst);
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}
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static struct configfs_item_operations hidg_item_ops = {
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.release = hid_attr_release,
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.show_attribute = f_hid_opts_attr_show,
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.store_attribute = f_hid_opts_attr_store,
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};
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#define F_HID_OPT(name, prec, limit) \
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static ssize_t f_hid_opts_##name##_show(struct f_hid_opts *opts, char *page)\
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{ \
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int result; \
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\
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mutex_lock(&opts->lock); \
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result = sprintf(page, "%d\n", opts->name); \
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mutex_unlock(&opts->lock); \
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\
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return result; \
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} \
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\
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static ssize_t f_hid_opts_##name##_store(struct f_hid_opts *opts, \
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const char *page, size_t len) \
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{ \
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int ret; \
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u##prec num; \
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\
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mutex_lock(&opts->lock); \
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if (opts->refcnt) { \
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ret = -EBUSY; \
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goto end; \
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} \
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\
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ret = kstrtou##prec(page, 0, &num); \
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if (ret) \
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goto end; \
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\
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if (num > limit) { \
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ret = -EINVAL; \
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goto end; \
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} \
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opts->name = num; \
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ret = len; \
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\
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end: \
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mutex_unlock(&opts->lock); \
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return ret; \
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} \
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\
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static struct f_hid_opts_attribute f_hid_opts_##name = \
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__CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_hid_opts_##name##_show,\
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f_hid_opts_##name##_store)
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F_HID_OPT(subclass, 8, 255);
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F_HID_OPT(protocol, 8, 255);
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F_HID_OPT(report_length, 16, 65536);
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static ssize_t f_hid_opts_report_desc_show(struct f_hid_opts *opts, char *page)
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{
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int result;
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mutex_lock(&opts->lock);
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result = opts->report_desc_length;
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memcpy(page, opts->report_desc, opts->report_desc_length);
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mutex_unlock(&opts->lock);
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return result;
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}
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static ssize_t f_hid_opts_report_desc_store(struct f_hid_opts *opts,
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const char *page, size_t len)
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{
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int ret = -EBUSY;
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char *d;
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mutex_lock(&opts->lock);
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if (opts->refcnt)
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goto end;
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if (len > PAGE_SIZE) {
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ret = -ENOSPC;
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goto end;
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}
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d = kmemdup(page, len, GFP_KERNEL);
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if (!d) {
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ret = -ENOMEM;
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goto end;
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}
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kfree(opts->report_desc);
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opts->report_desc = d;
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opts->report_desc_length = len;
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opts->report_desc_alloc = true;
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ret = len;
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end:
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mutex_unlock(&opts->lock);
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return ret;
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}
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static struct f_hid_opts_attribute f_hid_opts_report_desc =
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__CONFIGFS_ATTR(report_desc, S_IRUGO | S_IWUSR,
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f_hid_opts_report_desc_show,
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f_hid_opts_report_desc_store);
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static struct configfs_attribute *hid_attrs[] = {
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&f_hid_opts_subclass.attr,
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&f_hid_opts_protocol.attr,
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&f_hid_opts_report_length.attr,
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&f_hid_opts_report_desc.attr,
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NULL,
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};
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static struct config_item_type hid_func_type = {
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.ct_item_ops = &hidg_item_ops,
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.ct_attrs = hid_attrs,
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.ct_owner = THIS_MODULE,
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};
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static inline void hidg_put_minor(int minor)
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static inline void hidg_put_minor(int minor)
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{
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{
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ida_simple_remove(&hidg_ida, minor);
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ida_simple_remove(&hidg_ida, minor);
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@ -724,7 +854,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
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opts = kzalloc(sizeof(*opts), GFP_KERNEL);
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opts = kzalloc(sizeof(*opts), GFP_KERNEL);
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if (!opts)
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if (!opts)
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(-ENOMEM);
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mutex_init(&opts->lock);
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opts->func_inst.free_func_inst = hidg_free_inst;
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opts->func_inst.free_func_inst = hidg_free_inst;
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ret = &opts->func_inst;
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ret = &opts->func_inst;
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@ -746,6 +876,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
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if (idr_is_empty(&hidg_ida.idr))
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if (idr_is_empty(&hidg_ida.idr))
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ghid_cleanup();
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ghid_cleanup();
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}
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}
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config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
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unlock:
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unlock:
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mutex_unlock(&hidg_ida_lock);
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mutex_unlock(&hidg_ida_lock);
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@ -755,10 +886,15 @@ unlock:
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static void hidg_free(struct usb_function *f)
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static void hidg_free(struct usb_function *f)
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{
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{
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struct f_hidg *hidg;
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struct f_hidg *hidg;
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struct f_hid_opts *opts;
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hidg = func_to_hidg(f);
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hidg = func_to_hidg(f);
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opts = container_of(f->fi, struct f_hid_opts, func_inst);
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kfree(hidg->report_desc);
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kfree(hidg->report_desc);
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kfree(hidg);
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kfree(hidg);
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mutex_lock(&opts->lock);
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--opts->refcnt;
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mutex_unlock(&opts->lock);
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}
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}
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static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
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static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
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@ -789,6 +925,9 @@ struct usb_function *hidg_alloc(struct usb_function_instance *fi)
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opts = container_of(fi, struct f_hid_opts, func_inst);
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opts = container_of(fi, struct f_hid_opts, func_inst);
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mutex_lock(&opts->lock);
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++opts->refcnt;
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hidg->minor = opts->minor;
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hidg->minor = opts->minor;
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hidg->bInterfaceSubClass = opts->subclass;
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hidg->bInterfaceSubClass = opts->subclass;
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hidg->bInterfaceProtocol = opts->protocol;
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hidg->bInterfaceProtocol = opts->protocol;
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@ -800,10 +939,13 @@ struct usb_function *hidg_alloc(struct usb_function_instance *fi)
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GFP_KERNEL);
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GFP_KERNEL);
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if (!hidg->report_desc) {
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if (!hidg->report_desc) {
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kfree(hidg);
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kfree(hidg);
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mutex_unlock(&opts->lock);
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(-ENOMEM);
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}
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}
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}
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}
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mutex_unlock(&opts->lock);
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hidg->func.name = "hid";
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hidg->func.name = "hid";
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hidg->func.bind = hidg_bind;
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hidg->func.bind = hidg_bind;
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hidg->func.unbind = hidg_unbind;
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hidg->func.unbind = hidg_unbind;
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@ -27,6 +27,13 @@ struct f_hid_opts {
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unsigned short report_desc_length;
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unsigned short report_desc_length;
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unsigned char *report_desc;
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unsigned char *report_desc;
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bool report_desc_alloc;
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bool report_desc_alloc;
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/*
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* Protect the data form concurrent access by read/write
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* and create symlink/remove symlink.
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*/
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struct mutex lock;
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int refcnt;
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};
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};
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int ghid_setup(struct usb_gadget *g, int count);
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int ghid_setup(struct usb_gadget *g, int count);
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