diff options
Diffstat (limited to 'drivers/usb/core/of.c')
| -rw-r--r-- | drivers/usb/core/of.c | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c index 2be968353257..074fabc26d6c 100644 --- a/drivers/usb/core/of.c +++ b/drivers/usb/core/of.c @@ -3,7 +3,8 @@ * of.c The helpers for hcd device tree support * * Copyright (C) 2016 Freescale Semiconductor, Inc. - * Author: Peter Chen <peter.chen@freescale.com> + * Author: Peter Chen <peter.chen@freescale.com> + * Copyright (C) 2017 Johan Hovold <johan@kernel.org> */ #include <linux/of.h> @@ -38,6 +39,73 @@ struct device_node *usb_of_get_child_node(struct device_node *parent, EXPORT_SYMBOL_GPL(usb_of_get_child_node); /** + * usb_of_has_combined_node() - determine whether a device has a combined node + * @udev: USB device + * + * Determine whether a USB device has a so called combined node which is + * shared with its sole interface. This is the case if and only if the device + * has a node and its decriptors report the following: + * + * 1) bDeviceClass is 0 or 9, and + * 2) bNumConfigurations is 1, and + * 3) bNumInterfaces is 1. + * + * Return: True iff the device has a device node and its descriptors match the + * criteria for a combined node. + */ +bool usb_of_has_combined_node(struct usb_device *udev) +{ + struct usb_device_descriptor *ddesc = &udev->descriptor; + struct usb_config_descriptor *cdesc; + + if (!udev->dev.of_node) + return false; + + switch (ddesc->bDeviceClass) { + case USB_CLASS_PER_INTERFACE: + case USB_CLASS_HUB: + if (ddesc->bNumConfigurations == 1) { + cdesc = &udev->config->desc; + if (cdesc->bNumInterfaces == 1) + return true; + } + } + + return false; +} +EXPORT_SYMBOL_GPL(usb_of_has_combined_node); + +/** + * usb_of_get_interface_node() - get a USB interface node + * @udev: USB device of interface + * @config: configuration value + * @ifnum: interface number + * + * Look up the node of a USB interface given its USB device, configuration + * value and interface number. + * + * Return: A pointer to the node with incremented refcount if found, or + * %NULL otherwise. + */ +struct device_node * +usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum) +{ + struct device_node *node; + u32 reg[2]; + + for_each_child_of_node(udev->dev.of_node, node) { + if (of_property_read_u32_array(node, "reg", reg, 2)) + continue; + + if (reg[0] == ifnum && reg[1] == config) + return node; + } + + return NULL; +} +EXPORT_SYMBOL_GPL(usb_of_get_interface_node); + +/** * usb_of_get_companion_dev - Find the companion device * @dev: the device pointer to find a companion * |