diff options
Diffstat (limited to 'drivers/usb/core/of.c')
| -rw-r--r-- | drivers/usb/core/of.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c new file mode 100644 index 000000000000..763e4122ed5b --- /dev/null +++ b/drivers/usb/core/of.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * of.c The helpers for hcd device tree support + * + * Copyright (C) 2016 Freescale Semiconductor, Inc. + * Author: Peter Chen <peter.chen@freescale.com> + * Copyright (C) 2017 Johan Hovold <johan@kernel.org> + */ + +#include <linux/of.h> +#include <linux/of_graph.h> +#include <linux/usb/of.h> + +/** + * usb_of_get_device_node() - get a USB device node + * @hub: hub to which device is connected + * @port1: one-based index of port + * + * Look up the node of a USB device given its parent hub device and one-based + * port number. + * + * Return: A pointer to the node with incremented refcount if found, or + * %NULL otherwise. + */ +struct device_node *usb_of_get_device_node(struct usb_device *hub, int port1) +{ + struct device_node *node; + u32 reg; + + for_each_child_of_node(hub->dev.of_node, node) { + if (of_property_read_u32(node, "reg", ®)) + continue; + + if (reg == port1) + return node; + } + + return NULL; +} +EXPORT_SYMBOL_GPL(usb_of_get_device_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 descriptors 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); + +static bool usb_of_has_devices_or_graph(const struct usb_device *hub) +{ + const struct device_node *np = hub->dev.of_node; + struct device_node *child; + + if (of_graph_is_present(np)) + return true; + + for_each_child_of_node(np, child) { + if (of_property_present(child, "reg")) { + of_node_put(child); + return true; + } + } + + return false; +} + +/** + * usb_of_get_connect_type() - get a USB hub's port connect_type + * @hub: hub to which port is for @port1 + * @port1: one-based index of port + * + * Get the connect_type of @port1 based on the device node for @hub. If the + * port is described in the OF graph, the connect_type is "hotplug". If the + * @hub has a child device has with a 'reg' property equal to @port1 the + * connect_type is "hard-wired". If there isn't an OF graph or child node at + * all then the connect_type is "unknown". Otherwise, the port is considered + * "unused" because it isn't described at all. + * + * Return: A connect_type for @port1 based on the device node for @hub. + */ +enum usb_port_connect_type usb_of_get_connect_type(struct usb_device *hub, int port1) +{ + struct device_node *np, *child, *ep, *remote_np; + enum usb_port_connect_type connect_type; + + /* Only set connect_type if binding has ports/hardwired devices. */ + if (!usb_of_has_devices_or_graph(hub)) + return USB_PORT_CONNECT_TYPE_UNKNOWN; + + /* Assume port is unused if there's a graph or a child node. */ + connect_type = USB_PORT_NOT_USED; + + np = hub->dev.of_node; + /* + * Hotplug ports are connected to an available remote node, e.g. + * usb-a-connector compatible node, in the OF graph. + */ + if (of_graph_is_present(np)) { + ep = of_graph_get_endpoint_by_regs(np, port1, -1); + if (ep) { + remote_np = of_graph_get_remote_port_parent(ep); + of_node_put(ep); + if (of_device_is_available(remote_np)) + connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG; + of_node_put(remote_np); + } + } + + /* + * Hard-wired ports are child nodes with a reg property corresponding + * to the port number, i.e. a usb device. + */ + child = usb_of_get_device_node(hub, port1); + if (of_device_is_available(child)) + connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED; + of_node_put(child); + + return connect_type; +} +EXPORT_SYMBOL_GPL(usb_of_get_connect_type); + +/** + * 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); |