From 1a7e3948cb9f5bb9241112706267b8fbc7812c7a Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 9 Nov 2017 18:07:21 +0100 Subject: [PATCH] USB: add device-tree support for interfaces Add OF device-tree support for USB interfaces. USB "interface nodes" are children of USB "device nodes" and are identified by an interface number and a configuration value: &usb1 { /* host controller */ dev1: device@1 { /* device at port 1 */ compatible = "usb1234,5678"; reg = <1>; #address-cells = <2>; #size-cells = <0>; interface@0,2 { /* interface 0 of configuration 2 */ compatible = "usbif1234,5678.config2.0"; reg = <0 2>; }; }; }; The configuration component is not included in the textual representation of an interface-node unit address for configuration 1: &dev1 { interface@0 { /* interface 0 of configuration 1 */ compatible = "usbif1234,5678.config1.0"; reg = <0 1>; }; }; When a USB device of class 0 or 9 (hub) has only a single configuration with a single interface, a special case "combined node" is used instead of a device node with an interface node: &usb1 { device@2 { compatible = "usb1234,abcd"; reg = <2>; }; }; Combined nodes are shared by the two device structures representing the USB device and its interface in the kernel's device model. Note that, as for device nodes, the compatible strings for interface nodes are currently not used. For more details see "Open Firmware Recommended Practice: Universal Serial Bus Version 1" and the binding documentation. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/message.c | 18 ++++++++---- drivers/usb/core/of.c | 70 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/usb/of.h | 14 ++++++++++ 3 files changed, 96 insertions(+), 6 deletions(-) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 5a8ab77..f836bae 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -18,6 +18,7 @@ #include #include #include /* for usbcore internals */ +#include #include #include "usb.h" @@ -1583,6 +1584,7 @@ static void usb_release_interface(struct device *dev) kref_put(&intfc->ref, usb_release_interface_cache); usb_put_dev(interface_to_usbdev(intf)); + of_node_put(dev->of_node); kfree(intf); } @@ -1868,6 +1870,7 @@ free_interfaces: struct usb_interface_cache *intfc; struct usb_interface *intf; struct usb_host_interface *alt; + u8 ifnum; cp->interface[i] = intf = new_interfaces[i]; intfc = cp->intf_cache[i]; @@ -1886,11 +1889,17 @@ free_interfaces: if (!alt) alt = &intf->altsetting[0]; - intf->intf_assoc = - find_iad(dev, cp, alt->desc.bInterfaceNumber); + ifnum = alt->desc.bInterfaceNumber; + intf->intf_assoc = find_iad(dev, cp, ifnum); intf->cur_altsetting = alt; usb_enable_interface(dev, intf, true); intf->dev.parent = &dev->dev; + if (usb_of_has_combined_node(dev)) { + device_set_of_node_from_dev(&intf->dev, &dev->dev); + } else { + intf->dev.of_node = usb_of_get_interface_node(dev, + configuration, ifnum); + } intf->dev.driver = NULL; intf->dev.bus = &usb_bus_type; intf->dev.type = &usb_if_device_type; @@ -1905,9 +1914,8 @@ free_interfaces: intf->minor = -1; device_initialize(&intf->dev); pm_runtime_no_callbacks(&intf->dev); - dev_set_name(&intf->dev, "%d-%s:%d.%d", - dev->bus->busnum, dev->devpath, - configuration, alt->desc.bInterfaceNumber); + dev_set_name(&intf->dev, "%d-%s:%d.%d", dev->bus->busnum, + dev->devpath, configuration, ifnum); usb_get_dev(dev); } kfree(new_interfaces); diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c index 2be9683..074fabc 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 + * Author: Peter Chen + * Copyright (C) 2017 Johan Hovold */ #include @@ -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 * diff --git a/include/linux/usb/of.h b/include/linux/usb/of.h index 6cbe7a5..0294cca 100644 --- a/include/linux/usb/of.h +++ b/include/linux/usb/of.h @@ -12,6 +12,8 @@ #include #include +struct usb_device; + #if IS_ENABLED(CONFIG_OF) enum usb_dr_mode of_usb_get_dr_mode_by_phy(struct device_node *np, int arg0); bool of_usb_host_tpl_support(struct device_node *np); @@ -19,6 +21,9 @@ int of_usb_update_otg_caps(struct device_node *np, struct usb_otg_caps *otg_caps); struct device_node *usb_of_get_child_node(struct device_node *parent, int portnum); +bool usb_of_has_combined_node(struct usb_device *udev); +struct device_node *usb_of_get_interface_node(struct usb_device *udev, + u8 config, u8 ifnum); struct device *usb_of_get_companion_dev(struct device *dev); #else static inline enum usb_dr_mode @@ -40,6 +45,15 @@ static inline struct device_node *usb_of_get_child_node { return NULL; } +static inline bool usb_of_has_combined_node(struct usb_device *udev) +{ + return false; +} +static inline struct device_node * +usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum) +{ + return NULL; +} static inline struct device *usb_of_get_companion_dev(struct device *dev) { return NULL; -- 2.7.4