Hi Greg, thanks for the review!
On Sun, Sep 20, 2020 at 04:17:20PM +0200, Greg Kroah-Hartman wrote: > On Thu, Sep 17, 2020 at 11:46:22AM -0700, Matthias Kaehlcke wrote: > > The main issue this driver addresses is that a USB hub needs to be > > powered before it can be discovered. For onboard hubs this is often > > solved by supplying the hub with an 'always-on' regulator, which is > > kind of a hack. Some onboard hubs may require further initialization > > steps, like changing the state of a GPIO or enabling a clock, which > > requires further hacks. This driver creates a platform device > > representing the hub which performs the necessary initialization. > > Currently it only supports switching on a single regulator, support > > for multiple regulators or other actions can be added as needed. > > Different initialization sequences can be supported based on the > > compatible string. > > > > Besides performing the initialization the driver can be configured > > to power the hub off during system suspend. This can help to extend > > battery life on battery powered devices which have no requirements > > to keep the hub powered during suspend. The driver can also be > > configured to leave the hub powered when a wakeup capable USB device > > is connected when suspending, and power it off otherwise. > > > > Technically the driver consists of two drivers, the platform driver > > described above and a very thin USB driver that subclasses the > > generic driver. The purpose of this driver is to provide the platform > > driver with the USB devices corresponding to the hub(s) (a hub > > controller may provide multiple 'logical' hubs, e.g. one to support > > USB 2.0 and another for USB 3.x). > > > > Co-developed-by: Ravi Chandra Sadineni <[email protected]> > > Signed-off-by: Ravi Chandra Sadineni <[email protected]> > > Signed-off-by: Matthias Kaehlcke <[email protected]> > > --- > > > > Changes in v2: > > - check wakeup enabled state of the USB controller instead of > > using 'wakeup-source' property > > - use sysfs attribute instead of DT property to determine if > > the hub should be powered off at all during system suspend > > - added missing brace in onboard_hub_suspend() > > - updated commit message > > - use pm_ptr for pm_ops as suggested by Alan > > > > Changes in v1: > > - renamed the driver to 'onboard_usb_hub' > > - single file for platform and USB driver > > - USB hub devices register with the platform device > > - the DT includes a phandle of the platform device > > - the platform device now controls when power is turned off > > - the USB driver became a very thin subclass of the generic USB > > driver > > - enabled autosuspend support > > > > drivers/usb/misc/Kconfig | 15 ++ > > drivers/usb/misc/Makefile | 1 + > > drivers/usb/misc/onboard_usb_hub.c | 329 +++++++++++++++++++++++++++++ > > 3 files changed, 345 insertions(+) > > create mode 100644 drivers/usb/misc/onboard_usb_hub.c > > > > diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig > > index 6818ea689cd9..e941244e24e5 100644 > > --- a/drivers/usb/misc/Kconfig > > +++ b/drivers/usb/misc/Kconfig > > @@ -275,3 +275,18 @@ config USB_CHAOSKEY > > > > To compile this driver as a module, choose M here: the > > module will be called chaoskey. > > + > > +config USB_ONBOARD_HUB > > + tristate "Onboard USB hub support" > > + depends on OF > > What about COMPILE_TEST as well? ok > > + help > > + Say Y here if you want to support onboard USB hubs. The driver > > + powers supported hubs on and may perform other initialization > > + steps. > > + > > + The driver can also switch off the power of the hub during > > + system suspend if it is configured accordingly. This may > > + reduce power consumption while the system is suspended. > > + > > + To compile this driver as a module, choose M here: the > > + module will be called onboard_usb_hub. > > diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile > > index da39bddb0604..6f10a1c6f7e9 100644 > > --- a/drivers/usb/misc/Makefile > > +++ b/drivers/usb/misc/Makefile > > @@ -31,3 +31,4 @@ obj-$(CONFIG_USB_CHAOSKEY) += chaoskey.o > > > > obj-$(CONFIG_USB_SISUSBVGA) += sisusbvga/ > > obj-$(CONFIG_USB_LINK_LAYER_TEST) += lvstest.o > > +obj-$(CONFIG_USB_ONBOARD_HUB) += onboard_usb_hub.o > > diff --git a/drivers/usb/misc/onboard_usb_hub.c > > b/drivers/usb/misc/onboard_usb_hub.c > > new file mode 100644 > > index 000000000000..206798029041 > > --- /dev/null > > +++ b/drivers/usb/misc/onboard_usb_hub.c > > @@ -0,0 +1,329 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Driver for onboard USB hubs > > + * > > + * Copyright (c) 2020, Google LLC > > + */ > > + > > +#include <linux/init.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/mutex.h> > > +#include <linux/of.h> > > +#include <linux/of_platform.h> > > +#include <linux/platform_device.h> > > +#include <linux/regulator/consumer.h> > > +#include <linux/suspend.h> > > +#include <linux/usb.h> > > +#include <linux/usb/hcd.h> > > +#include "../core/usb.h" > > Why do you need private usb core functions? An earlier version of the driver used usb_port_disable(), but that isn't needed anymore, I'll remove the include. > > + > > +/************************** Platform driver **************************/ > > + > > +struct udev_node { > > + struct usb_device *udev; > > + struct list_head list; > > +}; > > + > > +struct onboard_hub { > > + struct regulator *vdd; > > + struct device *dev; > > + bool power_off_in_suspend; > > + struct list_head udev_list; > > + struct mutex lock; > > + bool has_wakeup_capable_descendants; > > +}; > > + > > +static int onboard_hub_power_on(struct onboard_hub *hub) > > +{ > > + int err; > > + > > + err = regulator_enable(hub->vdd); > > + if (err) { > > + dev_err(hub->dev, "failed to enable regulator: %d\n", err); > > + return err; > > + } > > Nit, no need for { } or return err here, just return err one line below. ack > > + > > + return 0; > > +} > > + > > +static int onboard_hub_power_off(struct onboard_hub *hub) > > +{ > > + int err; > > + > > + err = regulator_disable(hub->vdd); > > + if (err) { > > + dev_err(hub->dev, "failed to enable regulator: %d\n", err); > > + return err; > > + } > > + > > + return 0; > > Same here. ack > > +} > > + > > +static int __maybe_unused onboard_hub_suspend(struct device *dev) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(dev); > > + struct udev_node *node; > > + int rc = 0; > > + > > + hub->has_wakeup_capable_descendants = false; > > + > > + if (!hub->power_off_in_suspend) > > + return 0; > > + > > + mutex_lock(&hub->lock); > > + > > + list_for_each_entry(node, &hub->udev_list, list) { > > + if (!device_may_wakeup(node->udev->bus->controller)) > > + break; > > + > > + if (usb_wakeup_enabled_descendants(node->udev)) { > > + hub->has_wakeup_capable_descendants = true; > > + break; > > + } > > + } > > + > > + mutex_unlock(&hub->lock); > > + > > + if (!hub->has_wakeup_capable_descendants) > > + rc = onboard_hub_power_off(hub); > > + > > + return rc; > > +} > > + > > +static int __maybe_unused onboard_hub_resume(struct device *dev) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(dev); > > + int rc = 0; > > + > > + if (hub->power_off_in_suspend && !hub->has_wakeup_capable_descendants) > > + rc = onboard_hub_power_on(hub); > > + > > + return rc; > > +} > > + > > +static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct > > usb_device *udev) > > +{ > > + struct udev_node *node; > > + > > + node = devm_kzalloc(hub->dev, sizeof(*node), GFP_KERNEL); > > + if (!node) > > + return -ENOMEM; > > + > > + node->udev = udev; > > No reference counting? Are you sure about this? I thought it isn't strictly needed, since this function is only called by the onboard_hub_usbdev driver, which also calls onboard_hub_remove_usbdev() on disconnect. So my thinking was that the driver trusts itself, like the kernel. Am I missing a case? > > + > > + mutex_lock(&hub->lock); > > + list_add(&node->list, &hub->udev_list); > > + mutex_unlock(&hub->lock); > > + > > + return 0; > > +} > > + > > +static int onboard_hub_remove_usbdev(struct onboard_hub *hub, struct > > usb_device *udev) > > +{ > > + struct udev_node *node; > > + > > + mutex_lock(&hub->lock); > > + > > + list_for_each_entry(node, &hub->udev_list, list) { > > list_for_each_entry_safe()? I can change it, but IIUC it shouldn't be really necessary, since the loop is aborted after removing the node. > > + if (node->udev == udev) { > > + list_del(&node->list); > > + devm_kfree(hub->dev, node); > > + break; > > + } > > + } > > + > > + mutex_unlock(&hub->lock); > > + > > + if (node == NULL) > > + return -EINVAL; > > + > > + return 0; > > +} > > + > > +static ssize_t power_off_in_suspend_show(struct device *dev, struct > > device_attribute *attr, > > + char *buf) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(dev); > > + > > + return sprintf(buf, "%d\n", hub->power_off_in_suspend); > > +} > > + > > +static ssize_t power_off_in_suspend_store(struct device *dev, struct > > device_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(dev); > > + bool val; > > + int ret; > > + > > + ret = strtobool(buf, &val); > > You should use kstrtobool() instead, right? Will change > > + if (ret < 0) > > + return ret; > > + > > + hub->power_off_in_suspend = val; > > + > > + return count; > > +} > > +static DEVICE_ATTR_RW(power_off_in_suspend); > > + > > +static int onboard_hub_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct onboard_hub *hub; > > + int rc; > > + > > + hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); > > + if (!hub) > > + return -ENOMEM; > > + > > + hub->vdd = devm_regulator_get(dev, "vdd"); > > + if (IS_ERR(hub->vdd)) > > + return PTR_ERR(hub->vdd); > > + > > + hub->dev = dev; > > + mutex_init(&hub->lock); > > + INIT_LIST_HEAD(&hub->udev_list); > > + > > + dev_set_drvdata(dev, hub); > > + > > + rc = sysfs_create_file(&dev->kobj, &dev_attr_power_off_in_suspend.attr); > > Use the default platform device files group, never create/add your own > sysfs files "by hand", otherwise it could go easily wrong. Ok > > + if (rc) > > + return rc; > > + > > + return onboard_hub_power_on(hub); > > +} > > + > > +static int onboard_hub_remove(struct platform_device *pdev) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(&pdev->dev); > > + > > + sysfs_remove_file(&pdev->dev.kobj, &dev_attr_power_off_in_suspend.attr); > > If you do the above, no need to remove this here. > > > + > > + return onboard_hub_power_off(hub); > > +} > > + > > +static const struct of_device_id onboard_hub_match[] = { > > + { .compatible = "onboard-usb-hub" }, > > + { .compatible = "realtek,rts5411" }, > > + {} > > +}; > > +MODULE_DEVICE_TABLE(of, onboard_hub_match); > > + > > +static SIMPLE_DEV_PM_OPS(onboard_hub_pm_ops, onboard_hub_suspend, > > onboard_hub_resume); > > + > > +static struct platform_driver onboard_hub_driver = { > > + .probe = onboard_hub_probe, > > + .remove = onboard_hub_remove, > > + > > + .driver = { > > + .name = "onboard-usb-hub", > > + .of_match_table = onboard_hub_match, > > + .pm = pm_ptr(&onboard_hub_pm_ops), > > + }, > > +}; > > + > > +/************************** USB driver **************************/ > > + > > +#define VENDOR_ID_REALTEK 0x0bda > > + > > +static struct onboard_hub *_find_onboard_hub(struct device *dev) > > +{ > > + const phandle *ph; > > + struct device_node *np; > > + struct platform_device *pdev; > > + > > + ph = of_get_property(dev->of_node, "hub", NULL); > > + if (!ph) { > > + dev_err(dev, "failed to read 'hub' property\n"); > > + return ERR_PTR(-EINVAL); > > + } > > + > > + np = of_find_node_by_phandle(be32_to_cpu(*ph)); > > + if (!np) { > > + dev_err(dev, "failed find device node for onboard hub\n"); > > + return ERR_PTR(-EINVAL); > > + } > > + > > + pdev = of_find_device_by_node(np); > > + of_node_put(np); > > + if (!pdev) > > + return ERR_PTR(-EPROBE_DEFER); > > Why can you defer here? We know there is a node, so if the device can not be found it probably hasn't been probed yet? > > + > > + return dev_get_drvdata(&pdev->dev); > > +} > > + > > +static int onboard_hub_usbdev_probe(struct usb_device *udev) > > +{ > > + struct device *dev = &udev->dev; > > + struct onboard_hub *hub; > > + > > + /* ignore supported hubs without device tree node */ > > + if (!dev->of_node) > > + return -ENODEV; > > + > > + hub = _find_onboard_hub(dev); > > + if (IS_ERR(hub)) > > + return PTR_ERR(dev); > > + > > + dev_set_drvdata(dev, hub); > > + > > + onboard_hub_add_usbdev(hub, udev); > > + > > + return 0; > > +} > > + > > +static void onboard_hub_usbdev_disconnect(struct usb_device *udev) > > +{ > > + struct onboard_hub *hub = dev_get_drvdata(&udev->dev); > > + > > + onboard_hub_remove_usbdev(hub, udev); > > + > > + put_device(hub->dev); > > +} > > + > > +static const struct usb_device_id onboard_hub_id_table[] = { > > + { .idVendor = VENDOR_ID_REALTEK, > > + .idProduct = 0x0411, /* RTS5411 USB 3.0 */ > > + .match_flags = USB_DEVICE_ID_MATCH_DEVICE }, > > + { .idVendor = VENDOR_ID_REALTEK, > > + .idProduct = 0x5411, /* RTS5411 USB 2.0 */ > > + .match_flags = USB_DEVICE_ID_MATCH_DEVICE }, > > USB_DEVICE() should be used here instead for both of these, right? ack > > + {}, > > +}; > > + > > +MODULE_DEVICE_TABLE(usb, onboard_hub_id_table); > > + > > +static struct usb_device_driver onboard_hub_usbdev_driver = { > > + > > + .name = "onboard-usb-hub", > > + .probe = onboard_hub_usbdev_probe, > > + .disconnect = onboard_hub_usbdev_disconnect, > > + .generic_subclass = 1, > > + .supports_autosuspend = 1, > > + .id_table = onboard_hub_id_table, > > +}; > > + > > +/************************** Driver (de)registration > > **************************/ > > + > > +static int __init onboard_hub_init(void) > > +{ > > + int rc; > > + > > + rc = platform_driver_register(&onboard_hub_driver); > > + if (rc) > > + return rc; > > + > > + return usb_register_device_driver(&onboard_hub_usbdev_driver, > > THIS_MODULE); > > No unwinding of the platform driver register if this fails? Right, will add unwinding. > And THIS_MODULE should not be needed, did we get the api wrong here? It seems you suggest to use usb_register() instead, SGTM > > +} > > +device_initcall(onboard_hub_init); > > Why device_initcall() if this could be a module? Why not a normal > module_init()? Ok, will change it to module_init() Thanks Matthias
