| Message ID | 1469007629-31757-5-git-send-email-peter.chen@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/20/2016 02:40 AM, Peter Chen wrote: > Some hard-wired USB devices need to do power sequence to let the > device work normally, the typical power sequence like: enable USB > PHY clock, toggle reset pin, etc. But current Linux USB driver > lacks of such code to do it, it may cause some hard-wired USB devices > works abnormal or can't be recognized by controller at all. > > In this patch, it calls power sequence library APIs to finish > the power sequence events. At first, it calls pwrseq_alloc_generic > to create a generic power sequence instance, then it will do power > on sequence at hub's probe for all devices under this hub > (includes root hub). > > At hub_disconnect, it will do power off sequence which is at powered > on list. > > Signed-off-by: Peter Chen <peter.chen@nxp.com> > --- > drivers/usb/core/Makefile | 1 + > drivers/usb/core/hub.c | 12 ++++-- > drivers/usb/core/hub.h | 12 ++++++ > drivers/usb/core/pwrseq.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 122 insertions(+), 3 deletions(-) > create mode 100644 drivers/usb/core/pwrseq.c > > diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile > index da36b78..5fd2f54 100644 > --- a/drivers/usb/core/Makefile > +++ b/drivers/usb/core/Makefile > @@ -10,5 +10,6 @@ usbcore-y += port.o > usbcore-$(CONFIG_OF) += of.o > usbcore-$(CONFIG_PCI) += hcd-pci.o > usbcore-$(CONFIG_ACPI) += usb-acpi.o > +usbcore-$(CONFIG_PWRSEQ_GENERIC) += pwrseq.o > > obj-$(CONFIG_USB) += usbcore.o > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index bee1351..a346a8b 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -1700,6 +1700,7 @@ static void hub_disconnect(struct usb_interface *intf) > hub->error = 0; > hub_quiesce(hub, HUB_DISCONNECT); > > + hub_pwrseq_off(hub); > mutex_lock(&usb_port_peer_mutex); > > /* Avoid races with recursively_mark_NOTATTACHED() */ > @@ -1733,6 +1734,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) > struct usb_endpoint_descriptor *endpoint; > struct usb_device *hdev; > struct usb_hub *hub; > + int ret = -ENODEV; > > desc = intf->cur_altsetting; > hdev = interface_to_usbdev(intf); > @@ -1839,6 +1841,7 @@ descriptor_error: > INIT_DELAYED_WORK(&hub->leds, led_work); > INIT_DELAYED_WORK(&hub->init_work, NULL); > INIT_WORK(&hub->events, hub_event); > + INIT_LIST_HEAD(&hub->pwrseq_on_list); > usb_get_intf(intf); > usb_get_dev(hdev); > > @@ -1852,11 +1855,14 @@ descriptor_error: > if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND) > hub->quirk_check_port_auto_suspend = 1; > > - if (hub_configure(hub, endpoint) >= 0) > - return 0; > + if (hub_configure(hub, endpoint) >= 0) { > + ret = hub_pwrseq_on(hub); > + if (!ret) > + return 0; > + } > > hub_disconnect(intf); > - return -ENODEV; > + return ret; > } > > static int > diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h > index 34c1a7e..9473f6f 100644 > --- a/drivers/usb/core/hub.h > +++ b/drivers/usb/core/hub.h > @@ -78,6 +78,7 @@ struct usb_hub { > struct delayed_work init_work; > struct work_struct events; > struct usb_port **ports; > + struct list_head pwrseq_on_list; /* powered pwrseq node list */ > }; > > /** > @@ -166,3 +167,14 @@ static inline int hub_port_debounce_be_stable(struct usb_hub *hub, > { > return hub_port_debounce(hub, port1, false); > } > + > +#if IS_ENABLED(CONFIG_PWRSEQ_GENERIC) > +int hub_pwrseq_on(struct usb_hub *hub); > +void hub_pwrseq_off(struct usb_hub *hub); > +#else > +static inline int hub_pwrseq_on(struct usb_hub *hub) > +{ > + return 0; > +} > +static inline void hub_pwrseq_off(struct usb_hub *hub) {} > +#endif /* CONFIG_PWRSEQ_GENERIC */ > diff --git a/drivers/usb/core/pwrseq.c b/drivers/usb/core/pwrseq.c > new file mode 100644 > index 0000000..837fe66 > --- /dev/null > +++ b/drivers/usb/core/pwrseq.c > @@ -0,0 +1,100 @@ > +/* > + * pwrseq.c USB device power sequence management > + * > + * Copyright (C) 2016 Freescale Semiconductor, Inc. > + * Author: Peter Chen <peter.chen@nxp.com> > + * > + * This program is free software: you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 of > + * the License as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/list.h> > +#include <linux/of.h> > +#include <linux/power/pwrseq.h> > +#include <linux/slab.h> > +#include <linux/usb.h> > +#include <linux/usb/hcd.h> > + > +#include "hub.h" > + > +struct usb_pwrseq_node { > + struct pwrseq *pwrseq; > + struct list_head list; > +}; > + > +static int hub_of_pwrseq_on(struct device_node *np, struct usb_hub *hub) > +{ > + struct pwrseq *pwrseq; > + struct usb_pwrseq_node *pwrseq_node; > + int ret; > + > + pwrseq = pwrseq_alloc_generic(); > + if (IS_ERR(pwrseq)) > + return PTR_ERR(pwrseq); > + > + ret = pwrseq_get(np, pwrseq); > + if (ret) > + goto pwr_free; > + > + ret = pwrseq_on(np, pwrseq); > + if (ret) > + goto pwr_put; > + > + pwrseq_node = kzalloc(sizeof(*pwrseq_node), GFP_KERNEL); > + pwrseq_node->pwrseq = pwrseq; > + list_add(&pwrseq_node->list, &hub->pwrseq_on_list); > + > + return 0; > + > +pwr_put: > + pwrseq_put(pwrseq); > +pwr_free: > + pwrseq_free(pwrseq); > + return ret; > +} > + > +int hub_pwrseq_on(struct usb_hub *hub) > +{ > + struct device *parent; > + struct usb_device *hdev = hub->hdev; > + struct device_node *np; > + int ret; > + > + if (hdev->parent) > + parent = &hdev->dev; > + else > + parent = bus_to_hcd(hdev->bus)->self.controller; > + > + for_each_child_of_node(parent->of_node, np) { > + ret = hub_of_pwrseq_on(np, hub); > + if (ret) > + return ret; > + } > + > + return 0; > +} > + > +void hub_pwrseq_off(struct usb_hub *hub) > +{ > + struct pwrseq *pwrseq; > + struct usb_pwrseq_node *pwrseq_node, *tmp_node; > + > + list_for_each_entry_safe(pwrseq_node, tmp_node, > + &hub->pwrseq_on_list, list) { > + pwrseq = pwrseq_node->pwrseq; > + pwrseq_off(pwrseq); > + pwrseq_put(pwrseq); > + pwrseq_free(pwrseq); > + list_del(&pwrseq_node->list); > + kfree(pwrseq_node); > + } > +} Patch 4 does not apply for me (The Makefile has a "usbcore-$(CONFIG_OF) += of.o" line which I don't see in 4.7 or linux/next master). Is there another patch set this series depends on?
On Wed, Jul 27, 2016 at 09:25:11AM -0700, Joshua Clayton wrote: > > > On 07/20/2016 02:40 AM, Peter Chen wrote: > > Some hard-wired USB devices need to do power sequence to let the > > device work normally, the typical power sequence like: enable USB > > PHY clock, toggle reset pin, etc. But current Linux USB driver > > lacks of such code to do it, it may cause some hard-wired USB devices > > works abnormal or can't be recognized by controller at all. > > > > In this patch, it calls power sequence library APIs to finish > > the power sequence events. At first, it calls pwrseq_alloc_generic > > to create a generic power sequence instance, then it will do power > > on sequence at hub's probe for all devices under this hub > > (includes root hub). > > > > At hub_disconnect, it will do power off sequence which is at powered > > on list. > > > > Signed-off-by: Peter Chen <peter.chen@nxp.com> > > --- > > drivers/usb/core/Makefile | 1 + > > drivers/usb/core/hub.c | 12 ++++-- > > drivers/usb/core/hub.h | 12 ++++++ > > drivers/usb/core/pwrseq.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 122 insertions(+), 3 deletions(-) > > create mode 100644 drivers/usb/core/pwrseq.c > > > > diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile > > index da36b78..5fd2f54 100644 > > --- a/drivers/usb/core/Makefile > > +++ b/drivers/usb/core/Makefile > > @@ -10,5 +10,6 @@ usbcore-y += port.o > > usbcore-$(CONFIG_OF) += of.o > > usbcore-$(CONFIG_PCI) += hcd-pci.o > > usbcore-$(CONFIG_ACPI) += usb-acpi.o > > +usbcore-$(CONFIG_PWRSEQ_GENERIC) += pwrseq.o > > > > obj-$(CONFIG_USB) += usbcore.o > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > > index bee1351..a346a8b 100644 > > --- a/drivers/usb/core/hub.c > > +++ b/drivers/usb/core/hub.c > > @@ -1700,6 +1700,7 @@ static void hub_disconnect(struct usb_interface *intf) > > hub->error = 0; > > hub_quiesce(hub, HUB_DISCONNECT); > > > > + hub_pwrseq_off(hub); > > mutex_lock(&usb_port_peer_mutex); > > > > /* Avoid races with recursively_mark_NOTATTACHED() */ > > @@ -1733,6 +1734,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) > > struct usb_endpoint_descriptor *endpoint; > > struct usb_device *hdev; > > struct usb_hub *hub; > > + int ret = -ENODEV; > > > > desc = intf->cur_altsetting; > > hdev = interface_to_usbdev(intf); > > @@ -1839,6 +1841,7 @@ descriptor_error: > > INIT_DELAYED_WORK(&hub->leds, led_work); > > INIT_DELAYED_WORK(&hub->init_work, NULL); > > INIT_WORK(&hub->events, hub_event); > > + INIT_LIST_HEAD(&hub->pwrseq_on_list); > > usb_get_intf(intf); > > usb_get_dev(hdev); > > > > @@ -1852,11 +1855,14 @@ descriptor_error: > > if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND) > > hub->quirk_check_port_auto_suspend = 1; > > > > - if (hub_configure(hub, endpoint) >= 0) > > - return 0; > > + if (hub_configure(hub, endpoint) >= 0) { > > + ret = hub_pwrseq_on(hub); > > + if (!ret) > > + return 0; > > + } > > > > hub_disconnect(intf); > > - return -ENODEV; > > + return ret; > > } > > > > static int > > diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h > > index 34c1a7e..9473f6f 100644 > > --- a/drivers/usb/core/hub.h > > +++ b/drivers/usb/core/hub.h > > @@ -78,6 +78,7 @@ struct usb_hub { > > struct delayed_work init_work; > > struct work_struct events; > > struct usb_port **ports; > > + struct list_head pwrseq_on_list; /* powered pwrseq node list */ > > }; > > > > /** > > @@ -166,3 +167,14 @@ static inline int hub_port_debounce_be_stable(struct usb_hub *hub, > > { > > return hub_port_debounce(hub, port1, false); > > } > > + > > +#if IS_ENABLED(CONFIG_PWRSEQ_GENERIC) > > +int hub_pwrseq_on(struct usb_hub *hub); > > +void hub_pwrseq_off(struct usb_hub *hub); > > +#else > > +static inline int hub_pwrseq_on(struct usb_hub *hub) > > +{ > > + return 0; > > +} > > +static inline void hub_pwrseq_off(struct usb_hub *hub) {} > > +#endif /* CONFIG_PWRSEQ_GENERIC */ > > diff --git a/drivers/usb/core/pwrseq.c b/drivers/usb/core/pwrseq.c > > new file mode 100644 > > index 0000000..837fe66 > > --- /dev/null > > +++ b/drivers/usb/core/pwrseq.c > > @@ -0,0 +1,100 @@ > > +/* > > + * pwrseq.c USB device power sequence management > > + * > > + * Copyright (C) 2016 Freescale Semiconductor, Inc. > > + * Author: Peter Chen <peter.chen@nxp.com> > > + * > > + * This program is free software: you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 of > > + * the License as published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + * > > + * You should have received a copy of the GNU General Public License > > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > > + */ > > + > > +#include <linux/list.h> > > +#include <linux/of.h> > > +#include <linux/power/pwrseq.h> > > +#include <linux/slab.h> > > +#include <linux/usb.h> > > +#include <linux/usb/hcd.h> > > + > > +#include "hub.h" > > + > > +struct usb_pwrseq_node { > > + struct pwrseq *pwrseq; > > + struct list_head list; > > +}; > > + > > +static int hub_of_pwrseq_on(struct device_node *np, struct usb_hub *hub) > > +{ > > + struct pwrseq *pwrseq; > > + struct usb_pwrseq_node *pwrseq_node; > > + int ret; > > + > > + pwrseq = pwrseq_alloc_generic(); > > + if (IS_ERR(pwrseq)) > > + return PTR_ERR(pwrseq); > > + > > + ret = pwrseq_get(np, pwrseq); > > + if (ret) > > + goto pwr_free; > > + > > + ret = pwrseq_on(np, pwrseq); > > + if (ret) > > + goto pwr_put; > > + > > + pwrseq_node = kzalloc(sizeof(*pwrseq_node), GFP_KERNEL); > > + pwrseq_node->pwrseq = pwrseq; > > + list_add(&pwrseq_node->list, &hub->pwrseq_on_list); > > + > > + return 0; > > + > > +pwr_put: > > + pwrseq_put(pwrseq); > > +pwr_free: > > + pwrseq_free(pwrseq); > > + return ret; > > +} > > + > > +int hub_pwrseq_on(struct usb_hub *hub) > > +{ > > + struct device *parent; > > + struct usb_device *hdev = hub->hdev; > > + struct device_node *np; > > + int ret; > > + > > + if (hdev->parent) > > + parent = &hdev->dev; > > + else > > + parent = bus_to_hcd(hdev->bus)->self.controller; > > + > > + for_each_child_of_node(parent->of_node, np) { > > + ret = hub_of_pwrseq_on(np, hub); > > + if (ret) > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +void hub_pwrseq_off(struct usb_hub *hub) > > +{ > > + struct pwrseq *pwrseq; > > + struct usb_pwrseq_node *pwrseq_node, *tmp_node; > > + > > + list_for_each_entry_safe(pwrseq_node, tmp_node, > > + &hub->pwrseq_on_list, list) { > > + pwrseq = pwrseq_node->pwrseq; > > + pwrseq_off(pwrseq); > > + pwrseq_put(pwrseq); > > + pwrseq_free(pwrseq); > > + list_del(&pwrseq_node->list); > > + kfree(pwrseq_node); > > + } > > +} > Patch 4 does not apply for me > (The Makefile has a "usbcore-$(CONFIG_OF) += of.o" > line which I don't see in 4.7 or linux/next master). > Is there another patch set this series depends on? It seems below patch has not been queued: https://git.kernel.org/cgit/linux/kernel/git/peter.chen/usb.git/commit/?h=add_pwrseq_for_usb&id=2efd73d0f935ffbc66135553da0ac807c0b4c3fe This pwrseq-lib patch set does not depend on it, I will send patch set on top of a clean mainline next time, sorry for confusing.
Peter, On 07/27/2016 06:45 PM, Peter Chen wrote: > On Wed, Jul 27, 2016 at 09:25:11AM -0700, Joshua Clayton wrote: >> Patch 4 does not apply for me >> (The Makefile has a "usbcore-$(CONFIG_OF) += of.o" >> line which I don't see in 4.7 or linux/next master). >> Is there another patch set this series depends on? > It seems below patch has not been queued: > > https://git.kernel.org/cgit/linux/kernel/git/peter.chen/usb.git/commit/?h=add_pwrseq_for_usb&id=2efd73d0f935ffbc66135553da0ac807c0b4c3fe > > This pwrseq-lib patch set does not depend on it, I will send patch set > on top of a clean mainline next time, sorry for confusing. > Good to know. I just wanted to make sure I wasn't missing something important. Thanks, Joshua Clayton
diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile index da36b78..5fd2f54 100644 --- a/drivers/usb/core/Makefile +++ b/drivers/usb/core/Makefile @@ -10,5 +10,6 @@ usbcore-y += port.o usbcore-$(CONFIG_OF) += of.o usbcore-$(CONFIG_PCI) += hcd-pci.o usbcore-$(CONFIG_ACPI) += usb-acpi.o +usbcore-$(CONFIG_PWRSEQ_GENERIC) += pwrseq.o obj-$(CONFIG_USB) += usbcore.o diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index bee1351..a346a8b 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1700,6 +1700,7 @@ static void hub_disconnect(struct usb_interface *intf) hub->error = 0; hub_quiesce(hub, HUB_DISCONNECT); + hub_pwrseq_off(hub); mutex_lock(&usb_port_peer_mutex); /* Avoid races with recursively_mark_NOTATTACHED() */ @@ -1733,6 +1734,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) struct usb_endpoint_descriptor *endpoint; struct usb_device *hdev; struct usb_hub *hub; + int ret = -ENODEV; desc = intf->cur_altsetting; hdev = interface_to_usbdev(intf); @@ -1839,6 +1841,7 @@ descriptor_error: INIT_DELAYED_WORK(&hub->leds, led_work); INIT_DELAYED_WORK(&hub->init_work, NULL); INIT_WORK(&hub->events, hub_event); + INIT_LIST_HEAD(&hub->pwrseq_on_list); usb_get_intf(intf); usb_get_dev(hdev); @@ -1852,11 +1855,14 @@ descriptor_error: if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND) hub->quirk_check_port_auto_suspend = 1; - if (hub_configure(hub, endpoint) >= 0) - return 0; + if (hub_configure(hub, endpoint) >= 0) { + ret = hub_pwrseq_on(hub); + if (!ret) + return 0; + } hub_disconnect(intf); - return -ENODEV; + return ret; } static int diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 34c1a7e..9473f6f 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -78,6 +78,7 @@ struct usb_hub { struct delayed_work init_work; struct work_struct events; struct usb_port **ports; + struct list_head pwrseq_on_list; /* powered pwrseq node list */ }; /** @@ -166,3 +167,14 @@ static inline int hub_port_debounce_be_stable(struct usb_hub *hub, { return hub_port_debounce(hub, port1, false); } + +#if IS_ENABLED(CONFIG_PWRSEQ_GENERIC) +int hub_pwrseq_on(struct usb_hub *hub); +void hub_pwrseq_off(struct usb_hub *hub); +#else +static inline int hub_pwrseq_on(struct usb_hub *hub) +{ + return 0; +} +static inline void hub_pwrseq_off(struct usb_hub *hub) {} +#endif /* CONFIG_PWRSEQ_GENERIC */ diff --git a/drivers/usb/core/pwrseq.c b/drivers/usb/core/pwrseq.c new file mode 100644 index 0000000..837fe66 --- /dev/null +++ b/drivers/usb/core/pwrseq.c @@ -0,0 +1,100 @@ +/* + * pwrseq.c USB device power sequence management + * + * Copyright (C) 2016 Freescale Semiconductor, Inc. + * Author: Peter Chen <peter.chen@nxp.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 of + * the License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/list.h> +#include <linux/of.h> +#include <linux/power/pwrseq.h> +#include <linux/slab.h> +#include <linux/usb.h> +#include <linux/usb/hcd.h> + +#include "hub.h" + +struct usb_pwrseq_node { + struct pwrseq *pwrseq; + struct list_head list; +}; + +static int hub_of_pwrseq_on(struct device_node *np, struct usb_hub *hub) +{ + struct pwrseq *pwrseq; + struct usb_pwrseq_node *pwrseq_node; + int ret; + + pwrseq = pwrseq_alloc_generic(); + if (IS_ERR(pwrseq)) + return PTR_ERR(pwrseq); + + ret = pwrseq_get(np, pwrseq); + if (ret) + goto pwr_free; + + ret = pwrseq_on(np, pwrseq); + if (ret) + goto pwr_put; + + pwrseq_node = kzalloc(sizeof(*pwrseq_node), GFP_KERNEL); + pwrseq_node->pwrseq = pwrseq; + list_add(&pwrseq_node->list, &hub->pwrseq_on_list); + + return 0; + +pwr_put: + pwrseq_put(pwrseq); +pwr_free: + pwrseq_free(pwrseq); + return ret; +} + +int hub_pwrseq_on(struct usb_hub *hub) +{ + struct device *parent; + struct usb_device *hdev = hub->hdev; + struct device_node *np; + int ret; + + if (hdev->parent) + parent = &hdev->dev; + else + parent = bus_to_hcd(hdev->bus)->self.controller; + + for_each_child_of_node(parent->of_node, np) { + ret = hub_of_pwrseq_on(np, hub); + if (ret) + return ret; + } + + return 0; +} + +void hub_pwrseq_off(struct usb_hub *hub) +{ + struct pwrseq *pwrseq; + struct usb_pwrseq_node *pwrseq_node, *tmp_node; + + list_for_each_entry_safe(pwrseq_node, tmp_node, + &hub->pwrseq_on_list, list) { + pwrseq = pwrseq_node->pwrseq; + pwrseq_off(pwrseq); + pwrseq_put(pwrseq); + pwrseq_free(pwrseq); + list_del(&pwrseq_node->list); + kfree(pwrseq_node); + } +}
Some hard-wired USB devices need to do power sequence to let the device work normally, the typical power sequence like: enable USB PHY clock, toggle reset pin, etc. But current Linux USB driver lacks of such code to do it, it may cause some hard-wired USB devices works abnormal or can't be recognized by controller at all. In this patch, it calls power sequence library APIs to finish the power sequence events. At first, it calls pwrseq_alloc_generic to create a generic power sequence instance, then it will do power on sequence at hub's probe for all devices under this hub (includes root hub). At hub_disconnect, it will do power off sequence which is at powered on list. Signed-off-by: Peter Chen <peter.chen@nxp.com> --- drivers/usb/core/Makefile | 1 + drivers/usb/core/hub.c | 12 ++++-- drivers/usb/core/hub.h | 12 ++++++ drivers/usb/core/pwrseq.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 122 insertions(+), 3 deletions(-) create mode 100644 drivers/usb/core/pwrseq.c