Subject: [PATCH v3 4/6] usb: core: add power sequence handling for USB devices

From: [email-masked] (Peter Chen)
Date: Thu, 28 Jul 2016 09:45:21 +0800

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 <[email-masked]>
> > ---
> >  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 <[email-masked]>
> > + *
> > + * 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. 

-- 

Best Regards,
Peter Chen