On Mon, 22 Aug 2016, Peter Chen wrote: > On Mon, Aug 15, 2016 at 05:13:14PM +0800, 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@xxxxxxx> > > Tested-by Joshua Clayton <stillcompiling@xxxxxxxxx> > > Hi Alan, > > The power sequence library code has been reviewed several rounds, would > you please help to review the change for USB part? Some small problems... See below. > > --- a/drivers/usb/core/Makefile > > +++ b/drivers/usb/core/Makefile > > @@ -9,5 +9,6 @@ usbcore-y += port.o of.o > > > > usbcore-$(CONFIG_PCI) += hcd-pci.o > > usbcore-$(CONFIG_ACPI) += usb-acpi.o > > +usbcore-$(CONFIG_PWRSEQ_GENERIC) += pwrseq.o Please use a tab to align this with the lines above. > > --- /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@xxxxxxx> > > + * > > + * 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); You need to check that the kzalloc succeeded. > > + 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; > > +} This subroutine looks very generic. The only place where it cares that it was called for a USB hub is the list_add(), and that could easily become generic also (make this function take &hub->pwrseq_on_list as its second argument, instead of hub). It looks like this routine really belongs in the power sequence library. > > + > > +int hub_pwrseq_on(struct usb_hub *hub) > > +{ The names of this routine and the subroutine above are too similar. After all, both functions require OF support. > > + 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); > > + } > > +} This routine also looks like it belongs in a library. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
