Hi, Roger Quadros <rogerq@xxxxxx> writes: > It provides APIs for the following tasks > > - Registering an OTG/dual-role capable controller > - Registering Host and Gadget controllers to OTG core > - Providing inputs to and kicking the OTG state machine I think I have already mentioned this, but after over 10 years of OTG, nobody seems to care about it, why are we still touching at all I don't know. For common non-OTG role-swapping we really don't need any of this and, quite frankly, I fail to see enough users for this. Apparently there's only chipidea which, AFAICT, already had working dual-role before this OTG State Machine was added to the kernel. > Provide a dual-role device (DRD) state machine. there's not such thing as DRD state machine. You don't need to go through all these states, actually. > DRD mode is a reduced functionality OTG mode. In this mode > we don't support SRP, HNP and dynamic role-swap. > > In DRD operation, the controller mode (Host or Peripheral) > is decided based on the ID pin status. Once a cable plug (Type-A > or Type-B) is attached the controller selects the state > and doesn't change till the cable in unplugged and a different > cable type is inserted. > > As we don't need most of the complex OTG states and OTG timers > we implement a lean DRD state machine in usb-otg.c. > The DRD state machine is only interested in 2 hardware inputs > 'id' and 'b_sess_vld'. > > Signed-off-by: Roger Quadros <rogerq@xxxxxx> > --- > v11: > - remove usb_otg_kick_fsm(). > - typo fixes: structa/structure, upto/up to. > - remove "obj-$(CONFIG_USB_OTG_CORE) += common/" from Makefile. > > drivers/usb/Kconfig | 18 + > drivers/usb/common/Makefile | 6 +- > drivers/usb/common/usb-otg.c | 877 +++++++++++++++++++++++++++++++++++++++++++ > drivers/usb/core/Kconfig | 14 - > drivers/usb/gadget/Kconfig | 1 + > include/linux/usb/gadget.h | 2 + > include/linux/usb/hcd.h | 1 + > include/linux/usb/otg-fsm.h | 7 + > include/linux/usb/otg.h | 174 ++++++++- > 9 files changed, 1070 insertions(+), 30 deletions(-) > create mode 100644 drivers/usb/common/usb-otg.c > > diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig > index 8689dcb..ed596ec 100644 > --- a/drivers/usb/Kconfig > +++ b/drivers/usb/Kconfig > @@ -32,6 +32,23 @@ if USB_SUPPORT > config USB_COMMON > tristate > > +config USB_OTG_CORE > + tristate why tristate if you can never set it to 'M'? > diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c > new file mode 100644 > index 0000000..a23ab1e > --- /dev/null > +++ b/drivers/usb/common/usb-otg.c > @@ -0,0 +1,877 @@ > +/** > + * drivers/usb/common/usb-otg.c - USB OTG core > + * > + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com > + * Author: Roger Quadros <rogerq@xxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 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. > + */ > + > +#include <linux/kernel.h> > +#include <linux/list.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_platform.h> > +#include <linux/usb/of.h> > +#include <linux/usb/otg.h> > +#include <linux/usb/gadget.h> > +#include <linux/workqueue.h> > + > +/* OTG device list */ > +LIST_HEAD(otg_list); not static? Who needs to touch this private list? > +static DEFINE_MUTEX(otg_list_mutex); > + > +static int usb_otg_hcd_is_primary_hcd(struct usb_hcd *hcd) > +{ > + if (!hcd->primary_hcd) > + return 1; these seems inverted. If hcd->primary is NULL (meaning, there's no ->primary_hcd), then we tell caller that this _is_ a primary hcd? Care to explain? > + return hcd == hcd->primary_hcd; > +} > + > +/** > + * usb_otg_get_data() - get usb_otg data structure > + * @otg_dev: OTG controller device > + * > + * Check if the OTG device is in our OTG list and return > + * usb_otg data, else NULL. > + * > + * otg_list_mutex must be held. > + * > + * Return: usb_otg data on success, NULL otherwise. > + */ > +static struct usb_otg *usb_otg_get_data(struct device *otg_dev) > +{ > + struct usb_otg *otg; > + > + if (!otg_dev) > + return NULL; > + > + list_for_each_entry(otg, &otg_list, list) { > + if (otg->dev == otg_dev) > + return otg; > + } > + > + return NULL; > +} > + > +/** > + * usb_otg_start_host() - start/stop the host controller > + * @otg: usb_otg instance > + * @on: true to start, false to stop > + * > + * Start/stop the USB host controller. This function is meant > + * for use by the OTG controller driver. > + * > + * Return: 0 on success, error value otherwise. > + */ > +int usb_otg_start_host(struct usb_otg *otg, int on) > +{ > + struct otg_hcd_ops *hcd_ops = otg->hcd_ops; > + int ret; > + > + dev_dbg(otg->dev, "otg: %s %d\n", __func__, on); > + if (!otg->host) { > + WARN_ONCE(1, "otg: fsm running without host\n"); if (WARN_ONCE(!otg->host, "otg: fsm running without host\n")) return 0; but, frankly, if you require a 'host' and a 'gadget' don't start this layer until you have both. > + return 0; > + } > + > + if (on) { > + if (otg->flags & OTG_FLAG_HOST_RUNNING) > + return 0; > + > + /* start host */ > + ret = hcd_ops->add(otg->primary_hcd.hcd, > + otg->primary_hcd.irqnum, > + otg->primary_hcd.irqflags); this is usb_add_hcd(), is it not? Why add an indirection? > + if (ret) { > + dev_err(otg->dev, "otg: host add failed %d\n", ret); > + return ret; > + } > + > + if (otg->shared_hcd.hcd) { > + ret = hcd_ops->add(otg->shared_hcd.hcd, > + otg->shared_hcd.irqnum, > + otg->shared_hcd.irqflags); > + if (ret) { > + dev_err(otg->dev, "otg: shared host add failed %d\n", > + ret); > + hcd_ops->remove(otg->primary_hcd.hcd); > + return ret; > + } > + } > + otg->flags |= OTG_FLAG_HOST_RUNNING; > + } else { > + if (!(otg->flags & OTG_FLAG_HOST_RUNNING)) > + return 0; > + > + otg->flags &= ~OTG_FLAG_HOST_RUNNING; > + > + /* stop host */ > + if (otg->shared_hcd.hcd) > + hcd_ops->remove(otg->shared_hcd.hcd); usb_del_hcd()? > + hcd_ops->remove(otg->primary_hcd.hcd); > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_start_host); > + > +/** > + * usb_otg_start_gadget() - start/stop the gadget controller > + * @otg: usb_otg instance > + * @on: true to start, false to stop > + * > + * Start/stop the USB gadget controller. This function is meant > + * for use by the OTG controller driver. > + * > + * Return: 0 on success, error value otherwise. > + */ > +int usb_otg_start_gadget(struct usb_otg *otg, int on) > +{ > + struct usb_gadget *gadget = otg->gadget; > + int ret; > + > + dev_dbg(otg->dev, "otg: %s %d\n", __func__, on); > + if (!gadget) { > + WARN_ONCE(1, "otg: fsm running without gadget\n"); > + return 0; > + } ditto > + if (on) { > + if (otg->flags & OTG_FLAG_GADGET_RUNNING) > + return 0; > + > + ret = otg->gadget_ops->start(otg->gadget); > + if (ret) { > + dev_err(otg->dev, "otg: gadget start failed: %d\n", > + ret); > + return ret; > + } > + > + otg->flags |= OTG_FLAG_GADGET_RUNNING; > + } else { > + if (!(otg->flags & OTG_FLAG_GADGET_RUNNING)) > + return 0; > + > + ret = otg->gadget_ops->stop(otg->gadget); > + if (ret) { > + dev_err(otg->dev, "otg: gadget stop failed: %d\n", > + ret); > + return ret; > + } > + otg->flags &= ~OTG_FLAG_GADGET_RUNNING; > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_start_gadget); > + > +/** > + * drd_set_protocol() - Set USB protocol if possible > + * @fsm: DRD FSM instance > + * @protocol: USB protocol to set the state machine to > + * > + * Sets the OTG FSM protocol to @protocol if it changed. > + * fsm->lock must be held. > + * > + * Return: 0 on success, error value otherwise. > + */ > +static int drd_set_protocol(struct otg_fsm *fsm, int protocol) > +{ > + struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm); > + int ret = 0; > + > + if (fsm->protocol != protocol) { > + dev_dbg(otg->dev, "otg: changing role fsm->protocol= %d; new protocol= %d\n", > + fsm->protocol, protocol); > + /* stop old protocol */ > + if (fsm->protocol == PROTO_HOST) { > + ret = otg_start_host(otg, 0); > + } else if (fsm->protocol == PROTO_GADGET) { > + otg->gadget_ops->connect_control(otg->gadget, false); > + ret = otg_start_gadget(otg, 0); > + } > + > + if (ret) > + return ret; > + > + /* start new protocol */ > + if (protocol == PROTO_HOST) { > + ret = otg_start_host(otg, 1); > + } else if (protocol == PROTO_GADGET) { > + ret = otg_start_gadget(otg, 1); > + otg->gadget_ops->connect_control(otg->gadget, true); > + } > + > + if (ret) > + return ret; > + > + fsm->protocol = protocol; > + return 0; > + } > + > + return 0; > +} > + > +/** > + * drd_set_state() - Set the DRD state machine state. > + * @fsm: DRD FSM instance > + * @new_state: the new state the DRD FSM must be set to > + * > + * Sets the state of the DRD state machine. > + * fsm->lock must be held. > + */ > +static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state) > +{ > + struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm); > + > + if (otg->state == new_state) > + return; > + > + fsm->state_changed = 1; > + dev_dbg(otg->dev, "otg: set state: %s\n", > + usb_otg_state_string(new_state)); > + switch (new_state) { > + case OTG_STATE_B_IDLE: > + drd_set_protocol(fsm, PROTO_UNDEF); > + otg_drv_vbus(otg, 0); > + break; > + case OTG_STATE_B_PERIPHERAL: > + drd_set_protocol(fsm, PROTO_GADGET); > + otg_drv_vbus(otg, 0); > + break; > + case OTG_STATE_A_HOST: > + drd_set_protocol(fsm, PROTO_HOST); > + otg_drv_vbus(otg, 1); > + break; > + default: > + dev_warn(otg->dev, "%s: otg: invalid state: %s\n", > + __func__, usb_otg_state_string(new_state)); > + break; > + } > + > + otg->state = new_state; > +} > + > +/** > + * drd_statemachine() - DRD state change judgement > + * @otg: usb_otg instance > + * > + * Checks the state machine inputs and state and makes a state change > + * if required. > + * > + * For DRD we're only interested in some of the OTG states > + * i.e. OTG_STATE_B_IDLE: both peripheral and host are stopped > + * OTG_STATE_B_PERIPHERAL: peripheral active > + * OTG_STATE_A_HOST: host active > + * we're only interested in the following inputs > + * fsm->id, fsm->b_sess_vld > + * > + * Return: 0 if state wasn't changed, 1 if state changed. > + */ > +int drd_statemachine(struct usb_otg *otg) > +{ > + struct otg_fsm *fsm = &otg->fsm; > + enum usb_otg_state state; > + int ret; > + > + mutex_lock(&fsm->lock); > + > + fsm->state_changed = 0; > + state = otg->state; > + > + switch (state) { > + case OTG_STATE_UNDEFINED: > + if (!fsm->id) > + drd_set_state(fsm, OTG_STATE_A_HOST); > + else if (fsm->id && fsm->b_sess_vld) > + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL); > + else > + drd_set_state(fsm, OTG_STATE_B_IDLE); > + break; > + case OTG_STATE_B_IDLE: > + if (!fsm->id) > + drd_set_state(fsm, OTG_STATE_A_HOST); > + else if (fsm->b_sess_vld) > + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL); > + break; > + case OTG_STATE_B_PERIPHERAL: > + if (!fsm->id) > + drd_set_state(fsm, OTG_STATE_A_HOST); > + else if (!fsm->b_sess_vld) > + drd_set_state(fsm, OTG_STATE_B_IDLE); > + break; > + case OTG_STATE_A_HOST: > + if (fsm->id && fsm->b_sess_vld) > + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL); > + else if (fsm->id && !fsm->b_sess_vld) > + drd_set_state(fsm, OTG_STATE_B_IDLE); > + break; > + > + default: > + dev_err(otg->dev, "%s: otg: invalid usb-drd state: %s\n", > + __func__, usb_otg_state_string(state)); > + break; > + } > + > + ret = fsm->state_changed; > + mutex_unlock(&fsm->lock); > + dev_dbg(otg->dev, "otg: quit statemachine, changed %d\n", > + fsm->state_changed); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(drd_statemachine); why is this exported at all? It only runs from the work_struct below. BTW, that work_struct looks unnecessary. > + > +/** > + * usb_drd_work() - Dual-role state machine work function > + * @work: work_struct context > + * > + * Runs the DRD state machine. Scheduled whenever there is a change > + * in FSM inputs. > + */ > +static void usb_drd_work(struct work_struct *work) > +{ > + struct usb_otg *otg = container_of(work, struct usb_otg, work); > + > + pm_runtime_get_sync(otg->dev); > + while (drd_statemachine(otg)) > + ; > + pm_runtime_put_sync(otg->dev); so, once this gets kicked it'll keep on running until a state doesn't change. > +} > + > +/** > + * usb_otg_register() - Register the OTG/dual-role device to OTG core > + * @dev: OTG/dual-role controller device. > + * @config: OTG configuration. > + * > + * Registers the OTG/dual-role controller device with the USB OTG core. > + * > + * Return: struct usb_otg * if success, ERR_PTR() otherwise. > + */ > +struct usb_otg *usb_otg_register(struct device *dev, > + struct usb_otg_config *config) > +{ > + struct usb_otg *otg; > + int ret = 0; > + > + if (!dev || !config || !config->fsm_ops) > + return ERR_PTR(-EINVAL); > + > + /* already in list? */ > + mutex_lock(&otg_list_mutex); > + if (usb_otg_get_data(dev)) { > + dev_err(dev, "otg: %s: device already in otg list\n", > + __func__); > + ret = -EINVAL; > + goto unlock; > + } > + > + /* allocate and add to list */ > + otg = kzalloc(sizeof(*otg), GFP_KERNEL); > + if (!otg) { > + ret = -ENOMEM; > + goto unlock; > + } > + > + otg->dev = dev; > + /* otg->caps is controller caps + DT overrides */ > + otg->caps = *config->otg_caps; > + ret = of_usb_update_otg_caps(dev->of_node, &otg->caps); > + if (ret) > + goto err_wq; > + > + if ((otg->caps.hnp_support || otg->caps.srp_support || > + otg->caps.adp_support) && !config->otg_work) { > + dev_err(dev, > + "otg: otg_work must be provided for OTG support\n"); > + ret = -EINVAL; > + goto err_wq; > + } > + > + if (config->otg_work) /* custom otg_work ? */ > + INIT_WORK(&otg->work, config->otg_work); > + else > + INIT_WORK(&otg->work, usb_drd_work); why do you need to cope with custom work handlers? > + otg->wq = create_freezable_workqueue("usb_otg"); > + if (!otg->wq) { > + dev_err(dev, "otg: %s: can't create workqueue\n", > + __func__); > + ret = -ENOMEM; > + goto err_wq; > + } > + > + /* set otg ops */ > + otg->fsm.ops = config->fsm_ops; > + > + mutex_init(&otg->fsm.lock); > + > + list_add_tail(&otg->list, &otg_list); > + mutex_unlock(&otg_list_mutex); > + > + return otg; > + > +err_wq: > + kfree(otg); > +unlock: > + mutex_unlock(&otg_list_mutex); > + return ERR_PTR(ret); > +} > +EXPORT_SYMBOL_GPL(usb_otg_register); > + > +/** > + * usb_otg_unregister() - Unregister the OTG/dual-role device from USB OTG core > + * @dev: OTG controller device. > + * > + * Unregisters the OTG/dual-role controller device from USB OTG core. > + * Prevents unregistering till both the associated Host and Gadget controllers > + * have unregistered from the OTG core. > + * > + * Return: 0 on success, error value otherwise. > + */ > +int usb_otg_unregister(struct device *dev) > +{ > + struct usb_otg *otg; > + > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(dev); > + if (!otg) { > + dev_err(dev, "otg: %s: device not in otg list\n", > + __func__); > + mutex_unlock(&otg_list_mutex); > + return -EINVAL; > + } > + > + /* prevent unregister till both host & gadget have unregistered */ > + if (otg->host || otg->gadget) { > + dev_err(dev, "otg: %s: host/gadget still registered\n", > + __func__); > + mutex_unlock(&otg_list_mutex); > + return -EBUSY; > + } I think a better choice would've been to unregister host and gadget in case they haven't been unregistered yet. That's a common expectation. Specially since driver core does the same thing when you unregister a parent device. > + /* OTG FSM is halted when host/gadget unregistered */ > + destroy_workqueue(otg->wq); > + > + /* remove from otg list */ > + list_del(&otg->list); > + kfree(otg); > + mutex_unlock(&otg_list_mutex); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_unregister); > + > +/** > + * usb_otg_start_fsm() - Start the OTG FSM > + * @otg: usb_otg instance > + * > + * Start the OTG FSM if we can. The HCD, UDC and gadget function driver > + * must be ready for the OTG FSM to start. > + * > + * fsm->lock must be held. > + */ > +static void usb_otg_start_fsm(struct usb_otg *otg) > +{ > + struct otg_fsm *fsm = &otg->fsm; > + > + if (fsm->running) > + goto kick_fsm; > + > + if (!otg->host) { > + dev_info(otg->dev, "otg: can't start till host registers\n"); > + return; > + } > + > + if (!otg->gadget) { > + dev_info(otg->dev, > + "otg: can't start till gadget UDC registers\n"); > + return; > + } okay, so you never kick the FSM until host and gadget are registered. Why do you need to test for the case where the FSM is running without host/gadget? You seem to guarantee that will never be the case. > + if (!otg->gadget_ready) { > + dev_info(otg->dev, > + "otg: can't start till gadget function registers\n"); > + return; > + } > + > + fsm->running = true; > +kick_fsm: > + queue_work(otg->wq, &otg->work); > +} > + > +/** > + * usb_otg_stop_fsm() - Stop the OTG FSM > + * @otg: usb_otg instance > + * > + * Stops the HCD, UDC and the OTG FSM. > + * > + * fsm->lock must be held. > + */ > +static void usb_otg_stop_fsm(struct usb_otg *otg) > +{ > + struct otg_fsm *fsm = &otg->fsm; > + > + if (!fsm->running) > + return; > + > + /* no more new events queued */ > + fsm->running = false; > + > + flush_workqueue(otg->wq); > + otg->state = OTG_STATE_UNDEFINED; > + > + /* stop host/gadget immediately */ > + if (fsm->protocol == PROTO_HOST) { > + otg_start_host(otg, 0); > + } else if (fsm->protocol == PROTO_GADGET) { > + otg->gadget_ops->connect_control(otg->gadget, false); > + otg_start_gadget(otg, 0); > + } > + fsm->protocol = PROTO_UNDEF; > +} > + > +/** > + * usb_otg_sync_inputs() - Sync OTG inputs with the OTG state machine > + * @otg: usb_otg instance > + * > + * Used by the OTG driver to update the inputs to the OTG > + * state machine. > + * > + * Can be called in IRQ context. > + */ > +void usb_otg_sync_inputs(struct usb_otg *otg) > +{ > + /* Don't kick FSM till it has started */ > + if (!otg->fsm.running) > + return; > + > + /* Kick FSM */ > + queue_work(otg->wq, &otg->work); > +} > +EXPORT_SYMBOL_GPL(usb_otg_sync_inputs); > + > +/** > + * usb_otg_register_hcd() - Register the host controller to OTG core > + * @hcd: host controller > + * @irqnum: interrupt number > + * @irqflags: interrupt flags > + * @ops: HCD ops to interface with the HCD > + * > + * This is used by the USB Host stack to register the host controller > + * to the OTG core. Host controller must not be started by the > + * caller as it is left up to the OTG state machine to do so. > + * hcd->otg_dev must contain the related otg controller device. > + * > + * Return: 0 on success, error value otherwise. > + */ > +int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum, > + unsigned long irqflags, struct otg_hcd_ops *ops) > +{ > + struct usb_otg *otg; > + struct device *hcd_dev = hcd->self.controller; > + struct device *otg_dev = hcd->otg_dev; > + > + if (!otg_dev) > + return -EINVAL; > + > + /* we're otg but otg controller might not yet be registered */ > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(otg_dev); > + mutex_unlock(&otg_list_mutex); > + if (!otg) { > + dev_dbg(hcd_dev, > + "otg: controller not yet registered. deferring.\n"); > + return -EPROBE_DEFER; > + } > + > + /* HCD will be started by OTG fsm when needed */ > + mutex_lock(&otg->fsm.lock); > + if (otg->primary_hcd.hcd) { > + /* probably a shared HCD ? */ > + if (usb_otg_hcd_is_primary_hcd(hcd)) { > + dev_err(otg_dev, "otg: primary host already registered\n"); > + goto err; > + } > + > + if (hcd->shared_hcd == otg->primary_hcd.hcd) { > + if (otg->shared_hcd.hcd) { > + dev_err(otg_dev, "otg: shared host already registered\n"); > + goto err; > + } > + > + otg->shared_hcd.hcd = hcd; > + otg->shared_hcd.irqnum = irqnum; > + otg->shared_hcd.irqflags = irqflags; > + otg->shared_hcd.ops = ops; > + dev_info(otg_dev, "otg: shared host %s registered\n", > + dev_name(hcd->self.controller)); > + } else { > + dev_err(otg_dev, "otg: invalid shared host %s\n", > + dev_name(hcd->self.controller)); > + goto err; > + } > + } else { > + if (!usb_otg_hcd_is_primary_hcd(hcd)) { > + dev_err(otg_dev, "otg: primary host must be registered first\n"); > + goto err; > + } > + > + otg->primary_hcd.hcd = hcd; > + otg->primary_hcd.irqnum = irqnum; > + otg->primary_hcd.irqflags = irqflags; > + otg->primary_hcd.ops = ops; > + otg->hcd_ops = ops; > + dev_info(otg_dev, "otg: primary host %s registered\n", > + dev_name(hcd->self.controller)); > + } > + > + /* > + * we're ready only if we have shared HCD > + * or we don't need shared HCD. > + */ > + if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) { > + otg->host = hcd_to_bus(hcd); > + /* FIXME: set bus->otg_port if this is true OTG port with HNP */ > + > + /* start FSM */ > + usb_otg_start_fsm(otg); > + } else { > + dev_dbg(otg_dev, "otg: can't start till shared host registers\n"); > + } > + > + mutex_unlock(&otg->fsm.lock); > + > + return 0; > + > +err: > + mutex_unlock(&otg->fsm.lock); > + return -EINVAL; > +} > +EXPORT_SYMBOL_GPL(usb_otg_register_hcd); > + > +/** > + * usb_otg_unregister_hcd() - Unregister the host controller from OTG core > + * @hcd: host controller device > + * > + * This is used by the USB Host stack to unregister the host controller > + * from the OTG core. Ensures that host controller is not running > + * on successful return. > + * > + * Returns: 0 on success, error value otherwise. > + */ > +int usb_otg_unregister_hcd(struct usb_hcd *hcd) > +{ > + struct usb_otg *otg; > + struct device *hcd_dev = hcd_to_bus(hcd)->controller; > + struct device *otg_dev = hcd->otg_dev; > + > + if (!otg_dev) > + return -EINVAL; /* we're definitely not OTG */ > + > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(otg_dev); > + mutex_unlock(&otg_list_mutex); > + if (!otg) { > + dev_err(hcd_dev, "otg: host %s wasn't registered with otg\n", > + dev_name(hcd_dev)); > + return -EINVAL; > + } > + > + mutex_lock(&otg->fsm.lock); > + if (hcd == otg->primary_hcd.hcd) { > + otg->primary_hcd.hcd = NULL; > + dev_info(otg_dev, "otg: primary host %s unregistered\n", > + dev_name(hcd_dev)); > + } else if (hcd == otg->shared_hcd.hcd) { > + otg->shared_hcd.hcd = NULL; > + dev_info(otg_dev, "otg: shared host %s unregistered\n", > + dev_name(hcd_dev)); > + } else { > + mutex_unlock(&otg->fsm.lock); > + dev_err(otg_dev, "otg: host %s wasn't registered with otg\n", > + dev_name(hcd_dev)); > + return -EINVAL; > + } > + > + /* stop FSM & Host */ > + usb_otg_stop_fsm(otg); > + otg->host = NULL; > + > + mutex_unlock(&otg->fsm.lock); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_unregister_hcd); > + > +/** > + * usb_otg_register_gadget() - Register the gadget controller to OTG core > + * @gadget: gadget controller instance > + * @ops: gadget interface ops > + * > + * This is used by the USB gadget stack to register the gadget controller > + * to the OTG core. Gadget controller must not be started by the > + * caller as it is left up to the OTG state machine to do so. > + * > + * Returns: 0 on success, error value otherwise. > + */ > +int usb_otg_register_gadget(struct usb_gadget *gadget, > + struct otg_gadget_ops *ops) > +{ > + struct usb_otg *otg; > + struct device *gadget_dev = &gadget->dev; > + struct device *otg_dev = gadget->otg_dev; > + > + if (!otg_dev) > + return -EINVAL; /* we're definitely not OTG */ > + > + /* we're otg but otg controller might not yet be registered */ > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(otg_dev); > + mutex_unlock(&otg_list_mutex); > + if (!otg) { > + dev_dbg(gadget_dev, > + "otg: controller not yet registered, deferring.\n"); > + return -EPROBE_DEFER; > + } > + > + mutex_lock(&otg->fsm.lock); > + if (otg->gadget) { > + dev_err(otg_dev, "otg: gadget already registered with otg\n"); > + mutex_unlock(&otg->fsm.lock); > + return -EINVAL; > + } > + > + otg->gadget = gadget; > + otg->gadget_ops = ops; > + dev_info(otg_dev, "otg: gadget %s registered\n", > + dev_name(&gadget->dev)); > + > + /* FSM will be started in usb_otg_gadget_ready() */ > + mutex_unlock(&otg->fsm.lock); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_register_gadget); > + > +/** > + * usb_otg_unregister_gadget() - Unregister the gadget controller from OTG core > + * @gadget: gadget controller > + * > + * This is used by the USB gadget stack to unregister the gadget controller > + * from the OTG core. Ensures that gadget controller is not running > + * on successful return. > + * > + * Returns: 0 on success, error value otherwise. > + */ > +int usb_otg_unregister_gadget(struct usb_gadget *gadget) > +{ > + struct usb_otg *otg; > + struct device *gadget_dev = &gadget->dev; > + struct device *otg_dev = gadget->otg_dev; > + > + if (!otg_dev) > + return -EINVAL; > + > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(otg_dev); > + mutex_unlock(&otg_list_mutex); > + if (!otg) { > + dev_err(gadget_dev, > + "otg: gadget %s wasn't registered with otg\n", > + dev_name(&gadget->dev)); > + return -EINVAL; > + } > + > + mutex_lock(&otg->fsm.lock); > + if (otg->gadget != gadget) { > + mutex_unlock(&otg->fsm.lock); > + dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n", > + dev_name(&gadget->dev)); > + return -EINVAL; > + } > + > + /* FSM must be stopped in usb_otg_gadget_ready() */ > + if (otg->gadget_ready) { > + dev_err(otg_dev, > + "otg: gadget %s unregistered before being unready, forcing stop\n", > + dev_name(&gadget->dev)); > + usb_otg_stop_fsm(otg); > + } > + > + otg->gadget = NULL; > + mutex_unlock(&otg->fsm.lock); > + > + dev_info(otg_dev, "otg: gadget %s unregistered\n", > + dev_name(&gadget->dev)); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_unregister_gadget); > + > +/** > + * usb_otg_gadget_ready() - Notify gadget function driver ready status > + * @gadget: gadget controller > + * @ready: 0: function driver ready, 1: function driver not ready > + * > + * Notify the OTG core about status of the gadget function driver. > + * As OTG core is responsible to start/stop the gadget controller, it > + * must be aware when the gadget function driver is available or not. > + * This function is used by the Gadget core to inform the OTG core > + * about the gadget function driver readyness. > + * > + * Return: 0 on sucess, error value otherwise. > + */ > +int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready) > +{ > + struct usb_otg *otg; > + struct device *gadget_dev = &gadget->dev; > + struct device *otg_dev = gadget->otg_dev; > + > + if (!otg_dev) > + return -EINVAL; > + > + mutex_lock(&otg_list_mutex); > + otg = usb_otg_get_data(otg_dev); > + mutex_unlock(&otg_list_mutex); > + if (!otg) { > + dev_err(gadget_dev, > + "otg: gadget %s wasn't registered with otg\n", > + dev_name(&gadget->dev)); > + return -EINVAL; > + } > + > + mutex_lock(&otg->fsm.lock); > + if (otg->gadget != gadget) { > + mutex_unlock(&otg->fsm.lock); > + dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n", > + dev_name(&gadget->dev)); > + return -EINVAL; > + } > + > + /* Start/stop FSM & gadget */ > + otg->gadget_ready = ready; > + if (ready) > + usb_otg_start_fsm(otg); > + else > + usb_otg_stop_fsm(otg); > + > + dev_dbg(otg_dev, "otg: gadget %s %sready\n", dev_name(&gadget->dev), > + ready ? "" : "not "); > + > + mutex_unlock(&otg->fsm.lock); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(usb_otg_gadget_ready); > + > +MODULE_LICENSE("GPL"); GPL or GPL 2-only? > diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h > index f4fc0aa..1d74fb8 100644 > --- a/include/linux/usb/gadget.h > +++ b/include/linux/usb/gadget.h > @@ -328,6 +328,7 @@ struct usb_gadget_ops { > * @in_epnum: last used in ep number > * @mA: last set mA value > * @otg_caps: OTG capabilities of this gadget. > + * @otg_dev: OTG controller device, if needs to be used with OTG core. do you really know of any platform which has a separate OTG controller? -- balbi
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