On Thu, Jun 02, 2016 at 09:37:24AM +0800, Lu Baolu wrote: > Several Intel platforms implement USB dual role by having completely > separate xHCI and dwc3 IPs in PCH or SOC silicons. These two IPs share > a single USB port. There is another external port mux which controls > where the data lines should go. While the USB controllers are part of > the silicon, the port mux design are platform specific. > > This patch adds the generic code to handle such multiple roles of a > usb port. It exports the necessary interfaces for other components to > register or unregister a usb mux device, and to control its role. > It registers the mux device with sysfs as well, so that users are able > to control the port role from user space. > > Some other archs (e.g. Renesas R-Car gen2 SoCs) need an external mux to > swap usb roles as well. This code could also be leveraged for those archs. > Sorry to review this so late, from my point, it is a dual-role switch driver too, we are reviewing USB OTG/dual-role framework [1], it is not necessary to create another framework to do it. And USB OTG framework has already tested at Renesas's platform [2]. [1] http://www.spinics.net/lists/linux-usb/msg140835.html [2] http://www.spinics.net/lists/linux-usb/msg140827.html Peter > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > Reviewed-by: Felipe Balbi <balbi@xxxxxxxxxx> > --- > Documentation/ABI/testing/sysfs-bus-platform | 18 +++ > drivers/usb/Kconfig | 2 + > drivers/usb/Makefile | 1 + > drivers/usb/mux/Kconfig | 8 ++ > drivers/usb/mux/Makefile | 4 + > drivers/usb/mux/portmux-core.c | 202 +++++++++++++++++++++++++++ > include/linux/usb/portmux.h | 90 ++++++++++++ > 7 files changed, 325 insertions(+) > create mode 100644 drivers/usb/mux/Kconfig > create mode 100644 drivers/usb/mux/Makefile > create mode 100644 drivers/usb/mux/portmux-core.c > create mode 100644 include/linux/usb/portmux.h > > diff --git a/Documentation/ABI/testing/sysfs-bus-platform b/Documentation/ABI/testing/sysfs-bus-platform > index 5172a61..b994e4e 100644 > --- a/Documentation/ABI/testing/sysfs-bus-platform > +++ b/Documentation/ABI/testing/sysfs-bus-platform > @@ -18,3 +18,21 @@ Description: > devices to opt-out of driver binding using a driver_override > name such as "none". Only a single driver may be specified in > the override, there is no support for parsing delimiters. > + > +What: /sys/bus/platform/devices/.../portmux.N/name > + /sys/bus/platform/devices/.../portmux.N/state > +Date: April 2016 > +Contact: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > +Description: > + In some platforms, a single USB port is shared between a USB host > + controller and a device controller. A USB mux driver is needed to > + handle the port mux. Read-only attribute "name" shows the name of > + the port mux device. "state" attribute shows and stores the mux > + state. > + For read: > + 'unknown' - the mux hasn't been set yet; > + 'peripheral' - mux has been switched to PERIPHERAL controller; > + 'host' - mux has been switched to HOST controller. > + For write: > + 'peripheral' - mux will be switched to PERIPHERAL controller; > + 'host' - mux will be switched to HOST controller. > diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig > index 8689dcb..328916e 100644 > --- a/drivers/usb/Kconfig > +++ b/drivers/usb/Kconfig > @@ -148,6 +148,8 @@ endif # USB > > source "drivers/usb/phy/Kconfig" > > +source "drivers/usb/mux/Kconfig" > + > source "drivers/usb/gadget/Kconfig" > > config USB_LED_TRIG > diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile > index dca7856..9a92338 100644 > --- a/drivers/usb/Makefile > +++ b/drivers/usb/Makefile > @@ -6,6 +6,7 @@ > > obj-$(CONFIG_USB) += core/ > obj-$(CONFIG_USB_SUPPORT) += phy/ > +obj-$(CONFIG_USB_SUPPORT) += mux/ > > obj-$(CONFIG_USB_DWC3) += dwc3/ > obj-$(CONFIG_USB_DWC2) += dwc2/ > diff --git a/drivers/usb/mux/Kconfig b/drivers/usb/mux/Kconfig > new file mode 100644 > index 0000000..ba778f2 > --- /dev/null > +++ b/drivers/usb/mux/Kconfig > @@ -0,0 +1,8 @@ > +# > +# USB port mux driver configuration > +# > + > +menuconfig USB_PORTMUX > + bool "USB dual role port MUX support" > + help > + Generic USB dual role port mux support. > diff --git a/drivers/usb/mux/Makefile b/drivers/usb/mux/Makefile > new file mode 100644 > index 0000000..f85df92 > --- /dev/null > +++ b/drivers/usb/mux/Makefile > @@ -0,0 +1,4 @@ > +# > +# Makefile for USB port mux drivers > +# > +obj-$(CONFIG_USB_PORTMUX) += portmux-core.o > diff --git a/drivers/usb/mux/portmux-core.c b/drivers/usb/mux/portmux-core.c > new file mode 100644 > index 0000000..75fbb45 > --- /dev/null > +++ b/drivers/usb/mux/portmux-core.c > @@ -0,0 +1,202 @@ > +/** > + * portmux-core.c - USB Port Mux support > + * > + * Copyright (C) 2016 Intel Corporation > + * > + * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > + * > + * 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. > + */ > + > +#include <linux/slab.h> > +#include <linux/err.h> > +#include <linux/usb/portmux.h> > + > +static int usb_mux_change_state(struct portmux_dev *pdev, > + enum portmux_role role) > +{ > + struct device *dev = &pdev->dev; > + int ret = -EINVAL; > + > + dev_WARN_ONCE(dev, > + !mutex_is_locked(&pdev->mux_mutex), > + "mutex is unlocked\n"); > + > + switch (role) { > + case PORTMUX_HOST: > + if (pdev->desc->ops->set_host_cb) > + ret = pdev->desc->ops->set_host_cb(pdev->dev.parent); > + break; > + case PORTMUX_DEVICE: > + if (pdev->desc->ops->set_device_cb) > + ret = pdev->desc->ops->set_device_cb(pdev->dev.parent); > + break; > + default: > + break; > + } > + > + if (!ret) > + pdev->mux_state = role; > + > + return ret; > +} > + > +static const char * const role_name[] = { > + "unknown", /* PORTMUX_UNKNOWN */ > + "host", /* PORTMUX_HOST */ > + "peripheral" /* PORTMUX_DEVICE */ > +}; > + > +static ssize_t state_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct portmux_dev *pdev = dev_get_drvdata(dev); > + > + return sprintf(buf, "%s\n", role_name[pdev->mux_state]); > +} > + > +static ssize_t state_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct portmux_dev *pdev = dev_get_drvdata(dev); > + enum portmux_role role; > + > + if (sysfs_streq(buf, "peripheral")) > + role = PORTMUX_DEVICE; > + else if (sysfs_streq(buf, "host")) > + role = PORTMUX_HOST; > + else > + return -EINVAL; > + > + mutex_lock(&pdev->mux_mutex); > + usb_mux_change_state(pdev, role); > + mutex_unlock(&pdev->mux_mutex); > + > + return count; > +} > +static DEVICE_ATTR_RW(state); > + > +static ssize_t name_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct portmux_dev *pdev = dev_get_drvdata(dev); > + > + return sprintf(buf, "%s\n", pdev->desc->name); > +} > +static DEVICE_ATTR_RO(name); > + > +static struct attribute *portmux_attrs[] = { > + &dev_attr_state.attr, > + &dev_attr_name.attr, > + NULL, > +}; > + > +static struct attribute_group portmux_attr_grp = { > + .attrs = portmux_attrs, > +}; > + > +static const struct attribute_group *portmux_group[] = { > + &portmux_attr_grp, > + NULL, > +}; > + > +static void portmux_dev_release(struct device *dev) > +{ > + dev_vdbg(dev, "%s\n", __func__); > +} > + > +/** > + * portmux_register - register a port mux > + * @dev: device the mux belongs to > + * @desc: the descriptor of this port mux > + * > + * Called by port mux drivers to register a mux. Returns a valid > + * pointer to struct portmux_dev on success or an ERR_PTR() on > + * error. > + */ > +struct portmux_dev *portmux_register(struct portmux_desc *desc) > +{ > + static atomic_t portmux_no = ATOMIC_INIT(-1); > + struct portmux_dev *pdev; > + int ret; > + > + /* parameter sanity check */ > + if (!desc || !desc->name || !desc->ops || !desc->dev) > + return ERR_PTR(-EINVAL); > + > + pdev = kzalloc(sizeof(*pdev), GFP_KERNEL); > + if (!pdev) > + return ERR_PTR(-ENOMEM); > + > + mutex_init(&pdev->mux_mutex); > + pdev->desc = desc; > + pdev->dev.parent = desc->dev; > + pdev->dev.release = portmux_dev_release; > + dev_set_name(&pdev->dev, "portmux.%lu", > + (unsigned long)atomic_inc_return(&portmux_no)); > + pdev->dev.groups = portmux_group; > + ret = device_register(&pdev->dev); > + if (ret) { > + kfree(pdev); > + return ERR_PTR(ret); > + } > + > + dev_set_drvdata(&pdev->dev, pdev); > + > + return pdev; > +} > +EXPORT_SYMBOL_GPL(portmux_register); > + > +/** > + * portmux_unregister - unregister a port mux > + * @pdev: the port mux device > + * > + * Called by port mux drivers to release a mux. > + */ > +void portmux_unregister(struct portmux_dev *pdev) > +{ > + device_unregister(&pdev->dev); > + kfree(pdev); > +} > +EXPORT_SYMBOL_GPL(portmux_unregister); > + > +/** > + * portmux_switch - switch the port role > + * @pdev: the port mux device > + * @role: the target role > + * > + * Called by other components to switch the port role. > + */ > +int portmux_switch(struct portmux_dev *pdev, enum portmux_role role) > +{ > + int ret; > + > + mutex_lock(&pdev->mux_mutex); > + ret = usb_mux_change_state(pdev, role); > + mutex_unlock(&pdev->mux_mutex); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(portmux_switch); > + > +#ifdef CONFIG_PM_SLEEP > +/** > + * portmux_complete - refresh port state during system resumes back > + * @pdev: the port mux device > + * > + * Called by port mux drivers to refresh port state during system > + * resumes back. > + */ > +void portmux_complete(struct portmux_dev *pdev) > +{ > + mutex_lock(&pdev->mux_mutex); > + usb_mux_change_state(pdev, pdev->mux_state); > + mutex_unlock(&pdev->mux_mutex); > +} > +EXPORT_SYMBOL_GPL(portmux_complete); > +#endif > diff --git a/include/linux/usb/portmux.h b/include/linux/usb/portmux.h > new file mode 100644 > index 0000000..093620a > --- /dev/null > +++ b/include/linux/usb/portmux.h > @@ -0,0 +1,90 @@ > +/** > + * portmux.h - USB Port Mux definitions > + * > + * Copyright (C) 2016 Intel Corporation > + * > + * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > + * > + * 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. > + */ > + > +#ifndef __LINUX_USB_PORTMUX_H > +#define __LINUX_USB_PORTMUX_H > + > +#include <linux/device.h> > + > +/** > + * struct portmux_ops - ops two switch the port > + * > + * @set_host_cb: callback for switching port to host > + * @set_device_cb: callback for switching port to device > + */ > +struct portmux_ops { > + int (*set_host_cb)(struct device *dev); > + int (*set_device_cb)(struct device *dev); > +}; > + > +/** > + * struct portmux_desc - port mux device descriptor > + * > + * @name: the name of the mux device > + * @dev: the parent of the mux device > + * @ops: ops to switch the port role > + */ > +struct portmux_desc { > + const char *name; > + struct device *dev; > + const struct portmux_ops *ops; > +}; > + > +/** > + * enum portmux_role - role of the port > + */ > +enum portmux_role { > + PORTMUX_UNKNOWN, > + PORTMUX_HOST, > + PORTMUX_DEVICE, > +}; > + > +/** > + * struct portmux_dev - A mux device > + * > + * @desc: the descriptor of the mux > + * @dev: device of this mux > + * @mux_mutex: lock to serialize port switch operation > + * @mux_state: state of the mux > + */ > +struct portmux_dev { > + const struct portmux_desc *desc; > + struct device dev; > + > + /* lock for mux_state */ > + struct mutex mux_mutex; > + enum portmux_role mux_state; > +}; > + > +/* > + * Functions for mux driver > + */ > +struct portmux_dev *portmux_register(struct portmux_desc *desc); > +void portmux_unregister(struct portmux_dev *pdev); > +#ifdef CONFIG_PM_SLEEP > +void portmux_complete(struct portmux_dev *pdev); > +#endif > + > +/* > + * Functions for mux consumer > + */ > +#if defined(CONFIG_USB_PORTMUX) > +int portmux_switch(struct portmux_dev *pdev, enum portmux_role role); > +#else > +static inline int portmux_switch(struct portmux_dev *pdev, > + enum portmux_role role) > +{ > + return 0; > +} > +#endif > + > +#endif /* __LINUX_USB_PORTMUX_H */ > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
