usb: add support for Intel dual role port mux

Intel SOC chips are featured with USB dual role. The host role is provided by Intel xHCI IP, and the gadget role is provided by IP from designware. Tablet platform designs always share a single port for both host and gadget controllers. There is a mux to switch the port to the right controller according to the cable type. OS needs to provide the callback to control the mux when a plug-in event raises. The method to control the mux is platform dependent. At least three types of implementation can be found across current devices. 1) GPIO pins; 2) a unit which can be controlled by memory mapped registers; 3) ACPI ASL code.

This patch series adds supports for Intel dual role port mux. It includes:
(1) A helper layer on top of extcon for individual mux driver. It listens to the USB-HOST extcon cable and call the switch call-back when the cable state changes.
(2) Drivers for GPIO controlled port mux which could be found on Baytrail devices. A mfd driver is used to split the GPIOs into a USB gpio extcon device, a fixed regulator for gpio controlled USB VCC, and a USB mux device. Driver for USB gpio extcon device is already in upstream Linux. This patch series includes a driver for GPIO USB mux.
(3) Drivers for USB port mux controlled through memory mapped registers and the logic to create the mux device. This type of dual role port mux could be found in Cherry Trail and Broxton devices.

Lu Baolu (7):
regulator: fixed: add support for ACPI interface
usb: mux: add generic code for dual role port mux
usb: mux: add driver for Intel gpio controlled port mux
usb: mux: add driver for Intel drcfg controlled port mux
mfd: intel_vuport: Add Intel virtual USB port MFD Driver
usb: pci-quirks: add Intel USB drcfg mux device
MAINTAINERS: add maintainer entry for Intel USB dual role mux drivers

Change log:

v6->v7:
- Two patches have been picked up by extcon maintainer. Hence, remove them since this version.
- extcon: usb-gpio: add device binding for platform device
- extcon: usb-gpio: add support for ACPI gpio interface
- In patch "regulator: fixed: add support for ACPI interface", a static gpio name is used to get the regulator gpio.
- In patch "mfd: intel_vuport: Add Intel virtual USB port MFD Driver", unnecessary "gpio-name" string property has been removed.

v5->v6:
Work internally with Felipe to improve the whole patch series. Below changes have been made since last version.
- rework the common code to make it a generic interface for mux devices;
- split the vbus gpio handling to a fixed regulator device;
- removed unnecessary filtering for state change;
- removed unnecessary WARN statement;
- removed globals in mux drivers;
- removed unnecessary register polling and waiting in drcfg driver;

v4->v5:
- Change the extcon interfaces with the new ones suggested by 2a9de9c0f08d6 (extcon: Use the unique id for external connector instead of string)
- remove patch "usb: pci-quirks: add Intel USB drcfg mux device" from this serial due to that it's not driver staff. Will be submitted seperately.

v3->v4:
- Check all patches with "checkpatch.pl --strict", and fix all CHECKs;
- Change sysfs node from "intel_mux" to "port_mux";
- Refines below confusing functions:
intel_usb_mux_register() -> intel_usb_mux_bind_cable() intel_usb_mux_unregister() -> intel_usb_mux_unbind_cable();
- Remove unnecessary struct intel_mux_dev.

v2->v3:
- uvport mfd driver got reviewed by Lee Jones, the following changes were made accordingly.
- seperate uvport driver from the mux drivers in MAINTAINERS file
- refine the description in Kconfig
- refine the mfd_cell structure data

v1->v2:
- move mux driver from drivers/usb/misc to drivers/usb/mux;
- replace debugfs with sysfs for user level mux control;
- remove unnecessary register restore if mux registeration failed;
- Add "Acked-by: Chanwoo Choi <[email protected]>" to extcon changes;
- Make the file names and exported function names more specific;
- Remove the usb_mux_get_dev() interface;
- Move "struct intel_usb_mux" from .h to .c file;
- Fix various kbuild robot warnings.

 Documentation/ABI/testing/sysfs-bus-platform |  17 +++
 MAINTAINERS                                  |  10 ++
 drivers/mfd/Kconfig                          |   8 +
 drivers/mfd/Makefile                         |   1 +
 drivers/mfd/intel-vuport.c                   |  89 +++++++++++
 drivers/regulator/fixed.c                    |  46 ++++++
 drivers/usb/Kconfig                          |   2 +
 drivers/usb/Makefile                         |   1 +
 drivers/usb/host/pci-quirks.c                |  45 +++++-
 drivers/usb/host/xhci-ext-caps.h             |   2 +
 drivers/usb/mux/Kconfig                      |  30 ++++
 drivers/usb/mux/Makefile                     |   6 +
 drivers/usb/mux/portmux-core.c               | 217 +++++++++++++++++++++++++++
 drivers/usb/mux/portmux-intel-drcfg.c        | 171 +++++++++++++++++++++
 drivers/usb/mux/portmux-intel-gpio.c         | 149 ++++++++++++++++++
 include/linux/usb/portmux.h                  |  78 ++++++++++
 16 files changed, 870 insertions(+), 2 deletions(-)
 create mode 100644 drivers/mfd/intel-vuport.c
 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 drivers/usb/mux/portmux-intel-drcfg.c
 create mode 100644 drivers/usb/mux/portmux-intel-gpio.c
 create mode 100644 include/linux/usb/portmux.h

2.1.4

Add support to retrieve fixed voltage configure information through ACPI interface. This is needed for Intel Bay Trail devices, where a GPIO is used to control the USB vbus.

---
 drivers/regulator/fixed.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

index ff62d69..68057dc 100644
@@ -30,6 +30,9 @@
 #include <linux/of_gpio.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/regulator/machine.h>
+#include <linux/acpi.h>
+#include <linux/property.h>
+#include <linux/gpio/consumer.h>
 
 struct fixed_voltage_data {
 	struct regulator_desc desc;

@@ -104,6 +107,44 @@ of_get_fixed_voltage_config(struct device *dev,
 	return config;
 }
 
+/**
+ * acpi_get_fixed_voltage_config - extract fixed_voltage_config structure info
+ * @dev: device requesting for fixed_voltage_config
+ * @desc: regulator description
+ *
+ * Populates fixed_voltage_config structure by extracting data through ACPI
+ * interface, returns a pointer to the populated structure of NULL if memory
+ * alloc fails.
+ */
+static struct fixed_voltage_config *
+acpi_get_fixed_voltage_config(struct device *dev,
+			      const struct regulator_desc *desc)
+{
+	struct fixed_voltage_config *config;
+	const char *supply_name, *gpio_name;
+	struct gpio_desc *gpiod;
+	int ret;
+
+	config = devm_kzalloc(dev, sizeof(*config), GFP_KERNEL);
+	if (!config)
+		return ERR_PTR(-ENOMEM);
+
+	ret = device_property_read_string(dev, "supply-name", &supply_name);
+	if (!ret)
+		config->supply_name = supply_name;
+
+	gpiod = gpiod_get(dev, "vbus_en", GPIOD_ASIS);
+	if (IS_ERR(gpiod))
+		return PTR_ERR(gpiod);
+
+	config->gpio = desc_to_gpio(gpiod);
+	config->enable_high = device_property_read_bool(dev,
+							"enable-active-high");
+	gpiod_put(gpiod);
+
+	return config;
+}
+
 static struct regulator_ops fixed_voltage_ops = {
 };
 

@@ -124,6 +165,11 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 						     &drvdata->desc);
 		if (IS_ERR(config))
 			return PTR_ERR(config);
+	} else if (ACPI_HANDLE(&pdev->dev)) {
+		config = acpi_get_fixed_voltage_config(&pdev->dev,
+						       &drvdata->desc);
+		if (IS_ERR(config))
+			return PTR_ERR(config);
 	} else {
 		config = dev_get_platdata(&pdev->dev);
 	}

2.1.4

Hi,

I will change the gpio name to "gpio". Is that okay?

Best regards,
Lu Baolu

Yes, that looks good (and lines up with DT so hopefully the code can be shared).

Hi,

Fair enough. Thanks.

Best regards,
Lu Baolu

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 usb port mux. It listens to the USB HOST extcon cable, and switch the port by calling the port switch ops provided by the individual port mux driver. It also registers the mux device with sysfs, so that users can control the port mux 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 be leveraged for those archs as well.

---
 Documentation/ABI/testing/sysfs-bus-platform |  17 +++
 drivers/usb/Kconfig                          |   2 +
 drivers/usb/Makefile                         |   1 +
 drivers/usb/mux/Kconfig                      |  11 ++
 drivers/usb/mux/Makefile                     |   4 +
 drivers/usb/mux/portmux-core.c               | 217 +++++++++++++++++++++++++++
 include/linux/usb/portmux.h                  |  78 ++++++++++
 7 files changed, 330 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

index 5172a61..f33f0a5 100644
@@ -18,3 +18,20 @@ 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 <[email protected]>
+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:
+		'peripheral' - mux switched to PERIPHERAL controller;
+		'host'       - mux switched to HOST controller.
+		For write:
+		'peripheral' - mux will be switched to PERIPHERAL controller;
+		'host'       - mux will be switched to HOST controller.

index 8689dcb..328916e 100644
@@ -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

index dca7856..9a92338 100644
@@ -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/

new file mode 100644
index 0000000..d91909f
@@ -0,0 +1,11 @@
+#
+# USB port mux driver configuration
+#
+
+menu "USB Port MUX drivers"
+config USB_PORTMUX
+	select EXTCON
+	def_bool n
+	help
+	  Generic USB dual role port mux support.
+endmenu

new file mode 100644
index 0000000..f85df92
@@ -0,0 +1,4 @@
+#
+# Makefile for USB port mux drivers
+#
+obj-$(CONFIG_USB_PORTMUX)		+= portmux-core.o

2.1.4

In some Intel platforms, a single usb port is shared between USB host and device controller. The shared port is under control of GPIO pins.

This patch adds the support for USB GPIO controlled port mux.

---
 drivers/usb/mux/Kconfig              |  11 +++
 drivers/usb/mux/Makefile             |   1 +
 drivers/usb/mux/portmux-intel-gpio.c | 149 +++++++++++++++++++++++++++++++++++
 3 files changed, 161 insertions(+)
 create mode 100644 drivers/usb/mux/portmux-intel-gpio.c

index d91909f..1dc1f33 100644
@@ -8,4 +8,15 @@ config USB_PORTMUX
 	def_bool n
 	help
 	  Generic USB dual role port mux support.
+
+config INTEL_MUX_GPIO
+	tristate "Intel dual role port mux controlled by GPIOs"
+	depends on GPIOLIB
+	depends on REGULATOR
+	depends on X86 && ACPI
+	select USB_PORTMUX
+	help
+	  Say Y here to enable support for Intel dual role port mux
+	  controlled by GPIOs.
+
 endmenu

index f85df92..4eb5582 100644
@@ -2,3 +2,4 @@
 # Makefile for USB port mux drivers
 #
 obj-$(CONFIG_USB_PORTMUX)		+= portmux-core.o
+obj-$(CONFIG_INTEL_MUX_GPIO)		+= portmux-intel-gpio.o

2.1.4

Several Intel PCHs and SOCs have an internal mux that is used to share one USB port between device controller and host controller. The mux is handled through the Dual Role Configuration Register.

---
 drivers/usb/mux/Kconfig               |   8 ++
 drivers/usb/mux/Makefile              |   1 +
 drivers/usb/mux/portmux-intel-drcfg.c | 171 ++++++++++++++++++++++++++++++++++
 3 files changed, 180 insertions(+)
 create mode 100644 drivers/usb/mux/portmux-intel-drcfg.c

index 1dc1f33..ae3f746 100644
@@ -19,4 +19,12 @@ config INTEL_MUX_GPIO
 	  Say Y here to enable support for Intel dual role port mux
 	  controlled by GPIOs.
 
+config INTEL_MUX_DRCFG
+	tristate "Intel dual role port mux controlled by register"
+	depends on X86
+	select USB_PORTMUX
+	help
+	  Say Y here to enable support for Intel dual role port mux
+	  controlled by the Dual Role Configuration Register.
+
 endmenu

index 4eb5582..0f102b5 100644
@@ -3,3 +3,4 @@
 #
 obj-$(CONFIG_USB_PORTMUX)		+= portmux-core.o
 obj-$(CONFIG_INTEL_MUX_GPIO)		+= portmux-intel-gpio.o
+obj-$(CONFIG_INTEL_MUX_DRCFG)		+= portmux-intel-drcfg.o

2.1.4

Some Intel platforms have an USB port mux controlled by GPIOs. There's a single ACPI platform device that provides 1) USB ID extcon device; 2) USB vbus regulator device; and 3) USB port switch device. This MFD driver will split these 3 devices for their respective drivers.

---
 drivers/mfd/Kconfig        |  8 +++++
 drivers/mfd/Makefile       |  1 +
 drivers/mfd/intel-vuport.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 drivers/mfd/intel-vuport.c

index eea61e3..7e115ab 100644
@@ -1578,5 +1578,13 @@ config MFD_VEXPRESS_SYSREG
 	  System Registers are the platform configuration block
 	  on the ARM Ltd. Versatile Express board.
 
+config MFD_INTEL_VUPORT
+	tristate "Intel virtual USB port controller"
+	select MFD_CORE
+	depends on X86 && ACPI
+	help
+	  Say Y here to enable support for Intel's dual role port mux
+	  controlled by GPIOs.
+
 endmenu
 endif

index 5eaa6465d..65b0518 100644
@@ -203,3 +203,4 @@ intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 intel-soc-pmic-$(CONFIG_INTEL_PMC_IPC)	+= intel_soc_pmic_bxtwc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
 obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
+obj-$(CONFIG_MFD_INTEL_VUPORT)	+= intel-vuport.o

2.1.4

In some Intel platforms, a single usb port is shared between USB host and device controllers. The shared port is under control of a switch which is defined in the Intel vendor defined extended capability for xHCI.

This patch adds the support to detect and create the platform device for the port mux switch.

---
 drivers/usb/host/pci-quirks.c    | 45 ++++++++++++++++++++++++++++++++++++++--
 drivers/usb/host/xhci-ext-caps.h |  2 ++
 2 files changed, 45 insertions(+), 2 deletions(-)

index 35af362..9bb7aa1 100644
@@ -16,10 +16,11 @@
 #include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/dmi.h>
+#include <linux/platform_device.h>
+
 #include "pci-quirks.h"
 #include "xhci-ext-caps.h"
 
-
 #define UHCI_USBLEGSUP		0xc0		/* legacy support */
 #define UHCI_USBCMD		0		/* command register */
 #define UHCI_USBINTR		4		/* interrupt register */

@@ -78,6 +79,8 @@
 #define USB_INTEL_USB3_PSSEN   0xD8
 #define USB_INTEL_USB3PRM      0xDC
 
+#define DEVICE_ID_INTEL_BROXTON_P_XHCI		0x5aa8
+
 /*
  * amd_chipset_gen values represent AMD different chipset generations
  */

@@ -956,6 +959,41 @@ void usb_disable_xhci_ports(struct pci_dev *xhci_pdev)
 }
 EXPORT_SYMBOL_GPL(usb_disable_xhci_ports);
 
+static void create_intel_usb_mux_device(struct pci_dev *xhci_pdev,
+					void __iomem *base)
+{
+	struct platform_device *plat_dev;
+	struct property_set pset;
+	int ret;
+
+	struct property_entry pentry[] = {
+		PROPERTY_ENTRY_U64("reg-start",
+				   pci_resource_start(xhci_pdev, 0) + 0x80d8),
+		PROPERTY_ENTRY_U64("reg-size", 8),
+		{ },
+	};
+
+	if (!xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_INTEL_USB_MUX))
+		return;
+
+	plat_dev = platform_device_alloc("intel-mux-drcfg",
+					 PLATFORM_DEVID_NONE);
+	if (!plat_dev)
+		return;
+
+	plat_dev->dev.parent = &xhci_pdev->dev;
+	pset.properties = pentry;
+	platform_device_add_properties(plat_dev, &pset);
+
+	ret = platform_device_add(plat_dev);
+	if (ret) {
+		dev_warn(&xhci_pdev->dev,
+			 "failed to create mux device with error %d",
+				ret);
+		platform_device_put(plat_dev);
+	}
+}
+
 /**
  * PCI Quirks for xHCI.
  *

@@ -1022,8 +1060,11 @@ static void quirk_usb_handoff_xhci(struct pci_dev *pdev)
 	writel(val, base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
 
 hc_init:
-	if (pdev->vendor == PCI_VENDOR_ID_INTEL)
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
 		usb_enable_intel_xhci_ports(pdev);
+		if (pdev->device == DEVICE_ID_INTEL_BROXTON_P_XHCI)
+			create_intel_usb_mux_device(pdev, base);
+	}
 
 	op_reg_base = base + XHCI_HC_LENGTH(readl(base));
 

index e0244fb..e368ccb 100644
@@ -51,6 +51,8 @@
 #define XHCI_EXT_CAPS_ROUTE	5
 /* IDs 6-9 reserved */
 #define XHCI_EXT_CAPS_DEBUG	10
+/* Vendor defined 192-255 */
+#define XHCI_EXT_CAPS_INTEL_USB_MUX	192
 /* USB Legacy Support Capability - section 7.1.1 */
 #define XHCI_HC_BIOS_OWNED	(1 << 16)
 #define XHCI_HC_OS_OWNED	(1 << 24)

2.1.4

Add a maintainer entry for Intel USB dual role mux drivers and add myself as a maintainer.

---
 MAINTAINERS | 10 ++++++++++
 1 file changed, 10 insertions(+)

index 1d5b4be..682c8a5 100644
@@ -5879,6 +5879,16 @@ S:	Maintained
 F:	arch/x86/include/asm/intel_telemetry.h
 F:	drivers/platform/x86/intel_telemetry*
 
+INTEL USB DUAL ROLE PORT MUX DRIVERS
+M:	Lu Baolu <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	include/linux/usb/intel-mux.h
+F:	drivers/usb/mux/intel-mux.c
+F:	drivers/usb/mux/intel-mux-gpio.c
+F:	drivers/usb/mux/intel-mux-drcfg.c
+F:	drivers/mfd/intel-vuport.c
+
 IOC3 ETHERNET DRIVER
 M:	Ralf Baechle <[email protected]>
 L:	[email protected]

2.1.4

Hi,