Put in some documentation for the new character device ABI
so we can properly etch it in stone.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This creates GPIO tools under tools/gpio/* and adds a single
example program to list the GPIOs on a system. When proper
devices are created it provides this minimal output:
Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
A new chardev that is to be used for userspace GPIO access is
added in this patch. It is intended to gradually replace the
horribly broken sysfs ABI.
Using a chardev has many upsides:
- All operations are per-gpiochip, which is the actual
device underlying the GPIOs, making us tie in to the
kernel device model properly.
- Hotpluggable GPIO controllers can come and go, as this
kind of problem has been know to userspace for character
devices since ages, and if a gpiochip handle is held in
userspace we know we will break something, whereas the
sysfs is stateless.
- The one-value-per-file rule of sysfs is really hard to
maintain when you want to twist more than one knob at a time,
for example have in-kernel APIs to switch several GPIO
lines at the same time, and this will be possible to do
with a single ioctl() from userspace, saving a lot of
context switching.
We also need to add a new bus type for GPIO. This is
necessary for example for userspace coldplug, where sysfs is
traversed to find the boot-time device nodes and create the
character devices in /dev.
This new chardev ABI is *non* *optional* and can be counted
on to be present in the future, emphasizing the preference
of this ABI.
The ABI only implements one single ioctl() to get the name
and number of GPIO lines of a chip. Even this is debatable:
see it as a minimal example for review. This ABI shall be
ruthlessly reviewed and etched in stone.
The old /sys/class/gpio is still optional to compile in,
but will be deprecated.
Unique device IDs are created using IDR, which is overkill
and insanely scalable, but also well tested.
Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The ACCES 104-DIO-48E device provides 48 lines digital I/O via two
Programmable Peripheral Interface (PPI) chips of type 82C55. Bit C3 at
each 24-bit Group can be used as an external interrupt, triggered by a
rising edge.
This driver provides GPIO and IRQ support for these 48 channels of
digital I/O. The base port address for the device may be configured via
the dio_48e_base module parameter. The interrupt line number for the
device may be configured via the dio_48e_irq module parameter.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The WinSystems WS16C48 device provides 48 lines of digital I/O. In
addition, the first 24 lines may be used for interrupt-handled edge
detection; rising edge detection and falling edge detection are
supported.
This driver provides GPIO and IRQ support for these 48 channels of
digital I/O. The base port address for the device may be configured via
the ws16c48_base module parameter. The interrupt line number for the
device may be configured via the ws16c48_irq module parameter.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS for 4.5 plus some 4.4 fixes.
The executive summary:
- ATH79 platform improvments, use DT bindings for the ATH79 USB PHY.
- Avoid useless rebuilds for zboot.
- jz4780: Add NEMC, BCH and NAND device tree nodes
- Initial support for the MicroChip's DT platform. As all the device
drivers are missing this is still of limited use.
- Some Loongson3 cleanups.
- The unavoidable whitespace polishing.
- Reduce clock skew when synchronizing the CPU cycle counters on CPU
startup.
- Add MIPS R6 fixes.
- Lots of cleanups across arch/mips as fallout from KVM.
- Lots of minor fixes and changes for IEEE 754-2008 support to the
FPU emulator / fp-assist software.
- Minor Ralink, BCM47xx and bcm963xx platform support improvments.
- Support SMP on BCM63168"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (84 commits)
MIPS: zboot: Add support for serial debug using the PROM
MIPS: zboot: Avoid useless rebuilds
MIPS: BMIPS: Enable ARCH_WANT_OPTIONAL_GPIOLIB
MIPS: bcm63xx: nvram: Remove unused bcm63xx_nvram_get_psi_size() function
MIPS: bcm963xx: Update bcm_tag field image_sequence
MIPS: bcm963xx: Move extended flash address to bcm_tag header file
MIPS: bcm963xx: Move Broadcom BCM963xx image tag data structure
MIPS: bcm63xx: nvram: Use nvram structure definition from header file
MIPS: bcm963xx: Add Broadcom BCM963xx board nvram data structure
MAINTAINERS: Add KVM for MIPS entry
MIPS: KVM: Add missing newline to kvm_err()
MIPS: Move KVM specific opcodes into asm/inst.h
MIPS: KVM: Use cacheops.h definitions
MIPS: Break down cacheops.h definitions
MIPS: Use EXCCODE_ constants with set_except_vector()
MIPS: Update trap codes
MIPS: Move Cause.ExcCode trap codes to mipsregs.h
MIPS: KVM: Make kvm_mips_{init,exit}() static
MIPS: KVM: Refactor added offsetof()s
MIPS: KVM: Convert EXPORT_SYMBOL to _GPL
...
Pull x86 platform driver updates from Darren Hart:
"Emergency travel prevented me from completing my final testing on this
until today. Nothing here that couldn't wait until RC1 fixes, but I
thought it best to get it out sooner rather than later as it does
contain a build warning fix.
Summary:
A build warning fix, MAINTAINERS cleanup, and a new DMI quirk:
ideapad-laptop:
- Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS:
- Combine multiple telemetry entries
intel_telemetry_debugfs:
- Fix unused warnings in telemetry debugfs"
* tag 'platform-drivers-x86-v4.5-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
ideapad-laptop: Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS: Combine multiple telemetry entries
intel_telemetry_debugfs: Fix unused warnings in telemetry debugfs
Pull rdma updates from Doug Ledford:
"Initial roundup of 4.5 merge window patches
- Remove usage of ib_query_device and instead store attributes in
ib_device struct
- Move iopoll out of block and into lib, rename to irqpoll, and use
in several places in the rdma stack as our new completion queue
polling library mechanism. Update the other block drivers that
already used iopoll to use the new mechanism too.
- Replace the per-entry GID table locks with a single GID table lock
- IPoIB multicast cleanup
- Cleanups to the IB MR facility
- Add support for 64bit extended IB counters
- Fix for netlink oops while parsing RDMA nl messages
- RoCEv2 support for the core IB code
- mlx4 RoCEv2 support
- mlx5 RoCEv2 support
- Cross Channel support for mlx5
- Timestamp support for mlx5
- Atomic support for mlx5
- Raw QP support for mlx5
- MAINTAINERS update for mlx4/mlx5
- Misc ocrdma, qib, nes, usNIC, cxgb3, cxgb4, mlx4, mlx5 updates
- Add support for remote invalidate to the iSER driver (pushed
through the RDMA tree due to dependencies, acknowledged by nab)
- Update to NFSoRDMA (pushed through the RDMA tree due to
dependencies, acknowledged by Bruce)"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (169 commits)
IB/mlx5: Unify CQ create flags check
IB/mlx5: Expose Raw Packet QP to user space consumers
{IB, net}/mlx5: Move the modify QP operation table to mlx5_ib
IB/mlx5: Support setting Ethernet priority for Raw Packet QPs
IB/mlx5: Add Raw Packet QP query functionality
IB/mlx5: Add create and destroy functionality for Raw Packet QP
IB/mlx5: Refactor mlx5_ib_qp to accommodate other QP types
IB/mlx5: Allocate a Transport Domain for each ucontext
net/mlx5_core: Warn on unsupported events of QP/RQ/SQ
net/mlx5_core: Add RQ and SQ event handling
net/mlx5_core: Export transport objects
IB/mlx5: Expose CQE version to user-space
IB/mlx5: Add CQE version 1 support to user QPs and SRQs
IB/mlx5: Fix data validation in mlx5_ib_alloc_ucontext
IB/sa: Fix netlink local service GFP crash
IB/srpt: Remove redundant wc array
IB/qib: Improve ipoib UD performance
IB/mlx4: Advertise RoCE v2 support
IB/mlx4: Create and use another QP1 for RoCEv2
IB/mlx4: Enable send of RoCE QP1 packets with IP/UDP headers
...
Pull NTB updates from Jon Mason:
"A new driver to support AMD NTB, a NTB performance test driver, NTB
bugs fixes, and the ability to recover from running out of DMA
descriptors"
* tag 'ntb-4.5' of git://github.com/jonmason/ntb:
NTB: Fix macro parameter conflict with field name
NTB: Add support for AMD PCI-Express Non-Transparent Bridge
ntb: ntb perf tool
NTB: Address out of DMA descriptor issue with NTB
NTB: Clear property bits in BAR value
NTB: ntb_process_tx error path bug
Pull block driver updates from Jens Axboe:
"This is the block driver pull request for 4.5, with the exception of
NVMe, which is in a separate branch and will be posted after this one.
This pull request contains:
- A set of bcache stability fixes, which have been acked by Kent.
These have been used and tested for more than a year by the
community, so it's about time that they got in.
- A set of drbd updates from the drbd team (Andreas, Lars, Philipp)
and Markus Elfring, Oleg Drokin.
- A set of fixes for xen blkback/front from the usual suspects, (Bob,
Konrad) as well as community based fixes from Kiri, Julien, and
Peng.
- A 2038 time fix for sx8 from Shraddha, with a fix from me.
- A small mtip32xx cleanup from Zhu Yanjun.
- A null_blk division fix from Arnd"
* 'for-4.5/drivers' of git://git.kernel.dk/linux-block: (71 commits)
null_blk: use sector_div instead of do_div
mtip32xx: restrict variables visible in current code module
xen/blkfront: Fix crash if backend doesn't follow the right states.
xen/blkback: Fix two memory leaks.
xen/blkback: make st_ statistics per ring
xen/blkfront: Handle non-indirect grant with 64KB pages
xen-blkfront: Introduce blkif_ring_get_request
xen-blkback: clear PF_NOFREEZE for xen_blkif_schedule()
xen/blkback: Free resources if connect_ring failed.
xen/blocks: Return -EXX instead of -1
xen/blkback: make pool of persistent grants and free pages per-queue
xen/blkback: get the number of hardware queues/rings from blkfront
xen/blkback: pseudo support for multi hardware queues/rings
xen/blkback: separate ring information out of struct xen_blkif
xen/blkfront: correct setting for xen_blkif_max_ring_order
xen/blkfront: make persistent grants pool per-queue
xen/blkfront: Remove duplicate setting of ->xbdev.
xen/blkfront: Cleanup of comments, fix unaligned variables, and syntax errors.
xen/blkfront: negotiate number of queues/rings to be used with backend
xen/blkfront: split per device io_lock
...
This adds support for AMD's PCI-Express Non-Transparent Bridge
(NTB) device on the Zeppelin platform. The driver connnects to the
standard NTB sub-system interface, with modification to add hooks
for power management in a separate patch. The AMD NTB device has 3
memory windows, 16 doorbell, 16 scratch-pad registers, and supports
up to 16 PCIe lanes running a Gen3 speeds.
Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Reviewed-by: Allen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Merge third patch-bomb from Andrew Morton:
"I'm pretty much done for -rc1 now:
- the rest of MM, basically
- lib/ updates
- checkpatch, epoll, hfs, fatfs, ptrace, coredump, exit
- cpu_mask simplifications
- kexec, rapidio, MAINTAINERS etc, etc.
- more dma-mapping cleanups/simplifications from hch"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits)
MAINTAINERS: add/fix git URLs for various subsystems
mm: memcontrol: add "sock" to cgroup2 memory.stat
mm: memcontrol: basic memory statistics in cgroup2 memory controller
mm: memcontrol: do not uncharge old page in page cache replacement
Documentation: cgroup: add memory.swap.{current,max} description
mm: free swap cache aggressively if memcg swap is full
mm: vmscan: do not scan anon pages if memcg swap limit is hit
swap.h: move memcg related stuff to the end of the file
mm: memcontrol: replace mem_cgroup_lruvec_online with mem_cgroup_online
mm: vmscan: pass memcg to get_scan_count()
mm: memcontrol: charge swap to cgroup2
mm: memcontrol: clean up alloc, online, offline, free functions
mm: memcontrol: flatten struct cg_proto
mm: memcontrol: rein in the CONFIG space madness
net: drop tcp_memcontrol.c
mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM
mm: memcontrol: allow to disable kmem accounting for cgroup2
mm: memcontrol: account "kmem" consumers in cgroup2 memory controller
mm: memcontrol: move kmem accounting code to CONFIG_MEMCG
mm: memcontrol: separate kmem code from legacy tcp accounting code
...
Pull more power management and ACPI updates from Rafael Wysocki:
"This includes fixes on top of the previous batch of PM+ACPI updates
and some new material as well.
From the new material perspective the most significant are the driver
core changes that should allow USB devices to stay suspended over
system suspend/resume cycles if they have been runtime-suspended
already beforehand. Apart from that, ACPICA is updated to upstream
revision 20160108 (cosmetic mostly, but including one fixup on top of
the previous ACPICA update) and there are some devfreq updates the
didn't make it before (due to timing).
A few recent regressions are fixed, most importantly in the cpuidle
menu governor and in the ACPI backlight driver and some x86 platform
drivers depending on it.
Some more bugs are fixed and cleanups are made on top of that.
Specifics:
- Modify the driver core and the USB subsystem to allow USB devices
to stay suspended over system suspend/resume cycles if they have
been runtime-suspended already beforehand and fix some bugs on top
of these changes (Tomeu Vizoso, Rafael Wysocki).
- Update ACPICA to upstream revision 20160108, including updates of
the ACPICA's copyright notices, a code fixup resulting from a
regression fix that was necessary in the upstream code only (the
regression fixed by it has never been present in Linux) and a
compiler warning fix (Bob Moore, Lv Zheng).
- Fix a recent regression in the cpuidle menu governor that broke it
on practically all architectures other than x86 and make a couple
of optimizations on top of that fix (Rafael Wysocki).
- Clean up the selection of cpuidle governors depending on whether or
not the kernel is configured for tickless systems (Jean Delvare).
- Revert a recent commit that introduced a regression in the ACPI
backlight driver, address the problem it attempted to fix in a
different way and revert one more cosmetic change depending on the
problematic commit (Hans de Goede).
- Add two more ACPI backlight quirks (Hans de Goede).
- Fix a few minor problems in the core devfreq code, clean it up a
bit and update the MAINTAINERS information related to it (Chanwoo
Choi, MyungJoo Ham).
- Improve an error message in the ACPI fan driver (Andy Lutomirski).
- Fix a recent build regression in the cpupower tool (Shreyas
Prabhu)"
* tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (32 commits)
cpuidle: menu: Avoid pointless checks in menu_select()
sched / idle: Drop default_idle_call() fallback from call_cpuidle()
cpupower: Fix build error in cpufreq-info
cpuidle: Don't enable all governors by default
cpuidle: Default to ladder governor on ticking systems
time: nohz: Expose tick_nohz_enabled
ACPICA: Update version to 20160108
ACPICA: Silence a -Wbad-function-cast warning when acpi_uintptr_t is 'uintptr_t'
ACPICA: Additional 2016 copyright changes
ACPICA: Reduce regression fix divergence from upstream ACPICA
ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Satellite R830
ACPI / video: Revert "thinkpad_acpi: Use acpi_video_handles_brightness_key_presses()"
ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit
ACPI / video: Fix using an uninitialized mutex / list_head in acpi_video_handles_brightness_key_presses()
ACPI / video: Revert "ACPI / video: driver must be registered before checking for keypresses"
ACPI / fan: Improve acpi_device_update_power error message
ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Portege R700
cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0
MAINTAINERS: Add devfreq-event entry
MAINTAINERS: Add missing git repository and directory for devfreq
...
Pull ARM SoC driver updates from Olof Johansson:
"Driver updates for ARM SoCs. Some for SoC-family code under
drivers/soc, but also some other driver updates that don't belong
anywhere else. We also bring in the drivers/reset code through
arm-soc.
Some of the larger updates:
- Qualcomm support for SMEM, SMSM, SMP2P. All used to communicate
with other parts of the chip/board on these platforms, all
proprietary protocols that don't fit into other subsystems and live
in drivers/soc for now.
- System bus driver for UniPhier
- Driver for the TI Wakeup M3 IPC device
- Power management for Raspberry PI
+ Again a bunch of other smaller updates and patches"
* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (38 commits)
bus: uniphier: allow only built-in driver
ARM: bcm2835: clarify RASPBERRYPI_FIRMWARE dependency
MAINTAINERS: Drop Kumar Gala from QCOM
bus: uniphier-system-bus: add UniPhier System Bus driver
ARM: bcm2835: add rpi power domain driver
dt-bindings: add rpi power domain driver bindings
ARM: bcm2835: Define two new packets from the latest firmware.
drivers/soc: make mediatek/mtk-scpsys.c explicitly non-modular
soc: mediatek: SCPSYS: Add regulator support
MAINTAINERS: Change QCOM entries
soc: qcom: smd-rpm: Add existing platform support
memory/tegra: Add number of TLB lines for Tegra124
reset: hi6220: fix modular build
soc: qcom: Introduce WCNSS_CTRL SMD client
ARM: qcom: select ARM_CPU_SUSPEND for power management
MAINTAINERS: Add rules for Qualcomm dts files
soc: qcom: enable smsm/smp2p modular build
serial: msm_serial: Make config tristate
soc: qcom: smp2p: Qualcomm Shared Memory Point to Point
soc: qcom: smsm: Add driver for Qualcomm SMSM
...
Pull ARM 64-bit DT updates from Olof Johansson:
"This is the first release where we split up the 64-bit contributions a
bit more, and in particular we are having a separate DT branch for
them.
Contents:
- New devices added to Broadcom NorthStar2
- Misc fixes for Exynos7 boards
- QCOM updates for MSM8916
- Rockchip tweaks for rk3368 SoC and eval board
- A series of fixes for APM X-Gene v1 and v2
- Renesas R8A7795 CPU/PSCI additions
- Marvell Berlin4CT PSCI, cpuidle, watchdog portions
- Freescale LS1043a SoC and dev board support
+ some treewide or other misc changes"
* tag 'armsoc-dt64' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (104 commits)
dts/ls2080a: Update DTSI to add support of SP805 WDT
Documentation: DT: Add entry for ARM SP805-WDT
arm64: dts: X-Gene v2: I2C1 clock is always on
arm64: dts: X-Gene v1: I2C0 clock is always on
arm64: dts: Fix to use standard DT node names for X-Gene 1 and X-Gene 2 platforms
arm64: dts: hikey: add label properties to UARTs
arm64: dts: apq8016-sbc: add label properties for UART, I2C, and SPI
arm64: dts: apq8016-sbc: enable UART0 on LS connector
arm64: dts: juno: Add idle-states to device tree
arm64: dts: Added syscon-reboot node for FSL's LS2080A SoC
arm64: dts: add LS1043a-RDB board support
arm64: dts: add Freescale LS1043a SoC support
Documentation: DT: Add entry for Freescale LS1043a-RDB board
arm64: dts: uniphier: add PH1-LD10 SoC/board support
arm64: renesas: r8a7795: fix SATA clock assignment
arm64: dts: salvator-x: Enable SATA controller
arm64: dts: r8a7795: Add SATA controller node
arm64: renesas: r8a7795: add internal delay for i2c IPs
arm64: renesas: salvator-x: Add board part number to DT bindings
arm64: dts: r8a7795: Add pmu device nodes
...
Pull ARM SoC platform updates from Olof Johansson:
"Updates for new platform support:
- New platform: Tango4 from Sigma Designs.
- Broadcom BCM2836 (Raspberry Pi 2 SoC)
- Enable cpufreq on Freescale i.MX7D
- Rockchip: SMP support for rk3036, general support for rk3228
- SMP support on Broadcom Kona and NSP
- Cleanups for OMAP removing legacy IOMMU data
+ a bunch of misc fixes and tweaks for various platforms"
* tag 'armsoc-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (46 commits)
ARM: tango: Fix UP build issues
ARM: tango: pass ARM arch level for smc.S
ARM: bcm2835: Add Kconfig support for bcm2836
ARM: OMAP2+: Add support for dm814x and dra62x usb
ARM: OMAP2+: Add mmc hwmod entries for dm814x
ARM: OMAP2+: Update 81xx clock and power domains for default, active and sgx
ARM: OMAP2+: Fix SoC detection for dra62x j5-eco
ARM: tango4: Initial platform support
ARM: bcm2835: Add a compat string for bcm2836 machine probe
dt-bindings: Add root properties for Raspberry Pi 2
ARM: imx: select SRC for i.MX7
ARM: uniphier: select PINCTRL
ARM: OMAP2+: Remove device creation for omap-pcm-audio
ARM: OMAP1: Remove device creation for omap-pcm-audio
ARM: rockchip: enable support for RK3228 SoCs
ARM: rockchip: use const and __initconst for rk3036 smp_operations
ARM: zynq: Select ARCH_HAS_RESET_CONTROLLER
ARM: BCM: Add SMP support for Broadcom 4708
ARM: BCM: Add SMP support for Broadcom NSP
ARM: BCM: Clean up SMP support for Broadcom Kona
...
Pull ARM SoC cleanups from Olof Johansson:
"A smallish number of general cleanup commits this release cycle. Some
of these are minor tweaks:
- shmobile change of binding for their GIC (using arm,pl390 now)
- ARCH_RENESAS introduction
- Misc other renesas updates
There's also a couple of treewide commits from Masahiro Yamada
cleaning up const/__initconst for SMP operation structs and a switch
to using "depends on" instead of if-constructs on most of the Kconfig
platform targets"
* tag 'armsoc-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
staging: board: armadillo800eva: Use "arm,pl390"
staging: board: kzm9d: Use "arm,pl390"
ARM: shmobile: r8a7778 dtsi: Use "arm,pl390" for GIC
ARM: shmobile: emev2 dtsi: Use "arm,pl390" for GIC
ARM: shmobile: r8a7740 dtsi: Use "arm,pl390" for GIC
ARM: shmobile: r7s72100 dtsi: Use "arm,pl390" for GIC
ARM: use "depends on" for SoC configs instead of "if" after prompt
ARM/clocksource: use automatic DT probing for ux500 PRCMU
ARM: use const and __initconst for smp_operations
ARM: hisi: do not export smp_operations structures
ARM: mvebu: remove unused mach/gpio.h
ARM: shmobile: Remove legacy mach/irqs.h
ARM: shmobile: Introduce ARCH_RENESAS
MAINTAINERS: Remove link to oss.renesas.com which is closed
Linus Walleij
William Breathitt Gray
Linus Torvalds
Souvik Kumar Chakravarty
Simon Arlott
James Hogan
Rich Felker
Xiangliang Yu