ACPI: Add _DEP support to fix battery issue on Asus T100TA

ACPI 5.0 introduces _DEP (Operation Region Dependencies) to designate
device objects that OSPM should assign a higher priority in start
ordering due to future operation region accesses.

On Asus T100TA, ACPI battery info are read from a I2C slave device via
I2C operation region. Before I2C operation region handler is installed,
battery _STA always returns 0. There is a _DEP method of designating
start order under battery device node.

This patch is to implement _DEP feature to fix battery issue on the
Asus T100TA.  Introducing acpi_dep_list and adding dep_unmet count
in struct acpi_device. During ACPI namespace scan, create struct
acpi_dep_data for a valid pair of master (device pointed to by _DEP)/
slave(device with _DEP), record master's and slave's ACPI handle in
it and put it into acpi_dep_list. The dep_unmet count will increase
by one if there is a device under its _DEP. Driver's probe() should
return EPROBE_DEFER when find dep_unmet is larger than 0. When I2C
operation region handler is installed, remove all struct acpi_dep_data
on the acpi_dep_list whose master is pointed to I2C host controller
and decrease slave's dep_unmet. When dep_unmet decreases to 0, all
_DEP conditions are met and then do acpi_bus_attach() for the device
in order to resolve battery _STA issue on the Asus T100TA.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=69011
Tested-by: Jan-Michael Brummer <jan.brummer@tabos.org>
Tested-by: Adam Williamson <adamw@happyassassin.net>
Tested-by: Michael Shigorin <shigorin@gmail.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / PM: Fixed a typo in a comment

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branches 'acpi-lpss', 'acpi-video' and 'acpi-scan' into linux-next

* acpi-lpss:
  dmaengine: dw: enable runtime PM
  ACPI / LPSS: introduce a 'proxy' device to power on LPSS for DMA
  ACPI / LPSS: allow to use specific PM domain during ->probe()
  ACPI / LPSS: add all LPSS devices to the specific power domain

* acpi-video:
  ACPI / video: Run _BCL before deciding registering backlight

* acpi-scan:
  ACPI: Add _DEP support to fix battery issue on Asus T100TA
Merge branch 'device-properties' into linux-next

* device-properties:
  leds: leds-gpio: Fix legacy GPIO number case
  ACPI / property: Drop size_prop from acpi_dev_get_property_reference()
  leds: leds-gpio: Convert gpio_blink_set() to use GPIO descriptors
  ACPI / GPIO: Document ACPI GPIO mappings API
  net: rfkill: gpio: Add default GPIO driver mappings for ACPI
  ACPI / GPIO: Driver GPIO mappings for ACPI GPIOs
  input: gpio_keys_polled: Make use of device property API
  leds: leds-gpio: Make use of device property API
  gpio: Support for unified device properties interface
  Driver core: Unified interface for firmware node properties
  input: gpio_keys_polled: Add support for GPIO descriptors
  leds: leds-gpio: Add support for GPIO descriptors
  gpio: sch: Consolidate core and resume banks
  gpio / ACPI: Add support for _DSD device properties
  misc: at25: Make use of device property API
  ACPI: Allow drivers to match using Device Tree compatible property
  Driver core: Unified device properties interface for platform firmware
  ACPI: Add support for device specific properties
Merge branches 'pm-runtime' and 'pm-sleep' into linux-next

* pm-runtime:
  PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is selected
  PM / Runtime: Kconfig: move ia64 dependency to arch/ia64/Kconfig
  PM / Runtime: Rework RPM get callback routines

* pm-sleep:
  PM / hibernate: Deletion of an unnecessary check before the function call "vfree"
  PM / Hibernate: Migrate to ktime_t
Merge branches 'powercap', 'pm-domains', 'pm-clk' and 'pm-config' into linux-next

* powercap:
  powercap / RAPL: fix build dependency on iosf_mbi
  powercap / RAPL: add new model ids
  powercap / RAPL: handle atom and core differences
  powercap / RAPL: abstract per cpu type functions

* pm-domains:
  PM / Domains: Power on the PM domain right after attach completes
  PM / Domains: Move struct pm_domain_data to pm_domain.h
  PM / Domains: Extract code to power off/on a PM domain
  PM / Domains: Make genpd parameter of pm_genpd_present() const

* pm-clk:
  PM / clock_ops: make __pm_clk_enable more generic
  PM / clock_ops: Add pm_clk_add_clk()

* pm-config:
  PM: Kconfig: fix unmet dependency for CPU_PM
cpufreq: Ref the policy object sooner

Do it before it's assigned to cpufreq_cpu_data, otherwise when a driver
tries to get the cpu frequency during initialization the policy kobj is
referenced and we get this warning:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 64 at include/linux/kref.h:47 kobject_get+0x64/0x70()
Modules linked in:
CPU: 1 PID: 64 Comm: irq/77-tegra-ac Not tainted 3.18.0-rc4-next-20141114ccu-00050-g3eff942 #326
[<c0016fac>] (unwind_backtrace) from [<c001272c>] (show_stack+0x10/0x14)
[<c001272c>] (show_stack) from [<c06085d8>] (dump_stack+0x98/0xd8)
[<c06085d8>] (dump_stack) from [<c002892c>] (warn_slowpath_common+0x84/0xb4)
[<c002892c>] (warn_slowpath_common) from [<c00289f8>] (warn_slowpath_null+0x1c/0x24)
[<c00289f8>] (warn_slowpath_null) from [<c0220290>] (kobject_get+0x64/0x70)
[<c0220290>] (kobject_get) from [<c03e944c>] (cpufreq_cpu_get+0x88/0xc8)
[<c03e944c>] (cpufreq_cpu_get) from [<c03e9500>] (cpufreq_get+0xc/0x64)
[<c03e9500>] (cpufreq_get) from [<c0285288>] (actmon_thread_isr+0x134/0x198)
[<c0285288>] (actmon_thread_isr) from [<c0069008>] (irq_thread_fn+0x1c/0x40)
[<c0069008>] (irq_thread_fn) from [<c0069324>] (irq_thread+0x134/0x174)
[<c0069324>] (irq_thread) from [<c0040290>] (kthread+0xdc/0xf4)
[<c0040290>] (kthread) from [<c000f4b8>] (ret_from_fork+0x14/0x3c)
---[ end trace b7bd64a81b340c59 ]---

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branches 'pm-cpuidle' and 'pm-cpufreq' into linux-next

* pm-cpuidle:
  drivers: cpuidle: Remove cpuidle-arm64 duplicate error messages
  drivers: cpuidle: Add idle-state-name description to ARM idle states
  drivers: cpuidle: Add status property to ARM idle states
  cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic

* pm-cpufreq:
  cpufreq: Ref the policy object sooner
  cpufreq: Kconfig: Remove architecture specific menu entries
  cpufreq: pcc: Enable autoload of pcc-cpufreq for ACPI processors
  intel_pstate: Add CPUID for BDW-H CPU
  intel_pstate: Add support for HWP
  x86: Add support for Intel HWP feature detection.
  cpufreq: respect the min/max settings from user space
  cpufreq: cpufreq-dt: Handle regulator_get_voltage() failure
  cpufreq: cpufreq-dt: Improve debug about matching OPP
  cpufreq: Loongson1: Add cpufreq driver for Loongson1B
  cpufreq: allow powersave governor as the default without expert mode
Merge branch 'acpi-pm' into linux-next

* acpi-pm:
  ACPI / PM: Fixed a typo in a comment