No longer needed since semaphores were removed.
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <David1.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Non-scheduler code is longer supported.

v2: agd: rebased on upstream
Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Ken Wang  <Qingqing.Wang@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

No longer needed now that semaphores are gone.

V2: remove the first amdgpu_sync_wait in amdgpu_ib_schedule
Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Ken Wang  <Qingqing.Wang@amd.com> (V1)
Reviewed-by: Monk Liu <monk.liu@amd.com> (V2)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

No longer used.
Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Ken Wang  <Qingqing.Wang@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The other ones don't have any VAs assigned anyway or are uninteresting to us.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Make UVD/VCE VM emulation more efficient.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Stop copying that to the bo list entry, it doesn't change anyway.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Move that into the BO list. No functional change.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Rename it to amdgpu_cs_parser_bos and move validation and bo list init there.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Remove unused user_ptr field, group fields by usage.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

And also update the comment.

v2: agd: rebase on usptream.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

No need to actually check the current placement. Just use the allowed domains
when the threshold is reached.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The threshold should only be computed once.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

We recently redid the indenting, but missed these two if statements.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Otherwise we could try to evict overlapping userptr BOs in get_user_pages(),
leading to a possible circular locking dependency.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>

Fixes: 0417d424 (drm/tegra: Stop cancelling page flip events)
Signed-off-by: Dave Airlie <airlied@redhat.com>

First drm-misc pull req for 4.6. Big one is the drm_event cleanup, which
is also prep work for adding android fence support to kms (Gustavo is
planning to do that). Otherwise random small bits all over.

* tag 'topic/drm-misc-2016-02-08' of git://anongit.freedesktop.org/drm-intel: (33 commits)
  gma500: clean up an excessive and confusing helper
  drm/gma500: remove helper function
  drm/vmwgfx: Nuke preclose hook
  drm/vc4: Nuke preclose hook
  drm/tilcdc: Nuke preclose hook
  drm/tegra: Stop cancelling page flip events
  drm/shmob: Nuke preclose hook
  drm/rcar: Nuke preclose hook
  drm/omap: Nuke close hooks
  drm/msm: Nuke preclose hooks
  drm/imx: Unconfuse preclose logic
  drm/exynos: Remove event cancelling from postclose
  drm/atmel: Nuke preclose
  drm/i915: Nuke intel_modeset_preclose
  drm: Nuke vblank event file cleanup code
  drm: Clean up pending events in the core
  drm/vblank: Use drm_event_reserve_init
  drm/vmwgfx: fix a NULL dereference
  drm/crtc-helper: Add caveat to disable_unused_functions doc
  drm/gma500: Remove empty preclose hook
  ...

- support for v3 vbt dsi blocks (Jani)
- improve mmio debug checks (Mika Kuoppala)
- reorg the ddi port translation table entries and related code (Ville)
- reorg gen8 interrupt handling for future platforms (Tvrtko)
- refactor tile width/height computations for framebuffers (Ville)
- kerneldoc integration for intel_pm.c (Jani)
- move default context from engines to device-global dev_priv (Dave Gordon)
- make seqno/irq ordering coherent with execlist (Chris)
- decouple internal engine number from UABI (Chris&Tvrtko)
- tons of small fixes all over, as usual

* tag 'drm-intel-next-2016-01-24' of git://anongit.freedesktop.org/drm-intel: (148 commits)
  drm/i915: Update DRIVER_DATE to 20160124
  drm/i915: Seal busy-ioctl uABI and prevent leaking of internal ids
  drm/i915: Decouple execbuf uAPI from internal implementation
  drm/i915: Use ordered seqno write interrupt generation on gen8+ execlists
  drm/i915: Limit the auto arming of mmio debugs on vlv/chv
  drm/i915: Tune down "GT register while GT waking disabled" message
  drm/i915: tidy up a few leftovers
  drm/i915: abolish separate per-ring default_context pointers
  drm/i915: simplify allocation of driver-internal requests
  drm/i915: Fix NULL plane->fb oops on SKL
  drm/i915: Do not put big intel_crtc_state on the stack
  Revert "drm/i915: Add two-stage ILK-style watermark programming (v10)"
  drm/i915: add DOC: headline to RC6 kernel-doc
  drm/i915: turn some bogus kernel-doc comments to normal comments
  drm/i915/sdvo: revert bogus kernel-doc comments to normal comments
  drm/i915/gen9: Correct max save/restore register count during gpu reset with GuC
  drm/i915: Demote user facing DMC firmware load failure message
  drm/i915: use hlist_for_each_entry
  drm/i915: skl_update_scaler() wants a rotation bitmask instead of bit number
  drm/i915: Don't reject primary plane windowing with color keying enabled on SKL+
  ...

This is a left over from the great clean ups in the past. It's confusing as
it returns an int, yet has one caller that never uses it. The caller already
has all the right private variables local so the entire function can be
replaced by a simple if call.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160129193731.8475.47809.stgit@localhost.localdomainAcked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

We were getting build warning about:
drivers/gpu/drm/gma500/mdfld_dsi_output.c:407:2: warning: initialization
	from incompatible pointer type

The callback to dpms was pointing to a helper function which had a
return type of void, whereas the callback should point to a function
which has a return type of int.
On closer look it turned out that we do not need the helper function
since if we call drm_helper_connector_dpms() directly, the first check
that drm_helper_connector_dpms() does is: if (mode == connector->dpms)
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1454393155-13142-1-git-send-email-sudipm.mukherjee@gmail.comAcked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Again since the drm core takes care of event unlinking/disarming this
is now just needless code.

v2: I've completely missed eaction->fpriv_head and all the related
code. We need to nuke that too to avoid accidentally deferencing the
freed-up vmwgfx-private fpriv.

v3: Also remove vmw_fpriv->fence_events and unused variables I missed.

Cc: Thomas Hellström <thellstrom@vmware.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452548477-15905-23-git-send-email-daniel.vetter@ffwll.chSigned-off-by: Daniel Vetter <daniel.vetter@intel.com>

Again since the drm core takes care of event unlinking/disarming this
is now just needless code.

v2: Fixup misplaced hunk.

Cc: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-14-git-send-email-daniel.vetter@ffwll.ch

Again since the drm core takes care of event unlinking/disarming this
is now just needless code.

v2: Fixup misplaced hunks.

Cc: Rob Clark <robdclark@gmail.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-13-git-send-email-daniel.vetter@ffwll.ch

The core takes care of that now.

v2: Fixup misplaced hunk.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Terje Bergström <tbergstrom@nvidia.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-12-git-send-email-daniel.vetter@ffwll.ch

Again since the drm core takes care of event unlinking/disarming this
is now just needless code.

v2: Fixup misplaced hunk.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-11-git-send-email-daniel.vetter@ffwll.ch

Again since the drm core takes care of event unlinking/disarming this
is now just needless code.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-10-git-send-email-daniel.vetter@ffwll.ch

Again since the core takes care of this we can remove them. While at
it also remove the postclose hook, it's empty.

v2: Laurent pointed me at even more code to delete.

v3: Remove unused flags (Tomi).

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-9-git-send-email-daniel.vetter@ffwll.ch

They only complete the page flip events to avoid oops when the drm
file closes. The core takes care of that now and we can remove this
code.

Cc: Rob Clark <robdclark@gmail.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-8-git-send-email-daniel.vetter@ffwll.ch

So this one is special, since it tries to prevent races when userspace
crashes simply by disabling the vblank machinery. Well except that imx
always has vblanks enabled, and the disable_vblank hook actually just
tries to cancel a pending pageflip. Without any locking whatsoever. Of
course this is wrong, since it'll result in the hw not actually
displaying what drm thinks is the current frontbuffer.

Well since the core takes care of the disappearing DRM fd now. So we
can nuke all this confused code without ill side-effects.

Someone else needs to audit the locking for ->newfb and
->page_flip_event and fix it up. Common approach is to reuse
dev->event_lock for this.

Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-7-git-send-email-daniel.vetter@ffwll.ch

The core takes care of this now. And since kfree(NULL) is ok we can
simplify the function even further now.

Note: There's another spin on this patch, but for different reasons,
in-flight already: http://www.spinics.net/lists/dri-devel/msg97922.html

Cc: Inki Dae <inki.dae@samsung.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-6-git-send-email-daniel.vetter@ffwll.ch

The only thing this did was cancle pending flip events, and the core
takes care of that now.

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-5-git-send-email-daniel.vetter@ffwll.ch

Now that the drm core unlinks/disarms events there's no need to do so
ourselves anymore. Nuke the code.
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-4-git-send-email-daniel.vetter@ffwll.ch

The core code now takes care of unlinking drm_events from the file in
a generic way, so this code isn't needed any more.

For those wondering where the drm_vblank_put went to: With the new
logic events only get unlinked, but still exist. Hence any resources
(like vblank counters) don't need to be released since the event user
will still process the event normally. In this case this is the
callsites of send_vblank_event, which of course already have a
drm_vblank_put.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-3-git-send-email-daniel.vetter@ffwll.ch

There's really no reason to not do so, instead of replicating this
for every use-case and every driver. Now we can't just nuke the events,
since that would still mean that all drm_event users would need to know
when that has happened, since calling e.g. drm_send_event isn't allowed
any more. Instead just unlink them from the file, and detect this case
and handle it appropriately in all functions.

v2: Adjust existing kerneldoc too.

v3: Improve wording of the kerneldoc and split out vblank cleanup (Laurent).

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-2-git-send-email-daniel.vetter@ffwll.ch

Well we can't use that directly since that code must hold
dev->event_lock already. Extract an _unlocked version.

Embarrassingly I've totally forgotten about this patch and any kind of
event-based vblank wait totally blew up, killing the kernel.

v2: Pick the right base struct, someone didn't noticed that gcc was
unhappy. No bug since the addresses at least matched (Daniel Stone)

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453978864-1513-1-git-send-email-daniel.vetter@ffwll.ch

Pull ARM SoC fixes from Olof Johansson:
 "The first real batch of fixes for this release cycle, so there are a
  few more than usual.

  Most of these are fixes and tweaks to board support (DT bugfixes,
  etc).  I've also picked up a couple of small cleanups that seemed
  innocent enough that there was little reason to wait (const/
  __initconst and Kconfig deps).

  Quite a bit of the changes on OMAP were due to fixes to no longer
  write to rodata from assembly when ARM_KERNMEM_PERMS was enabled, but
  there were also other fixes.

  Kirkwood had a bunch of gpio fixes for some boards.  OMAP had RTC
  fixes on OMAP5, and Nomadik had changes to MMC parameters in DT.

  All in all, mostly the usual mix of various fixes"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (46 commits)
  ARM: multi_v7_defconfig: enable DW_WATCHDOG
  ARM: nomadik: fix up SD/MMC DT settings
  ARM64: tegra: Add chosen node for tegra132 norrin
  ARM: realview: use "depends on" instead of "if" after prompt
  ARM: tango: use "depends on" instead of "if" after prompt
  ARM: tango: use const and __initconst for smp_operations
  ARM: realview: use const and __initconst for smp_operations
  bus: uniphier-system-bus: revive tristate prompt
  arm64: dts: Add missing DMA Abort interrupt to Juno
  bus: vexpress-config: Add missing of_node_put
  ARM: dts: am57xx: sbc-am57x: correct Eth PHY settings
  ARM: dts: am57xx: cl-som-am57x: fix CPSW EMAC pinmux
  ARM: dts: am57xx: sbc-am57x: fix UART3 pinmux
  ARM: dts: am57xx: cl-som-am57x: update SPI Flash frequency
  ARM: dts: am57xx: cl-som-am57x: set HOST mode for USB2
  ARM: dts: am57xx: sbc-am57x: fix SB-SOM EEPROM I2C address
  ARM: dts: LogicPD Torpedo: Revert Duplicative Entries
  ARM: dts: am437x: pixcir_tangoc: use correct flags for irq types
  ARM: dts: am4372: fix irq type for arm twd and global timer
  ARM: dts: at91: sama5d4 xplained: fix phy0 IRQ type
  ...

Pull mailbox fixes from Jassi Brar:

 - fix getting element from the pcc-channels array by simply indexing
   into it

 - prevent building mailbox-test driver for archs that don't have IOMEM

* 'mailbox-devel' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox: Fix dependencies for !HAS_IOMEM archs
  mailbox: pcc: fix channel calculation in get_pcc_channel()

Pull USB fixes from Greg KH:
 "Here are some USB fixes for 4.5-rc3.

  The usual, xhci fixes for reported issues, combined with some small
  gadget driver fixes, and a MAINTAINERS file update.  All have been in
  linux-next with no reported issues"

* tag 'usb-4.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  xhci: harden xhci_find_next_ext_cap against device removal
  xhci: Fix list corruption in urb dequeue at host removal
  usb: host: xhci-plat: fix NULL pointer in probe for device tree case
  usb: xhci-mtk: fix AHB bus hang up caused by roothubs polling
  usb: xhci-mtk: fix bpkts value of LS/HS periodic eps not behind TT
  usb: xhci: apply XHCI_PME_STUCK_QUIRK to Intel Broxton-M platforms
  usb: xhci: set SSIC port unused only if xhci_suspend succeeds
  usb: xhci: add a quirk bit for ssic port unused
  usb: xhci: handle both SSIC ports in PME stuck quirk
  usb: dwc3: gadget: set the OTG flag in dwc3 gadget driver.
  Revert "xhci: don't finish a TD if we get a short-transfer event mid TD"
  MAINTAINERS: fix my email address
  usb: dwc2: Fix probe problem on bcm2835
  Revert "usb: dwc2: Move reset into dwc2_get_hwparams()"
  usb: musb: ux500: Fix NULL pointer dereference at system PM
  usb: phy: mxs: declare variable with initialized value
  usb: phy: msm: fix error handling in probe.

Pull staging and IIO driver fixes from Greg KH:
 "Here are some IIO and staging driver fixes for 4.5-rc3.

  All of them, except one, are for IIO drivers, and one is for a speakup
  driver fix caused by some earlier patches, to resolve a reported build
  failure"

* tag 'staging-4.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  Staging: speakup: Fix allyesconfig build on mn10300
  iio: dht11: Use boottime
  iio: ade7753: avoid uninitialized data
  iio: pressure: mpl115: fix temperature offset sign
  iio: imu: Fix dependencies for !HAS_IOMEM archs
  staging: iio: Fix dependencies for !HAS_IOMEM archs
  iio: adc: Fix dependencies for !HAS_IOMEM archs
  iio: inkern: fix a NULL dereference on error
  iio:adc:ti_am335x_adc Fix buffered mode by identifying as software buffer.
  iio: light: acpi-als: Report data as processed
  iio: dac: mcp4725: set iio name property in sysfs
  iio: add HAS_IOMEM dependency to VF610_ADC
  iio: add IIO_TRIGGER dependency to STK8BA50
  iio: proximity: lidar: correct return value
  iio-light: Use a signed return type for ltr501_match_samp_freq()