This patch adds common framebuffer device helpers and register defines
for S5PV210 based machines.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This reverts commit 66803762 ("mtd: mxc_nand: add RESET command support").
Support for NAND_CMD_RESET was added separately in commit d4840180
("mtd: mxc_nand: set NFC registers after reset"), causing a build error:
drivers/mtd/nand/mxc_nand.c: In function 'mxc_nand_command':
drivers/mtd/nand/mxc_nand.c:689: error: duplicate case value
drivers/mtd/nand/mxc_nand.c:606: error: previously used here
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This patch adds setup code for Samsung OneNAND controller driver. The
driver needs to be aware on which SoC it is running, so the actual
device id is being changed in cpu init code. S3C64xx SoCs have 2 OneNAND
controllers while S5PC100 and S5PC110 has only one.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[ben-linux@fluff.org: sort map.h entries]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The software events hlist doesn't fully comply with the new
rcu checks api.
We need to consider three different sides that access the hlist:
- the hlist allocation/release side. This side happens when an
events is created or released, accesses to the hlist are
serialized under the cpuctx mutex.
- the events insertion/removal in the hlist. This side is always
serialized against the above one. The hlist is always present
during such operations. This side happens when a software event
is scheduled in/out. The serialization that ensures the software
event is really attached to the context is made under the
ctx->lock.
- events triggering. This is the read side, it can happen
concurrently with any update side.
This patch deals with them one by one and anticipates with the
separate rcu mem space patches in preparation.
This patch fixes various annoying rcu warnings.
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
This is a small fix for a problem affecting live-mode, introduced
recently:
root@tropicana:~# perf trace rwtop
perf trace started with Perl
script /root/libexec/perf-core/scripts/perl/rwtop.pl
Fatal: did not read header event
commit d00a47cce5 added a skip()
function to skip over e.g. header_page, but this doesn't work for
live mode. This patch re-implements skip() to use read() instead of
lseek() to fix that.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1273032130.6383.28.camel@tropicana>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch removes all obsolete files from plat-s5pc1xx. This directory is
no longer needed. S5PC100 SoC is now completely supported in plat-s5p
framework.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch moves support for gpio interrupts from plat-s5pc1xx to
mach-s5pc100 directory.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch moves S5PC100 SoC support to plat-s5p framework. Most
periperal support code has been already moved from plat-s5pc1xx to
mach-s5pc100.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Move sdhci helpers from plat-s5pc1xx to mach-s5pc100.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch adds required platform definitions to enable s3c-fb
driver. Two framebuffer windows in 480x800x16bpp mode are defined.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add basic support for Samsung Aquila board. This board is based
on S5PC110 SoC.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The arch/arm/mach-s5pv210/Kconfig had a choice entry
to choose which of the two machines to build, which is
silly since you can easily build more than one machine
at a time.
Remove the choice entry so that both machines and any
future additions can all build in harmony.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch introduces nice defines for the initial values for UART devices
on SMDKC100.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The definition of the framebuffer parameters was created when s3c-fb.c
driver was patched to support setting the refresh rate directly (commit
600ce1a0fa). That patch was completely wrong
and was reverted in commit eb29a5cc0b what breaked the
framebuffer on s5pc100. This patch updates framebuffer definitions to
correct values.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add support for external interrupts on S5PV210.
Signed-off-by: Jongpill Lee <boyko.lee@samsung.com>
Signed-off-by: Pannaga Bhushan <p.bhushan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
[ben-linux@fluff.org: Ext => IRQ_EINT in title]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch adds touchscreen support for S5PV210.
Note: TSADC in S5PV210 support 2 touchscreen interfaces,
Only 1 is implemented as of now.
Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
[ben-linux@fluff.org: minor title fix]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch adds touchscreen support for S5P6440.
Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
[ben-linux@fluff.org: minor header fix]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch adds touchscreen support for S3C64XX.
Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
[ben-linux@fluff.org: minor title fix]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
WARNING: at drivers/firmware/dmi_scan.c:423 dmi_matches+0x70/0x160()
dmi check: not initialized yet.
This is caused by commit aa2110c
(ACPI: add boot option acpi=copy_dsdt to fix corrupt DSDT).
DMI is not initialized yet in acpi_early_init on ia64.
The DSDT DMI check table is x86 specific, so make it empty on other archs.
And this fixes the warnings on ia64.
Reported-and-tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'for-2.6.35' of git://linux-nfs.org/~bfields/linux: (45 commits)
Revert "nfsd4: distinguish expired from stale stateids"
nfsd: safer initialization order in find_file()
nfs4: minor callback code simplification, comment
NFSD: don't report compiled-out versions as present
nfsd4: implement reclaim_complete
nfsd4: nfsd4_destroy_session must set callback client under the state lock
nfsd4: keep a reference count on client while in use
nfsd4: mark_client_expired
nfsd4: introduce nfs4_client.cl_refcount
nfsd4: refactor expire_client
nfsd4: extend the client_lock to cover cl_lru
nfsd4: use list_move in move_to_confirmed
nfsd4: fold release_session into expire_client
nfsd4: rename sessionid_lock to client_lock
nfsd4: fix bare destroy_session null dereference
nfsd4: use local variable in nfs4svc_encode_compoundres
nfsd: further comment typos
sunrpc: centralise most calls to svc_xprt_received
nfsd4: fix unlikely race in session replay case
nfsd4: fix filehandle comment
...
* 'nfs-for-2.6.35' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (78 commits)
SUNRPC: Don't spam gssd with upcall requests when the kerberos key expired
SUNRPC: Reorder the struct rpc_task fields
SUNRPC: Remove the 'tk_magic' debugging field
SUNRPC: Move the task->tk_bytes_sent and tk_rtt to struct rpc_rqst
NFS: Don't call iput() in nfs_access_cache_shrinker
NFS: Clean up nfs_access_zap_cache()
NFS: Don't run nfs_access_cache_shrinker() when the mask is GFP_NOFS
SUNRPC: Ensure rpcauth_prune_expired() respects the nr_to_scan parameter
SUNRPC: Ensure memory shrinker doesn't waste time in rpcauth_prune_expired()
SUNRPC: Dont run rpcauth_cache_shrinker() when gfp_mask is GFP_NOFS
NFS: Read requests can use GFP_KERNEL.
NFS: Clean up nfs_create_request()
NFS: Don't use GFP_KERNEL in rpcsec_gss downcalls
NFSv4: Don't use GFP_KERNEL allocations in state recovery
SUNRPC: Fix xs_setup_bc_tcp()
SUNRPC: Replace jiffies-based metrics with ktime-based metrics
ktime: introduce ktime_to_ms()
SUNRPC: RPC metrics and RTT estimator should use same RTT value
NFS: Calldata for nfs4_renew_done()
NFS: Squelch compiler warning in nfs_add_server_stats()
...
* 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing:
sunrpc: Include missing smp_lock.h
procfs: Kill the bkl in ioctl
procfs: Push down the bkl from ioctl
procfs: Use generic_file_llseek in /proc/vmcore
procfs: Use generic_file_llseek in /proc/kmsg
procfs: Use generic_file_llseek in /proc/kcore
procfs: Kill BKL in llseek on proc base
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clocksource: Add clocksource_register_hz/khz interface
posix-cpu-timers: Optimize run_posix_cpu_timers()
time: Remove xtime_cache
mqueue: Convert message queue timeout to use hrtimers
hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIME
timers: Introduce the concept of timer slack for legacy timers
ntp: Remove tickadj
ntp: Make time_adjust static
time: Add xtime, wall_to_monotonic to feature-removal-schedule
timer: Try to survive timer callback preempt_count leak
timer: Split out timer function call
timer: Print function name for timer callbacks modifying preemption count
time: Clean up warp_clock()
cpu-timers: Avoid iterating over all threads in fastpath_timer_check()
cpu-timers: Change SIGEV_NONE timer implementation
cpu-timers: Return correct previous timer reload value
cpu-timers: Cleanup arm_timer()
cpu-timers: Simplify RLIMIT_CPU handling
* 'timers-for-linus-hpet' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, hpet: Add reference to chipset erratum documentation for disable-hpet-msi-quirk
x86, hpet: Restrict read back to affected ATI chipsets
* 'timers-for-linus-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
avr32: Fix typo in read_persistent_clock()
sparc: Convert sparc to use read/update_persistent_clock
cris: Convert cris to use read/update_persistent_clock
m68k: Convert m68k to use read/update_persistent_clock
m32r: Convert m32r to use read/update_peristent_clock
blackfin: Convert blackfin to use read/update_persistent_clock
ia64: Convert ia64 to use read/update_persistent_clock
avr32: Convert avr32 to use read/update_persistent_clock
h8300: Convert h8300 to use read/update_persistent_clock
frv: Convert frv to use read/update_persistent_clock
mn10300: Convert mn10300 to use read/update_persistent_clock
alpha: Convert alpha to use read/update_persistent_clock
xtensa: Fix unnecessary setting of xtime
time: Clean up direct xtime usage in xen
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: Clear CPU mask in affinity_hint when none is provided
genirq: Add CPU mask affinity hint
genirq: Remove IRQF_DISABLED from core code
genirq: Run irq handlers with interrupts disabled
genirq: Introduce request_any_context_irq()
genirq: Expose irq_desc->node in proc/irq
Fixed up trivial conflicts in Documentation/feature-removal-schedule.txt
When cppcheck found this flaw
[./i2c/busses/i2c-highlander.c:284]: (style) Warning - using char variable in bit operation
it was noted that the 'read'-variable could be simply removed as read_write can
only be 0 or 1 anyhow. So, we remove the flaw and simplify the code.
Reported-by: d binderman <dcb314@hotmail.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Drop NO_IRQ as 0 is the preferred way to describe 'no irq'
(http://lkml.org/lkml/2005/11/21/221). This change is safe, as the driver is
only used on powerpc, where NO_IRQ is 0 anyhow.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Sean MacLennan <smaclennan@pikatech.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Drop NO_IRQ as 0 is the preferred way to describe 'no irq'
(http://lkml.org/lkml/2005/11/21/221). This change is safe, as the driver is
only used on powerpc, where NO_IRQ is 0 anyhow.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Jochen Friedrich <jochen@scram.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Drop NO_IRQ as 0 is the preferred way to describe 'no irq'
(http://lkml.org/lkml/2005/11/21/221). This change is safe, as the driver is
only used on powerpc, where NO_IRQ is 0 anyhow.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Ben Dooks <ben-linux@fluff.org>
This talkative function is also called on timeouts. As timeouts can
happen on regular writes to EEPROMs (no error case), this creates false
positives. Giving lots of details is interesting only for developers
anyhow, so just use the function if DEBUG is #defined.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Cc: Roel Kluin <roel.kluin@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Commit
beea494 ([ARM] Remove EEPROM slave emulation from i2c-pxa driver.)
removed all uses of eedbg, so the definition can go, too.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Fix this warning:
i2c-nomadik.c:707: warning: suggest parentheses around operand of '!' or change '&' to '&&' or '!' to '~'
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
So that the module can be loaded again after an unload.
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Clean up existing Errata 1p153 handling to use generic
errata handling mechanism through dev flag.
Signed-off-by: Manjunatha GK <manjugk@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
While waiting for completion of the i2c transfer, the
MPU could hit OFF mode and cause several msecs of
delay that made i2c transfers fail more often. The
extra delays and subsequent re-trys cause i2c clocks
to be active more often. This has also an negative
effect on power consumption.
Created a mechanism for passing and using the
constraint setting function in driver code. The used
mpu wake up latency constraints are now set individually
per bus, and they are calculated based on clock rate
and fifo size.
Thanks to Jarkko Nikula, Moiz Sonasath, Paul Walmsley,
and Nishanth Menon for tuning out the details of
this patch.
Updates by Kevin as requested by Tony:
- Remove omap_set_i2c_constraint_func() in favor of conditionally
adding the flag in omap_i2c_add_bus() in order to keep all the OMAP
conditional checking in a single location.
- Update set_mpu_wkup_lat prototypes to match OMAP PM layer so
OMAP PM function can be used directly in pdata.
Cc: Moiz Sonasath <m-sonasath@ti.com>
Cc: Jarkko Nikula <jhnikula@gmail.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Under certain rare conditions, I2C_STAT[13].RDR bit may be set
and the corresponding interrupt fire, even there is no data in
the receive FIFO, or the I2C data transfer is still ongoing.
These spurious RDR events must be ignored by the software.
This patch handles and ignores RDR spurious interrupts.
The below sequence is required in interrupt handler for
handling this errata:
1. If RDR is set to 1, clear RDR
2. Read I2C status register and check for BusBusy bit. If BusBusy
bit is set, skip remaining steps.
3. If BusBusy bit is not set, perform read operation on I2C status
register.
4. If RDR is set, clear the same. Check RDR again and clear if it sets
RDR bit again.
5. Perform I2C Data Read operation N number of times(where N is value
read from the register BUFSTAT-RXSTAT bit fields).
Note:
This errata is not applicable for omap2420 and omap4.
It is applicable for:
1. omap2430
2. omap34xx(including omap3630).
Signed-off-by: Manjunatha GK <manjugk@ti.com>
Cc: Hema Kalliguddi <hemahk@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Aaro Koskinen <Aaro.Koskinen@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch is rebased version of earlier post to add I2C
driver support to OMAP4 platform. On OMAP4, all
I2C register address offsets are changed from OMAP1/2/3 I2C.
In order to not have #ifdef's at various places in code,
as well as to support multi-OMAP build, an array is created
to hold the register addresses with it's offset.
This patch was submitted, reviewed and acked on mailing list
already. For more details refer below link
http://www.mail-archive.com/linux-i2c@vger.kernel.org/msg02281.html
This updated verion has a depedancy on "Add support for 16-bit registers"
posted on linux-omap. Below is the patch-works link for the same
http://patchwork.kernel.org/patch/72295/
Signed-off-by: Syed Rafiuddin <rafiuddin.syed@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Cc: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The errata 1.153 workaround is busy waiting on XUDF bit in interrupt
context, which may lead to kernel hangs. The problem can be reproduced
by running the bus with wrong (too high) speed.
Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This is to avoid insanely long lines and levels of indentation.
Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Cc: Nishant Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
A smbus quick transfer has no data after the address byte.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
i2c event of next read/write byte may trigger before current int state
is cleared in the interrupt handler. So, this should be done at the
beginning of interrupt handler to avoid losing new i2c events.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add some debug() code to decode the error register.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
There isn't much point in managing our own custom timeout timer when the
completion interface already includes support for it. This makes the
resulting code much simpler and robust.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The S3C I2C controller indicates completion of I2C transfers before
the bus has a stop condition on it. In order to ensure that we do not
attempt to start a new transfer before the bus is idle the driver
currently inserts a 1ms delay. This is vastly larger than is generally
required and has a visible effect on performance under load, such as
when bringing up audio CODECs or reading back status information with
non-bulk I2C reads.
Replace the sleep with a spin on the IIC status register for up to 1ms.
This will busy wait but testing on my SMDK6410 system indicates that
the overwhelming majority of transactions complete on the first spin,
with maximum latencies of less than 10 spins so the absolute overhead
of busy waiting should be at worst comprable to msleep(), and the
overall system performance is dramatically improved.
The main risk is poor interaction with multimaster systems where
we may miss the bus going idle before the next transaction. Defend
against this by falling back to the original 1ms delay after 20 spins.
The overall effect in my testing is an approximately 20% improvement
in kernel startup time.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
