summaryrefslogtreecommitdiffstats
path: root/sound/soc/codecs/wm8731.c
AgeCommit message (Collapse)Author
2011-11-21ASoC: Ensure WM8731 register cache is synced when resuming from disabledMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: stable@vger.kernel.org
2011-10-10ASoC: wm8731: Convert to snd_soc_cache_syncAxel Lin
Convert to snd_soc_cache_sync for sync reg_cache with the hardware. Signed-off-by: Axel Lin <axel.lin@gmail.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-07-29ASoC: Add device tree binding for WM8731Mark Brown
Tested with the famous "hey, look! this compiles" test plan. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked by: Grant Likely <grant.likely@secretlab.ca>
2011-07-05ASoC: Manage WM8731 ACTIVE bit as a supply widgetMark Brown
Now we have supply widgets there's no need to open code the handling of the ACTIVE bit. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Tested-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Liam Girdwood <lrg@ti.com>
2011-05-26ASoC: wm8731: fix wm8731_check_osc() connected conditionNicolas Ferre
The crystal oscillator is only enabled if the WM8731_SYSCLK_XTAL master clock is specified. Fix the connected() struct snd_soc_dapm_route function to take this into account. Oscillator is not enabled on machine that need it otherwise. Machine drivers have to make sure that they use the proper SYSCLK value. Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-03-30ASoC: Remove -codec from WM8731 driver nameMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com>
2011-03-30ASoC: Convert WM8731 to table based DAPM setupMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com>
2010-12-28ASoC: codecs: Remove unused reg_cache fields from device structsLars-Peter Clausen
The multi-component patch(commit f0fba2ad1) moved the allocation of the register cache from the driver to the ASoC core. Most drivers where adjusted to this, but there are quite a few drivers left which now have an unused reg_cache field in their private device struct. This patch removes these unused fields. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-12-02ASoC: Automatically manage WM8731 deemphasisMark Brown
The deemphasis filter should be selected based on sample rate for optimal performance. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-12-02ASoC: Split WM8731 enumeration array into individual enumsMark Brown
This is much more maintainable than the array. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-12-02ASoC: Provide WM8731 microphone boost TLV informationMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-12-01Merge branch 'for-2.6.37' into for-2.6.38Mark Brown
2010-12-01ASoC: WM8731: Fix incorrect mask for bypass path disableDimitris Papastamos
According to the datasheet the bypass path enable/disable is bit 3 therefore we need 0x8 and not 0x4. Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-11-22ASoC: Do not include soc-dapm.hJarkko Nikula
There is no need to include soc-dapm.h since soc.h includes it. Signed-off-by: Jarkko Nikula <jhnikula@gmail.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-11-16ASoC: Fix incorrect kfree in wm8731_probe error pathAxel Lin
We allocated memory for wm8731 in wm8731_spi_probe / wm8731_i2c_probe, and will free the memory in either wm8731_spi_probe / wm8731_i2c_probe error path or wm8731_spi_remove / wm8731_i2c_remove. Thus we should not call kfree(wm8731) in wm8731_probe, otherwise we have double free of wm8731. Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-11-06ASoC: Decouple DAPM from CODECsLiam Girdwood
Decoupling Dynamic Audio Power Management (DAPM) from codec devices is required when developing ASoC further. Such as for other ASoC components to have DAPM widgets or when extending DAPM to handle cross-device paths. This patch decouples DAPM related variables from struct snd_soc_codec and moves them to new struct snd_soc_dapm_context that is used to encapsulate DAPM context of a device. ASoC core and API of DAPM functions are modified to use DAPM context instead of codec. This patch does not change current functionality and a large part of changes come because of structure and internal API changes. Core implementation is from Liam Girdwood <lrg@slimlogic.co.uk> with some minor core changes, codecs and machine driver conversions from Jarkko Nikula <jhnikula@gmail.com>. Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Jarkko Nikula <jhnikula@gmail.com> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Manuel Lauss <manuel.lauss@googlemail.com> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Cliff Cai <cliff.cai@analog.com> Cc: Kevin Hilman <khilman@deeprootsystems.com> Cc: Ryan Mallon <ryan@bluewatersys.com> Cc: Timur Tabi <timur@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Arnaud Patard (Rtp) <arnaud.patard@rtp-net.org> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Eric Miao <eric.y.miao@gmail.com> Cc: Jassi Brar <jassi.brar@samsung.com> Cc: Daniel Gloeckner <dg@emlix.com> Cc: Kuninori Morimoto <morimoto.kuninori@renesas.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-09-30ASoC: Remove unneeded use of spi_bus_typeDimitris Papastamos
No need to explicitly set the bus type, spi_register_driver does that for us. Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-09-15ASoC: Remove needless codec->bias_level assignment to SND_SOC_BIAS_OFFJarkko Nikula
This assignment is done by the snd_soc_register_codec so there is no need to redo it in probe function of a codec driver. Signed-off-by: Jarkko Nikula <jhnikula@gmail.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-09-10ASoC: Fix incorrect register cache size configurationDimitris Papastamos
The reg_cache_size is the number of elements in the register cache, not the size of the cache itself. This is not a problem if the size of each element of the cache is 1 byte but it matters in any other case. Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-08-17ASoC: Support non-crystal master clocks for WM8731Mark Brown
Instead of unconditionally enabling the crystal oscillator on the WM8731 only enable it when explicitly selected via set_sysclk(), allowing machine drivers to specify that they drive a clock into MCLK alone. This avoids any conflicts between the oscillator and the external MCLK source and saves power for systems which do not need the oscillator. This should also deliver a small power saving on systems using the crystal since the oscillator will only be enabled when the ADC or DAC is active. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-08-12ASoC: Remove unneeded control_data management from Wolfson driversMark Brown
Now soc-cache.c can figure out the I2C and SPI control data from the device for the CODEC we don't need to manually assign it in drivers. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-08-12ASoC: multi-component - ASoC Multi-Component SupportLiam Girdwood
This patch extends the ASoC API to allow sound cards to have more than one CODEC and more than one platform DMA controller. This is achieved by dividing some current ASoC structures that contain both driver data and device data into structures that only either contain device data or driver data. i.e. struct snd_soc_codec ---> struct snd_soc_codec (device data) +-> struct snd_soc_codec_driver (driver data) struct snd_soc_platform ---> struct snd_soc_platform (device data) +-> struct snd_soc_platform_driver (driver data) struct snd_soc_dai ---> struct snd_soc_dai (device data) +-> struct snd_soc_dai_driver (driver data) struct snd_soc_device ---> deleted This now allows ASoC to be more tightly aligned with the Linux driver model and also means that every ASoC codec, platform and (platform) DAI is a kernel device. ASoC component private data is now stored as device private data. The ASoC sound card struct snd_soc_card has also been updated to store lists of it's components rather than a pointer to a codec and platform. The PCM runtime struct soc_pcm_runtime now has pointers to all its components. This patch adds DAPM support for ASoC multi-component and removes struct snd_soc_socdev from DAPM core. All DAPM calls are now made on a card, codec or runtime PCM level basis rather than using snd_soc_socdev. Other notable multi-component changes:- * Stream operations now de-reference less structures. * close_delayed work() now runs on a DAI basis rather than looping all DAIs in a card. * PM suspend()/resume() operations can now handle N CODECs and Platforms per sound card. * Added soc_bind_dai_link() to bind the component devices to the sound card. * Added soc_dai_link_probe() and soc_dai_link_remove() to probe and remove DAI link components. * sysfs entries can now be registered per component per card. * snd_soc_new_pcms() functionailty rolled into dai_link_probe(). * snd_soc_register_codec() now does all the codec list and mutex init. This patch changes the probe() and remove() of the CODEC drivers as follows:- o Make CODEC driver a platform driver o Moved all struct snd_soc_codec list, mutex, etc initialiasation to core. o Removed all static codec pointers (drivers now support > 1 codec dev) o snd_soc_register_pcms() now done by core. o snd_soc_register_dai() folded into snd_soc_register_codec(). CS4270 portions: Acked-by: Timur Tabi <timur@freescale.com> Some TLV320aic23 and Cirrus platform fixes. Signed-off-by: Ryan Mallon <ryan@bluewatersys.com> TI CODEC and OMAP fixes Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com> Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> Signed-off-by: Jarkko Nikula <jhnikula@gmail.com> Samsung platform and misc fixes :- Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Jassi Brar <jassi.brar@samsung.com> Signed-off-by: Seungwhan Youn <sw.youn@samsung.com> MPC8610 and PPC fixes. Signed-off-by: Timur Tabi <timur@freescale.com> i.MX fixes and some core fixes. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> J4740 platform fixes:- Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> CC: Tony Lindgren <tony@atomide.com> CC: Nicolas Ferre <nicolas.ferre@atmel.com> CC: Kevin Hilman <khilman@deeprootsystems.com> CC: Sascha Hauer <s.hauer@pengutronix.de> CC: Atsushi Nemoto <anemo@mba.ocn.ne.jp> CC: Kuninori Morimoto <morimoto.kuninori@renesas.com> CC: Daniel Gloeckner <dg@emlix.com> CC: Manuel Lauss <mano@roarinelk.homelinux.net> CC: Mike Frysinger <vapier.adi@gmail.com> CC: Arnaud Patard <apatard@mandriva.com> CC: Wan ZongShun <mcuos.com@gmail.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-05-20Merge branch 'topic/asoc' into for-linusTakashi Iwai
Conflicts: sound/soc/codecs/ad1938.c
2010-05-10ASoC: Use more idiomatic driver name for WM8731Mark Brown
Make dev_() prints much prettier. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-05-10ASoC: Refactor WM8731 regulator management into bias managementMark Brown
This allows more flexible integration with subsystem features. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-05-10ASoC: Remove unneeded suspend bias managment from CODEC driversMark Brown
The core will ensure that the device is in either STANDBY or OFF bias before suspending, restoring the bias in the driver is unneeded. Some drivers doing slightly more roundabout things have been left alone for now. Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-04-17ASoC: Add indirection for CODEC private dataMark Brown
One of the features of the multi CODEC work is that it embeds a struct device in the CODEC to provide diagnostics via a sysfs class rather than via the device tree, at which point it's much better to use the struct device private data rather than having two places to store it. Provide an accessor function to allow this change to be made more easily, and update all the CODEC drivers are updated. To ensure use of the accessor the private data structure member is renamed, meaning that if code developed with older an older core that still uses private_data is merged it will fail to build. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-04-12ASoC: Use SNDRV_PCM_RATE_8000_96000 macro for WM8731Bill Gatliff
Signed-off-by: Bill Gatliff <bgat@billgatliff.com> Acked-by: Richard Purdie <rpurdie@rpsys.net> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-01-04ASoC: Only restore non-default registers for WM8731Mark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-11-12ASoC: Remove redundant snd_soc_dapm_new_widgets() callsMark Brown
The DAPM widgets are now insntantiated by the core when creating the card so there is no need for the individual CODEC drivers to do so. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-03ASoC: Factor out snd_soc_init_card()Mark Brown
snd_soc_init_card() is always called as the last part of the CODEC probe function so we can factor it out into the core card setup rather than have each CODEC replicate the code to do the initialiastation. This will be required to support multiple CODECs per card. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-10-26ASoC: Add regulator support for WM8731Mark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-10-15ASoC: Remove snd_soc_suspend_device()Mark Brown
The PM core will grow pm_link infrastructure in 2.6.33 which can be used to implement the intended functionality of the ASoC-specific device suspend and resume callbacks so drop them. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-08-10ASoC: Drop unneeded declaration of removed wm8731 SPI write functionMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-08-07Merge branch 'reg-cache' into for-2.6.32Mark Brown
2009-08-03ASoC: Factor out 7 bit register 9 bit data SPI writeMark Brown
This converts all the Wolfson drivers using this format (the only devices that do) except WM8753 to use it. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-08-03ASoC: Add I/O control bus information to factored out cache setupMark Brown
While writes tend to be able to use a fairly bus independant format to do the writes reads are all bus specific. To allow us to factor out this code include the bus type as a parameter when setting up the cache. Initially just use this to factor out hw_write_t for I2C. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-07-08ASoC: Limit WM8731 to symmetric ratesMark Brown
While the hardware is capable of some limited asynmmetric modes the driver does not currently support those modes so tell applications that only symmetric rates are available. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-07-08ASoC: Correct WM8731 Mic Capture Switch control nameMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-07-08ASoC: Add TLV information for WM8731Mark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-07-05ASoC: Begin to factor out register cache I/O functionsMark Brown
A lot of CODECs share the same register data formats and therefore replicate the code to manage access to and caching of the register map. In order to reduce code duplication centralised versions of this code will be introduced with drivers able to configure the use of the common code by calling the new snd_soc_codec_set_cache_io() API call during startup. As an initial user the 7 bit address/9 bit data format used by many Wolfson devices is supported for write only CODECs and the drivers with straightforward register cache implementations are converted to use it. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-07-05ASoC: Fix leaks in WM8731 probe error handlingMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-06-13ASoC: Add suspend and resume callbacks to Wolfson CODEC driversMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-05-12sound: remove driver_data direct access of struct deviceGreg Kroah-Hartman
In the near future, the driver core is going to not allow direct access to the driver_data pointer in struct device. Instead, the functions dev_get_drvdata() and dev_set_drvdata() should be used. These functions have been around since the beginning, so are backwards compatible with all older kernel versions. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2009-03-04ASoC: make ops a pointer in 'struct snd_soc_dai'Eric Miao
Considering the fact that most cpu_dai or codec_dai are using a same 'snd_soc_dai_ops' for several similar interfaces, 'ops' would be better made a pointer instead, to make sharing easier and code a bit cleaner. The patch below is rather preliminary since the asoc tree is being actively developed, and this touches almost every piece of code, (and possibly many others in development need to be changed as well). Building of all codecs are OK, yet to every SoC, I didn't test that. Signed-off-by: Eric Miao <eric.miao@marvell.com> Acked-by: Timur Tabi <timur@freescale.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-19ASoC: Disable WM8731 line bypass by defaultMark Brown
This avoids temporarily enabling the ouput stages during startup which can cause audible effets in the output stages. Reported-by: Fredrik Redgård <rik@svep.se> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-18ASoC: Add device init/exit annotations to new-style Wolfson CODEC driversMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-18ASoC: Check for errors when writing WM8731 reset registerMark Brown
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-18ASoC: Implement SPI device unregistration for WM8731Mark Brown
Completely untested. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>