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path: root/include/linux/spi/spi.h
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2007-06-16spi doc updatesDavid Brownell
Update two points in the SPI interface documentation: - Update description of the "chip stays selected after message ends" mode. In some cases it's required for correctness; it isn't just a performance tweak. (Yes: to use this mode on mult-device busses, another programming interface will be needed. One draft has been circulated already.) - Clarify spi_setup(), highlighting that callers must ensure that no requests are queued (can't change configuration except between I/Os), and that the device must be deselected when this returns (which is a key part of why it's called during device init). Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08SPI kerneldocDavid Brownell
Various documentation updates for the SPI infrastructure, to clarify things that may not have been clear, to cope with lack of editing, and fix omissions. Also, plug SPI into the kernel-api DocBook template, and fix all the resulting glitches in document generation. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] SPI doc clarificationsDavid Brownell
This clarifies some aspects of the SPI programming interface, based on feedback from Hans-Peter Nilsson. The in-memory representation of words is right-aligned, so for example a twelve bit word is stored using sixteen bits with four undefined bits in the MSB. And controller drivers must reject protocol tweaking modes they do not support. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] SPI cleanup() method param becomes non-constHans-Peter Nilsson
I'd like to assign NULL to kfree()d members of a structure. I can't do that without ugly casting (see the PXA patch) when the structure pointed to is const-qualified. I don't really see a reason why the cleanup method isn't allowed to alter the object it should clean up. :-) No, I didn't test the PXA patch, but I verified that the NULL-assignment doesn't stop me from doing rmmod/insmodding my own spi_bitbang-based driver. Signed-off-by: Hans-Peter Nilsson <hp@axis.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] spi: remove return in spi_unregister_driver()Ben Dooks
Make the spi_unregister_driver() code fit in with the rest of the header file, and only do the action if the driver passed is non-NULL. This also makes the code a line smaller. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] spi: add spi_set_drvdata() and spi_get_drvdata()Ben Dooks
Add wrappers for getting and setting the driver data using spi_device instead of using dev_{get|set}_drvdata with &spi->dev, to mirror the platform_{get|set}_drvdata. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-07Revert "Driver core: convert SPI code to use struct device"Greg Kroah-Hartman
This reverts commit 2943ecf2ed32632473c06f1975db47a7aa98c10f. This should go through the SPI maintainer, it was my fault that it did not. Especially as it conflicts with other patches he has pending. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-07Driver core: convert SPI code to use struct deviceGreg Kroah-Hartman
Converts from using struct "class_device" to "struct device" making everything show up properly in /sys/devices/ with symlinks from the /sys/class directory. Cc: <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-30[PATCH] SPI: define null tx_buf to mean "shift out zeroes"David Brownell
Some issues were recently turned up with the current specification of what it means for spi_transfer.tx_buf to be null, as part of transfers which are (from the SPI protocol driver perspective) pure reads. Specifically, that it seems better to change the TX behaviour there from "undefined" to "will shift zeroes". This lets protocol drivers (like the ads7846 driver) depend on that behavior. It's what most controller drivers in the tree are already doing (with one exception and one case of driver wanting-to-oops), it's what Microwire hardware will necessarily be doing, and it removes an issue whereby certain security audits would need to define such a value anyway as part of removing covert channels. This patch changes the specification to require shifting zeroes, and updates all currently merged SPI controller drivers to do so. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28[PATCH] SPI: infrastructure to initialize spi_device.mode earlyDavid Brownell
This patch adds earlier initialization of spi_device.mode, as needed on boards using nondefault chipselect polarity. An example would be ones using the RS5C348 RTC without an external signal inverter between the RTC chipselect and the SPI controller. Without this mechanism, the first setup() call for that chip would wrongly enable chips, corrupting transfers to/from other chips sharing that SPI bus. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-16[PATCH] SPI: busnum == 0 needs to workDavid Brownell
We need to be able to have a "SPI bus 0" matching chip numbering; but that number was wrongly used to flag dynamic allocation of a bus number. This patch resolves that issue; now negative numbers trigger dynamic alloc. It also updates the how-to-write-a-controller-driver overview to mention this stuff. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-05-16[PATCH] SPI: devices can require LSB-first encodingsDavid Brownell
Add spi_device hook for LSB-first word encoding, and update all the (in-tree) controller drivers to reject such devices. Eventually, some controller drivers will be updated to support lsb-first encodings on the wire; no current drivers need this. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-05-16[PATCH] SPI: spi whitespace fixesDavid Brownell
This removes superfluous whitespace in the <linux/spi/spi.h> header. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-05-16[PATCH] SPI: per-transfer overrides for wordsize and clockingImre Deak
Some protocols (like one for some bitmap displays) require different clock speed or word size settings for each transfer in an SPI message. This adds those parameters to struct spi_transfer. They are to be used when they are nonzero; otherwise the defaults from spi_device are to be used. The patch also adds a setup_transfer callback to spi_bitbang, uses it for messages that use those overrides, and implements it so that the pure bitbanging code can help resolve any questions about how it should work. Signed-off-by: Imre Deak <imre.deak@nokia.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13[PATCH] spi: remove fastcall crapAndrew Morton
gcc4 generates warnings when a non-FASTCALL function pointer is assigned to a FASTCALL one. Perhaps it has taste. Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13[PATCH] spi: use linked lists rather than an arrayVitaly Wool
This makes the SPI core and its users access transfers in the SPI message structure as linked list not as an array, as discussed on LKML. From: David Brownell <dbrownell@users.sourceforge.net> Updates including doc, bugfixes to the list code, add spi_message_add_tail(). Plus, initialize things _before_ grabbing the locks in some cases (in case it grows more expensive). This also merges some bitbang updates of mine that didn't yet make it into the mm tree. Signed-off-by: Vitaly Wool <vwool@ru.mvista.com> Signed-off-by: Dmitry Pervushin <dpervushin@gmail.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13[PATCH] SPI core tweaks, bugfixDavid Brownell
This includes various updates to the SPI core: - Fixes a driver model refcount bug in spi_unregister_master() paths. - The spi_master structures now have wrappers which help keep drivers from needing class-level get/put for device data or for refcounts. - Check for a few setup errors that would cause oopsing later. - Docs say more about memory management. Highlights the use of DMA-safe i/o buffers, and zero-initializing spi_message and such metadata. - Provide a simple alloc/free for spi_message and its spi_transfer; this is only one of the possible memory management policies. Nothing to break code that already works. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13[PATCH] spi: add spi_driver to SPI frameworkDavid Brownell
This is a refresh of the "Simple SPI Framework" found in 2.6.15-rc3-mm1 which makes the following changes: * There's now a "struct spi_driver". This increase the footprint of the core a bit, since it now includes code to do what the driver core was previously handling directly. Documentation and comments were updated to match. * spi_alloc_master() now does class_device_initialize(), so it can at least be refcounted before spi_register_master(). To match, spi_register_master() switched over to class_device_add(). * States explicitly that after transfer errors, spi_devices will be deselected. We want fault recovery procedures to work the same for all controller drivers. * Minor tweaks: controller_data no longer points to readonly data; prevent some potential cast-from-null bugs with container_of calls; clarifies some existing kerneldoc, And a few small cleanups. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13[PATCH] spi: simple SPI frameworkDavid Brownell
This is the core of a small SPI framework, implementing the model of a queue of messages which complete asynchronously (with thin synchronous wrappers on top). - It's still less than 2KB of ".text" (ARM). If there's got to be a mid-layer for something so simple, that's the right size budget. :) - The guts use board-specific SPI device tables to build the driver model tree. (Hardware probing is rarely an option.) - This version of Kconfig includes no drivers. At this writing there are two known master controller drivers (PXA/SSP, OMAP MicroWire) and three protocol drivers (CS8415a, ADS7846, DataFlash) with LKML mentions of other drivers in development. - No userspace API. There are several implementations to compare. Implement them like any other driver, and bind them with sysfs. The changes from last version posted to LKML (on 11-Nov-2005) are minor, and include: - One bugfix (removes a FIXME), with the visible effect of making device names be "spiB.C" where B is the bus number and C is the chipselect. - The "caller provides DMA mappings" mechanism now has kerneldoc, for DMA drivers that want to be fancy. - Hey, the framework init can be subsys_init. Even though board init logic fires earlier, at arch_init ... since the framework init is for driver support, and the board init support uses static init. - Various additional spec/doc clarifications based on discussions with other folk. It adds a brief "thank you" at the end, for folk who've helped nudge this framework into existence. As I've said before, I think that "protocol tweaking" is the main support that this driver framework will need to evolve. From: Mark Underwood <basicmark@yahoo.com> Update the SPI framework to remove a potential priority inversion case by reverting to kmalloc if the pre-allocated DMA-safe buffer isn't available. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>