Commit Graph

86 Commits

Author SHA1 Message Date
Linus Torvalds 159d8133d0 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina:
 "Usual rocket science -- mostly documentation and comment updates"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  sparse: fix comment
  doc: fix double words
  isdn: capi: fix "CAPI_VERSION" comment
  doc: DocBook: Fix typos in xml and template file
  Bluetooth: add module name for btwilink
  driver core: unexport static function create_syslog_header
  mmc: core: typo fix in printk specifier
  ARM: spear: clean up editing mistake
  net-sysfs: fix comment typo 'CONFIG_SYFS'
  doc: Insert MODULE_ in module-signing macros
  Documentation: update URL to hfsplus Technote 1150
  gpio: update path to documentation
  ixgbe: Fix format string in ixgbe_fcoe.
  Kconfig: Remove useless "default N" lines
  user_namespace.c: Remove duplicated word in comment
  CREDITS: fix formatting
  treewide: Fix typo in Documentation/DocBook
  mm: Fix warning on make htmldocs caused by slab.c
  ata: ata-samsung_cf: cleanup in header file
  idr: remove unused prototype of idr_free()
2014-04-02 16:23:38 -07:00
Mark Brown a78389844e Merge remote-tracking branch 'spi/topic/dma' into spi-next 2014-03-30 00:50:56 +00:00
Jiri Kosina d4263348f7 Merge branch 'master' into for-next 2014-02-20 14:54:28 +01:00
Masanari Iida e227867f12 treewide: Fix typo in Documentation/DocBook
This patch fix spelling typo in Documentation/DocBook.
It is because .html and .xml files are generated by make htmldocs,
I have to fix a typo within the source files.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-02-19 14:58:17 +01:00
Mark Brown 6ad45a27cb spi: Make core DMA mapping functions generate scatterlists
We cannot unconditionally use dma_map_single() to map data for use with
SPI since transfers may exceed a page and virtual addresses may not be
provided with physically contiguous pages. Further, addresses allocated
using vmalloc() need to be mapped differently to other addresses.

Currently only the MXS driver handles all this, a few drivers do handle
the possibility that buffers may not be physically contiguous which is
the main potential problem but many don't even do that. Factoring this
out into the core will make it easier for drivers to do a good job so if
the driver is using the core DMA code then generate a scatterlist
instead of mapping to a single address so do that.

This code is mainly based on a combination of the existing code in the MXS
and PXA2xx drivers. In future we should be able to extend it to allow the
core to concatenate adjacent transfers if they are compatible, improving
performance.

Currently for simplicity clients are not allowed to use the scatterlist
when they do DMA mapping, in the future the existing single address
mappings will be replaced with use of the scatterlist most likely as
part of pre-verifying transfers.

This change makes it mandatory to use scatterlists when using the core DMA
mapping so update the s3c64xx driver to do this when used with dmaengine.
Doing so makes the code more ugly but it is expected that the old s3c-dma
code can be removed very soon.

Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-04 20:31:49 +00:00
Mark Brown 3a2eba9bd0 spi: Provide core support for full duplex devices
It is fairly common for SPI devices to require that one or both transfer
directions is always active. Currently drivers open code this in various
ways with varying degrees of efficiency. Start factoring this out by
providing flags SPI_MASTER_MUST_TX and SPI_MASTER_MUST_RX. These will cause
the core to provide buffers for the requested direction if none are
specified in the underlying transfer.

Currently this is fairly inefficient since we actually allocate a data
buffer which may get large, support for mapping transfers using a
scatterlist will allow us to avoid this for DMA based transfers.

Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-04 20:31:33 +00:00
Mark Brown 99adef310f spi: Provide core support for DMA mapping transfers
The process of DMA mapping buffers for SPI transfers does not vary between
devices so in order to save duplication of code in drivers this can be
factored out into the core, allowing it to be integrated with the work that
is being done on factoring out the common elements from the data path
including more sharing of dmaengine code.

In order to use this masters need to provide a can_dma() operation and while
the hardware is prepared they should ensure that DMA channels are provided
in tx_dma and rx_dma. The core will then ensure that the buffers are mapped
for DMA prior to calling transfer_one_message().

Currently the cleanup on error is not complete, this needs to be improved.

Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-03 13:05:21 +00:00
Baruch Siach e9305331f6 spi: correct the transfer_one_message documentation wording
The transfer_one_message callback handles messages, not transfers.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-27 18:45:02 +00:00
Baruch Siach 6e5f52674f spi: spi.h: clarify the documentation of transfer_one
Explicitly note the transfer_one and transfer_one_message are mutually
exclusive, to make the text a little more newcomers friendly.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-27 18:43:36 +00:00
Mark Brown 3c1039745e Merge remote-tracking branch 'spi/topic/core' into spi-linus 2014-01-23 13:07:01 +00:00
Geert Uytterhoeven bd6857a0c6 spi: Correct set_cs() documentation
The documentation for spi_master.set_cs() says:

    assert or deassert chip select, true to assert

i.e. its "enable" parameter uses assertion-level logic.

This does not match the implementation of spi_set_cs(), which calls
spi_master.set_cs() with the wanted logic level of the chip select line,
which depends on the polarity of the chip select signal.

Correct the documentation to match the implementation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-21 18:11:49 +00:00
Geert Uytterhoeven 0516712c65 spi: Clarify transfer_one() w.r.t. spi_finalize_current_transfer()
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-21 18:11:49 +00:00
Geert Uytterhoeven 269ccca8ec spi: Kill superfluous cast in spi_w8r16()
spi_write_then_read() takes a "void *" for rxbuf, so there's no need to
cast the buffer pointer to "u8 *".

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-13 11:20:21 +00:00
Mark Brown d3fbd45701 spi: Use bitfields for multiple data lines
Trent Piepho observed that since the current realistic maximum number of
data lines is four we can pack the spi_transfer struct more efficiently
if we use a bitfield for the number of bits, allowing the fields to fit
in a single byte along with cs_change.

If space becomes an issue further optimiation is possible by only using
the constants and packing the values chosen for them.

Reported-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-01-13 10:13:28 +00:00
Trent Piepho 89c1f60746 spi: Order fields in spi_device for better packing
Now that spi_device->mode is a u16, the chip_select, bits_per_mode,
and mode fields pack poorly, taking 8 bytes:  four data and four
padding.  By moving (u8)bits_per_word up one position, to after
(u8)chip_select, they pack better and only use 4 bytes.

Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Reviewed-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>g
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-12-16 21:03:42 +00:00
Mark Brown 82f85cf98f Merge remote-tracking branch 'spi/topic/wr' into spi-next 2013-10-25 09:51:41 +01:00
Mark Brown 2cc6e2e0c8 Merge remote-tracking branch 'spi/topic/s3c64xx' into spi-loop 2013-10-11 20:10:13 +01:00
Mark Brown b158935f70 spi: Provide common spi_message processing loop
The loops which SPI controller drivers use to process the list of transfers
in a spi_message are typically very similar and have some error prone areas
such as the handling of /CS. Help simplify drivers by factoring this code
out into the core - if drivers provide a transfer_one() function instead
of a transfer_one_message() function the core will handle processing at the
message level.

/CS can be controlled by either setting cs_gpio or providing a set_cs
function. If this is not possible for hardware reasons then both can be
omitted and the driver should continue to implement manual /CS handling.

This is a first step in refactoring and it is expected that there will be
further enhancements, for example factoring out of the mapping of transfers
for DMA and the initiation and completion of interrupt driven transfers.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-10-11 20:09:50 +01:00
Mark Brown 2841a5fc37 spi: Provide per-message prepare and unprepare operations
Many SPI drivers perform setup and tear down on every message, usually
doing things like DMA mapping the message. Provide hooks for them to use
to provide such operations.

This is of limited value for drivers that implement transfer_one_message()
but will be of much greater utility with future factoring out of standard
implementations of that function.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-10-11 20:09:13 +01:00
Lars-Peter Clausen 05071aa864 spi: Add a spi_w8r16be() helper
This patch adds a new spi_w8r16be() helper, which is similar to spi_w8r16()
except that it converts the read data word from big endian to native endianness
before returning it. The reason for introducing this new helper is that for SPI
slave devices it is quite common that the read 16 bit data word is in big
endian. So users of spi_w8r16() have to convert the result to native endianness
manually. A second reason is that in this case the endianness of the return
value of spi_w8r16() depends on its sign. If it is negative (i.e. a error code)
it is already in native endianness, if it is positive it is in big endian. The
sparse code checker doesn't like this kind of mixed endianness and special
annotations are necessary to keep it quiet (E.g. casting to be16 using __force).
Doing the conversion to native endianness in the helper function does not
require such annotations since we are not mixing different endiannesses in the
same variable.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-10-03 13:52:03 +01:00
Mark Brown 666d5b4c74 spi: core: Add devm_spi_register_master()
Help simplify the cleanup code for SPI master drivers by providing a
managed master registration function, ensuring that the master is
automatically unregistered whenever the device is unbound.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-09-17 00:59:36 +01:00
Mark Brown 85cac43132 Merge remote-tracking branch 'spi/topic/qspi' into spi-next 2013-09-01 13:49:06 +01:00
Mark Brown 9020b75467 Merge remote-tracking branch 'spi/topic/msglen' into spi-next 2013-09-01 13:48:58 +01:00
Mark Brown db04e17055 Merge remote-tracking branch 'spi/topic/checks' into spi-next 2013-09-01 13:48:48 +01:00
Mark Brown 21e34a3306 Merge remote-tracking branch 'spi/topic/quad' into spi-qspi 2013-08-23 12:00:15 +01:00
wangyuhang f477b7fb13 spi: DUAL and QUAD support
fix the previous patch some mistake below:
1. DT in slave node, use "spi-tx-nbits = <1/2/4>" in place of using
   "spi-tx-dual, spi-tx-quad" directly, same to rx. So correct the
   previous way to get the property in @of_register_spi_devices().
2. Change the value of transfer bit macro(SPI_NBITS_SINGLE, SPI_NBITS_DUAL
   SPI_NBITS_QUAD) to 0x01, 0x02 and 0x04 to match the actual wires.
3. Add the following check
   (1)keep the tx_nbits and rx_nbits in spi_transfer is not beyond the
      single, dual and quad.
   (2)keep tx_nbits and rx_nbits are contained by @spi_device->mode
      example: if @spi_device->mode = DUAL, then tx/rx_nbits can not be set
               to QUAD(SPI_NBITS_QUAD)
   (3)if "@spi_device->mode & SPI_3WIRE", then tx/rx_nbits should be in
      single(SPI_NBITS_SINGLE)

Signed-off-by: wangyuhang <wangyuhang2014@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-22 13:47:29 +01:00
Stephen Warren b6aa23ccae spi: fix SPI_BIT_MASK so it always fits into 32-bits
On a 64-bit platform, ~0UL fills 64-bits, which causes SPI_BIT_MASK(32)
not to fit into 32 bits. This causes a warning when the result is assigned
to a 32-bit variable. Use ~0U instead to prevent this. This fixes:

drivers/spi/spi-gpio.c: In function 'spi_gpio_probe':
drivers/spi/spi-gpio.c:446:2: warning: large integer implicitly truncated to unsigned type [-Woverflow]

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-02 11:31:22 +01:00
Mark Brown 49834de234 spi: Provide core support for runtime PM during transfers
Most SPI drivers that implement runtime PM support use identical code to
do so: they acquire a runtime PM lock in prepare_transfer_hardware() and
then they release it in unprepare_transfer_hardware(). The variations in
this are mostly missing error checking and the choice to use autosuspend.

Since these runtime PM calls are normally the only thing in the prepare
and unprepare callbacks and the autosuspend API transparently does the
right thing on devices with autosuspend disabled factor all of this out
into the core with a flag to enable the behaviour.

Signed-off-by: Mark Brown <broonie@linaro.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
2013-07-29 17:59:20 +01:00
Sourav Poddar 078726ce6d driver: spi: Modify core to compute the message length
Make spi core calculate the message length while
populating the other transfer parameters.

Usecase, driver can use it to populate framelength filed in their
controller.

Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-18 16:22:01 +01:00
Mark Brown a2fd4f9fa3 spi: Support transfer speed checking in the core
Allow drivers to avoid implementing their own checks for simple rates by
specifying the limits in the master structure.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:34:51 +01:00
Stephen Warren eca8960a8e spi: fix incorrect handling of min param in SPI_BPW_RANGE_MASK
SPI_BPW_RANGE_MASK is intended to work by calculating two masks; one
representing support for all bits up-to-and-including the "max" supported
value, and one representing support for all bits up-to-but-not-including
the "min" supported value, and then taking the difference between the
two, resulting in a mask representing support for all bits between
(inclusive) the min and max values.

However, the second mask ended up representing all bits up-to-and-
including rather up-to-but-not-including. Fix this bug.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-01 19:46:16 +01:00
Stephen Warren 4dd9572abc spi: fix undefined behaviour in SPI_BPW_RANGE_MASK
The parameters to SPI_BPW_RANGE_MASK() are in the range 1..32. If 32 is
used as a parameter, part of the expression is "1 << 32". Since 32 is >=
the size of the type in use, such a shift is undefined behaviour. Add
macro SPI_BIT_MASK to Implement a special case and thus avoid undefined
behaviour. Use this new macro rather than BIT() when implementing
SPI_BPW_RANGE_MASK().

This fixes build warnings such as:
drivers/spi/spi-gpio.c:446:2: warning: left shift count >= width of type [enabled by default]

SPI_BPW_MASK() already avoids this, since its parameter is also in range
1..32, yet it only shifts by up to one less than the input parameter.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-01 19:46:16 +01:00
Stephen Warren 2922a8de99 spi: introduce macros to set bits_per_word_mask
Introduce two macros to make setting up spi_master.bits_per_word_mask
easier, and avoid mistakes like writing BIT(n) instead of BIT(n - 1).

SPI_BPW_MASK is for a single supported value of bits_per_word_mask.

SPI_BPW_RANGE_MASK represents a contiguous set of bit lengths.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-05-22 10:57:43 -05:00
Mark Brown 88b0357dde Merge remote-tracking branch 'spi/fix/grant' into spi-linus 2013-05-13 18:27:18 +04:00
Andreas Larsson 446411e18b spi: Initialize cs_gpio and cs_gpios with -ENOENT
The return value from of_get_named_gpio is -ENOENT when the given index
matches a hole in the "cs-gpios" property phandle list. However, the
default value of cs_gpio in struct spi_device and entries of cs_gpios in
struct spi_master is -EINVAL, which is documented to indicate that a
GPIO line should not be used for the given spi_device.

This sets the default value of cs_gpio in struct spi_device and entries
of cs_gpios in struct spi_master to -ENOENT. Thus, -ENOENT is the only
value used to indicate that no GPIO line should be used.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2013-04-07 10:12:20 +01:00
Stephen Warren 543bb255a1 spi: add ability to validate xfer->bits_per_word in SPI core
Allow SPI masters to define the set of bits_per_word values they support.
If they do this, then the SPI core will reject transfers that attempt to
use an unsupported bits_per_word value. This eliminates the need for each
SPI driver to implement this checking in most cases.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-04-01 14:14:32 +01:00
Linus Torvalds b5c78e04dd Staging tree update for 3.9-rc1
Here's the big staging tree merge for 3.9-rc1
 
 Lots of cleanups and updates for drivers all through the staging tree.
 We are pretty much "code neutral" here, adding just about as many lines
 as we removed.
 
 All of these have been in linux-next for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging tree update from Greg Kroah-Hartman:
 "Here's the big staging tree merge for 3.9-rc1

  Lots of cleanups and updates for drivers all through the staging tree.
  We are pretty much "code neutral" here, adding just about as many
  lines as we removed.

  All of these have been in linux-next for a while."

* tag 'staging-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (804 commits)
  staging: comedi: vmk80xx: wait for URBs to complete
  staging: comedi: drivers: addi-data: hwdrv_apci3200.c: Add a missing semicolon
  staging: et131x: Update TODO list
  staging: et131x: Remove assignment of skb->dev
  staging: wlan-ng: hfa384x.h: fix for error reported by smatch
  staging/zache checkpatch ERROR: spaces prohibited around that
  staging/ozwpan: Mark read only parameters and structs as const
  staging/ozwpan: Remove empty and unused function oz_cdev_heartbeat
  staging/ozwpan: Mark local functions as static (fix sparse warnings)
  staging/ozwpan: Add missing header includes
  staging/usbip: Mark local functions as static (fix sparse warnings)
  staging/xgifb: Remove duplicated code in loops.
  staging/xgifb: Consolidate return paths
  staging/xgifb: Remove code without effect
  staging/xgifb: Remove unnecessary casts
  staging/xgifb: Consolidate if/else if with identical code branches
  staging: vt6656: replaced custom TRUE definition with true
  staging: vt6656: replaced custom FALSE definition with false
  staging: vt6656: replace custom BOOL definition with bool
  staging/rtl8187se: Mark functions as static to silence sparse
  ...
2013-02-21 12:11:44 -08:00
Andreas Larsson 095c3752e6 spi: Document cs_gpios and cs_gpio in kernel-doc
This adds missing kernel-doc entries for cs_gpios in struct spi_master and
cs_gpio in struct spi_device.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
[grant.likely: tweaked the language of the descriptions]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2013-02-11 00:05:31 +00:00
Lars-Peter Clausen 6d9eecd418 spi: Add helper functions for setting up transfers
Quite often the pattern used for setting up and transferring a synchronous SPI
transaction looks very much like the following:

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(&msg);

This patch adds two new helper functions for handling this case. The first
helper function spi_message_init_with_transfers() takes a spi_message and an
array of spi_transfers. It will initialize the message and then call
spi_message_add_tail() for each transfer in the array. E.g. the following

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

can be rewritten as

	spi_message_init_with_transfers(&msg, xfers, ARRAY_SIZE(xfers));

The second function spi_sync_transfer() takes a SPI device and an array of
spi_transfers. It will allocate a new spi_message (on the stack) and add all
transfers in the array to the message. Finally it will call spi_sync() on the
message.

E.g. the follwing

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(spi, &msg);

can be rewritten as

	struct spi_transfer xfers[] = {
		...
	};

	ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));

A coccinelle script to find such instances will follow.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-02-09 11:02:07 +00:00
Jean-Christophe PLAGNIOL-VILLARD 7431798490 of_spi: add generic binding support to specify cs gpio
This will allow to use gpio for chip select with no modification in the
driver binding

When use the cs-gpios, the gpio number will be passed via the cs_gpio field
and the number of chip select will automatically increased with max(hw cs, gpio cs).

So if for example the controller has 2 CS lines, and the cs-gpios
property looks like this:

cs-gpios = <&gpio1 0 0> <0> <&gpio1 1 0> <&gpio1 2 0>;

Then it should be configured so that num_chipselect = 4 with the
following mapping:

cs0 : &gpio1 0 0
cs1 : native
cs2 : &gpio1 1 0
cs3 : &gpio1 2 0

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: spi-devel-general@lists.sourceforge.net
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
[grant.likely: fixed up type of cs count so min() can do type checking]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2012-11-21 23:25:33 +00:00
Randy Dunlap dbabe0d659 spi: fix spi.h kernel-doc warning
Fix kernel-doc warning in spi.h (copy/paste):

Warning(include/linux/spi/spi.h:365): No description found for parameter 'unprepare_transfer_hardware'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2012-04-27 11:03:38 -06:00
Shubhrajyoti D 8f53602be5 spi: Trivial warning fix
The loop count i traverses for ntrans which is unsigned
so make the loop count i also unsigned.

Fix the below warning
In file included from drivers/spi/spi-omap2-mcspi.c:38:
include/linux/spi/spi.h: In function 'spi_message_alloc':
include/linux/spi/spi.h:556: warning: comparison between signed and unsigned integer expressions

Cc: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2012-03-09 10:56:10 -07:00
Linus Walleij ffbbdd2132 spi: create a message queueing infrastructure
This rips the message queue in the PL022 driver out and pushes
it into (optional) common infrastructure. Drivers that want to
use the message pumping thread will need to define the new
per-messags transfer methods and leave the deprecated transfer()
method as NULL.

Most of the design is described in the documentation changes that
are included in this patch.

Since there is a queue that need to be stopped when the system
is suspending/resuming, two new calls are implemented for the
device drivers to call in their suspend()/resume() functions:
spi_master_suspend() and spi_master_resume().

ChangeLog v1->v2:
- Remove Kconfig entry and do not make the queue support optional
  at all, instead be more agressive and have it as part of the
  compulsory infrastructure.
- If the .transfer() method is implemented, delete print a small
  deprecation notice and do not start the transfer pump.
- Fix a bitrotted comment.
ChangeLog v2->v3:
- Fix up a problematic sequence courtesy of Chris Blair.
- Stop rather than destroy the queue on suspend() courtesy of
  Chris Blair.

Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2012-03-07 19:19:48 -07:00
Lars-Peter Clausen 3acbb0142d SPI: Add helper macro for spi_driver boilerplate
This patch introduces the module_spi_driver macro which is a convenience macro
for SPI driver modules similar to module_platform_driver. It is intended to be
used by drivers which init/exit section does nothing but register/unregister
the SPI driver. By using this macro it is possible to eliminate a few lines of
boilerplate code per SPI driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-17 12:15:39 -08:00
Mark Brown 0c4a159018 spi: Use void pointers for data in simple SPI I/O operations
Currently the simple SPI I/O operations all take pointers to u8 * buffers
to operate on. This creates needless type compatibility issues and the
underlying spi_transfer structure uses void pointers anyway so convert the
API over to take void pointers too.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-20 00:43:07 -06:00
Feng Tang 2b9603a0d7 spi: enable spi_board_info to be registered after spi_master
Currently spi_register_board_info() has to be called before its related
spi_master be registered, otherwise these board info will be just ignored.

This patch will remove this order limit, it adds a global spi master list
like the existing global board info listr. Whenever a board info or a
spi_master is registered, the spi master list or board info list
will be scanned, and a new spi device will be created if there is a
master-board info match.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-21 23:52:16 -06:00
Ernst Schwab 5c79a5ae23 spi.h: missing kernel-doc notation, please fix
Added comments in kernel-doc notation for previously added struct fields.

Signed-off-by: Ernst Schwab <eschwab@online.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-08-17 22:55:38 -06:00
Ernst Schwab cf32b71e98 spi/mmc_spi: SPI bus locking API, using mutex
SPI bus locking API to allow exclusive access to the SPI bus, especially, but
not limited to, for the mmc_spi driver.

Coded according to an outline from Grant Likely; here is his
specification (accidentally swapped function names corrected):

It requires 3 things to be added to struct spi_master.
- 1 Mutex
- 1 spin lock
- 1 flag.

The mutex protects spi_sync, and provides sleeping "for free"
The spinlock protects the atomic spi_async call.
The flag is set when the lock is obtained, and checked while holding
the spinlock in spi_async().  If the flag is checked, then spi_async()
must fail immediately.

The current runtime API looks like this:
spi_async(struct spi_device*, struct spi_message*);
spi_sync(struct spi_device*, struct spi_message*);

The API needs to be extended to this:
spi_async(struct spi_device*, struct spi_message*)
spi_sync(struct spi_device*, struct spi_message*)
spi_bus_lock(struct spi_master*)  /* although struct spi_device* might
be easier */
spi_bus_unlock(struct spi_master*)
spi_async_locked(struct spi_device*, struct spi_message*)
spi_sync_locked(struct spi_device*, struct spi_message*)

Drivers can only call the last two if they already hold the spi_master_lock().

spi_bus_lock() obtains the mutex, obtains the spin lock, sets the
flag, and releases the spin lock before returning.  It doesn't even
need to sleep while waiting for "in-flight" spi_transactions to
complete because its purpose is to guarantee no additional
transactions are added.  It does not guarantee that the bus is idle.

spi_bus_unlock() clears the flag and releases the mutex, which will
wake up any waiters.

The difference between spi_async() and spi_async_locked() is that the
locked version bypasses the check of the lock flag.  Both versions
need to obtain the spinlock.

The difference between spi_sync() and spi_sync_locked() is that
spi_sync() must hold the mutex while enqueuing a new transfer.
spi_sync_locked() doesn't because the mutex is already held.  Note
however that spi_sync must *not* continue to hold the mutex while
waiting for the transfer to complete, otherwise only one transfer
could be queued up at a time!

Almost no code needs to be written.  The current spi_async() and
spi_sync() can probably be renamed to __spi_async() and __spi_sync()
so that spi_async(), spi_sync(), spi_async_locked() and
spi_sync_locked() can just become wrappers around the common code.

spi_sync() is protected by a mutex because it can sleep
spi_async() needs to be protected with a flag and a spinlock because
it can be called atomically and must not sleep

Signed-off-by: Ernst Schwab <eschwab@online.de>
[grant.likely@secretlab.ca: use spin_lock_irqsave()]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Matt Fleming <matt@console-pimps.org>
Tested-by: Antonio Ospite <ospite@studenti.unina.it>
2010-06-28 17:49:29 -07:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking 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>
2010-03-30 22:02:32 +09:00
David Brownell 568d0697f4 spi: handle TX-only/RX-only
Support two new half-duplex SPI implementation restrictions, for links
that talk to TX-only or RX-only devices.  (Existing half-duplex flavors
support both transfer directions, just not at the same time.)

Move spi_async() into the spi.c core, and stop inlining it.  Then make
that function perform error checks and reject messages that demand more
than the underlying controller can support.

Based on a patch from Marek Szyprowski which did this only for the
bitbanged GPIO driver.

Cc: Marek Szyprowski <m.szyprowski@samsung.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>
2009-09-23 07:39:44 -07:00