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Author SHA1 Message Date
Mingkai Hu b36ece8325 spi/mpc8xxx: refactor the common code for SPI/eSPI controller
Refactor the common code in file spi_fsl_spi.c to spi_fsl_lib.c used
by SPI/eSPI controller driver as a library, and leave the QE/CPM SPI
controller code in the SPI controller driver spi_fsl_spi.c.

Because the register map of the SPI controller and eSPI controller
is so different, also leave the code operated the register to the
driver code, not the common code.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:38:12 -06:00
Mingkai Hu 3272029fb3 spi/mpc8xxx: rename spi_mpc8xxx.c to spi_fsl_spi.c
This will pave the way to refactor out the common code which can be used
by the eSPI controller driver, and rename the SPI controller dirver to the
file spi_fsl_spi.c.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:38:12 -06:00
Grant Likely 492c032bec Merge commit 'v2.6.36-rc7' into spi/next 2010-10-12 21:38:02 -06:00
Linus Walleij f9d629c737 spi/pl022: fix dubious allocation staticize platform data
This removes some dubious allocation of a local chipinfo struct
in favor of a constant preset, tagging that one const revealed
further problems with platform data being modified so fixed up
these too.

Reported-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Linus Walleij 5a1c98be1d spi/pl022: get rid of chipinfo dev pointer
What is the dev pointer doing inside the platform data anyway.
We have another pointer to the actual device at hand, use that.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Kevin Wells bde435a9ca spi/pl022: Add spi->mode support to AMBA SPI driver
This patch adds spi->mode support for the AMBA pl022 driver and
allows spidev to correctly alter SPI modes. Unused fields used in
the pl022 header file for the pl022_config_chip have been removed.

The ab8500 client driver selects the data transfer size instead
of the platform data.

For platforms that use the amba pl022 driver, the unused fields
in the controller data structure have been removed and the .mode
field in the SPI board info structure is used instead.

Signed-off-by: Kevin Wells <wellsk40@gmail.com>
Tested-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
matt mooney fadcf49b9b spi: change to new flag variable
Replace EXTRA_CFLAGS with ccflags-y.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Linus Walleij b1b6b9aa6f spi/pl022: add PrimeCell generic DMA support
This extends the PL022 SSP/SPI driver with generic DMA engine
support using the PrimeCell DMA engine interface. Also fix up the
test code for the U300 platform.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Grant Likely cdbc8f042f spi/topcliff: Tidy up Kconfig help text
The original didn't specify Topcliff in the config prompt text.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Grant Likely 65308c46b7 spi/topcliff: cleanups for style and conciseness
This patch makes multiple cleanups to the new topcliff pch spi driver
including, but not limited to,
- removing superfluous brackets around variables
- open coding functions that are only used once
- removing unnecessary line breaks
- removing unused functions
- simplifying the interrupt enable/disable code
- remove unnecessary (void *) casts.
- remove b_mem_fail from pch_spi_set_tx to code it more cleanly
- shorten dev_dbg() messages for conciseness and readability

More cleanups are still needed in this driver.  In particular,
- the driver filename should be changed to spi_topcliff_pch.c
- many of the dev_dbg() lines should be trimmed (particularly the ones
  on unconditional code paths).
- I suspect that the locking model not correct.  I'd like to know what
  drivers' critical regions are, and how they are protected.
- get_resources and release_resources probably should be open coded in
  .probe and .release respectively.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-12 21:37:37 -06:00
Masayuki Ohtake e8b17b5b3f spi/topcliff: Add topcliff platform controller hub (PCH) spi bus driver
Topcliff PCH is the platform controller hub that is going to be used
in Intel's upcoming general embedded platform. All IO peripherals in
Topcliff PCH are actually devices sitting on AMBA bus.  This patch
adds a driver for the SPI bus integrated into the Topcliff device.

Signed-off-by: Masayuki Ohtake <masa-korg@dsn.okisemi.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-08 12:44:49 -06:00
Sinan Akman 2b7a32f7ec of/spi: Fix OF-style driver binding of spi devices
This patch adds the OF hook to the spi core so that devices
can automatically be registered based on device tree data.  This fixes
a problem with spi devices not binding to drivers after the cleanup of
the spi & i2c binding code.

Signed-off-by: Sinan Akman <sinan@writeme.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-02 21:28:29 -06:00
Roel Kluin 23699f98f8 spi: spi-gpio.c tests SPI_MASTER_NO_RX bit twice, but not SPI_MASTER_NO_TX
The SPI_MASTER_NO_TX bit (can't do buffer write) wasn't tested.  This
code was introduced in commit 3c8e1a84 (spi/spi-gpio: add support for
controllers without MISO or MOSI pin).  This patch fixes a bug in
choosing which transfer ops to use.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-02 21:09:08 -06:00
Jassi Brar 0c92ecf10d spi/s3c64xx: Correction for 16,32 bits bus width
We can't do without setting channel and bus width to
same size. In order to do that, use loop read/writes in
polling mode and appropriate burst size in DMA mode.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:33 +09:00
Jassi Brar b42a81ca0f spi/s3c64xx: Consider the clk_from_cmu flag
Newer SoCs have the SPI clock scaling control in platform's
clock management unit. Inorder for such SoCs to work, we need
to check the flag clk_from_cmu before making any clock changes.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:33 +09:00
Jassi Brar e02ddd442a spi/s3c64xx: Prevent unnecessary map-unmap
Since we use DMA mode only for xfers bigger than FIFO size,
do not map/unmap buffers for polling mode transfers.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:31 +09:00
Julia Lawall 4a4fd47155 spi/amba-pl022: Fix error case return statement.
The return -EINVAL appears to only make sense if the if branch that it is
aligned with is taken, and the indentation indicates that this is the
authors intent, so move it into that branch.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable braces4@
position p1,p2;
statement S1,S2;
@@

(
if (...) { ... }
|
if (...) S1@p1 S2@p2
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

if (p1[0].column == p2[0].column):
  cocci.print_main("branch",p1)
  cocci.print_secs("after",p2)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:30 +09:00
Julia Lawall e447d3588e spi/orion: Drop unnecessary null test
list_for_each_entry binds its first argument to a non-null value, and thus
any null test on the value of that argument is superfluous.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
iterator I;
expression x,E;
@@

I(x,...) { <...
- (x != NULL) &&
  E
  ...> }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:29 +09:00
Felipe Balbi 079a176d87 spi: omap2_mcspi: make use of dev_vdbg()
dev_vdbg() is only compiled when VERBOSE is defined, so
there's no need to wrap dev_dbg() on #ifdef VERBOSE .. #endif
as we can use dev_vdbg() directly.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-29 17:31:29 +09:00
christophe leroy 37880c909c spi/mpc8xxx: fix buffer overrun on large transfers
It fixes an issue when sending-only or receiving-only more than
PAGE_SIZE bytes.

Signed-off-by: christophe leroy <christophe.leroy@c-s.fr>
Acked-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-16 14:07:45 -06:00
Linus Walleij 25c8e03bdb spi/pl022: move probe call to subsys_initcall()
The PL022 SPI bus is sometimes used for early stuff like
regulators that need to be present at module_init() time, so
we move this to a subsys_initcall().

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 22:50:10 -06:00
Linus Walleij 545074fb95 spi/pl022: fix APB pclk power regression on U300
With the introduction of an AMBA PrimeCell per-cell block clock,
the pclk was left on after probe() unless explicitly disabled.
This clock is wired to the same clock on PL022 causing it to stay
always on since.

Fix this up properly by clocking the pclk whenever we want to
write into any PL022 registers and clocking the external clock
whenever we want to transmit messages on the bus.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Tested-by : Kevin Wells <wellsk40@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 12:24:30 -06:00
Mark Brown be7852a839 spi/spi_s3c64xx: Warn if PIO transfers time out
When using PIO we have a timeout for the TX and RX FIFOs to ensure that
the data actually gets transferred. Warn if we hit that timeout - it
should never happen, but this makes sure we'll find out if it does.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 12:23:03 -06:00
Jassi Brar c3f139b655 spi/s3c64xx: Fix incorrect reuse of 'val' local variable.
Instead of, wrongly, reusing the 'val' variable, use a dedicated
one for reading the status register.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 12:05:02 -06:00
Jassi Brar 251ee478f2 spi/s3c64xx: Fix compilation warning
Fix compilation warning by typecasting the tx_buf pointer.

[I'm not thrilled with resorting to a cast; but I cannot see a better
way to go about this.  I don't want to drop the const from struct
spi_transfer ~~glikely]

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 12:03:45 -06:00
Feng Tang e3e55ff585 spi/dw_spi: clean the cs_control code
commit 052dc7c45i "spi/dw_spi: conditional transfer mode change"
introduced cs_control code, which has a bug by using bit offset
for spi mode to set transfer mode in control register. Also it
forces devices who don't need cs_control to re-configure the
control registers for each spi transfer. This patch will fix them

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 10:50:00 -06:00
Yong Wang cbcc062abb spi/dw_spi: Allow interrupt sharing
Allow interrupt sharing since exclusive interrupt line for
DW SPI controller is not provided on every platform.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 10:49:50 -06:00
Mark Brown 9d8f86b560 spi/spi_s3c64xx: Increase dead reckoning time in wait_for_xfer()
For small transfers at high speeds the expected transfer time can easily
be well under 1ms, causing the delay in wait_for_xfer() to be only the
dead reckoning fudge factor of 5ms currently included. Experiments on
some of my systems shows that this is marginal for some transfers so
double it to 10ms.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 10:00:15 -06:00
Mark Brown d2a787fc57 spi/spi_s3c64xx: Move to subsys_initcall()
Allow the use of the S3C64xx SPI controller with things like PMICs by
moving the init up to subsys_initcall().

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-08 09:59:37 -06:00
David Lamparter 34860089c9 spi: free children in spi_unregister_master, not siblings
introduced by 49dce689 ("spi doesn't need class_device") and bad-fixed
by 350d0076 ("spi: fix double-free on spi_unregister_master"),
spi_unregister_master would previously device_unregister all of the spi
master's siblings (instead of its children). hilarity ensues.

fix it to unregister children.

Signed-off-by: David Lamparter <equinox@diac24.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-01 09:15:24 -06:00
Mark Brown 8944f4f3d9 spi/spi_s3c64xx: Staticise non-exported functions
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-01 08:55:23 -06:00
Mark Brown cc0fc0bbeb spi/spi_s3c64xx: Make probe more robust against missing board config
The S3C64xx SPI driver requires the machine to call s3c64xx_spi_set_info()
to select a few options, including the clock to use for the SPI controller.
If this is not done then a NULL will be passed as the clock name for
clk_get(), causing an obscure crash. Guard against this and other missing
configuration by validating that the clock name has been filled in in
the platform data that ets passed in.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-09-01 08:55:22 -06:00
Greg Ungerer 5e1c53356d m68knommu: include sched.h in ColdFire/SPI driver
Using the coldfire qspi driver, I get the following error:

drivers/spi/coldfire_qspi.c: In function 'mcfqspi_irq_handler':
drivers/spi/coldfire_qspi.c:166: error: 'TASK_NORMAL' undeclared (first use in this function)
drivers/spi/coldfire_qspi.c:166: error: (Each undeclared identifier is reported only once

It is solved by adding the following include to coldfire_sqpi.c:

    #include <linux/sched.h>

Fix suggested by Jate Sujjavanich <jsujjavanich@syntech-fuelmaster.com>

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
2010-08-18 12:44:31 +10:00
Linus Torvalds b171aa2770 Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6
* 'next-spi' of git://git.secretlab.ca/git/linux-2.6:
  spi/amba_pl022: Fix probe and remove hook section annotations.
  spi/mpc5121: change annotations for probe and remove functions
  spi/bitbang: reinitialize transfer parameters for every message
  spi/spi-gpio: add support for controllers without MISO or MOSI pin
  spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
  SPI100k: Fix 8-bit and RX-only transfers
  spi/mmc_spi: mmc_spi adaptations for SPI bus locking API
  spi/mmc_spi: SPI bus locking API, using mutex

Fix trivial conflict in drivers/spi/mpc512x_psc_spi.c due to 'struct
of_device' => 'struct platform_device' rename and __init/__exit to
__devinit/__devexit fix.
2010-08-14 11:54:09 -07:00
Grant Likely 2dc1158137 of/device: Replace struct of_device with struct platform_device
of_device is just an alias for platform_device, so remove it entirely.  Also
replace to_of_device() with to_platform_device() and update comment blocks.

This patch was initially generated from the following semantic patch, and then
edited by hand to pick up the bits that coccinelle didn't catch.

@@
@@
-struct of_device
+struct platform_device

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: David S. Miller <davem@davemloft.net>
2010-08-06 09:25:50 -06:00
Grant Likely 22ae782f86 of/address: Clean up function declarations
This patch moves the declaration of of_get_address(), of_get_pci_address(),
and of_pci_address_to_resource() out of arch code and into the common
linux/of_address header file.

This patch also fixes some of the asm/prom.h ordering issues.  It still
includes some header files that it ideally shouldn't be, but at least the
ordering is consistent now so that of_* overrides work.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-08-01 01:42:42 -06:00
Kevin Wells b4225885de spi/amba_pl022: Fix probe and remove hook section annotations.
Probe and remove hooks belong in the __devinit and __devexit sections
respectively.  This patch fixes incorrect annotations on the pl022 spi
driver.

Signed-off-by: Kevin Wells <wellsk40@gmail.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-08-01 01:35:29 -06:00
Anatolij Gustschin 12b15e8328 of/spi: call of_register_spi_devices() from spi core code
Move of_register_spi_devices() call from drivers to
spi_register_master(). Also change the function to use
the struct device_node pointer from master spi device
instead of passing it as function argument.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-30 00:03:59 -06:00
Grant Likely 5ffdcd94ea Merge commit 'v2.6.35-rc6' into spi/test 2010-07-25 17:52:21 -06:00
Anton Vorontsov 56825c88ff powerpc/cpm: Reintroduce global spi_pram struct (fixes build issue)
spi_t was removed in commit 644b2a680c
("powerpc/cpm: Remove SPI defines and spi structs"), the commit assumed
that spi_t isn't used anywhere outside of the spi_mpc8xxx driver. But
it appears that the struct is needed for micropatch code. So, let's
reintroduce the struct.

Fixes the following build issue:

    CC      arch/powerpc/sysdev/micropatch.o
  micropatch.c: In function 'cpm_load_patch':
  micropatch.c:629: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
  micropatch.c:629: error: 'spp' undeclared (first use in this function)
  micropatch.c:629: error: (Each undeclared identifier is reported only once
  micropatch.c:629: error: for each function it appears in.)

Reported-by: LEROY Christophe <christophe.leroy@c-s.fr>
Reported-by: Tony Breeds <tony@bakeyournoodle.com>
Cc: <stable@kernel.org> [ .33, .34 ]
Signed-off-by: Anton Vorontsov <avorontsov@mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2010-07-11 11:03:22 -05:00
Anatolij Gustschin cf40f082f8 spi/mpc5121: change annotations for probe and remove functions
Change annotations from __init/__exit to __devinit/__devexit
to get rid of section mismatch warning.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-05 11:34:07 -06:00
Brian Niebuhr b8f2e7bb6c spi/bitbang: reinitialize transfer parameters for every message
This patch fixes the setup_transfer logic to account for the case where
multiple messages to different SPI devices are in the queue simultaneously.
With the current logic, the second message in the queue will end up
using the transfer parameters for the previous message in the queue.

The fix is to reinitialize the transfer parameters for each message
rather than only once on the first message.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03 22:59:18 -06:00
Marek Szyprowski 3c8e1a84fd spi/spi-gpio: add support for controllers without MISO or MOSI pin
There are some boards that do not strictly follow SPI standard and use
only 3 wires (SCLK, MOSI or MISO, SS) for connecting some simple auxiliary
chips and controls them with GPIO based 'spi controller'. In this
configuration the MISO or MOSI line is missing (it is not required if the
chip does not transfer any data back to host or host only reads data from
chip).

This patch adds support for such non-standard configuration in GPIO-based
SPI controller. It has been tested in configuration without MISO pin.

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03 22:45:44 -06:00
Marek Szyprowski 04bb2a031c spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
This patch adds a new flags argument to bitbang_txrx_be_cpha0 and
bitbang_txrx_be_cpha1 transfer functions. This enables support for
SPI_MASTER_NO_{TX,RX} transfer modes. The change should have no impact
on speed of the existing drivers. bitbank_txrx_* functions are usually
inlined into the drivers. When the argument is equal to constant zero,
the optimizer would be able to eliminate the dead code (flags checks)
easily. Tested on ARM and GCC 4.4.x and in all cases the checks were
eliminated in the inlined function.

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03 22:45:44 -06:00
Cory Maccarrone 5c2818cdfa SPI100k: Fix 8-bit and RX-only transfers
This change fixes 8-bit transfers and RX-only transfers.  The
SPI100k framework requires minimum 16-bit words to be written, so 8-bit
transfers must be shited by 8 bits and sent out as a 16-bit word.

Additionally, receive-only transfers were failing due to the
perceived need to fill the TX buffer with something.  This is in
fact not needed.

Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03 22:45:44 -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
Anatolij Gustschin ef7f2e831c of/spi: mpc512x_psc_spi.c: Fix build failures
Fixes build errors caused by the:
 - OF device_node pointer being moved into struct device
 - removal of the match_table field from struct of_platform_driver

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-06-02 13:45:06 -06:00
Grant Likely b53550781b of/spi: Fix build failure on spi_ppc4xx.c
This patch fixes a build error caused by the OF device_node pointer
being moved into struct device.

Fixes bug introduced by commit 61c7a080a5
(of: Always use 'struct device.of_node' to get device node pointer)

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
CC: Sean MacLennan <smaclennan@pikatech.com>
CC: spi-devel-general@lists.sourceforge.net
CC: devicetree-discuss@lists.ozlabs.org
2010-06-02 13:38:33 -06:00
Grant Likely bf6a67ee34 spi/xilinx: Fix compile error
Commit 58f9b0b024, "of: eliminate
of_device->node and dev_archdata->{of,prom}_node" changed the location
of the device_node pointer.  Most drivers were converted to the new
location, but the xilinx_spi_of driver was missed and now fails to
compile.

This patch fixes up the xilinx_spi_of driver to use the new location.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-05-25 00:48:24 -06:00
Grant Likely b1e50ebcf2 Merge remote branch 'origin' into secretlab/next-spi 2010-05-25 00:38:26 -06:00