The s3c64xx SPI driver uses a custom DT binding to specify
the GPIO used to drive the chip select (CS) line instead of
using the generic "cs-gpios" property already defined in:
Documentation/devicetree/bindings/spi/spi-bus.txt.

It's unfortunate that drivers are not using standard bindings
and creating custom ones instead but in most cases this can't
be changed without breaking Device Tree backward compatibility.

But in the case of this driver, its DT binding has been broken
for more than a year. Since after commit (dated June, 21 2013):

3146beec ("spi: s3c64xx: Added provision for dedicated cs pin")

DT backward compatibility was broken and nobody noticed until
now when the commit was reverted. So it seems to be safe to
change the binding to use the standard SPI "cs-gpios" property
instead of using a custom one just for this driver.

This patch also allows boards that don't use a GPIO pin for the
CS to work with the driver since the SPI core will take care of
setting spi->cs_gpio to -ENOENT if a board wants to use the built
in CS instead of a GPIO as explained in the SPI bus DT binding:
Documentation/devicetree/bindings/spi/spi-bus.txt.

For non-DT platforms, spi->cs_gpio will be set to -ENOENT as well
unless they specify a GPIO pin in their platform data. So both
native and GPIO chip select is also supported for legacy boards.

The above use case was what motivated commit 3146beec which broke
the DT binding backward compatibility in the first place.
Signed-off-by: NNaveen Krishna Chatradhi <ch.naveen@samsung.com>
[javier.martinez@collabora.co.uk: split changes and improve commit message]
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

This reverts commit 3146beec.

This commit resulted in a DT backward compatibility breakage.

Some devices use the native chip select (CS) instead of a GPIO
pin to drive the CS line. But the SPI driver made it mandatory
to specify a GPIO pin in the SPI device node controller-data.
So, using the built-in CS was not possible with the driver.

Commit 3146beec tried to fix that by adding a "cs-gpio" property
which could be defined in the SPI device node to make the driver
request the GPIO from the controller-data node.

Unfortunately that changed the old DT binding semantics since
now it's mandatory to have the "cs-gpio" property defined in
the SPI device node in order to use a GPIO pin to drive the CS.

As an example, a SPI device was defined before the commit with:

spi@12d20000 {
    slave-node@0 {
        controller-data {
             cs-gpio = <&gpb1 2 0>;
        }
   }
}

and after the commit, the following DTS snippet must be used:

spi@12d20000 {
    cs-gpio;
    slave-node@0 {
        controller-data {
             cs-gpio = <&gpb1 2 0>;
        }
   }
}

So, after commit 3146beec the driver does not look for the GPIO
by default and it only looks for it if the top level "cs-gpio"
property is defined while the default used to be the opposite.
To always request the GPIO defined in the controller-data node.

This means that old FDT that of course didn't have this added
"cs-gpio" DT property in the SPI node broke after this change.

The offending commit can't be reverted cleanly since more than
a year have passed and other changes were made in the meantime
but this patch partially reverts the driver to it's original
state so old FDT can work again.

This patch will break Device Trees that were relying on the new
behavior of course but the patch should be reverted because:

a) There aren't DTS in mainline that use this new property.
b) They were relying on a behavior that broke DT compatibility.
c) The new binding is awkard, needing two properties with the
   same name (cs-gpio) on different nodes is confusing at least.
d) The new property was not added to the DT binding doc:
   Documentation/devicetree/bindings/spi/spi-samsung.txt
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

spi core will handle validating transfer length since commit 4d94bd21
"spi: core: Validate length of the transfers in message".
So remove the same checking in this driver.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Remove functions that only had an effect when using S3C_DMA and inline
dmaengine_terminate_all() since it's pointless to have a function which
expands to a single function call.
Signed-off-by: NMark Brown <broonie@linaro.org>

All the platforms which use the old S3C_DMA API have now been converted to
dmaengine so we can remove the legacy code from the driver, simplifying
maintenance.
Signed-off-by: NMark Brown <broonie@linaro.org>

When using dmaengine allow the core to do the DMA mapping. We still need
local mapping code for the non-dmaengine case so this doesn't save us
anything for now.
Signed-off-by: NMark Brown <broonie@linaro.org>

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: NMark Brown <broonie@linaro.org>

There is no meaningful code sharing between the PIO and DMA variants
(just the timeout calculation) so in order to make the code easier to
work with split the two cases.

Looking at the code it is not clear how the PIO version works for large
transmits, greater than FIFO size is only handled for RX.
Signed-off-by: NMark Brown <broonie@linaro.org>

The GPIO enable and disable is done in the core so does not need to be
replicated in the driver, delete the unneeded code. enable_cs() was not
referenced at all.
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NGeert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix doubled clock disable and unprepare during PM suspend which triggered
the warnings:

WARNING: at drivers/clk/clk.c:800 clk_disable+0x18/0x24()
Modules linked in:
CPU: 0 PID: 1745 Comm: sh Not tainted 3.10.14-01211-ge2549bb-dirty #62
[<c0015980>] (unwind_backtrace+0x0/0x138) from [<c0012a44>] (show_stack+0x10/0x14)
[<c0012a44>] (show_stack+0x10/0x14) from [<c0022818>] (warn_slowpath_common+0x4c/0x68)
[<c0022818>] (warn_slowpath_common+0x4c/0x68) from [<c0022850>] (warn_slowpath_null+0x1c/0x24)
[<c0022850>] (warn_slowpath_null+0x1c/0x24) from [<c036e274>] (clk_disable+0x18/0x24)
[<c036e274>] (clk_disable+0x18/0x24) from [<c02d5f78>] (s3c64xx_spi_suspend+0x28/0x54)
[<c02d5f78>] (s3c64xx_spi_suspend+0x28/0x54) from [<c02b3a54>] (platform_pm_suspend+0x2c/0x5c)
[<c02b3a54>] (platform_pm_suspend+0x2c/0x5c) from [<c02b8a30>] (dpm_run_callback+0x44/0x7c)
[<c02b8a30>] (dpm_run_callback+0x44/0x7c) from [<c02b8b70>] (__device_suspend+0x108/0x300)
[<c02b8b70>] (__device_suspend+0x108/0x300) from [<c02ba4e0>] (dpm_suspend+0x54/0x208)
[<c02ba4e0>] (dpm_suspend+0x54/0x208) from [<c0066bcc>] (suspend_devices_and_enter+0x98/0x458)
[<c0066bcc>] (suspend_devices_and_enter+0x98/0x458) from [<c0067150>] (pm_suspend+0x1c4/0x25c)
[<c0067150>] (pm_suspend+0x1c4/0x25c) from [<c0066044>] (state_store+0x6c/0xbc)
[<c0066044>] (state_store+0x6c/0xbc) from [<c0203290>] (kobj_attr_store+0x14/0x20)
[<c0203290>] (kobj_attr_store+0x14/0x20) from [<c0157530>] (sysfs_write_file+0xfc/0x164)
[<c0157530>] (sysfs_write_file+0xfc/0x164) from [<c00fd6b0>] (vfs_write+0xbc/0x1bc)
[<c00fd6b0>] (vfs_write+0xbc/0x1bc) from [<c00fdaf0>] (SyS_write+0x40/0x68)
[<c00fdaf0>] (SyS_write+0x40/0x68) from [<c000ea80>] (ret_fast_syscall+0x0/0x3c)

The clocks may be already disabled before suspending. Check PM runtime
suspend status and disable clocks only if device is not suspended.
During resume do not enable the clocks if device is runtime suspended.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

During PM resume and suspend do not ignore the return value of
spi_master_suspend() or spi_master_resume(). Instead pass it further.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

pm_runtime_put() wasn't called if clock rate could not be set up in
s3c64xx_spi_setup() leading to invalid count of device pm_runtime usage.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Mark device as PM runtime active during initialization to reflect
actual device power/clocks state. This reduces the enable count for SPI
bus controller gate clock so it can be disabled when the bus controller
is not used.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NMark Brown <broonie@linaro.org>

This is of very little value in itself but will be useful once the loop
iterating over the transfers is also factored out into the core.
Signed-off-by: NMark Brown <broonie@linaro.org>

The hardware level /CS handling is tied to the start of the data path so
is rolled into the same function as we use to manipulate GPIO /CS. In
order to support factoring out the /CS handling into the core separate the
two and explicitly start transfers separately to the /CS handling.
Signed-off-by: NMark Brown <broonie@linaro.org>

To help with bisection of future refactoring to share more of the code for
handling a spi_message pull the enabling of GPIO based /CS prior to all
the hardware setup for starting a transfer.
Signed-off-by: NMark Brown <broonie@linaro.org>

The hardware level /CS handling is tied to the start of the data path so
is rolled into the same function as we use to manipulate GPIO /CS. In
order to support factoring out the /CS handling into the core separate the
two and explicitly start transfers separately to the /CS handling.
Signed-off-by: NMark Brown <broonie@linaro.org>

Rather than using the driver custom platform data to store the chip select
GPIO use the cs_gpio field provided by the SPI core, supporting future
refectoring.
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NMark Brown <broonie@linaro.org>

Ensure that the FIFOs are fully drained before we deassert /CS or do any
delays that have been requested in order to ensure that the behaviour
visible on the bus matches that which was requested by the caller.
Signed-off-by: NMark Brown <broonie@linaro.org>

Otherwise we may try to start transfers immediately and then fail to
runtime resume the device causing us not to have clocks enabled.
Signed-off-by: NMark Brown <broonie@linaro.org>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>

Conflicts:
	drivers/spi/spi-s3c64xx.c

Add compatibles for s3c6410, s5pc100 and s5pc110/s5pv210 boards.
Signed-off-by: NMateusz Krawczuk <m.krawczuk@partner.samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Also improve the error reporting on failure and remove a duplicate put.
This provides a small code saving.
Signed-off-by: NMark Brown <broonie@linaro.org>

subsys_init_call() initializes driver too early.
It's preventing to move DMA channel allocation at the begining
(driver probe).

This patch reduces and simplifies initalization code by
using module_platform_driver() macro.
It's also efficiently delaying driver startup.
Signed-off-by: NLukasz Czerwinski <l.czerwinski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

We always need the device to be runtime PM enabled to use it so just skip
the DMA initialisation not the entire prepare when polling.
Signed-off-by: NMark Brown <broonie@linaro.org>

Since the driver supports only contiguous buffers, there is no need to
manually construct a scatterlist with just a single entry, when there is
a dedicated helper for this purpose.

This patch modifies prepare_dma() function to use available helper instead
of manually creating a scatterlist.
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Comments in linux/spi/spi.h and observed behavior show that .setup()
callback can be called multiple times without corresponding calls to
.cleanup(), what was incorrectly assumed by spi-s3c64xx driver, leading
to failures trying to request CS GPIO multiple times.

This patch modifies the behavior of spi-s3c64xx driver to request CS
GPIO only on first call to .setup() after last .cleanup().
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Not all fields of dma_slave_config struct are being initialized by
prepare_dma() function, leaving those which are not in undefined state,
which can confuse DMA drivers using them.

This patch adds call to memset() to zero the struct before initializing
a subset of its fields.
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Signed-off-by: NMark Brown <broonie@linaro.org>

sdd->ops->request is unsigned int, not unsigned long.
Also, sdd->rx_dma.ch is a 'struct dma_chan *'.
Thus, (void *) is converted to (struct dma_chan *)(unsigned long),
in order to fix possible sparse warnings.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Fix the following build warnings when LPAE is enabled:

drivers/spi/spi-s3c64xx.c:1466:2: warning: format '%x' expects argument of type 'unsigned int', but argument 4 has type
'resource_size_t' [-Wformat]
drivers/spi/spi-s3c64xx.c:1466:2: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type
'resource_size_t' [-Wformat]

Use vsprintf extension %pR to format resource.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Fix the following checkpatch error and warnings:

  ERROR: "(foo*)" should be "(foo *)"
  WARNING: line over 80 characters
  WARNING: quoted string split across lines
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>