Rejecting unsupported values of spi-tx-bus-width and spi-rx-bus-width
may break compatibility with future DTs. Just ignore them, falling back
to Single SPI Transfers.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark Brown <broonie@linaro.org>

The existing timeout value in wait_for_completion_timeout is
calculated from the transfer length and speed with tolerance of 10msec.
This is too low because this is used for error conditions such as
hardware hang etc.
The xfer->speed_hz considered may not be the actual speed set
because the best clock divisor is chosen from a limited set such that
the actual speed <= requested speed. This will lead to timeout being
less than actual transfer time.
Considering acceptable latencies, this timeout can be set to a
value double the expected transfer plus 100 msecs.
This patch adds the same in the core.
Signed-off-by: NHarini Katakam <harinik@xilinx.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

The core implementation of cs_change didn't follow the documentation
which says that cs_change in the middle of the transfer means to briefly
deassert chip select, instead it followed buggy drivers which change the
polarity of chip select.  Use a delay of 10us between deassert and
reassert simply from pulling numbers out of a hat.
Reported-by: NGerhard Sittig <gsi@denx.de>
Signed-off-by: NMark Brown <broonie@linaro.org>

There is no real reason why we require transfers to have a completion and
the only user of the completion now checks to see if one has been provided
before using it so stop enforcing this. This makes it more convenient for
drivers to chain multiple asynchronous transfers together.
Signed-off-by: NMark Brown <broonie@linaro.org>

When xfer->speed_hz is greater than master->max_speed_hz, it's generally safe
to use master->max_speed_hz as transfer speed.
Thus use master->max_speed_hz as transfer speed rather than return error when
xfer->speed_hz > master->max_speed_hz.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NMark Brown <broonie@linaro.org>

Zero length transfer becomes invalid since
"spi: core: Validate length of the transfers in message" commit,
but it should be valid to support an odd device, for example, which
requires long delay between chipselect and the first transfer, etc.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Tested-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Fixes below checkpatch warning:
WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt
+               msleep(10);
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

SPI transfer length should be multiple of SPI word size,
where SPI word size should be power-of-two multiple
Signed-off-by: NIvan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

While backporting 33cf00e5 ("spi: attach/detach SPI device to the ACPI
power domain"), I noticed that the code changes were suboptimal:

* Why use &spi->dev when we have dev at hand?

* After fixing the above, spi is used only once, so we don't really
  need a local variable for it.

This results in the following clean-up.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Prevents spurious compiler warnings.
Signed-off-by: NMark Brown <broonie@linaro.org>

In __spi_validate(), xfer->speed_hz is set to be spi->max_speed_hz if it is not
set for this transfer. However, if spi->max_speed_hz is also not set,
xfer->speed_hz is 0. Some drivers (e.g. au1550, tegra114, tegra20-sflash,
tegra20-slink, etc.) then use below code to avoid setting xfer->speed_hz to 0.

        /* Set speed to the spi max fequency if spi device has not set */
        spi->max_speed_hz = spi->max_speed_hz ? : tspi->spi_max_frequency;

Let's handle it in spi core.
If spi->max_speed_hz is not set, make it default to spi->master->max_speed_hz.
So In __spi_validate() if both xfer->speed_hz and spi->max_speed_hz are not set,
xfer->speed_hz will be set to spi->master->max_speed_hz.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
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>

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: NMark Brown <broonie@linaro.org>

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: NMark Brown <broonie@linaro.org>

Don't wait indefinitely for transfers to complete but time out after 10ms
more than we expect the transfer to take on the wire.
Signed-off-by: NMark Brown <broonie@linaro.org>

This reverts commit e120cc0d.

It causes a NULL pointer dereference with drivers using the generic
spi_transfer_one_message(), which always calls
spi_finalize_current_message(), which zeroes master->cur_msg.

Drivers implementing transfer_one_message() theirselves must always call
spi_finalize_current_message(), even if the transfer failed:

 * @transfer_one_message: the subsystem calls the driver to transfer a single
 *      message while queuing transfers that arrive in the meantime. When the
 *      driver is finished with this message, it must call
 *      spi_finalize_current_message() so the subsystem can issue the next
 *      transfer
Signed-off-by: NGeert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: NMark Brown <broonie@linaro.org>

master->transfer_one returns positive value is not a error.
So set ret to 0 when master->transfer_one returns positive value.
Otherwise, I hit "spi_master spi0: failed to transfer one message from queue"
error when my transfer_one callback returns 1.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
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>

ACPI enumerated devices has ACPI style _HID and _CID strings,
all of these strings can be used for both driver loading and matching.

Currently, in Platform, I2C and SPI bus, the ACPI style driver matching
is supported by invoking acpi_driver_match_device() in bus .match() callback.
But, the module autoloading is still broken.

For example, there is any ACPI device with _HID "INTABCD" that is
enumerated to platform bus, and we have a driver that can probe it.

The driver exports its module_alias as "acpi:INTABCD" use the following code
static const struct acpi_device_id xxx_acpi_match[] = {
        { "INTABCD", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, xxx_acpi_match);

But, unfortunately, the device' modalias is shown as "platform:INTABCD:00",
please refer to modalias_show() and platform_uevent() in
drivers/base/platform.c.
This results in that the driver will not be loaded automatically when the
device node is created, because their modalias do not match.

This also applies to I2C and SPI bus.

With this patch, the device' modalias will be shown as "acpi:INTABCD" as well.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Acked-by: NMark Brown <broonie@linaro.org>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

  - Rephrase the comments about tx/rx_nbits validity checks,
  - Remove the stale comment about SPI_3WIRE (the code it refers to was
    removed in commit 368ca4e0 ("spi:
    Eliminate 3WIRE spi_transfer check")).
Signed-off-by: NGeert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: NMark Brown <broonie@linaro.org>

Commit e13ac47b (spi: Use stable dev_name for ACPI enumerated SPI
slaves) changed the SPI device naming to be based on ACPI device name
instead of carrying bus number and chip select for devices enumerated
from ACPI namespace.

In case of a buggy BIOS that lists multiple SPI devices sharing the same
chip select (even though they should use different) the current code fails
to detect that and allows the devices to be added to the bus.

Fix this by walking through the bus and comparing spi->chip_select instead
of device name. This should work regardless what the device name will be in
future.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

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

This corrects a problem in spi_pump_messages() that leads to an spi
message hanging forever when a call to transfer_one_message() fails.
This failure occurs in my MCP2210 driver when the cs_change bit is set
on the last transfer in a message, an operation which the hardware does
not support.

Rationale
Since the transfer_one_message() returns an int, we must presume that it
may fail.  If transfer_one_message() should never fail, it should return
void.  Thus, calls to transfer_one_message() should properly manage a
failure.

Fixes: ffbbdd21 (spi: create a message queueing infrastructure)
Signed-off-by: NDaniel Santos <daniel.santos@pobox.com>
Signed-off-by: NMark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

Use list_first_entry_or_null() to save a few lines.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Checking for SPI_3WIRE isn't needed.  spi_setup() already prevents 3WIRE
mode from being combined with DUAL or QUAD mode support.  So there is no
need to differentiate between a single bit device with SPI_3WIRE set and
one with without.  It doesn't change the allowed bit widths.
Signed-off-by: NTrent Piepho <tpiepho@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Currently we do a bunch of per-message validation and initialisation in
__spi_async() which is called with the bus lock held. Since none of this
validation depends on the current bus status there's no need to hold the
lock to do it so split it out into a separate __spi_validate() function
which is called prior to taking the bus lock.

This could be slightly neater but keep things simple for now to show the
code motion clearly.

Based on observations from Martin Sperl.
Signed-off-by: NMark Brown <broonie@linaro.org>

devres_add() should be called when the action to be undone succeeded,
not when it failed. Fix the inverted test in devm_spi_register_master()
which was doing the opposite.

The user-visible issue without this fix is:
insmod spi-tegra114.ko
  Assume there's an MTD device on that SPI bus, which creates /dev/mtd0.
rmmod spi-tegra114
  Doesn't remove devices on the SPI bus.
insmod spi-tegra114.ko
  Creates a duplicate SPI device which creates /dev/mtd1.
hexdump -C /dev/mtd0
  That's the old device, which uses an SPI bus hosted by a non-existent
  module, which causes the oops below.

Unable to handle kernel paging request at virtual address bf0017c0
pgd = c0004000
[bf0017c0] *pgd=ad51b811, *pte=00000000, *ppte=00000000
Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM
...
PC is at 0xbf0017c0
LR is at spi_pump_messages+0x15c/0x204
pc : [<bf0017c0>] lr : [<c02f0af8>] psr: 60000113
...

Fixes: 666d5b4c ("spi: core: Add devm_spi_register_master()")
Signed-off-by: NStephen Warren <swarren@nvidia.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>

Current spi bus_num.chip_select "spix.y" based device naming scheme may not
be stable enough to be used in name based matching, for instance within
ALSA SoC subsystem.

This can be problem in PC kind of platforms if there are changes in SPI bus
configuration, amount of busses or probe order.

This patch addresses the problem by using the ACPI device name with
"spi-" prefix for ACPI enumerated SPI slave. For them device name
"spix.y" becomes "spi-INTABCD:ij".
Signed-off-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Modify struct acpi_dev_node to contain a pointer to struct acpi_device
associated with the given device object (that is, its ACPI companion
device) instead of an ACPI handle corresponding to it.  Introduce two
new macros for manipulating that pointer in a CONFIG_ACPI-safe way,
ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the
ACPI_HANDLE() macro to take the above changes into account.
Drop the ACPI_HANDLE_SET() macro entirely and rework its users to
use ACPI_COMPANION_SET() instead.  For some of them who used to
pass the result of acpi_get_child() directly to ACPI_HANDLE_SET()
introduce a helper routine acpi_preset_companion() doing an
equivalent thing.

The main motivation for doing this is that there are things
represented by struct acpi_device objects that don't have valid
ACPI handles (so called fixed ACPI hardware features, such as
power and sleep buttons) and we would like to create platform
device objects for them and "glue" them to their ACPI companions
in the usual way (which currently is impossible due to the
lack of valid ACPI handles).  However, there are more reasons
why it may be useful.

First, struct acpi_device pointers allow of much better type checking
than void pointers which are ACPI handles, so it should be more
difficult to write buggy code using modified struct acpi_dev_node
and the new macros.  Second, the change should help to reduce (over
time) the number of places in which the result of ACPI_HANDLE() is
passed to acpi_bus_get_device() in order to obtain a pointer to the
struct acpi_device associated with the given "physical" device,
because now that pointer is returned by ACPI_COMPANION() directly.
Finally, the change should make it easier to write generic code that
will build both for CONFIG_ACPI set and unset without adding explicit
compiler directives to it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> # on Haswell
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com> # for ATA and SDIO part

Fix the following checkpatch error and warnings.

  ERROR: space required after that ',' (ctx:VxV)
  WARNING: quoted string split across lines
  WARNING: max() should probably be max_t(int, nb, master->num_chipselect)
  WARNING: sizeof *spi should be sizeof(*spi)
  WARNING: sizeof *master should be sizeof(*master)
  WARNING: sizeof x should be sizeof(x)
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

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: NMark Brown <broonie@linaro.org>

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: NMark Brown <broonie@linaro.org>

If the SPI device is enumerated from ACPI namespace (it has an ACPI handle)
it might have ACPI methods that needs to be called in order to transition
the device to different power states (such as _PSx).

We follow what has been done for platform and I2C buses here and attach the
SPI device to the ACPI power domain if the device has an ACPI handle. This
makes sure that the device is powered on when its ->probe() is called.

For non-ACPI devices this patch is a no-op.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There is a minor fault about ACPI enumerated SPI devices with their modalias
attribute. Now modalias is set by device instance not by hardware ID.
For example "spi:INTABCD:00", "spi:INTABCD:01" etc.

This means each device instance gets different modalias which does match
with generated modules.alias. Currently this is not problem as matching can
happen also with "acpi:INTABCD" modalias.

Fix this by using ACPI hardware ID.
Signed-off-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

The dev_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the spi bus code to use the
correct field.
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMark Brown <broonie@linaro.org>

Provide tracepoints for the lifecycle of a message from submission to
completion and for the active time for masters to help with performance
analysis of SPI I/O.
Signed-off-by: NMark Brown <broonie@linaro.org>

Instead of getting the raw property, checking the length, and doing
endian conversion each time, use the OF function
of_property_read_u32() that does all that.

Error messages are slightly improved with error codes from
of_property_read_u32() for different ways the property may be invalid
(missing, too short, etc.)
Signed-off-by: NTrent Piepho <tpiepho@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

request_module() can handle format strings on its own, no need to create
the full module name ourself.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

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: NMark Brown <broonie@linaro.org>