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This reverts commit e4df3a0b62
("i2c: core: Dispose OF IRQ mapping at client removal time")
Calling irq_dispose_mapping() will destroy the mapping and disassociate
the IRQ from the IRQ chip to which it belongs. Keeping it is OK, because
existent mappings are reused properly.
Also, this commit breaks drivers using devm* for IRQ management on
OF-based systems because devm* cleanup happens in device code, after
bus's remove() method returns.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Reported-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[wsa: updated the commit message with findings fromt the other bug report]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Fixes: e4df3a0b62
This patch marks baytrail_i2c_acquire() that it might sleep. Also it chages
while-loop to do-while and, though it is matter of taste, gives a chance to
check one more time before report a timeout.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
It seems the idea behind the cross-check is to prevent acquire semaphore when
there is no release callback and vice versa. Thus, patch fixes a typo.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
There is no need to export functions that are used as the callbacks in the
struct dw_i2c_dev. Otherwise we get the following warnings:
drivers/i2c/busses/i2c-designware-baytrail.c:63:5: warning: symbol 'baytrail_i2c_acquire' was not declared. Should it be static?
drivers/i2c/busses/i2c-designware-baytrail.c:114:6: warning: symbol 'baytrail_i2c_release' was not declared. Should it be static?
While here, do few indentation fixes, remove i2c_dw_eval_lock_support() from
functions exported to the modules and redundant assignment of local sem
variable.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
It seems we have same message for different return values in get_sem() and
baytrail_i2c_acquire(). I suspect this is just a typo, so this patch fixes it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The patch converts hardcoded numerical constants to a named ones.
While here, align the variable name in get_sem() and reset_semaphore().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull i2c updates from Wolfram Sang:
"Summary:
- legacy PM code removed from the core, there were no users anymore
(thanks to Lars-Peter Clausen)
- new driver for Broadcom iProc
- bigger driver updates for designware, rk3x, cadence, ocores
- a bunch of smaller updates and bugfixes"
* 'i2c/for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (31 commits)
i2c: ocores: rework clk code to handle NULL cookie
i2c: designware-baytrail: another fixup for proper Kconfig dependencies
i2c: fix reference to functionality constants definition
i2c: iproc: Add Broadcom iProc I2C Driver
i2c: designware-pci: update Intel copyright line
i2c: ocores: add common clock support
i2c: hix5hd2: add COMPILE_TEST
i2c: clarify comments about the dev_released completion
i2c: ocores: fix clock-frequency binding usage
i2c: tegra: Maintain CPU endianness
i2c: designware-baytrail: use proper Kconfig dependencies
i2c: designware: Do not calculate SCL timing parameters needlessly
i2c: do not try to load modules for of-registered devices
i2c: designware: Add Intel Baytrail PMIC I2C bus support
i2c: designware: Add i2c bus locking support
of: i2c: Add i2c-mux-idle-disconnect DT property to PCA954x mux driver
i2c: designware: use {readl|writel}_relaxed instead of readl/writel
i2c: designware-pci: no need to provide clk_khz
i2c: designware-pci: remove Moorestown support
i2c: imx: whitespace and checkpatch cleanup
...
For, !HAVE_CLK the clk API returns a NULL cookie. Rework the
initialization code to handle that. If clk_get_rate() delivers 0, we use
the fallback mechanisms. The patch is pretty easy when ignoring white
space issues (git diff -b).
Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Pull kconfig updates from Michal Marek:
"Yann E Morin was supposed to take over kconfig maintainership, but
this hasn't happened. So I'm sending a few kconfig patches that I
collected:
- Fix for missing va_end in kconfig
- merge_config.sh displays used if given too few arguments
- s/boolean/bool/ in Kconfig files for consistency, with the plan to
only support bool in the future"
* 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kconfig: use va_end to match corresponding va_start
merge_config.sh: Display usage if given too few arguments
kconfig: use bool instead of boolean for type definition attributes
IOSF_MBI is tristate. Baytrail driver isn't.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add initial support to the Broadcom iProc I2C controller found in the
iProc family of SoCs.
The iProc I2C controller has separate internal TX and RX FIFOs, each has
a size of 64 bytes. The iProc I2C controller supports two bus speeds
including standard mode (100kHz) and fast mode (400kHz)
Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
While here, fix few indentations issues across the code. There is no functional
change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Allow bus clock specification as a common clock handle. This makes this
controller easier to use in a setup based on common clock framework.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Commit 9439eb3ab9 ("asm-generic: io: implement relaxed
accessor macros as conditional wrappers") has added
{read,write}{b,w,l,q}_relaxed to include/asm-generic/io.h.
So COMPILE_TEST can be added.
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
There was quite some confusion why this completion is there and if it is
still necessary. Sadly, it is. However, let's improve the comments and
share what we rediscovered.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
clock-frequency property is meant to control the bus frequency for i2c bus
drivers, but it was incorrectly used to specify i2c controller input clock
frequency.
Introduce new attribute, opencores,ip-clock-frequency, that specifies i2c
controller clock frequency and make clock-frequency attribute compatible
with other i2c drivers. Maintain backwards compatibility in case
opencores,ip-clock-frequency attribute is missing.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
DMA read requests could miss proper termination, so two more bytes would
have been read via PIO overwriting the end of the buffer with wrong
data. Make DMA stop handling more readable while we are here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Make the slave support depend on CONFIG_I2C_SLAVE. Otherwise it gets
included unconditionally, even when it is not needed.
I2C bus drivers which implement slave support must select
I2C_SLAVE.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Support CPU BE mode by adding endianness conversion for memcpy interactions.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
IOSF_MBI depends on PCI, so we should not select it but depend on it.
This ensures also we compile on X86 only, other archs will break because
of an arch specific include. Also depend on ACPI since this driver uses
it.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Do SCL timing parameter calculation conditionally depending are custom
parameters provided since calculated values will get instantly overwritten
by provided parameters.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Trying to register an I2C device asynchronously (via async_schedule() call)
results in an ugly warning from request_module() warning about potential
deadlock (because request_module tries to wait for async works to
complete). While we could try to switch to request_module_nowait(), other
buses, as well as I2C itself when not using device tree, do not try to load
modules, but rather rely on the standard infrastructure (udev) to execute
module loading, and we should be doing the same.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch implements an I2C bus sharing mechanism between the host and platform
hardware on select Intel BayTrail SoC platforms using the X-Powers AXP288 PMIC.
On these platforms access to the PMIC must be shared with platform hardware. The
hardware unit assumes full control of the I2C bus and the host must request
access through a special semaphore. Hardware control of the bus also makes it
necessary to disable runtime pm to avoid interfering with hardware transactions.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Adds support for acquiring and releasing a hardware bus lock in the i2c
designware core transfer function. This is needed for i2c bus controllers
that are shared with but not controlled by the kernel.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch solves deadlock between clock prepare mutex and regmap mutex reported
by Tomasz Figa in [1] by implementing solution from [2]: "always leave the clock
of the i2c controller in a prepared state".
[1] https://lkml.org/lkml/2014/7/2/171
[2] https://lkml.org/lkml/2014/7/2/207
On each i2c transfer handled by s3c24xx_i2c_xfer(), clk_prepare_enable() was
called, which calls clk_prepare() then clk_enable(). clk_prepare() takes
prepare_lock mutex before proceeding. Note that i2c transfer functions are
invoked from many places in kernel, typically with some other additional lock
held.
It may happen that function on CPU1 (e.g. regmap_update_bits()) has taken a
mutex (i.e. regmap lock mutex) then it attempts i2c communication in order to
proceed (so it needs to obtain clock related prepare_lock mutex during transfer
preparation stage due to clk_prepare() call). At the same time other task on
CPU0 wants to operate on clock (e.g. to (un)prepare clock for some other reason)
so it has taken prepare_lock mutex.
CPU0: CPU1:
clk_disable_unused() regulator_disable()
clk_prepare_lock() map->lock(map->lock_arg)
regmap_read() s3c24xx_i2c_xfer()
map->lock(map->lock_arg) clk_prepare_lock()
Implemented solution from [2] leaves i2c clock prepared. Preparation is done in
s3c24xx_i2c_probe() function. Without this patch, it is immediately unprepared
by clk_disable_unprepare() call. I've replaced this call with clk_disable() and
I've added clk_unprepare() call in s3c24xx_i2c_remove().
The s3c24xx_i2c_xfer() function now uses clk_enable() instead of
clk_prepare_enable() (and clk_disable() instead of clk_unprepare_disable()).
Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Due to a copy&paste error, the last byte of the shared memory was not
accessible via sysfs.
Reported-by: Debora Grosse <debora@mds.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add i2c-mux-idle-disconnect device tree property to PCA954x mux driver. The new
property forces the multiplexer to disconnect child buses in idle state. This is
used, for example, when there are several multiplexers on the same bus and the
devices on the underlying buses might have same I2C addresses.
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
[wsa: added a newline]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
readl/writel is too expensive especially on Cortex A9 w/ outer L2 cache.
This introduces i2c read/write delays on Marvell BG2/BG2Q SoCs when there
are heavy L2 cache maintenance operations at the same time.
The driver does not perform DMA, so it's safe to use the relaxed version.
From another side, the relaxed io accessor macros are available on all
architectures now, so we can use the relaxed versions instead.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The clk_khz field makes sense only if SS counters are not provided. Since we
provide them for Haswell and Baytrail explicitly we may omit the clk_khz
parameter.
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The Moorestown support bits were removed few years ago. This is a follow up to
that changes.
Suggested-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch fixes up some whitespace issues and addresses a few
checkpatch warnings.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Declaring attribute groups can be done with macros these days, let's use
them for consistency and readability reasons. Also, put the ATTR macros
directly below the referenced functions while we are here.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The ret variable is set and never used in the error path of i2c_imx_dma_request.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
ACPI specification allows I2C devices with multiple addresses. The current
implementation goes over all addresses and assigns the last one to the
device. This is typically not the primary address of the device.
Instead of doing that we assign the first address to the device and then
let the driver handle rest of the addresses as it wishes.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cadence I2C controller has the following bugs:
- completion indication is not given to the driver at the end of
a read/receive transfer with HOLD bit set.
- Invalid read transaction are generated on the bus when HW timeout
condition occurs with HOLD bit set.
As a result of the above, if a set of messages to be transferred with
repeated start includes any message following a read message,
completion is never indicated and timeout occurs.
Hence a check is implemented to return -EOPNOTSUPP for such sequences.
Signed-off-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Vishnu Motghare <vishnum@xilinx.com>
[wsa: fixed some whitespaces]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
wait_for_completion_timeout does not return negative values so
"result" handling here should be simplified to cover the actually
possible cases only.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
On Rockchip I2C the controller drops SDA low slightly too soon to meet
the "repeated start" requirements.
>From my own experimentation over a number of rates:
- controller appears to drop SDA at .875x (7/8) programmed clk high.
- controller appears to keep SCL high for 2x programmed clk high.
The first rule isn't enough to meet tSU;STA requirements in
Standard-mode on the system I tested on. The second rule is probably
enough to meet tHD;STA requirements in nearly all cases (especially
after accounting for the first), but it doesn't hurt to account for it
anyway just in case.
Even though the repeated start requirement only need to be accounted
for during a small part of the transfer, we'll adjust the timings for
the whole transfer to meet it. I believe that adjusting the timings
in just the right place to switch things up for repeated start would
require several extra interrupts and that doesn't seem terribly worth
it.
With this change and worst case rise/fall times, I see 100kHz i2c
going to ~85kHz. With slightly optimized rise/fall (800ns / 50ns) I
see i2c going to ~89kHz. Fast-mode isn't affected much because
tSU;STA is shorter relative to tHD;STA there.
As part of this change we needed to account for the SDA falling time.
The specification indicates that this should be the same, but we'll
follow Designware's lead and add a binding. Note that we deviate from
Designware and assign the default SDA falling time to be the same as
the SCL falling time, which is incredibly likely.
Signed-off-by: Doug Anderson <dianders@chromium.org>
[wsa: rebased to i2c/for-next]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The number of clock cycles to be written into the CLKDIV register
that determines the I2C clk high phase includes the rise time.
So to meet the timing requirements defined in the I2C specification
which defines the minimal time SCL has to be high, the rise time
has to taken into account. The same applies to the low phase with
falling time.
In my test on RK3288-Pink2 board, which is not an upstream board yet,
if external pull-up resistor is 4.7K, rise_ns is about 700ns.
So the measured high_ns is about 3900ns, which is less than 4000ns
(the minimum high_ns in I2C specification for Standard-mode).
To fix this bug min_low_ns should include fall time and min_high_ns
should include rise time.
This patch merged the patch from chromium project which can get the
rise and fall times for signals from the device tree. This allows us
to more accurately calculate timings. see:
https://chromium-review.googlesource.com/#/c/232774/
Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
[wsa: fixed a typo in the docs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The I2C controller sends a NACK to the slave when transfer size register
reaches zero, irrespective of the hold bit. So, in order to handle transfers
greater than 252 bytes, the transfer size register has to be maintained at a
value >= 1. This patch implements the same.
The interrupt status is cleared at the beginning of the isr instead of
the end, to avoid missing any interrupts.
Signed-off-by: Harini Katakam <harinik@xilinx.com>
[wsa: added braces around else branch]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
CPPCHECK rightfully says:
drivers/i2c/busses/i2c-pmcmsp.c:151: style: The function 'pmcmsptwi_reg_to_clock' is never used.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Support for keyword 'boolean' will be dropped later on.
No functional change.
Reference: http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com
Signed-off-by: Christoph Jaeger <cj@linux.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
There haven't been any I2C driver that use the legacy suspend/resume
callbacks for a while now and new drivers are supposed to use PM ops. So
remove support for legacy suspend/resume for I2C drivers.
Since there aren't any special bus specific things to do during
suspend/resume and since the PM core will automatically fallback directly to
using the device's PM ops if no bus PM ops are specified there is no need to
have any I2C bus PM ops.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull more i2c updates from Wolfram Sang:
"Included are two bugfixes needing some bigger refactoring (sh_mobile:
deferred probe with DMA, mv64xxx: fix offload support) and one
deprecated driver removal I thought would go in via ppc but I
misunderstood. It has a proper ack from BenH"
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: sh_mobile: fix uninitialized var when debug is enabled
macintosh: therm_pm72: delete deprecated driver
i2c: sh_mobile: I2C_SH_MOBILE should depend on HAS_DMA
i2c: sh_mobile: rework deferred probing
i2c: sh_mobile: refactor DMA setup
i2c: mv64xxx: rework offload support to fix several problems
i2c: mv64xxx: use BIT() macro for register value definitions
The highlight is the series that reworks the idle management on powernv, which
allows us to use deeper idle states on those machines.
There's the fix from Anton for the "BUG at kernel/smpboot.c:134!" problem.
An i2c driver for powernv. This is acked by Wolfram Sang, and he asked that we
take it through the powerpc tree.
A fix for audit from rgb at Red Hat, acked by Paul Moore who is one of the audit
maintainers.
A patch from Ben to export the symbol map of our OPAL firmware as a sysfs file,
so that tools can use it.
Also some CXL fixes, a couple of powerpc perf fixes, a fix for smt-enabled, and
the patch to add __force to get_user() so we can use bitwise types.
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Merge tag 'powerpc-3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull second batch of powerpc updates from Michael Ellerman:
"The highlight is the series that reworks the idle management on
powernv, which allows us to use deeper idle states on those machines.
There's the fix from Anton for the "BUG at kernel/smpboot.c:134!"
problem.
An i2c driver for powernv. This is acked by Wolfram Sang, and he
asked that we take it through the powerpc tree.
A fix for audit from rgb at Red Hat, acked by Paul Moore who is one of
the audit maintainers.
A patch from Ben to export the symbol map of our OPAL firmware as a
sysfs file, so that tools can use it.
Also some CXL fixes, a couple of powerpc perf fixes, a fix for
smt-enabled, and the patch to add __force to get_user() so we can use
bitwise types"
* tag 'powerpc-3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
powerpc/powernv: Ignore smt-enabled on Power8 and later
powerpc/uaccess: Allow get_user() with bitwise types
powerpc/powernv: Expose OPAL firmware symbol map
powernv/powerpc: Add winkle support for offline cpus
powernv/cpuidle: Redesign idle states management
powerpc/powernv: Enable Offline CPUs to enter deep idle states
powerpc/powernv: Switch off MMU before entering nap/sleep/rvwinkle mode
i2c: Driver to expose PowerNV platform i2c busses
powerpc: add little endian flag to syscall_get_arch()
power/perf/hv-24x7: Use kmem_cache_free() instead of kfree
powerpc/perf/hv-24x7: Use per-cpu page buffer
cxl: Unmap MMIO regions when detaching a context
cxl: Add timeout to process element commands
cxl: Change contexts_lock to a mutex to fix sleep while atomic bug
powerpc: Secondary CPUs must set cpu_callin_map after setting active and online
If NO_DMA=y:
drivers/built-in.o: In function `sh_mobile_i2c_dma_unmap':
i2c-sh_mobile.c:(.text+0x60de42): undefined reference to `dma_unmap_single'
drivers/built-in.o: In function `sh_mobile_i2c_xfer_dma':
i2c-sh_mobile.c:(.text+0x60df22): undefined reference to `dma_map_single'
i2c-sh_mobile.c:(.text+0x60df2e): undefined reference to `dma_mapping_error'
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
DMA is opt-in for this driver. So, we can't use deferred probing for
requesting DMA channels in probe, because our driver would get endlessly
deferred if DMA support is compiled in AND the DMA driver is missing.
Because we can't know when the DMA driver might show up, we always try
again when a DMA transfer would be possible. The downside is that there
is more overhead for setting up PIO transfers under the above scenario.
But well, having DMA enabled and the proper DMA driver missing looks
like a broken or test config anyhow.
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Refactor DMA setup to keep the errno so we can implement better
deferred probe support in the next step.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Originally, the I2C controller supported by the i2c-mv64xxx driver
requires a lot of software support: an interrupt is generated at each
step of an I2C transaction (after the start bit, after sending the
address, etc.) and the driver is in charge of re-programming the I2C
controller to do the next step of the I2C transaction. This explains
the fairly complex state machine that the driver has.
On Marvell Armada XP and later processors (Armada 375, 38x, etc.), the
I2C controller was extended with a part called the "I2C Bridge", which
allows to offload the I2C transaction completely to the
hardware. Initial support for this mechanism was added in commit
930ab3d403 ("i2c: mv64xxx: Add I2C Transaction Generator support").
However, the implementation done in this commit has two related
issues, which this commit fixes by completely changing how the offload
implementation is done:
* SMBus read transfers, where there is one write to select the
register immediately followed in the same transaction by one read,
were making the processor hang. This was easier visible on the
Marvell Armada XP WRT1900AC platform using a driver for an I2C LED
controller, or on other Armada XP platforms by using a simple
'i2cget' command to read an I2C EEPROM.
* The implementation was based on the fact that the offload engine
was re-programmed to transfer each message of an I2C xfer: this
meant that each message sent with the offload engine was starting
with a normal I2C start sequence. However, the I2C subsystem
assumes that all messages belonging to the same xfer will use the
so-called "repeated start" so that the entire I2C xfer is seen as
one transfer by the I2C devices and cannot be interrupt by other
I2C masters on the same bus.
In fact, the "I2C Bridge" allows to offload three types of xfer:
- xfer of one write message
- xfer of one read message
- xfer of one write message followed by one read message
For all other situations, we have to fallback to not using the "I2C
Bridge" in order to get proper I2C semantics.
Therefore, this commit reworks the offload implementation to put it
not at the message level, but at the xfer level: in the
mv64xxx_i2c_xfer() function, we decide if the transaction can be
offloaded (in which case it is handled by the
mv64xxx_i2c_offload_xfer() function), or otherwise it is handled by
the slow path (implemented in the existing mv64xxx_i2c_execute_msg()).
This allows to simplify the state machine, which no longer needs to
have any state related to the offload implementation: the offload
implementation is now completely separated from the slow path (with
the exception of the interrupt handler, of course).
In summary:
- mv64xxx_i2c_can_offload() will analyze an I2C xfer and decided of
the "I2C Bridge" can be used to offload it or not.
- mv64xxx_i2c_offload_xfer() will actually program the "I2C Bridge"
to offload one xfer (of either one or two messages), and block
using mv64xxx_i2c_wait_for_completion() until the xfer completes.
- The interrupt handler mv64xxx_i2c_intr() is modified to push the
offload related code to a separate function,
mv64xxx_i2c_intr_offload(). It will take care of reading the
received data if needed.
This commit was tested on:
- Armada XP OpenBlocks AX3-4 (EEPROM on I2C and RTC on I2C)
- Armada XP WRT1900AC (LED controller on I2C)
- Armada XP GP (EEPROM on I2C)
Fixes: 930ab3d403 ("i2c: mv64xxx: Add I2C Transaction Generator support")
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[wsa: fixed checkpatch warnings]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
