summaryrefslogtreecommitdiff
path: root/drivers/i2c
AgeCommit message (Collapse)Author
2015-02-21Merge branch 'i2c/for-3.20' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 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 ...
2015-02-20i2c: ocores: rework clk code to handle NULL cookieWolfram Sang
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>
2015-02-19Merge branch 'kconfig' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 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
2015-02-19i2c: designware-baytrail: another fixup for proper Kconfig dependenciesWolfram Sang
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>
2015-02-17i2c: iproc: Add Broadcom iProc I2C DriverRay Jui
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>
2015-02-17i2c: designware-pci: update Intel copyright lineAndy Shevchenko
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>
2015-02-05i2c: ocores: add common clock supportMax Filippov
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>
2015-02-05i2c: hix5hd2: add COMPILE_TESTZhangfei Gao
Commit 9439eb3ab9d1ec ("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>
2015-02-05i2c: clarify comments about the dev_released completionWolfram Sang
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>
2015-02-05i2c: ocores: fix clock-frequency binding usageMax Filippov
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>
2015-01-30i2c: sh_mobile: terminate DMA reads properlyWolfram Sang
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>
2015-01-26i2c: Only include slave support if selectedJean Delvare
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>
2015-01-26i2c: tegra: Maintain CPU endiannessDmitry Osipenko
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>
2015-01-26i2c: designware-baytrail: use proper Kconfig dependenciesWolfram Sang
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>
2015-01-26i2c: designware: Do not calculate SCL timing parameters needlesslyJarkko Nikula
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>
2015-01-26i2c: do not try to load modules for of-registered devicesDmitry Torokhov
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>
2015-01-26i2c: designware: Add Intel Baytrail PMIC I2C bus supportDavid Box
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>
2015-01-26i2c: designware: Add i2c bus locking supportDavid Box
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>
2015-01-24i2c: s3c2410: fix ABBA deadlock by keeping clock preparedPaul Osmialowski
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
2015-01-24i2c: slave-eeprom: fix boundary check when using sysfsWolfram Sang
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>
2015-01-23of: i2c: Add i2c-mux-idle-disconnect DT property to PCA954x mux driverAlexander Sverdlin
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>
2015-01-23i2c: designware: use {readl|writel}_relaxed instead of readl/writelJisheng Zhang
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>
2015-01-23i2c: designware-pci: no need to provide clk_khzAndy Shevchenko
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>
2015-01-23i2c: designware-pci: remove Moorestown supportAndy Shevchenko
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>
2015-01-22i2c: imx: whitespace and checkpatch cleanupPhilipp Zabel
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>
2015-01-22i2c: simplify boilerplate code for attribute groupsWolfram Sang
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>
2015-01-14i2c: imx: remove unused return value assignmentsPhilipp Zabel
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>
2015-01-14i2c: ACPI: Pick the first address if device has multipleMika Westerberg
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>
2015-01-14i2c: cadence: Check for errata condition involving master receiveHarini Katakam
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>
2015-01-13i2c: imx: fix handling of wait_for_completion_timeout resultNicholas Mc Guire
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>
2015-01-13i2c: rk3x: Account for repeated start time requirementDoug Anderson
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>
2015-01-13i2c: rk3x: fix bug that cause measured high_ns doesn't meet I2C specificationaddy ke
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>
2015-01-13i2c: cadence: Handle > 252 byte transfersHarini Katakam
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>
2015-01-13i2c: pmcmsp: remove dead codeWolfram Sang
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>
2015-01-07kconfig: use bool instead of boolean for type definition attributesChristoph Jaeger
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>
2014-12-22i2c: Remove support for legacy PMLars-Peter Clausen
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>
2014-12-20Merge branch 'i2c/for-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 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
2014-12-20i2c: sh_mobile: fix uninitialized var when debug is enabledWolfram Sang
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-12-19Merge tag 'powerpc-3.19-2' of ↵Linus Torvalds
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
2014-12-17i2c: sh_mobile: I2C_SH_MOBILE should depend on HAS_DMAGeert Uytterhoeven
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>
2014-12-17i2c: sh_mobile: rework deferred probingWolfram Sang
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>
2014-12-17i2c: sh_mobile: refactor DMA setupWolfram Sang
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>
2014-12-17i2c: mv64xxx: rework offload support to fix several problemsThomas Petazzoni
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 930ab3d403a ("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: 930ab3d403ae ("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>
2014-12-17i2c: mv64xxx: use BIT() macro for register value definitionsThomas Petazzoni
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-12-15Merge tag 'driver-core-3.19-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core update from Greg KH: "Here's the set of driver core patches for 3.19-rc1. They are dominated by the removal of the .owner field in platform drivers. They touch a lot of files, but they are "simple" changes, just removing a line in a structure. Other than that, a few minor driver core and debugfs changes. There are some ath9k patches coming in through this tree that have been acked by the wireless maintainers as they relied on the debugfs changes. Everything has been in linux-next for a while" * tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits) Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries" fs: debugfs: add forward declaration for struct device type firmware class: Deletion of an unnecessary check before the function call "vunmap" firmware loader: fix hung task warning dump devcoredump: provide a one-way disable function device: Add dev_<level>_once variants ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries ath: use seq_file api for ath9k debugfs files debugfs: add helper function to create device related seq_file drivers/base: cacheinfo: remove noisy error boot message Revert "core: platform: add warning if driver has no owner" drivers: base: support cpu cache information interface to userspace via sysfs drivers: base: add cpu_device_create to support per-cpu devices topology: replace custom attribute macros with standard DEVICE_ATTR* cpumask: factor out show_cpumap into separate helper function driver core: Fix unbalanced device reference in drivers_probe driver core: fix race with userland in device_add() sysfs/kernfs: make read requests on pre-alloc files use the buffer. sysfs/kernfs: allow attributes to request write buffer be pre-allocated. fs: sysfs: return EGBIG on write if offset is larger than file size ...
2014-12-14Merge branch 'i2c/for-3.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux Pull i2c updates from Wolfram Sang: "For 3.19, the I2C subsystem has to offer special candy this time. Right in time for Christmas :) - I2C slave framework: finally, a generic mechanism for Linux being an I2C slave (if the bus driver supports that). Docs are still missing but will come later this cycle, the code is good enough to go. - I2C muxes represent their topology in sysfs much more detailed. This will help users to navigate around much easier. - irq population of i2c clients is now done at probe time, not device creation time, to have better support for deferred probing. - new drivers for Imagination SCB, Amlogic Meson - DMA support added for Freescale IMX, Renesas SHMobile - slightly bigger driver updates to OMAP, i801, AT91, and rk3x (mostly quirk handling, timing updates, and using better kernel interfaces) - eeprom driver can now write with byte-access (very slow, but OK to have) - and the bunch of smaller fixes, cleanups, ID updates..." * 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits) i2c: sh_mobile: remove unneeded DMA mask i2c: rcar: add slave support i2c: slave-eeprom: add eeprom simulator driver i2c: core changes for slave support MAINTAINERS: add I2C dt bindings also to I2C realm i2c: designware: Fix falling time bindings doc i2c: davinci: switch to use platform_get_irq Documentation: i2c: Use PM ops instead of legacy suspend/resume i2c: sh_mobile: optimize irq entry i2c: pxa: add support for SCCB devices omap: i2c: don't check bus state IP rev3.3 and earlier i2c: s3c2410: Handle i2c sys_cfg register in i2c driver i2c: rk3x: add Kconfig dependency on COMMON_CLK i2c: omap: add notes related to i2c multimaster mode i2c: omap: don't reset controller if Arbitration Lost detected i2c: omap: implement workaround for handling invalid BB-bit values i2c: omap: cleanup register definitions i2c: rk3x: handle dynamic clock rate changes correctly i2c: at91: enable probe deferring on dma channel request i2c: at91: remove legacy DMA support ...
2014-12-14i2c: Driver to expose PowerNV platform i2c bussesNeelesh Gupta
The patch exposes the available i2c busses on the PowerNV platform to the kernel and implements the bus driver to support i2c and smbus commands. The driver uses the platform device infrastructure to probe the busses on the platform and registers them with the i2c driver framework. Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Wolfram Sang <wsa@the-dreams.de> (I2C part, excluding the bindings) Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-11i2c: sh_mobile: remove unneeded DMA maskWolfram Sang
We don't need the mask since we obtain the channels via DT. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-12-11i2c: rcar: add slave supportWolfram Sang
The first I2C slave provider using the new generic interface. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-12-11i2c: slave-eeprom: add eeprom simulator driverWolfram Sang
The first user of the i2c-slave interface is an eeprom simulator. It is a shared memory which can be accessed by the remote master via I2C and locally via sysfs. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>