summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-bcm2835.c
Commit message (Collapse)AuthorAgeFilesLines
* spi: bcm2835: Remove unnecessary workaround to call gpio_set_valueAxel Lin2016-02-151-5/+0
| | | | | | | | | This should be fixed by commit 4c02cba18cc9 ("pinctrl: bcm2835: Fix initial value for direction_output") Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
*-. Merge remote-tracking branches 'spi/topic/ath97', 'spi/topic/atmel', ↵Mark Brown2015-11-041-7/+7
|\ \ | | | | | | | | | 'spi/topic/au1550', 'spi/topic/bcm2835' and 'spi/topic/bcm2835aux' into spi-next
| | * spi: bcm2835: change initialization order and switch to platform_get_irqMartin Sperl2015-10-161-7/+7
| |/ | | | | | | | | | | | | | | | | | | Change the initialization order of the HW so that the interrupt is only requested after the HW is initialized Also the use of irq_of_parse_and_map is replaced by platform_get_irq. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
| |
| \
*-. \ Merge remote-tracking branches 'spi/fix/atmel', 'spi/fix/bcm2835', ↵Mark Brown2015-09-221-3/+3
|\ \ \ | |_|/ |/| | | | | 'spi/fix/doc', 'spi/fix/mediatek', 'spi/fix/meson', 'spi/fix/mtk' and 'spi/fix/pxa2xx' into spi-linus
| | * spi: bcm2835: BUG: fix wrong use of PAGE_MASKMartin Sperl2015-09-101-3/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a bug in the alignment checking of transfers, that results in DMA not being used for un-aligned transfers that do not cross page-boundries, which is valid. This is due to a missconception of the meaning PAGE_MASK when implementing that check originally - (PAGE_SIZE - 1) should have been used instead. Also fixes a copy/paste error. Reported-by: <robert@axium.co.nz> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
* | spi: bcm2835: fix overflow in calculation of transfer timeMartin Sperl2015-07-291-4/+6
| | | | | | | | | | | | | | | | | | | | | | This resulted in the use of polling mode when other approaches (dma or interrupts) would have been more appropriate. Happened for transfers longer than 477 bytes. Reported-by: Noralf Tronnes <noralf@tronnes.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | spi: bcm2835: set up spi-mode before asserting cs-gpioMartin Sperl2015-07-291-5/+23
|/ | | | | | | | | | | | | | | | | | | | | | | | When using reverse polarity for clock (spi-cpol) on a device the clock line gets altered after chip-select has been asserted resulting in an additional clock beat, which confuses hardware. This did not show when using native-CS, as the same register is used to control cs as well as polarity, so the changes came into effect at the same time. Unfortunately this is not true with gpio-cs. To avoid this situation this patch moves the setup of polarity (spi-cpol and spi-cpha) outside of the chip-select into prepare_message, which is run prior to asserting chip-select. Also fixes resetting 3-wire mode after use of rx-mode, so that a 3-Wire sequence TX, RX, TX works as well (right now it runs TX, RX, RX instead) Reported-by: Noralf Tronnes <noralf@tronnes.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
* spi: bcm2835: bcm2835_dma_release() can be statickbuild test robot2015-05-121-2/+2
| | | | | Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix kbuild compile warnings/errors and a typoMartin Sperl2015-05-121-3/+5
| | | | | | | | | | | | | | | fixes several warnings/error emmitted by the kbuild system: * warn: cast from pointer to integer of different size using size_t instead of u32 * error: 'SZ_4K' undeclared moved to PAGE_SIZE and PAGE_MASK instead Review showed also a typo in the same code where tx_buff was checked twice instead of checking both rx and tx_buff. Reported by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enable dma modes for transfers meeting certain conditionsMartin Sperl2015-05-111-2/+301
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conditions per spi_transfer are: * transfer.len >= 96 bytes (to avoid mapping overhead costs) * transfer.len < 65536 bytes (limitaion by spi-hw block - could get extended) * an individual scatter/gather transfer length must be a multiple of 4 for anything but the last transfer - spi-hw block limit. (some shortcut has been taken in can_dma to avoid unnecessary mapping of pages which, for which there is a chance that there is a split with a transfer length not a multiple of 4) If it becomes a necessity these restrictions can get removed by additional code. Note that this patch requires a patch to dma-bcm2835.c by Noralf to enable scatter-gather mode inside the dmaengine, which has not been merged yet. That is why no patch to arch/arm/boot/dts/bcm2835.dtsi is included - the code works as before without dma when tx/rx are not set, but it writes a message warning about dma not used: spi-bcm2835 20204000.spi: no tx-dma configuration found - not using dma mode To enable dma-mode add the following lines to the device-tree: dmas = <&dma 6>, <&dma 7>; dma-names = "tx", "rx"; Tested-by: Noralf Trønnes <noralf@tronnes.org> (private communication) Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fallback to interrupt for polling timeouts exceeding 2 jiffiesMartin Sperl2015-04-271-37/+50
| | | | | | | | | | | | | | | | | | The polling mode of the driver is designed for transfers that run less than 30us - it will only execute under those circumstances. So it should run comfortably without getting interrupted by the scheduler. But there are situations where the raspberry pi is so overloaded that it can take up to 80 jiffies until the polling thread gets rescheduled - this has been observed especially under heavy IO situations. In such a situation we now fall back to the interrupt handler and log the situation at debug level. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: change timeout of polling driver to 1sMartin Sperl2015-04-271-3/+2
| | | | | | | | | | | | | | The way that the timeout code is written in the polling function the timeout does also trigger when interrupted or rescheduled while in the polling loop. This patch changes the timeout from effectively 20ms (=2 jiffies) to 1 second and removes the time that the transfer really takes out of the computation, as - per design - this is <30us and the jiffie resolution is 10ms so that does not make any difference what so ever. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enabling polling mode for transfers shorter than 30usMartin Sperl2015-04-101-26/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | In cases of short transfer times the CPU is spending lots of time in the interrupt handler and scheduler to reschedule the worker thread. Measurements show that we have times where it takes 29.32us to between the last clock change and the time that the worker-thread is running again returning from wait_for_completion_timeout(). During this time the interrupt-handler is running calling complete() and then also the scheduler is rescheduling the worker thread. This time can vary depending on how much of the code is still in CPU-caches, when there is a burst of spi transfers the subsequent delays are in the order of 25us, so the value of 30us seems reasonable. With polling the whole transfer of 4 bytes at 10MHz finishes after 6.16us (CS down to up) with the real transfer (clock running) taking 3.56us. So the efficiency has much improved and is also freeing CPU cycles, reducing interrupts and context switches. Because of the above 30us seems to be a reasonable limit for polling. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: transform native-cs to gpio-cs on first spi_setupMartin Sperl2015-04-101-5/+44
| | | | | | | | | | | | | | | | | Transforms the bcm-2835 native SPI-chip select to their gpio-cs equivalent. This allows for some support of some optimizations that are not possible due to HW-gliches on the CS line - especially filling the FIFO before enabling SPI interrupts (by writing to CS register) while the transfer is already in progress (See commit: e3a2be3030e2) This patch also works arround some issues in bcm2835-pinctrl which does not set the value when setting the GPIO as output - it just sets up output and (typically) leaves the GPIO as low. When a fix for this is merged then this gpio_set_value can get removed from bcm2835_spi_setup. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fill FIFO before enabling interrupts to reduce interrupts/messageMartin Sperl2015-03-291-0/+16
| | | | | | | | | | | | | | To reduce the number of interrupts/message we fill the FIFO before enabling interrupts - for short messages this reduces the interrupt count from 2 to 1 interrupt. There have been rare cases where short (<200ns) chip-select switches with native CS have been observed during such operation, this is why this optimization is only enabled for GPIO-CS. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix code formatting issueMartin Sperl2015-03-291-2/+1
| | | | | | Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: move to the transfer_one driver modelMartin Sperl2015-03-261-88/+124
| | | | | | | | | | | | | | | | | | | | | | This also allows for GPIO-CS to get used removing the limitation of 2/3 SPI devises on the SPI bus. Fixes: spi-cs-high with native CS with multiple devices on the spi-bus resetting the chip selects to "normal" polarity after a finished transfer. No other functionality/improvements added. Tested with the following 4 devices on the spi-bus: * mcp2515 with native CS * mcp2515 with gpio CS * fb_st7735r with native CS (plus spi-cs-high via transistor inverting polarity) * enc28j60 with gpio-CS Tested-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: enable support of 3-wire modeMartin Sperl2015-03-231-1/+5
| | | | | Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: clock divider can be a multiple of 2Martin Sperl2015-03-231-2/+3
| | | | | | | | The official documentation is wrong in this respect. Has been tested empirically for dividers 2-1024 Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fill/drain SPI-fifo as much as possible during interruptMartin Sperl2015-03-231-61/+17
| | | | | | | | | | | | | | | Implement the recommendation from the BCM2835 data-sheet with regards to polling drivers to fill/drain the FIFO as much data as possible also for the interrupt-driven case (which this driver is making use of). This means that for long transfers (>64bytes) we need one interrupt every 64 bytes instead of every 12 bytes, as the FIFO is 16 words (not bytes) wide. Tested with mcp251x (can bus), fb_st7735 (TFT framebuffer device) and enc28j60 (ethernet) drivers. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: bcm2835: fix all checkpath --strict messagesMartin Sperl2015-03-201-7/+11
| | | | | | | | | | | | | | | | | The following errors/warnings issued by checkpatch.pl --strict have been fixed: drivers/spi/spi-bcm2835.c:182: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:191: CHECK: braces {} should be used on all arms of this statement drivers/spi/spi-bcm2835.c:234: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:256: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:271: CHECK: Alignment should match open parenthesis drivers/spi/spi-bcm2835.c:346: CHECK: Alignment should match open parenthesis total: 0 errors, 0 warnings, 6 checks, 403 lines checked In 2 locations the arguments had to get split/moved to the next line so that the line width stays below 80 chars. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: Remove FSF mailing addressesJarkko Nikula2014-12-221-4/+0
| | | | | Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
* spi: drop owner assignment from platform_driversWolfram Sang2014-10-201-1/+0
| | | | | | | A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
* spi: Remove explictly set bus_num and num_chipselect to default settingAxel Lin2014-02-161-1/+0
| | | | | | | | | | | | | The purpose of commit 1e8a52e18cfb "spi: By default setup spi_masters with 1 chipselect and dynamics bus number" is to avoid setting default value for bus_num and num_chipselect in spi master drivers. So let's remove the duplicate code. Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-By: David Daney <david.daney@cavium.com> Acked-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Use devm_request_irq()Jingoo Han2013-12-171-7/+3
| | | | | | | Use devm_request_irq() to make cleanup paths simpler. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Mark Brown <broonie@linaro.org>
*-. Merge remote-tracking branches 'spi/fix/bcm2835', 'spi/fix/bcm63xx', ↵Mark Brown2013-11-281-1/+1
|\ \ | | | | | | | | | 'spi/fix/mpc512x-psc', 'spi/fix/mxs', 'spi/fix/pxa2xx', 'spi/fix/qspi', 'spi/fix/rspi' and 'spi/fix/txx9' into spi-linus
| * | spi: bcm2835: fix reference leak to master in bcm2835_spi_remove()Wei Yongjun2013-11-151-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | Once a spi_master_get() call succeeds, we need an additional spi_master_put() call to free the memory, otherwise we will leak a reference to master. Fix by removing the unnecessary spi_master_get() call. Fixes: 247263dba208 ('spi: bcm2835: use devm_spi_register_master()') Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Mark Brown <broonie@linaro.org>
* / tree-wide: use reinit_completion instead of INIT_COMPLETIONWolfram Sang2013-11-151-1/+1
|/ | | | | | | | | | | | 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: Wolfram 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* spi: bcm2835: use devm_spi_register_master()Jingoo Han2013-09-261-3/+1
| | | | | | | | Use devm_spi_register_master() to make cleanup paths simpler, and remove a duplicate put. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Add spi_master_get() call to prevent use after freeAxel Lin2013-08-221-1/+1
| | | | | | | | | | | | | The call to spi_unregister_master results in device memory being freed, it must no longer be accessed afterwards. Thus call spi_master_get() to get an extra reference to the device and call spi_master_put() only after the last access to device data. Note, current code has an extra spi_master_put() call in bcm2835_spi_remove(). Thus this patch just adds an spi_master_get() to balance the reference count. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: Use SPI_BPW_MASK macro for bits_per_word_mask settingAxel Lin2013-08-051-1/+1
| | | | | | | We have a SPI_BPW_MASK macro defined in spi.h, use it instead of open-coded. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bcm2835: don't check resource with devm_ioremap_resourceWolfram Sang2013-07-241-6/+0
| | | | | | | | devm_ioremap_resource does sanity checks on the given resource. No need to duplicate this in the driver. Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Mark Brown <broonie@linaro.org>
* spi: bmc2835: use devm_ioremap_resource()Laurent Navet2013-05-131-4/+3
| | | | | | | | | | Replace a call to deprecated devm_request_and_ioremap by devm_ioremap_resource. Found with coccicheck and this semantic patch: scripts/coccinelle/api/devm_request_and_ioremap.cocci. Signed-off-by: Laurent Navet <laurent.navet@gmail.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* spi: bcm2835: make use of new bits_per_word_mask core featureStephen Warren2013-04-011-35/+1
| | | | | | | | This driver only supports bits_per_word==8, so inform the SPI core of this. Remove all the open-coded validation that's no longer needed. Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* spi: add driver for BCM2835Chris Boot2013-03-121-0/+456
The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-13 20:42:22 +0000