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path: root/drivers/spi
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* Consolidate bool typeYork Sun2013-04-01-1/+1
| | | | | | | | | | | | | 'bool' is defined in random places. This patch consolidates them into a single header file include/linux/types.h, using stdbool.h introduced in C99. All other #define, typedef and enum are removed. They are all consistent with true = 1, false = 0. Replace FALSE, False with false. Replace TRUE, True with true. Skip *.py, *.php, lib/* files. Signed-off-by: York Sun <yorksun@freescale.com>
* Merge branch 'u-boot/master' into 'u-boot-arm/master'Albert ARIBAUD2013-03-28-150/+792
|\ | | | | | | | | | | | | Conflicts: drivers/spi/tegra20_sflash.c include/fdtdec.h lib/fdtdec.c
| * tegra114: add SPI driverAllen Martin2013-03-25-0/+421
| | | | | | | | | | | | | | | | | | | | Add driver for tegra114 SPI controller. This controller is not compatible with either the tegra20 or tegra30 controllers, so it requires a new driver. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * spi: add common fdt SPI driver interfaceAllen Martin2013-03-25-45/+197
| | | | | | | | | | | | | | | | | | | | | | Add a common interface to fdt based SPI drivers. Each driver is represented by a table entry in fdt_spi_drivers[]. If there are multiple SPI drivers in the table, the first driver to return success from spi_init() will be registered as the SPI driver. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * tegra20: spi: move fdt probe to spi_initAllen Martin2013-03-25-43/+67
| | | | | | | | | | | | | | | | | | | | Make the tegra20 SPI driver similar to the tegra30 (and soon to be tegra114) SPI drivers in preparation of common fdt SPI driver front end. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * tegra: spi: pull register structs out of headersAllen Martin2013-03-25-11/+110
| | | | | | | | | | | | | | | | | | | | Move register structs from headers into .c files and use common name. This is in preparation of making common fdt front end for SPI drivers. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * tegra: spi: remove non fdt supportAllen Martin2013-03-25-37/+4
| | | | | | | | | | | | | | | | | | Remove non fdt support from tegra20 and tegra30 SPI drivers in preparation of new common fdt based SPI driver front end. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * tegra: spi: rename tegra SPI driversAllen Martin2013-03-25-4/+4
| | | | | | | | | | | | | | | | | | Rename tegra SPI drivers to tegra20_flash and tegra20_slink in preparation for commonization and addition of tegra114_spi. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
| * tegra: remove support for UART SPI switchAllen Martin2013-03-25-24/+1
| | | | | | | | | | | | | | | | | | | | This feature was only used for tegra20 seaboard that had a pinmux conflict on the SPI pins. These boards were never manufactured, so remove this support to clean up SPI driver. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com>
* | x86: spi: Set maximum write size for ICHSimon Glass2013-03-19-0/+5
| | | | | | | | | | | | | | This SPI controller can only write 64 bytes at a time. Add this restriction in so that 'sf write' works correct for blocks larger than 64 bytes. Signed-off-by: Simon Glass <sjg@chromium.org>
* | x86: spi: Add Intel ICH driverSimon Glass2013-03-19-0/+893
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This supports Intel ICH7/9. The Intel controller is a little unusual in that it is mostly intended for use with SPI flash, and has some optimisations and features specifically for that application. In particular it is not possible to support ongoing transactions that continue over many calls with SPI_XFER_BEGIN and SPI_XFER_END. This driver supports writes of up to 64 bytes at a time, the limit for the controller. Future work will improve this. Signed-off-by: Bernie Thompson <bhthompson@chromium.org> Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Signed-off-by: Bill Richardson <wfrichar@chromium.org> Signed-off-by: Vadim Bendebury <vbendeb@chromium.org> Signed-off-by: Gabe Black <gabeblack@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org>
* | spi: Use spi_alloc_slave() in each SPI driverSimon Glass2013-03-19-83/+36
| | | | | | | | | | | | | | | | Rather than each driver having its own way to allocate a SPI slave, use the new allocation function everywhere. This will make it easier to extend the interface without breaking drivers. Signed-off-by: Simon Glass <sjg@chromium.org>
* | spi: Add function to allocate a new SPI slaveSimon Glass2013-03-19-0/+42
|/ | | | | | | | | | At present it is difficult to extend the SPI structure since all drivers allocate it themselves, and few of them zero all fields. Add a new function spi_alloc_slave() which can be used by SPI drivers to perform this allocation, and thus ensure that all drivers can better cope with SPI structure changes. Signed-off-by: Simon Glass <sjg@chromium.org>
* Merge branch 'u-boot-imx/master' into 'u-boot-arm/master'Albert ARIBAUD2013-03-15-20/+19
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| * mxs: spi: Remove CONFIG_MXS_SPI_DMA_ENABLEMarek Vasut2013-03-07-16/+0
| | | | | | | | | | | | | | | | | | | | The CONFIG_MXS_SPI_DMA_ENABLE is no longer relevant as the SPI DMA has proven to work correctly. Remove this configuration option. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
| * mxs: spi: Fix the MXS SPI for mx23Marek Vasut2013-03-07-2/+17
| | | | | | | | | | | | | | | | | | | | The MX23 has slightly different register layout. Adjust the SPI driver to match the layout, both the PIO and DMA part. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
| * mxs: mmc: spi: dma: Better wrap the MXS differencesMarek Vasut2013-03-07-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch streamlines the differences between the MX23 and MX28 by implementing a few helper functions to handle different DMA channel mapping, different clock domain for SSP block and fixes a few minor bugs. First of all, the DMA channel mapping is now fixed in dma.h by defining the actual channel map for both MX23 and MX28. Thus, MX23 now does no longer use MX28 channel map which was wrong. Also, there is a fix for MX28 DMA channel map, where the last four channels were incorrect. Next, because correct DMA channel map is in place, the mxs_dma_init_channel() call now bases the channel ID starting from SSP port #0. This removes the need for DMA channel offset being added and cleans up the code. For the same reason, the SSP0 offset can now be used in mxs_dma_desc_append(), thus no need to adjust dma channel number in the driver either. Lastly, the SSP clock ID is now retrieved by calling mxs_ssp_clock_by_bus() which handles the fact that MX23 has shared SSP clock for both ports, while MX28 has per-port SSP clock. Finally, the mxs_ssp_bus_id_valid() pulls out two implementations of the same functionality from MMC and SPI driver into common code. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
* | blackfin: add bf6xx spi driverScott Jiang2013-03-04-0/+309
|/ | | | | | | | | | Spi driver for bf60x is different from old one, so implement a new driver for it. Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com> Signed-off-by: Sonic Zhang <sonic.zhang@analog.com> Signed-off-by: Bob Liu <lliubbo@gmail.com> Signed-off-by: Sonic Zhang <sonic.adi@gmail.com>
* Merge branch 'master' of git://git.denx.de/u-boot-armTom Rini2013-02-12-7/+389
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| * tegra: add SPI SLINK driverAllen Martin2013-02-11-0/+344
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add driver for tegra SPI "SLINK" style driver. This controller is similar to the tegra20 SPI "SFLASH" controller. The difference is that the SLINK controller is a genernal purpose SPI controller and the SFLASH controller is special purpose and can only talk to FLASH devices. In addition there are potentially many instances of an SLINK controller on tegra and only a single instance of SFLASH. Tegra20 is currently ths only version of tegra that instantiates an SFLASH controller. This driver supports basic PIO mode of operation and is configurable (CONFIG_OF_CONTROL) to be driven off devicetree bindings. Up to 4 devices per controller may be attached, although typically only a single chip select line is exposed from tegra per controller so in reality this is usually limited to 1. To enable this driver, use CONFIG_TEGRA_SLINK Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com>
| * tegra: spi: add fdt support to tegra SPI SFLASH driverAllen Martin2013-02-11-2/+43
| | | | | | | | | | | | | | | | | | Add support for configuring tegra SPI driver from devicetree. Support is keyed off CONFIG_OF_CONTROL. Add entry in seaboard dts file for spi controller to describe seaboard spi. Signed-off-by: Allen Martin <amartin@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com>
| * mxs: clock: Use 'mxs' prefix for methodsOtavio Salvador2013-01-21-1/+1
| | | | | | | | | | | | | | Signed-off-by: Otavio Salvador <otavio@ossystems.com.br> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Marek Vasut <marex@denx.de> Cc: Stefano Babic <sbabic@denx.de>
| * mxs: ssp: Pull out the SSP bus to regs conversionMarek Vasut2013-01-21-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Create function which converts SSP bus number to SSP register pointer. This functionality is reimplemented multiple times in the code, thus make one common implementation. Moreover, make it a switch(), since the SSP ports are not mapped in such nice linear fashion on MX23, therefore having it a switch will simplify things there. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Andy Fleming <afleming@freescale.com> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Stefano Babic <sbabic@denx.de>
* | spi: xilinx_spi: Perform software reset during slave setupJason Wu2013-02-04-0/+5
|/ | | | | | to make sure it is in the clear state. Signed-off-by: Jason Wu <huanyu@xilinx.com>
* Merge branch 'u-boot-samsung/master' into 'u-boot-arm/master'Albert ARIBAUD2013-01-14-6/+90
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| * SPI: EXYNOS: Add FDT support to driver.Rajeshwari Shinde2013-01-08-6/+90
| | | | | | | | | | | | | | | | | | This patch adds FDT support to the SPI driver. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com> Acked-by: Simon Glass <sjg@chromium.org> Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
* | Merge 'u-boot-atmel/master' into 'u-boot-arm/master'Albert ARIBAUD2013-01-09-1/+1
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| * | spi: atmel: sam9m10g45 also support WDRBT bitBo Shen2012-12-09-1/+1
| |/ | | | | | | | | | | | | The at91sam9m10g45 also support WDRBT bit, add support for it Signed-off-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
* | kirkwood: make MPP arrays static constAlbert ARIBAUD2013-01-09-7/+5
| | | | | | | | | | | | | | | | | | | | This saves stack and code memory for local copy, and consumes initialized data memory. For 22 of the 29 kirkwood-based boards, this results in a global saving of about 30 bytes. For 7 of them, it results in an increase of 6 to 14 bytes. Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
* | OMAP3 SPI : Fixed bugs related to SPI transferajoy2012-12-10-32/+45
|/ | | | | | | | | | | | | | | | | | | | | | Added posted writes (read after writes) to effect the change immediately for channel confiuration and channel enable register Disable the channel to purge receieve data in TX_ONLY mode transfer otherwise rx data will get affected by the next immediate RX_ONLY mode transfer Wait for the EOT bit to be set after last byte has been loaded to TX shift register in the the TX_ONLY mode.This ensures TX data has been completely shifted out Disable the channel in RX_ONLY mode before reading the last data from RXX register to prevent the SPI slave to transmit next word Signed-off-by: Ajoy Kumar Das <akdas75@yahoo.in> Cc: Tom Rini <trini@ti.com> Cc: jacopo mondi <j.mondi@voltaelectronics.com>
* Merge branch 'u-boot-imx/master' into 'u-boot-arm/master'Albert ARIBAUD2012-11-25-4/+5
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| * spi: mxc_spi: Fix spi clock glitch durant resetFabio Estevam2012-11-19-2/+2
| | | | | | | | | | | | | | | | | | | | | | Measuring the spi clock line on a scope shows a 'glitch' during the reset of the spi. Fix this by toggling only the MXC_CSPICTRL_EN bit, so that the clock line becomes always stable. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Acked-by: Stefano Babic <sbabic@denx.de>
| * spi: mxc_spi: Fix handling of chip selectFabio Estevam2012-11-19-2/+3
| | | | | | | | | | | | | | | | | | In decode_cs() function the polarity of the chip select must be taken into account. Also, for the case of low active chip select, the CS was activated too early. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
* | SPI: Add SPI Driver for EXYNOS.Rajeshwari Shinde2012-11-15-0/+368
|/ | | | | | | | | | | | | | This patch adds SPI driver for EXYNOS. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Padmavathi Venna <padma.v@samsung.com> Signed-off-by: Gabe Black <gabeblack@google.com> Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com> Signed-off-by: Hatim Ali <hatim.rv@samsung.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Simon Glass <sjg@chromium.org> Tested-by: jy0922.shim@samsung.com Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
* Merge remote-tracking branch 'u-boot-ti/master'Albert ARIBAUD2012-10-26-6/+5
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| * omap3_spi: introduce CONFIG_OMAP3_SPI_D0_D1_SWAPPEDPeter Korsgaard2012-10-25-6/+5
| | | | | | | | | | | | | | | | | | | | D0/D1 Swapped or not is a board property, not anything specific to the am33xx SoC, so add a custom define for it. At the same time correct the bit handling for the swapped mode (DPE0 should be cleared and SI/DPE1 set). Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
* | powerpc/espi: remove write command length checkShaohui Xie2012-10-22-4/+2
|/ | | | | | | | | | | | Current espi controller driver assumes the command length of write command is not equal to '1', it was made based on SPANSION SPI flash, but some SPI flash driver such as SST does use write command length as '1', so write command on SST SPI flash will not work. And the length check for write command is not necessary for SPANSION, though it's harmless for SPANSION, it will stop write operation on flashes like SST, so we remove the check. Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com> Signed-off-by: Andy Fleming <afleming@freescale.com>
* Tegra20: Move some include files to arch-tegra for sharing with Tegra30Tom Warren2012-10-15-4/+3
| | | | | | | | | | | The move is pretty straight-forward. ap20.h and tegra20.h were renamed to ap.h and tegra.h. Some files remain in arch-tegra20 but 'include' a file in 'arch-tegra' with #defines & structs that will be common between T20 and T30 HW. HW-specific #defines, etc. stay in the 'arch-tegra20' 'root' file. All boards build OK w/MAKEALL -s tegra20. Checkpatch.pl runs clean. Seaboard works OK. Signed-off-by: Tom Warren <twarren@nvidia.com>
* Merge branch 'master' of git://git.denx.de/u-boot-armTom Rini2012-09-21-30/+39
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| * Merge remote-tracking branch 'u-boot-imx/master'Albert ARIBAUD2012-09-21-25/+33
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| | * MX28: SPI: Fix the DMA chainingMarek Vasut2012-09-06-18/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that in order for the SPI DMA to properly support continuous transfers longer than 65280 bytes, there are some very important parts that were left out from the documentation. Firstly, the XFER_SIZE register is not written with the whole length of a transfer, but is written by each and every chained descriptor with the length of the descriptors data buffer. Next, unlike the demo code supplied by FSL, which only writes one PIO word per descriptor, this does not apply if the descriptors are chained, since the XFER_SIZE register must be written. Therefore, it is essential to use four PIO words, CTRL0, CMD0, CMD1, XFER_SIZE. CMD0 and CMD1 are written with zero, since they don't apply. The DMA programs the PIO words in an incrementing order, so four PIO words. Finally, unlike the demo code supplied by FSL, the SSP_CTRL0_IGNORE_CRC must not be set during the whole transfer, but it must be set only on the last descriptor in the chain. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
| | * MX28: SPI: Fix the DMA DCache race conditionMarek Vasut2012-09-06-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes dcache-related problem. The problem manifested when dcache was enabled and the following command issued twice: mw 0x42000000 0 0x4000 ; sf probe ; sf read 0x42000000 0x0 0x10000 ; sha1sum 0x42000000 0x10000 The SHA1 checksum was correct during the first call. Yet with every subsequent call of the above command, it differed and was wrong. It turns out this was because of a race condition. On the first time the command was called, no cacheline contained any data from the destination memory location. The DMA transfered data into the location and the cache above the location was invalidated. Then the checksum was computed, but that meant the data were loaded into data cache. On any subsequent call, the DMA again transfered data into the same destination. Yet during the transfer, some of the DCache lines were evicted and written back into the main memory. Once the DMA transfer completed, the data cache was invalidated over the memory location as usual. But the data that were to be loaded back into the data cache by subsequent SHA1 checksuming were corrupted. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
| * | Tegra: Change Tegra20 to Tegra in common code, prep for T30Tom Warren2012-09-10-3/+3
| |/ | | | | | | | | | | | | | | | | | | Convert TEGRA20_ defines to either TEGRA_ or NV_PA_ where appropriate. Convert tegra20_ source file and function names to tegra_, also. Upcoming Tegra30 port will use common code/defines/names where possible. Signed-off-by: Tom Warren <twarren@nvidia.com> Acked-by: Stephen Warren <swarren@nvidia.com>
| * kw_spi: fix clock prescaler computationValentin Longchamp2012-09-03-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The computation was not correct with low clock values: setting a 1MHz clock would result in an overlap that would then configure a 25Mhz clock. This patch implements a correct computation method according to the kirkwood functionnal spec. table 600 (Serial Memory Interface Configuration Register). Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com> cc: Holger Brunck <holger.brunck@keymile.com> cc: Prafulla Wadaskar <prafulla@marvell.com> Acked-by: Prafulla Wadaskar <Prafulla@marvell.com> Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>
* | ColdFire: Queued SPI driverRichard Retanubun2012-09-20-0/+374
| | | | | | | | | | | | | | | | | | | | | | | | This patch adds a driver for Freescale Colfire Queued SPI bus. Coded to work with 8 bits per transfer to use with SPI flash. CPOL, CPHA, and CS_ACTIVE_HIGH can be configured. Tested with MCF5270 which have 4 chip selects. Activate by #define CONFIG_CF_QSPI in board config. Signed-off-by: Richard Retanubun <richardretanubun@ruggedcom.com>
* | mpc8xxx_spi: fix SPI support on MPC8308RDBIra W. Snyder2012-09-18-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | The MPC8308RDB Reference Manual states that no bits in the SPMODE register are allowed to change while the enable (EN) bit is set. This driver changes the character length bits (LEN) while the enable (EN) bit is set. Clearing the EN bit while changing the LEN bits makes the driver work correctly on MPC8308RDB. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
* | spi: xilinx: Remove unused variableStephan Linz2012-09-11-1/+0
|/ | | | | | | | | | Warning is: xilinx_spi.c: In function 'spi_setup_slave': xilinx_spi.c:81: warning: unused variable 'regs' Signed-off-by: Stephan Linz <linz@li-pro.net> CC: Michal Simek <monstr@monstr.eu>
* spi: atmel: add WDRBT bit to avoid receive overrunBo Shen2012-09-01-0/+4
| | | | | | | | | | The atmel at91sam9x5 series spi has feature to avoid receive overren Using the patch to enable it Signed-off-by: Bo Shen <voice.shen@atmel.com> Acked-by: Andreas Bießmann <andreas.devel@googlemail.com> Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
* MX28: SPI: Supercharge the SPI driverMarek Vasut2012-09-01-31/+65
| | | | | | | | | | This change implements DMA chaining into SPI driver. This allows the transfers to go much faster, while also fixing SF issues. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de>
* spi: fix mxs_spi_slave structure allocation to clear memoryMatt Sealey2012-09-01-1/+1
| | | | | | | | | | | | | | | Use calloc() instead of malloc() to allocate the mxs_spi_slave structure. Clearing the memory is necessary since most of the time this gets done super early in boot, but on warm reboots, and when SPI probing is done long after the init stages it could actually pick up previously used memory, and things like the chipselect polarity and other data end up being filled with trash data if not explicitly set by the board files. This solves a semi-random, almost unreproducable error whereby SPI devices act very, very strangly on boot. Signed-off-by: Matt Sealey <matt@genesi-usa.com> Acked-by: Stefano Babic <sbabic@denx.de>