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path: root/drivers/spi/spi_gpio.c
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2010-10-02spi: spi-gpio.c tests SPI_MASTER_NO_RX bit twice, but not SPI_MASTER_NO_TXRoel Kluin
The SPI_MASTER_NO_TX bit (can't do buffer write) wasn't tested. This code was introduced in commit 3c8e1a84 (spi/spi-gpio: add support for controllers without MISO or MOSI pin). This patch fixes a bug in choosing which transfer ops to use. Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03spi/spi-gpio: add support for controllers without MISO or MOSI pinMarek Szyprowski
There are some boards that do not strictly follow SPI standard and use only 3 wires (SCLK, MOSI or MISO, SS) for connecting some simple auxiliary chips and controls them with GPIO based 'spi controller'. In this configuration the MISO or MOSI line is missing (it is not required if the chip does not transfer any data back to host or host only reads data from chip). This patch adds support for such non-standard configuration in GPIO-based SPI controller. It has been tested in configuration without MISO pin. Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modesMarek Szyprowski
This patch adds a new flags argument to bitbang_txrx_be_cpha0 and bitbang_txrx_be_cpha1 transfer functions. This enables support for SPI_MASTER_NO_{TX,RX} transfer modes. The change should have no impact on speed of the existing drivers. bitbank_txrx_* functions are usually inlined into the drivers. When the argument is equal to constant zero, the optimizer would be able to eliminate the dead code (flags checks) easily. Tested on ARM and GCC 4.4.x and in all cases the checks were eliminated in the inlined function. Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-05-25spi: move bitbang txrx utility functions to private headerhartleys
A number of files in drivers/spi fail checkincludes.pl due to the double include of <linux/spi/spi_bitbang.h>. The first include is needed to get the struct spi_bitbang definition and the spi_bitbang_* function prototypes. The second include happens after defining EXPAND_BITBANG_TXRX to get the inlined bitbang_txrx_* utility functions. The <linux/spi/spi_bitbang.h> header is also included by a number of other spi drivers, as well as some arch/ code, in order to use struct spi_bitbang and the associated functions. To fix the double include, and remove any potential confusion about it, move the inlined bitbang_txrx_* functions to a new private header in drivers/spi and also remove the need to define EXPAND_BITBANG_TXRX. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2009-04-02spi-gpio: allow operation without CS signalMichael Buesch
Change spi-gpio so that it is possible to drive SPI communications over GPIO without the need for a chipselect signal. This is useful in very small setups where there's only one slave device on the bus. This patch does not affect existing setups. I use this for a tiny communication channel between an embedded device and a microcontroller. There are not enough GPIOs available for chipselect and it's not needed anyway in this case. Signed-off-by: Michael Buesch <mb@bu3sch.de> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-24spi: struct device - replace bus_id with dev_name(), dev_set_name()Kay Sievers
Cc: dbrownell@users.sourceforge.net Cc: spi-devel-general@lists.sourceforge.net Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-02-18spi-gpio: sanitize MISO bitvalueMichael Buesch
gpio_get_value() returns 0 or nonzero, but getmiso() expects 0 or 1. Sanitize the value to a 0/1 boolean. Signed-off-by: Michael Buesch <mb@bu3sch.de> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06spi_gpio driverDavid Brownell
Generalize the old at91rm9200 "bootstrap" bitbanging SPI master driver as "spi_gpio", so it works with arbitrary GPIOs and can be configured through platform_data. Such SPI masters support: - any number of bus instances (bus_num is the platform_device.id) - any number of chipselects (one GPIO per spi_device) - all four SPI_MODE values, and SPI_CS_HIGH - i/o word sizes from 1 to 32 bits; - devices configured as with any other spi_master controller When configured using platform_data, this provides relatively low clock rates. On platforms that support inlined GPIO calls, significantly improved transfer speeds are also possible with a semi-custom driver. (It's still painful when accessing flash memory, but less so.) Sanity checked by using this version to replace both native controllers on a board with six different SPI slaves, relying on three different SPI_MODE_* values and both SPI_CS_HIGH settings for correct operation. [akpm@linux-foundation.org: cleanups] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Magnus Damm <damm@igel.co.jp> Tested-by: Magnus Damm <damm@igel.co.jp> Cc: Torgil Svensson <torgil.svensson@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>