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This patch adds SPI support for carrying out the cros_ec protocol.
Signed-off-by: Hung-ying Tyan <tyanh@chromium.org>
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
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A SPI slave may take time to react to a request. For SPI flash devices
this time is defined as one bit time, or a whole byte for 'fast read'
mode.
If the SPI slave is another CPU, then the time it takes to react may
vary. It is convenient to allow the slave device to tag the start of
the actual reply so that the host can determine when this 'preamble'
finishes and the actual message starts.
Add a preamble flag to the available SPI flags. If supported by the
driver then it will ignore any received bytes before the preamble
on each transaction. This ensures that reliable communication with
the slave is possible.
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
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Some SPI controllers (e.g. Intel ICH) have a limit on the number of SPI
bytes that can be written at a time. Add this as a parameter so that
clients of the SPI interface can respect this value.
Signed-off-by: Simon Glass <sjg@chromium.org>
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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>
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Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Singed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
Signed-off-by: Shaohui Xie <b21989@freescale.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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This func helps mmc_spi driver set correct speed for mmc/sd, as
mmc card needs 400KHz clock for spi mode initialization.
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
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This patch gets rid of the spi_chipsel table and adds a handful of new
functions that makes the SPI layer cleaner and more flexible.
Instead of the spi_chipsel table, each board that wants to use SPI
gets to implement three hooks:
* spi_cs_activate(): Activates the chipselect for a given slave
* spi_cs_deactivate(): Deactivates the chipselect for a given slave
* spi_cs_is_valid(): Determines if the given bus/chipselect
combination can be activated.
Not all drivers may need those extra functions however. If that's the
case, the board code may just leave them out (assuming they know what
the driver needs) or rely on the linker to strip them out (assuming
--gc-sections is being used.)
To set up communication parameters for a given slave, the driver needs
to call spi_setup_slave(). This returns a pointer to an opaque
spi_slave struct which must be passed as a parameter to subsequent SPI
calls. This struct can be freed by calling spi_free_slave(), but most
driver probably don't want to do this.
Before starting one or more SPI transfers, the driver must call
spi_claim_bus() to gain exclusive access to the SPI bus and initialize
the hardware. When all transfers are done, the driver must call
spi_release_bus() to make the bus available to others, and possibly
shut down the SPI controller hardware.
spi_xfer() behaves mostly the same as before, but it now takes a
spi_slave parameter instead of a spi_chipsel function pointer. It also
got a new parameter, flags, which is used to specify chip select
behaviour. This may be extended with other flags in the future.
This patch has been build-tested on all powerpc and arm boards
involved. I have not tested NIOS since I don't have a toolchain for it
installed, so I expect some breakage there even though I've tried
fixing up everything I could find by visual inspection.
I have run-time tested this on AVR32 ATNGW100 using the atmel_spi and
DataFlash drivers posted as a follow-up. I'd like some help testing
other boards that use the existing SPI API.
But most of all, I'd like some comments on the new API. Is this stuff
usable for everyone? If not, why?
Changed in v4:
- Build fixes for various boards, drivers and commands
- Provide common struct spi_slave definition that can be extended by
drivers
- Pass a struct spi_slave * to spi_cs_activate and spi_cs_deactivate
- Make default bus and mode build-time configurable
- Override default SPI bus ID and mode on mx32ads and imx31_litekit.
Changed in v3:
- Add opaque struct spi_slave for controller-specific data associated
with a slave.
- Add spi_claim_bus() and spi_release_bus()
- Add spi_free_slave()
- spi_setup() is now called spi_setup_slave() and returns a
struct spi_slave
- soft_spi now supports four SPI modes (CPOL|CPHA)
- Add bus parameter to spi_setup_slave()
- Convert the new i.MX32 SPI driver
- Convert the new MC13783 RTC driver
Changed in v2:
- Convert the mpc8xxx_spi driver and the mpc8349emds board to the
new API.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Tested-by: Guennadi Liakhovetski <lg@denx.de>
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This is an SPI driver for i.MX and MXC based SoCs from Freescale. So far
only implemented and tested on i.MX31, can with a modified register layout
and definitions be used for i.MX27, I think, MXC CPUs have similar SPI
controllers too.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
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