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54 commits

Author SHA1 Message Date
Ben Warren
f8cc312bbe Move conditional compilation of MPC8XXX SPI driver to Makefile
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
2008-07-01 21:02:11 +02:00
Haavard Skinnemoen
d255bb0e78 SPI API improvements
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>
2008-06-03 20:28:50 +02:00
Guennadi Liakhovetski
38254f45b0 New i.MX31 SPI driver
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>
2008-04-18 00:43:23 -07:00
wdenk
77f855819e Initial revision 2002-09-26 02:01:47 +00:00