Re: [PATCH/RFC 0/2] simple SPI framework, refresh + ads7864 driver

[Vitaly Wool <vwool@ru.mvista.com>]

Hi,

can you please describe the data flow in case of DMA transfer? Thanks!

Vitaly

David Brownell wrote:

> Following this will be two patches, refreshing the minimalist SPI stack
> I've sent before.  Notable changes are:
>
>  - Various updates to support real hardware, including reporting the
>    IRQ associated with an SPI slave chip, providing void* handles for
>    various flavors of board and controller state, dma_addr_t for I/O
>    buffers, some control over protocol delays, and more.
>
>  - New spi_alloc_master().  The driver model is happier if drivers
>    don't allocate the class devices; this helps "rmmod" and friends,
>    kind of handy for debugging drivers.  It allocates controller
>    specific memory not unlike alloc_netdev().
>
>  - Various cleanup, notably removing Kconfig for all those drivers
>    that don't yet exist.  That was added purely to illustrate the
>    potential scope of an SPI framework, when more folk were asking
>    just why a Serial Peripheral Interface (*) was useful.
>
>  - More kerneldoc.  No Documentation/DocBook/spi.html though.
>
>  - Now there's a real ADS7864 touchscreen/sensor driver; lightly
>    tested, but it emits the right sort of input events and gives
>    syfs access to the temperature, battery, and voltage sensors.
>
> This version seems real enough to integrate with.
>
> One goal is promote reuse of driver code -- for SPI controllers and
> slave chips connected using SPI -- while fitting them better into the
> driver model framework.  Today, SPI devices only seem to get drivers
> that are board-specific; there's a fair amount of reinvent-the-wheel,
> and drivers that are unsuitable for upstream merging.
>
> I can now report this seems to be working with real controllers and
> real slave chips ... two of each to start with, but as yet there's no
> mix'n'match (with e.g. that touchscreen driver being used with a PXA
> SSP controller, not just OMAP MicroWire).  That should just take a
> little bit of time and debugging.
>
> - Dave
>
> (*) And distinguish it from Singapore Paranormal Investigators.  ;)
>
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