[U-Boot] [PATCH v2] spi/kirkwood: add weak functions board_spi_bus_claim/release

[Valentin Longchamp <valentin.longchamp@keymile.com>]

Hi Prafulla,

For the simplicity of the discussion, I have removed everything in the
discussion that is not relevant for the current open point.

On 03/30/2012 01:34 PM, Prafulla Wadaskar wrote:
> In Kirkwood specific claim_bus API, you will backup default configuration (which is NF in your case) for these particular pins (SPI_SI, SPI_SCK, SPI_CSn, MOSI, MISO).

But which MPP are these particular pins ?

Let's have a look at a single signal, SPI_SCK for instance. From the 88F6281
Hardware Spec [1], page 53, SPI_SCK can be MPP[2], MPP[10]. How can the generic
driver know which one actually is wired to the SPI device SCK pin on the
currently running hardware (when none is configured as then, since by default
for us MPP[2] is NF_IO[4] and MPP[10] is UA0_TXD ) ? This is a board specific !

If you tell me how I easily can find this out in the kirkwood driver, I will be
happy to implement your proposed solution. Otherwise, I think we should stick
with the board specific function.

[1]
http://www.marvell.com/embedded-processors/kirkwood/assets/HW_88F6281_OpenSource.pdf

Regards

-- 
Valentin Longchamp
Embedded Software Engineer
Hardware and Chip Integration
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