WLAN from SDIO to SPI: battle plan

Andy Green andy at openmoko.com
Thu Aug 21 00:48:25 CEST 2008


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Somebody in the thread at some point said:
| I wrote:
|> To be continued ...
|
| After getting nowhere with trying to talk to the prototype board, and
| seeing no end of those short pulses on MISO (*), I decided that my
| suspicion that poor signal integrity was to blame even at this
| moderate clock speed was probably more than a convenient excuse.
|
| (*) Here's a beautiful one. D5 is the clock, D2 is MISO:
|     http://people.openmoko.org/werner/wlan-spi/3.png
|
| Then it occurred to me that I could just as well use the WLAN module
| that's already in the device: after turning off the SDIO driver,
| switching to mmc_spi over s3c24xx_spi_gpio, and adapting all the GPIO
| definitions, the mainline SDIO stack happily welcomed the new member
| with SDIO_ID=0271:010A :-)
|
| I'll just go ahead with s3c24xx_spi_gpio for now, then rework and
| switch to s3c24xx_spi when the Atheros stack talks to the module as
| well.
|
| I'll give "pure" SPI (G_SPI) a try when the EVB arrives.

Well despite it isn't the hardware SPI we actually need, that's good
work: well done, that's quite a chunk of the battle.

- -Andy
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