[U-Boot] Marvell Kirkwood newbie question GPIO functions

[Prafulla Wadaskar]

> -----Original Message-----
> From: u-boot-bounces at lists.denx.de 
> [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Dieter Kiermaier
> Sent: Friday, June 19, 2009 2:23 PM
> To: u-boot at lists.denx.de
> Subject: Re: [U-Boot] Marvell Kirkwood newbie question GPIO functions
> 
> Hi again,
> 
> 
> > Hi Prafulla,
> >
> > > It's my pleasure to reply you :-)
> > > Basic Kirkwood Soc Support patches are available on the 
> > > u-boot-arm.git/next (will be mainlined soon) Sheevaplug board 
> > > support patches are also submitted those are under 
> review, you can 
> > > find them here...
> > > http://lists.denx.de/pipermail/u-boot/2009-June/054313.html
> > > http://lists.denx.de/pipermail/u-boot/2009-June/054314.html
> > > http://lists.denx.de/pipermail/u-boot/2009-June/054316.html
> > >
> > > Some other board patches are in pipeline
> >
> > thanks very much for your help.
> > So far I have seen that marvell git u-boot is used to push 
> it to mainline.
> > Great job!
> > What patches are in the pipeline?
Some other board supports (MV88F6281GTW_GE) and Kirkwood SPI driver support
Kirkwood USB support (at this moment)

> >
> > > > Currently I'm using the u-boot from git.marvell.com which has 
> > > > first board support for sheevaplug. I'm working on a custom 
> > > > hardware design but as a starting point the sheevaplug seems to 
> > > > work well.
> > >
> > > Objective for U-boot at git.marvell.com is to maintain a 
> usable copy 
> > > of u-boot with all accepted/unaccepted patches at one place to 
> > > support Kirkwood developers, but once all these patches are 
> > > mainlined, this repository will be removed.
> > >
> > > > Sadly there is no generic gpio support - at least I 
> couldn't find it.
> > > > Are there any plans to support a driver for this feature?
> > >
> > > BTW: what you want to do at u-boot level with GPIOs?
> > > Current Kirkwood drivers and board support does not need any 
> > > specific GPIO driver, you can access registers directly to 
> > > read/write GPIOs. But I think if this is a need in future, I will 
> > > add gpio driver support. You can provide me your requirements too.
> >
> > I'm working on a custom hardware using the sheevaplug as a 
> starting point.
> > Hopefully end of summer I finish the hardware work and have 
> my own board.
> > But I have some additional requirements. For example control some 
> > power supplies for LCD, boot an FPGA, program a clock chip 
> device and so on.
> > So my demands are:
> > - GPIO support (for programming the clock generator which 
> has a simple 
> > serial interface to clock in the configuration data)
> >         Yeah, I know that I can setup the GPIOs by writing 
> directly to 
> > the registers,
> >         but a gpio frameworks would be much nicer ;)
> >
> > - SPI (from the TDM module) support which works independet
> >   from NAND flash and SD-Card
> >
> > I have allready posted a query to arm-linux kernel mailing list and 
> > yesterday evening I have talked with Lennert on IRC 
> regarding SPI and 
> > linux .
> >
> > The SPI interface is needed in u-boot to boot my lattice 
> FPGA which is 
> > configured as slave serial device (and later on in linux to drive a 
> > touch controller).
> > There is allready a FPGA configuration framework inside 
> u-boot and I 
> > would like to integrate also a lattice FPGA into that. But 
> to do this 
> > I need SPI support.
> 
> 
> What I forgot to mention is the i2c driver inside u-boot.
> I need this to read the mac address from an additional eeprom.
> This makes mass production more ease and doesn't produce 
> hight costs :)
Kirkwood has in-built i2c(TWSI) controller, well.. the plans are in place enable driver for it, but this is not blocking issue right now hence pending ;-)

Just FYI: you can protect some flash sector and use it in place of eeprom, this will lower the board cost and complexity too.

But if you are planning to use some different GPIOs for i2c and bit-banged driver on the top of it, then you will need gpio control, so you can do it by using simple readl/writel calls meanwhile driver to come in :-)

The best way I will suggest you is:
Put pre-programmed eeprom around Kirkwood TWSI interface and enable "TWSI serial ROM initialization" you don't need anything else for this. (I hope you are having enough kirkwood documentation)
Ref: table 32: http://www.marvell.com/files/products/embedded_processors/kirkwood/HW_88F6281_OpenSource.pdf

Regards..
Prafulla . .

> 
> Dieter
> 
> >
> > > > I'm willing to contribute some code if someone guides me a bit?
> > >
> > > You are most welcomed....
> > > Pls feel free to raise your queries...
> >
> > Here they are :)
> > Thanks,
> > Dieter
> >
> > > Regards..
> > > Prafulla . .
> > >
> > > > Thanks in advance,
> > > > Dieter
> > > >
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> >
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