Aspeed 2500 EVB i2c transaction time out

[Shay Slobodkin]

> -----Original Message-----
> From: joel.stan at gmail.com [mailto:joel.stan at gmail.com] On Behalf Of Joel
> Stanley
> Sent: Thursday, July 21, 2016 7:36 PM
> To: Shay Slobodkin <shays at mellanox.com>
> Cc: openbmc at lists.ozlabs.org
> Subject: Re: Aspeed 2500 EVB i2c transaction time out

Hello Joel,

Thanks for your answer.
Until we merge from remote the new kernel trees you will push, I was wondering why in aspeed.c for EVB we have the below mapping (there is no i2c bus here): 
static struct pinctrl_map ast2500_mapping[] __initdata = {
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-8", "1e6e2000.pinmux", NULL, "I2C9"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-3", "1e6e2000.pinmux", NULL, "I2C4"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-2", "1e6e2000.pinmux", NULL, "I2C3"), };

While for Palmetto, we have the below set (with no shift like in EVB: i2c-x - I2C(x+1))
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-3", "1e6e2000.pinmux", NULL, "I2C3"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-4", "1e6e2000.pinmux", NULL, "I2C4"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-5", "1e6e2000.pinmux", NULL, "I2C5"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-6", "1e6e2000.pinmux", NULL, "I2C6"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-7", "1e6e2000.pinmux", NULL, "I2C7"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-8", "1e6e2000.pinmux", NULL, "I2C8"),
        PIN_MAP_MUX_GROUP_DEFAULT("i2c-8", "1e6e2000.pinmux", NULL, "I2C9"),

Maybe understanding this could be of some more assistance for us.

> 
> Hello Shay,
> 
> On Thu, Jul 21, 2016 at 8:26 PM, Shay Slobodkin <shays at mellanox.com>
> wrote:
> > Hi,
> >
> > We faced an i2c transaction time-out issue on Aspeed 2500 EVB board.
> >
> > It happens when we try to connect on board LM75 at 0x4d driver to bus 7.
> >
> > We used https://github.com/openbmc/linux/tree/dev-4.6 kernel and also
> > tried
> > https://github.com/shenki/linux/tree/dev-4.7 kernel.
> 
> I know that communication with the lm75 does work - I've had it working
> here on a my ast2500evb-ddr4.
> 
> The state of these two kernel trees is not great at this time. I plan to push a
> new tree next week based on the released 4.7 kernel with our new pinmux
> driver, which is the correct way to ensure pins are configured correctly.
> 
> If you can wait until then you should have more success. Sorry for the hassle.

We will wait for your additions and merge once ready.
Thank you.

> 
> Cheers,
> 
> Joel
> 
> >
> >
> >
> > We also tried to change i2c timeout counter (I2CD08) from 3 bits to 5
> > bits, according to Aspeed AST2400 to AST2500 migration guideline, but
> > it didn’t help.
> >
> >
> >
> > Is that a known issue?
> >
> > Is there a known solution you can point us to?
> >
> >
> >
> >
> >
> > Thanks for the assistance,
> >
> > Shay
> >
> >
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> >