[PATCH] Nokia RX-51: Decrease i2c speed to 100000

[Pali Rohár]

On Saturday 28 November 2020 14:02:20 Michael Nazzareno Trimarchi wrote:
> Hi
> 
> On Sat, Nov 28, 2020 at 1:59 PM Pali Rohár <pali at kernel.org> wrote:
> >
> > On Saturday 28 November 2020 13:48:37 Michael Nazzareno Trimarchi wrote:
> > > Hi
> > >
> > > On Sat, Nov 21, 2020 at 11:30 PM Pali Rohár <pali at kernel.org> wrote:
> > > >
> > > > It looks like that i2c bus lot of times timeout on some units. Prior
> > > > migration to CONFIG_DM_I2C i2c speed was set to CONFIG_SYS_OMAP24_I2C_SPEED
> > > > value which was 100000. Lower speed fixes timeout problems, so change speed
> > > > back to its previous value.
> > > >
> > > > Signed-off-by: Pali Rohár <pali at kernel.org>
> > > > Fixes: 8d8c18170325 ("Nokia RX-51: Convert to CONFIG_DM_I2C")
> > > > ---
> > > > Please include this patch into U-Boot master branch for 2020.01 release
> > > > to have i2c bus working.
> > > > ---
> > > >  board/nokia/rx51/rx51.c | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/board/nokia/rx51/rx51.c b/board/nokia/rx51/rx51.c
> > > > index 3d62b5d9ad..2dd41604c9 100644
> > > > --- a/board/nokia/rx51/rx51.c
> > > > +++ b/board/nokia/rx51/rx51.c
> > > > @@ -704,9 +704,9 @@ void board_mmc_power_init(void)
> > > >  }
> > > >
> > > >  static const struct omap_i2c_platdata rx51_i2c[] = {
> > > > -       { I2C_BASE1, 2200000, OMAP_I2C_REV_V1 },
> > > > +       { I2C_BASE1, 100000, OMAP_I2C_REV_V1 },
> > >
> > > I can understand this one. I don't know what kind of speed was before
> >
> > Prior to mentioned commit which is doing conversion to DM, i2c speed was
> > set to 100000.
> >
> 
> Does this impact the led?

Yes, it starts working again.

> > > >         { I2C_BASE2, 100000, OMAP_I2C_REV_V1 },
> > > > -       { I2C_BASE3, 400000, OMAP_I2C_REV_V1 },
> > > > +       { I2C_BASE3, 100000, OMAP_I2C_REV_V1 },
> > >
> > > Can you report the peripherals have this problem? I mean
> > > a lot of i2c devices can run to 400Khz.
> >
> > Problematic is i2c LED device.
> >
> > > And how are those buses configured in the kernel?
> >
> > It configures it to 2200000, 100000, 400000, like prior this patch.
> > In kernel they are working fine. I really do not know why U-Boot has
> > problems...
> >
> 
> Maybe the selected pull up is not the same for pinmux configuration.
> Anyway I suggest only to change the value that impact the device,
> reduce the commit as mimal and describe what is the peripheral was
> involved

Commit is already minimal. It revers back to configuration which was
stable and was working prior DM migration.

> Michael
> 
> > >
> > > Michael
> > >
> > > >  };
> > > >
> > > >  U_BOOT_DEVICES(rx51_i2c) = {
> > > > --
> > > > 2.20.1
> > > >
> > >
> > >
> > > --
> > > Michael Nazzareno Trimarchi
> > > Amarula Solutions BV
> > > COO Co-Founder
> > > Cruquiuskade 47 Amsterdam 1018 AM NL
> > > T. +31(0)851119172
> > > M. +39(0)3479132170
> > > [`as] https://www.amarulasolutions.com
> 
> 
> 
> -- 
> Michael Nazzareno Trimarchi
> Amarula Solutions BV
> COO Co-Founder
> Cruquiuskade 47 Amsterdam 1018 AM NL
> T. +31(0)851119172
> M. +39(0)3479132170
> [`as] https://www.amarulasolutions.com