Re: [PATCH v5 2/3] I2C: mediatek: Add driver for MediaTek I2C controller

[Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

On Tue, Mar 31, 2015 at 07:50:58PM +0800, Eddie Huang wrote:
> Hi Sascha,
> 
> On Tue, 2015-03-31 at 15:08 +0800, Eddie Huang wrote:
> > Hi Sascha,
> > 
> > > > > speed <= 400000 here to make this more obvious?
> > > > There are two cases, not only speed<=400000, but I2C_MASTER_WRRD. I tend
> > > > to keep it.
> > >
> > > Still it looks strange. You only ever write this default value to the
> > > register. Putting this register write under an if() seems bogus since
> > > the same value will be in the register the next time this code is
> > > executed. It looks like you should move this register write to some
> > > initialization function.
> > OK, move to mtk_i2c_init_hw function
> > 
> Sorry for my negligence. Write-then-read (I2C_MASTER_WRRD) decides
> according to each I2C transfer, so I still need to judge whether set
> I2C_CONTROL_RS and DELAY_LEN here. Other control setting can move to
> init function.

You need to decide whether you have to set the I2C_CONTROL_RS bit, but
you don't need to write the same value to the DELAY_LEN register each
time. It won't change under your hood.

Sascha

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