On Mon, Dec 12, 2016 at 11:35:19AM -0800, Joe Perches wrote:
> On Mon, 2016-12-12 at 21:21 +0200, Mika Westerberg wrote:
> > On Mon, Dec 12, 2016 at 09:02:53PM +0200, Andy Shevchenko wrote:
> > > > + tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
> > > > + rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
> > > > + if (!dev->tx_fifo_depth) {
> > > > + dev->tx_fifo_depth = tx_fifo_depth;
> > > > + dev->rx_fifo_depth = rx_fifo_depth;
> > > > + } else if (tx_fifo_depth) {
> > > > + dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
> > > > + tx_fifo_depth);
> > > > + dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
> > > > + rx_fifo_depth);
> > > > + }
> > >
> > > So, let's clarify here:
> > > Is it possible to have an IP without parameter block enabled? I mean to
> > > read something arbitrary (or zeroes, or all-ones) from param1.
> >
> > Yes and it is Intel IP. Haswell IIRC and it returned zeroes.
>
> The "+ 1" in the first set of tx_fifo_depth
> makes the "else if" check unnecessary.
Good point. I did not notice that change at all.
The designware I2C databook I have here says that 0 is reserved value
and FIFO sizes start from 2 so the above is wrong either way.
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