[PATCH v2 4/7] staging: mt7621-pci: fix reset lines for each pcie port

[Dan Carpenter]

On Mon, Nov 26, 2018 at 08:57:09PM +0100, Sergio Paracuellos wrote:
> On Mon, Nov 26, 2018 at 10:57 AM Dan Carpenter <dan.carpenter at oracle.com> wrote:
> >
> > On Sat, Nov 24, 2018 at 06:54:54PM +0100, Sergio Paracuellos wrote:
> > > Depending of chip revision reset lines are inverted. It is also
> > > necessary to read PCIE_FTS_NUM register before enabling the phy.
> > > Hence update the code to achieve this.
> > >
> > > Fixes: 745eeeac68d7: "staging: mt7621-pci: factor out 'mt7621_pcie_enable_port'
> > > function"
> > > Reported-by: NeilBrown <neil at brown.name>
> > >
> > > Signed-off-by: Sergio Paracuellos <sergio.paracuellos at gmail.com>
> > > ---
> > >  drivers/staging/mt7621-pci/pci-mt7621.c | 38 +++++++++++++++++++++----
> > >  1 file changed, 32 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/staging/mt7621-pci/pci-mt7621.c b/drivers/staging/mt7621-pci/pci-mt7621.c
> > > index ba81b34dc1b7..1b63706e129b 100644
> > > --- a/drivers/staging/mt7621-pci/pci-mt7621.c
> > > +++ b/drivers/staging/mt7621-pci/pci-mt7621.c
> > > @@ -412,6 +412,33 @@ static void mt7621_enable_phy(struct mt7621_pcie_port *port)
> > >       set_phy_for_ssc(port);
> > >  }
> > >
> > > +static inline void mt7621_control_assert(struct mt7621_pcie_port *port)
> > > +{
> > > +     u32 chip_rev_id = rt_sysc_r32(MT7621_CHIP_REV_ID);
> > > +
> > > +     if ((chip_rev_id & 0xFFFF) == CHIP_REV_MT7621_E2)
> > > +             reset_control_assert(port->pcie_rst);
> > > +     else
> > > +             reset_control_deassert(port->pcie_rst);
> > > +}
> > > +
> > > +static inline void mt7621_control_deassert(struct mt7621_pcie_port *port)
> > > +{
> > > +     u32 chip_rev_id = rt_sysc_r32(MT7621_CHIP_REV_ID);
> > > +
> > > +     if ((chip_rev_id & 0xFFFF) == CHIP_REV_MT7621_E2)
> > > +             reset_control_deassert(port->pcie_rst);
> > > +     else
> > > +             reset_control_assert(port->pcie_rst);
> > > +}
> >
> > The commit message is very good that on some chips assert and deassert
> > mean the opposite but I feel like this should be commented in the code
> > as well or people reading this code will be very confused.
> >
> 
> Ok, Dan. Agreed. I will add some comment in next series.
> 
> > Also it would be better if we could change this from a white list to a
> > black list.  In other words, if they were to come out with new revs
> > of the hardware, we should assume that assert means assert and deassert
> > means deassert.
> 
> I understand what you are saying but I don't know how to handle those
> white and black lists... Is there some kind of example where I can
> take a look to handle this in a proper way?
> 

What I mean is flip it around so that it becomes:

static inline void mt7621_control_deassert(struct mt7621_pcie_port *port)
{
	u32 chip_rev_id = rt_sysc_r32(MT7621_CHIP_REV_ID);

	/* Some revisions have assert and deassert reversed.  */
	if (chip_in_list_of_reversed_revs) {
		reset_control_assert(port->pcie_rst);
		return;
	}

	reset_control_deassert(port->pcie_rst);
}

regards,
dan carpenter