[U-Boot] [PATCH v3 6/6] arm: mvf600: Add basic support for Vybrid MVF600TWR board

[Benoît Thébaudeau]

Hi Alison,

On Wednesday, May 22, 2013 10:23:12 AM, Wang Huan-B18965 wrote:

[...]

> > > +
> > > +#define ENET_PAD_CTRL	(PAD_CTL_PUS_47K_UP | PAD_CTL_SPEED_HIGH
> > | \
> > > +			PAD_CTL_DSE_50ohm | PAD_CTL_OBE_IBE_ENABLE)
> > > +
> > > +#define DDR_PAD_CTRL	PAD_CTL_DSE_25ohm
> > 
> > MUX_PAD_CTRL() could be added to the 4 pad control definitions above in
> > order to avoid repeating it everywhere below. But using MUX_PAD_CTRL()
> > relies on the fact that the pad control values in mvf_pins.h are all 0
> > (which is the case, but this is dangerous if this is changed later), so
> > a better approach could be to use NEW_PAD_CTRL(), e.g.:
> >         NEW_PAD_CTRL(MVF600_PAD_DDR_A15__DDR_A_15, DDR_PAD_CTRL),
> > instead of:
> >         MVF600_PAD_DDR_A15__DDR_A_15 | MUX_PAD_CTRL(DDR_PAD_CTRL),
> > 
> > > +
> [Alison Wang] I have a question about using NEW_PAD_CTRL(). If NEW_PAD_CTRL()
> is used, should the pad control values for MVF600_PAD_DDR_A15__DDR_A_15 in
> mvf_pins.h
> be the same as DDR_PAD_CTRL? I saw you didn't use the same value on other
> platforms,
> how do you define it?

No, you don't have to change mvf_pins.h. That's what NEW_PAD_CTRL() is useful
for: You can have any pad control value defined in mvf_pins.h, and a board can
override the pad control values when using definitions from mvf_pins.h, without
having to modify mvf_pins.h.

E.g.:
---
mvf_pins.h:
MVF600_PAD_PTA6__RMII0_CLKIN = IOMUX_PAD(0x0, 0x0, 2, 0x0, 0, PAD_CTRL1),

mvf600twr.c:
NEW_PAD_CTRL(MVF600_PAD_PTA6__RMII0_CLKIN, PAD_CTRL2),
---
would have the same effect as a theoretical:
---
mvf_pins.h:
MVF600_PAD_PTA6__RMII0_CLKIN = IOMUX_PAD(0x0, 0x0, 2, 0x0, 0, PAD_CTRL2),

mvf600twr.c:
MVF600_PAD_PTA6__RMII0_CLKIN,
---

But if you think that the pad control values that you have defined in
mvf600twr.c are not specific to this board and should be used as the default pad
control values for all boards based on the MVF600, then you should move those
definitions to mvf_pins.h, and use them there, which means that you will no
longer need MUX_PAD_CTRL() or NEW_PAD_CTRL() in mvf600twr.c:
---
mvf_pins.h:
#define MVF600_DDR_PAD_CTRL	PAD_CTL_DSE_25ohm
...
MVF600_PAD_DDR_A15__DDR_A_15 = IOMUX_PAD(0x0220, 0x0220, 0, 0x0000, 0,
                                         MVF600_DDR_PAD_CTRL),

mvf600twr.c:
MVF600_PAD_DDR_A15__DDR_A_15,
---

Best regards,
Benoît