Re: [PATCH 12/14] phy: qcom-qmp-combo: rename common-register pointers

Johan Hovold
2022-11-14T15:52:23Z

On Mon, Nov 14, 2022 at 06:38:36PM +0300, Dmitry Baryshkov wrote:
> On 14/11/2022 15:54, Johan Hovold wrote:
> > On Sat, Nov 12, 2022 at 02:31:27PM +0300, Dmitry Baryshkov wrote:
> >> On 11/11/2022 12:24, Johan Hovold wrote:
> >>> The common registers are shared by the USB and DP parts of the PHY so
> >>> drop the misleading "dp" prefix from the corresponding pointers.
> >>>
> >>> Note that the "DP" prefix could also be dropped from the corresponding
> >>> defines, but leave that in place for now.
> >>>
> >>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> >>> ---
> >>> drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 24 +++++++++++------------
> >>> 1 file changed, 12 insertions(+), 12 deletions(-)
> >>
> >> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >>
> >> Note regarding the last phrase: I'd suggest leaving the DP prefix in
> >> register names, it makes it easier to visually note & verify the
> >> register block.
> >
> > My point is that "DP" was never part of the COM register block name. The
> > confusion likely comes from the vendor driver naming these defines along
> > the lines of
> >
> > USB3_DP_COM_POWER_DOWN_CTRL
> >
> > Here "USB3_DP" is the common prefix for all defines that apply to both
> > "parts" of the PHY so the corresponding Linux define
> >
> > QPHY_V3_DP_COM_POWER_DOWN_CTRL
> >
> > should either include "USB3" or drop "DP".
>
> My thought was that we already have too many _COM_ defines in the qmp
> headers. Having QPHY_Vn_COM_something would make it too easy to mix it
> with QSERDES_Vn_COM_foo. Thus I'd vote to leave DP_COM prefix in place.
> While it might be not fully accurate, it serves the point of identifying
> the register block.

I don't mind terribly and I didn't even consider trying to rename the
current defines.

The lack of public conclusive documentation makes structuring this mess
much harder than it should have to be.

That said, I don't really think that the risk of mixing up
QPHY_Vn_COM_foo with QSERDES_Vn_COM_bar is something we need to worry
about as you already have a separating "QSERDES" in there. Those sets of
registers should be disjoint too if I remember correctly.

> > This becomes more apparent on SC8280XP where the corresponding define
> > is:
> >
> > USB43DP_COM_POWER_DOWN_CTRL
>
> I'd still use something like QPHY_V10_DP_COM_POWER_DOWN_CTRL here.

Yeah, but then you're just making names up. ;)

Johan