Re: [PATCH] phy: qcom: qmp: Add debug prints for register writes

Dmitry Baryshkov
2024-07-31T12:18:36Z

On Wed, Jul 31, 2024 at 04:28:46PM GMT, Vinod Koul wrote:
> On 30-07-24, 15:33, Manivannan Sadhasivam wrote:
> > These register prints are useful to validate the init sequence against the
> > Qcom internal documentation and also to share with the Qcom hw engineers to
> > debug issues related to PHY.
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> > drivers/phy/qualcomm/phy-qcom-qmp-common.h | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-common.h b/drivers/phy/qualcomm/phy-qcom-qmp-common.h
> > index 799384210509..e6a6bcfcac28 100644
> > --- a/drivers/phy/qualcomm/phy-qcom-qmp-common.h
> > +++ b/drivers/phy/qualcomm/phy-qcom-qmp-common.h
> > @@ -9,6 +9,7 @@
> > struct qmp_phy_init_tbl {
> > unsigned int offset;
> > unsigned int val;
> > + char *name;
> > /*
> > * mask of lanes for which this register is written
> > * for cases when second lane needs different values
> > @@ -20,6 +21,7 @@ struct qmp_phy_init_tbl {
> > { \
> > .offset = o, \
> > .val = v, \
> > + .name = #o, \
> > .lane_mask = 0xff, \
> > }
> >
> > @@ -27,6 +29,7 @@ struct qmp_phy_init_tbl {
> > { \
> > .offset = o, \
> > .val = v, \
> > + .name = #o, \
> > .lane_mask = l, \
> > }
> >
> > @@ -45,6 +48,7 @@ static inline void qmp_configure_lane(void __iomem *base,
> > if (!(t->lane_mask & lane_mask))
> > continue;
> >
> > + pr_debug("QMP PHY: Writing: %s --> 0x%02x\n", t->name, t->val);
>
> This lgtm, but fails to help when offset _might_ be incorrect, including
> the offset value as well (not just the name) would be better imo...

Can we please use dev_vdbg instead? Having dev_ part makes sure that we
can not mismatch PHYs and the sequences. _vdbg is less important, but
I don't think we want this in the log messages unless absolutely
required.

Also, could you possibly apply this to all other QMP drivers?

>
> > writel(t->val, base + t->offset);
> > }
> > }
> > --
> > 2.25.1
>
> --
> ~Vinod
>
> --
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--
With best wishes
Dmitry