Re: [PATCH net-next v2 01/10] net: dsa: lan9303: Fixed MDIO interface

[Egil Hjelmeland]

On 25. juli 2017 21:15, Vivien Didelot wrote:
> Hi Egil,
>
> Egil Hjelmeland <privat@xxxxxxxxxxxxxxxxxx> writes:
>
> > Fixes after testing on actual HW:
> >
> > - lan9303_mdio_write()/_read() must multiply register number
> >    by 4 to get offset
> >
> > - Indirect access (PMI) to phy register only work in I2C mode. In
> >    MDIO mode phy registers must be accessed directly. Introduced
> >    struct lan9303_phy_ops to handle the two modes. Renamed functions
> >    to clarify.
> >
> > - lan9303_detect_phy_setup() : Failed MDIO read return 0xffff.
> >    Handle that.
>
> Small patch series when possible are better. Bullet points in commit
> messages are likely to describe how a patch or series may be split up
> ;-)
>
> This patch seems to be the unique patch of the series resolving what is
> described in the cover letter as "Make the MDIO interface work".
>
> I'd suggest you to split up this one commit in several *atomic* and easy
> to review patches and send them separately as on thread named "net: dsa:
> lan9303: fix MDIO interface" (also note that imperative is prefered for
> subject lines, see: https://chris.beams.io/posts/git-commit/#imperative)
>
> <...>
>
> > -static int lan9303_port_phy_reg_wait_for_completion(struct lan9303 *chip)
> > +static int lan9303_indirect_phy_wait_for_completion(struct lan9303 *chip)
>
> For instance you can have a first commit only renaming the functions.
> The reason for it is to separate the functional changes from cosmetic
> changes, which makes it easier for review.
>
> <...>

Thank you for reviewing.

I can split the first patch.

I can also split the patch series to more digestible series. But
since most of the patches touches the same file, I assume that each
series must be completed and applied before starting on a new one.
So I really want to group the patches into only a few series in order
to not spend months on the process.


> > +	if ((reg != 0) && (reg != 0xffff))
>
> if (reg && reg != 0xffff) should be enough.

Of course.

> > +struct lan9303_phy_ops {
> > +	/* PHY 1 &2 access*/
>
> The spacing is weird in the comment. "/* PHY 1 & 2 access */" maybe?

Yes.

> > +int lan9303_mdio_phy_write(struct lan9303 *chip, int phy, int regnum, u16 val)
> > +{
> > +	struct lan9303_mdio *sw_dev = dev_get_drvdata(chip->dev);
> > +	struct mdio_device *mdio = sw_dev->device;
> > +
> > +	mutex_lock(&mdio->bus->mdio_lock);
> > +	mdio->bus->write(mdio->bus, phy, regnum, val);
> > +	mutex_unlock(&mdio->bus->mdio_lock);
>
> This is exactly what mdiobus_write(mdio->bus, phy, regnum, val) is
> doing. There are very few valid reasons to go play in the mii_bus
> structure, using generic APIs are strongly prefered. Plus you have
> checks and traces for free!

Lack of oversight was the only reason. I just adapted stuff from
lan9303_mdio_phy_write above. Will switch to mdiobus_write of course.

> Same here, mdiobus_read().
Ditto.

> Thanks,
>
>          Vivien

Appreciated,
Egil