Re: [PATCH net-next v2 2/4] net: phy: Add a helper to return the index for of the internal delay

[Dan Murphy]

Florian

On 5/22/20 11:11 AM, Florian Fainelli wrote:
> On 5/22/2020 5:25 AM, Dan Murphy wrote:
> > Add a helper function that will return the index in the array for the
> > passed in internal delay value.  The helper requires the array, size and
> > delay value.
> >
> > The helper will then return the index for the exact match or return the
> > index for the index to the closest smaller value.
> >
> > Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
> > ---
> >   drivers/net/phy/phy_device.c | 45 ++++++++++++++++++++++++++++++++++++
> >   include/linux/phy.h          |  2 ++
> >   2 files changed, 47 insertions(+)
> >
> > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> > index 7481135d27ab..40f53b379d2b 100644
> > --- a/drivers/net/phy/phy_device.c
> > +++ b/drivers/net/phy/phy_device.c
> > @@ -2661,6 +2661,51 @@ void phy_get_pause(struct phy_device *phydev, bool *tx_pause, bool *rx_pause)
> >   }
> >   EXPORT_SYMBOL(phy_get_pause);
> >   
> > +/**
> > + * phy_get_delay_index - returns the index of the internal delay
> > + * @phydev: phy_device struct
> > + * @delay_values: array of delays the PHY supports
> > + * @size: the size of the delay array
> > + * @delay: the delay to be looked up
> > + *
> > + * Returns the index within the array of internal delay passed in.
> Can we consider using s32 for storage that way the various
> of_read_property_read_u32() are a natural fit (int works too, but I
> would prefer being explicit).

Ack

> > + */
> > +int phy_get_delay_index(struct phy_device *phydev, int *delay_values, int size,
> > +			int delay)
> > +{
> > +	int i;
> > +
> > +	if (size <= 0)
> > +		return -EINVAL;
> > +
> > +	if (delay <= delay_values[0])
> > +		return 0;
> > +
> > +	if (delay > delay_values[size - 1])
> > +		return size - 1;
> Does not that assume that the delays are sorted by ascending order, if
> so, can you make it clear in the kernel doc?

Yes I guess it does. I can add this to the k doc


> > +
> > +	for (i = 0; i < size; i++) {
> > +		if (delay == delay_values[i])
> > +			return i;
> > +
> > +		/* Find an approximate index by looking up the table */
> > +		if (delay > delay_values[i - 1] &&
> && i > 0 so you do not accidentally under-run the array?

Yes and no it maybe better to start the for loop with i being 
initialized to 1 since the zeroth element is already validated above.

Dan