Re: [PATCH 3/6] net: arc_emac: support the phy reset for emac driver

[Caesar Wang]

Hi Sergei,

å 2016å03æ12æ 02:35, Sergei Shtylyov åé:
> On 03/11/2016 01:55 PM, Caesar Wang wrote:
>
> > This patch adds to support the emac phy reset.
> >
> > 1) phy-reset-gpios:
> > The phy-reset-gpios is an optional property for arc emac device tree 
> > boot.
> > Change the binding document to match the driver code.
>
>    The binding document is apparently changed in another patch. Not 
> sure what you wanted to say here...
>
> > 2) phy-reset-duration:
> > Different boards may require different phy reset duration. Add property
> > phy-reset-duration for device tree probe, so that the boards that need
> > a longer reset duration can specify it in their device tree.
> >
> > 3) phy-reset-active-high:
> > We need that for a custom hardware that needs the reverse reset 
> > sequence.
>
>    No, we don't really need that, "phy-reset-gpio" prop can contain 
> this data.
>
> > Of course, this patch will fix the issue on
> > https://patchwork.kernel.org/patch/8186801/.
> >
> > In some cases, the emac couldn't work if you don't have reset the phy.
> > Let's add it to happy work.
> >
> > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> > ---
> >
> >   drivers/net/ethernet/arc/emac_main.c | 41 
> > ++++++++++++++++++++++++++++++++++++
> >   1 file changed, 41 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/arc/emac_main.c 
> > b/drivers/net/ethernet/arc/emac_main.c
> > index 6446af1..42384f6a 100644
> > --- a/drivers/net/ethernet/arc/emac_main.c
> > +++ b/drivers/net/ethernet/arc/emac_main.c
> > @@ -764,6 +764,45 @@ static const struct net_device_ops 
> > arc_emac_netdev_ops = {
> >   #endif
> >   };
> >
> > +#ifdef CONFIG_OF
> > +static void emac_reset_phy(struct net_device *pdev)
> > +{
> > +    int err, phy_reset;
> > +    bool active_high = false;
> > +    int msec = 10;
> > +    struct device *dev = pdev->dev.parent;
> > +    struct device_node *np = dev->of_node;
> > +
> > +    if (!np)
> > +        return;
> > +
> > +    of_property_read_u32(np, "phy-reset-duration", &msec);
> > +    /* A sane reset duration should not be longer than 1s */
> > +    if (msec > 1000)
> > +        msec = 1;
> > +
> > +    phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
>
>    Forgot to say that these old integer-base GPIO APIs shouldn't be 
> used by the new code, there's new 'struct gpio_desc' based APIs, like 
> devm_gpiod_get() etc.
>
> > +    if (!gpio_is_valid(phy_reset))
> > +        return;
> > +
> > +    active_high = of_property_read_bool(np, "phy-reset-active-high");
>
>    Well, I still don't understand why this prop is needed, while the 
> GPIO sense is transparently handled by the gpiolib (at least when 
> using DT).

Okay, I have to admit that reference the exist way to do...


wxt@nb:~/kernel/drivers/net/ethernet$ ag reset-gpios
micrel/ks8851.c
1427:    gpio = of_get_named_gpio_flags(spi->dev.of_node, "reset-gpios",

arc/emac_main.c
787:    phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
797:        dev_err(dev, "failed to get phy-reset-gpios: %d\n", err);

arc/emac_main.c~
784:    phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
794:        dev_err(dev, "failed to get phy-reset-gpios: %d\n", err);

davicom/dm9000.c
1451:    reset_gpios = of_get_named_gpio_flags(dev->of_node, 
"reset-gpios", 0,

freescale/fec_main.c
3206:    phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
3216:        dev_err(&pdev->dev, "failed to get phy-reset-gpios: %d\n", 
err);

cadence/macb.c
2958:        int gpio = of_get_named_gpio(phy_node, "reset-gpios", 0);

...

Yep, the gpiolib that can include the prop to work with the same ways.



> [...]
>
> MBR, Sergei
>
>
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--
Thanks,
Caesar