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

Sergei Shtylyov
2016-03-11T18:35:17Z

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@rock-chips.com>
> ---
>
> 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).

[...]

MBR, Sergei