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

Sergei Shtylyov
2016-03-11T13:47:59Z

Hello.

On 3/11/2016 1:55 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.
>
> 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.
>
> 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);
> + if (!gpio_is_valid(phy_reset))
> + return;
> +
> + active_high = of_property_read_bool(np, "phy-reset-active-high");
> +
> + err = devm_gpio_request_one(dev, phy_reset, active_high ?
> + GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
> + "phy-reset");
> + if (err) {
> + dev_err(dev, "failed to get phy-reset-gpios: %d\n", err);
> + return;
> + }
> + msleep(msec);
> + gpio_set_value_cansleep(phy_reset, !active_high);
> +}
[...]

Why not make it the mii_bus::reset() method? It gets called before the
MDIO bus scan.

MBR, Sergei