Re: [PATCH v3 1/4] phylib: Add device reset GPIO support

From: Geert Uytterhoeven
Date: Sat Oct 21 2017 - 06:08:49 EST


On Sat, Oct 21, 2017 at 12:03 PM, Sergei Shtylyov
<sergei.shtylyov@xxxxxxxxxxxxxxxxxx> wrote:
> On 10/20/2017 9:11 PM, Florian Fainelli wrote:
>>> From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
>>> --- a/drivers/of/of_mdio.c
>>> +++ b/drivers/of/of_mdio.c
>
> [...]
>>>
>>> @@ -55,10 +56,22 @@ static int of_mdiobus_register_phy(struct mii_bus
>>> *mdio,
>>> is_c45 = of_device_is_compatible(child,
>>> "ethernet-phy-ieee802.3-c45");
>>> + /* Deassert the optional reset signal */
>>> + gpiod = fwnode_get_named_gpiod(&child->fwnode, "reset-gpios", 0,
>>> + GPIOD_OUT_LOW, "PHY reset");
>>> + if (PTR_ERR(gpiod) == -ENOENT)
>>> + gpiod = NULL;
>>> + else if (IS_ERR(gpiod))
>>> + return PTR_ERR(gpiod);
>>> +
>>> if (!is_c45 && !of_get_phy_id(child, &phy_id))
>>> phy = phy_device_create(mdio, addr, phy_id, 0, NULL);
>>> else
>>> phy = get_phy_device(mdio, addr, is_c45);
>>> +
>>> + /* Assert the reset signal again */
>>> + gpiod_set_value(gpiod, 1);
>>
>> You have a phy_device reference now, so why not call phy_device_reset()
>> directly here?
>
> Symmetry, perhaps? (There was a gpiod_set_value(gpiod, 0) call above
> it...

Not only because of symmetry: the validity of the phy object hasn't been
checked yet (that's done immediately below), and phy->mdio.reset hasn't been
filled in yet.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds