Hi Florian,
On Thu, Sep 28, 2017 at 7:22 PM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
> On 09/28/2017 08:53 AM, Geert Uytterhoeven wrote:
>> If the optional "reset-gpios" property is specified in DT, the generic
>> MDIO bus code takes care of resetting the PHY during device probe.
>> However, the PHY may still have to be reset explicitly after system
>> resume.
>>
>> This allows to restore Ethernet operation after resume from s2ram on
>> Salvator-XS, where the enable pin of the regulator providing PHY power
>> is connected to PRESETn, and PSCI suspend powers down the SoC.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>> ---
>> drivers/net/ethernet/renesas/ravb_main.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index fdf30bfa403bf416..96d1d48e302f8c9a 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>> @@ -19,6 +19,7 @@
>> #include <linux/etherdevice.h>
>> #include <linux/ethtool.h>
>> #include <linux/if_vlan.h>
>> +#include <linux/gpio/consumer.h>
>> #include <linux/kernel.h>
>> #include <linux/list.h>
>> #include <linux/module.h>
>> @@ -2268,6 +2269,7 @@ static int __maybe_unused ravb_resume(struct device *dev)
>> {
>> struct net_device *ndev = dev_get_drvdata(dev);
>> struct ravb_private *priv = netdev_priv(ndev);
>> + struct mii_bus *bus = priv->mii_bus;
>> int ret = 0;
>>
>> if (priv->wol_enabled) {
>> @@ -2302,6 +2304,13 @@ static int __maybe_unused ravb_resume(struct device *dev)
>> * reopen device if it was running before system suspended.
>> */
>>
>> + /* PHY reset */
>> + if (bus->reset_gpiod) {
>> + gpiod_set_value_cansleep(bus->reset_gpiod, 1);
>> + udelay(bus->reset_delay_us);
>> + gpiod_set_value_cansleep(bus->reset_gpiod, 0);
>> + }
>
> This is a clever hack, but unfortunately this is also misusing the MDIO
> bus reset line into a PHY reset line. As commented in patch 3, if this
> reset line is tied to the PHY, then this should be a PHY property and
OK.
> you cannot (ab)use the MDIO bus GPIO reset logic anymore...
And then I should add reset-gpios support to drivers/net/phy/micrel.c?
Or is there already generic code to handle per-PHY reset? I couldn't find it.
> Should not you also try to manage this reset line during ravb_open() to
> achiever better power savings?
I don't know. The Micrel KSZ9031RNXVA datasheet doesn't mention if it's
safe or not to assert reset for a prolonged time.
Thanks!
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
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