On 09/30/2017 01:23 PM, Sergei Shtylyov wrote:

Hello!

On 09/28/2017 10:21 PM, Florian Fainelli wrote:

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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@glider.be>
---
  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

[...]

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@@ -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.

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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.

There is not such a thing unfortunately, but it would presumably be

   It's strange you don't remember about my (abandoned) patches to
handle per=PHY reset GPIOs -- perhaps it's time to unearth them. Here
they are:

http://patchwork.ozlabs.org/patch/616495/
http://patchwork.ozlabs.org/patch/616501/

   I had v3 in the works before abandoning this series -- it doesn't
apply now.

Should Geert pick-up where you left and address the feedback given in
v2, or do you plan to post a rebased v3?

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called within drivers/net/phy/mdio_bus.c during bus->reset() time
because you need the PHY reset to be deasserted before you can
successfully read/write from the PHY, and if you can't read/write from
the PHY, the MDIO bus layer cannot read the PHY ID, and therefore cannot
match a PHY device with its driver, so things don't work.

   I did this a bit differently...

[...]

MBR, Sergei

-- 
Florian