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+rene...@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
> @@ -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
you cannot (ab)use the MDIO bus GPIO reset logic anymore...
Should not you also try to manage this reset line during ravb_open() to
achiever better power savings?
--
Florian
