From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH 2/4] ravb: Add optional PHY reset during system resume Date: Sun, 1 Oct 2017 09:34:44 -0700 Message-ID: <846bb632-9fcf-3306-c2cf-4d913fd1834a@gmail.com> References: <1506614014-4398-1-git-send-email-geert+renesas@glider.be> <1506614014-4398-3-git-send-email-geert+renesas@glider.be> <406f7aff-e386-31f3-39d3-17523443c265@gmail.com> <1a474c45-29ea-82fa-1ab0-0febfdc38bcb@gmail.com> <47456e34-2c2f-ec19-fcda-e3132a8037b3@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: Geert Uytterhoeven , "David S . Miller" , Simon Horman , Magnus Damm , Andrew Lunn , =?UTF-8?Q?Niklas_S=c3=b6derlund?= , "netdev@vger.kernel.org" , Linux-Renesas , "devicetree@vger.kernel.org" To: Sergei Shtylyov , Geert Uytterhoeven Return-path: In-Reply-To: <47456e34-2c2f-ec19-fcda-e3132a8037b3@cogentembedded.com> Content-Language: en-US Sender: linux-renesas-soc-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 09/30/2017 01:23 PM, Sergei Shtylyov wrote: > Hello! > > On 09/28/2017 10:21 PM, Florian Fainelli 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 >>>>> --- >>>>>   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 > [...] >>>>> @@ -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. >> >> 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? > >> 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