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Date:   Wed, 16 Dec 2020 08:31:34 +0300
From:   Serge Semin <Sergey.Semin@baikalelectronics.ru>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     Serge Semin <fancer.lancer@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        <netdev@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-kernel@vger.kernel.org>,
        Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
        Jose Abreu <joabreu@synopsys.com>,
        Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Vyacheslav Mitrofanov 
        <Vyacheslav.Mitrofanov@baikalelectronics.ru>,
        "David S. Miller" <davem@davemloft.net>,
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC] net: stmmac: Problem with adding the native GPIOs support
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On Wed, Dec 16, 2020 at 03:03:55AM +0100, Andrew Lunn wrote:
> > > From what you are saying, it sounds like from software you cannot
> > > independently control the GPIO controller reset?
> > 
> > No. The hardware implements the default MAC reset behavior. So the
> > GPIO controller gets reset synchronously with the MAC reset and that
> > can't be changed.
> 

> Is there pinmux support for these pins?  Can you disconnect them from
> the MAC? Often pins can be connected to different internal IP
> blocks. Maybe you can flip the pin mux, perform the MAC reset, and
> then put the pinmux back to connect the pins to the MAC IP again?

Alas no. Pins multiplexing isn't implemented in the Baikal-T1 SoC at all.
Each pin has been assigned with a single function. In this case DW GMAC
GPO/GPI pins always serve as GPO/GPI and nothing else.

-Sergey

> 
>      Andrew