Subject: Re: [PATCH 1/6] bus: Add shared MDIO bus framework
To: Andrew Lunn <andrew@lunn.ch>, Pramod Kumar <pramod.kumar@broadcom.com>
References: <1461230323-27891-1-git-send-email-pramod.kumar@broadcom.com>
 <1461230323-27891-2-git-send-email-pramod.kumar@broadcom.com>
 <20160425205650.GA31129@lunn.ch>
 <666dffb41a922b0c8638f2f002a2de08@mail.gmail.com>
 <20160426121335.GC11668@lunn.ch>
Cc: Rob Herring <robh+dt@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Chen-Yu Tsai <wens@csie.org>, Mark Rutland <mark.rutland@arm.com>,
        devicetree@vger.kernel.org, Pawel Moll <pawel.moll@arm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Suzuki K Poulose <suzuki.poulose@arm.com>, netdev@vger.kernel.org,
        Punit Agrawal <punit.agrawal@arm.com>, linux-kernel@vger.kernel.org,
        BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
        linux-arm-kernel@lists.infradead.org,
        Anup Patel <anup.patel@broadcom.com>
From: Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <571FA3F6.7000903@gmail.com>
Date: Tue, 26 Apr 2016 10:23:02 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <20160426121335.GC11668@lunn.ch>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 880
Lines: 21

On 26/04/16 05:13, Andrew Lunn wrote:
>> 4. Apart from these, by using MDIO mux framework we are making our
>> non-ethernet PHYs dependent on Linux network drivers which is not
>> acceptable. What if some product line does not need network subsystem at
>> all?
> 
> This is your only valid point. However, does Broadcom have a product
> line which does not include networking? Is not Broadcom a network SoC
> vendor?

But even with that, there is no reason why we could not decouple the
PHYLIB MDIO framework from PHYLIB and make it available as a more
standalone subsystem which can be utilized when you have a mix of MDIO
devices like here.

I am not clear on how common a shared MDIO bus is on other SoCs, but the
other Broadcom SoCs I am familiar with have dedicated MDIO buses
instances per type of PHY (PCIe, BUSB, Ethernet), thus making the split
a ton easier.
-- 
Florian