linux-kernel - Re: [PATCH v2 1/2] smc91x: always use 8-bit access if necessary

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Message-ID: <alpine.LFD.2.20.1608251347170.17623@knanqh.ubzr>
Date:   Thu, 25 Aug 2016 13:48:32 -0400 (EDT)
From:   Nicolas Pitre <nico@...xnic.net>
To:     Arnd Bergmann <arnd@...db.de>
cc:     linux-arm-kernel@...ts.infradead.org,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Russell King <linux@...linux.org.uk>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH v2 1/2] smc91x: always use 8-bit access if necessary

On Thu, 25 Aug 2016, Arnd Bergmann wrote:

> As Russell King found out the hard way, a change I did to fix multiplatform
> builds with this driver broke the old Assabet/Neponset platform: It turns
> out that while the driver is runtime configurable in principle, the
> runtime configuration does not cover the specific case of machines that
> can not do any 16-bit I/O on the smc91x registers.
> 
> The driver currently provides helpers to access 16-bit registers for
> architectures that are known at compile-time to only have 8-bit I/O,
> but my patch changed it to a runtime flag that never gets consulted
> most register accesses.
> 
> This introduces new SMC_out16()/SMC_in16 helpers (if anyone can suggest
> a better name, I'm glad to modify this) that behaves like SMC_outw()/SMC_inw()
> most of the time, but uses a pair of 8-bit accesses on platforms that
> have no support for wider register accesses.

Why don't you fold this directly into SMC_outw() instead?


Nicolas