From: Sven Van Asbroeck <thesven73@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: devel@driverdev.osuosl.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] staging: fieldbus: anybuss: force address space conversion
Date: Tue, 21 May 2019 12:53:45 -0400 [thread overview]
Message-ID: <CAGngYiUSgtAXL+utPHz79OEbvrL6_TD9Wfkc6396E9vwQHCFKw@mail.gmail.com> (raw)
In-Reply-To: <20190521162451.GA19139@kroah.com>
On Tue, May 21, 2019 at 12:24 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> what is so odd about this code that makes you have to jump through
> strange hoops that no other driver has to?
>
Basically because it creates a regmap which accesses __iomem memory,
instead of i2c/spi.
This was done because future hardware in the company's pipeline will access
device register space through spi, instead of through a parallel memory bus.
The lower driver just has to create the appropriate regmap, __iomem or
spi, and pass it to the
upper driver, which does not have to know about the exact way the h/w
gets accessed.
So regmap is used as a hw abstraction layer.
The issue here is that a regmap context is a 'void *' yet the parallel
memory base pointer
is 'void __iomem *'. And so the two are incompatible.
next prev parent reply other threads:[~2019-05-21 16:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-21 14:51 [PATCH] staging: fieldbus: anybuss: force address space conversion Sven Van Asbroeck
2019-05-21 15:10 ` Dan Carpenter
2019-05-21 15:19 ` Sven Van Asbroeck
2019-05-21 15:42 ` Greg KH
2019-05-21 15:53 ` Sven Van Asbroeck
2019-05-21 16:24 ` Greg KH
2019-05-21 16:53 ` Sven Van Asbroeck [this message]
2019-05-21 17:06 ` Sven Van Asbroeck
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