From mboxrd@z Thu Jan  1 00:00:00 1970
From: greg@kroah.com (Greg KH)
Date: Mon, 3 Jan 2011 13:29:11 -0800
Subject: FPGA registers userspace interface?
In-Reply-To: <AANLkTinRz_6_+eqQ2pp3zS7BPYzuqALbu63PnKCcAFjJ@mail.gmail.com>
References: <AANLkTikyfdSftQYmjsNZkzmTKO3K79_Jz7kzgK7_sWGy@mail.gmail.com>
	<4D21C86E.6060503@pjd.me.uk>
	<AANLkTik-Cby55gUWZjLw+R+g2QTPLOi8Lh+smxr5_9bV@mail.gmail.com>
	<AANLkTimiuVSxuVa7JS25h23Ls-QiE97FapE94yYuPeOJ@mail.gmail.com>
	<AANLkTinRz_6_+eqQ2pp3zS7BPYzuqALbu63PnKCcAFjJ@mail.gmail.com>
Message-ID: <20110103212911.GA4776@kroah.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On Mon, Jan 03, 2011 at 10:52:34PM +0200, Daniel Baluta wrote:
> > I thought about using 3 files in sysfs.
> > 1. address of the register
> > 2. data to write to the register
> > 3. trigger that do the write
> 
> The most effective solution would be to
> have one file per register.
> 
> Writing register:
> # echo value > /sys/path/to/file
> 
> Reading register:
> # cat /sys/path/to/file
> 
> Also, since your FPGA is in development phase I assume that
> the registers base address is changing (or am I wrong?). You can
> solve this with an additional writable sysfs entry  which will
> hold the current base address.

Also remember that debugfs would also be good for something like this,
being much easier to use than sysfs.

Note the rule when using debugfs:
	There is are no rules when using debugfs.

Which works much better when doing development :)

thanks,

greg k-h