Date: Mon, 27 Oct 2014 16:32:05 +0100
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
To: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Mark Brown <broonie@kernel.org>, atull@opensource.altera.com,
        jgunthorpe@obsidianresearch.com, hpa@zytor.com,
        Michal Simek <monstr@monstr.eu>, michal.simek@xilinx.com,
        rdunlap@infradead.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org, robh+dt@kernel.org,
        Grant Likely <grant.likely@linaro.org>, iws@ovro.caltech.edu,
        linux-doc@vger.kernel.org, Pavel Machek <pavel@denx.de>,
        philip@balister.org, rubini@gnudd.com, jason@lakedaemon.net,
        kyle.teske@ni.com, nico@linaro.org, Felipe Balbi <balbi@ti.com>,
        m.chehab@samsung.com, davidb@codeaurora.org,
        Rob Landley <rob@landley.net>, davem@davemloft.net, cesarb@cesarb.net,
        sameo@linux.intel.com, akpm@linux-foundation.org,
        Linus Walleij <linus.walleij@linaro.org>,
        mgerlach@opensource.altera.com, Alan Tull <delicious.quinoa@gmail.com>,
        dinguyen@opensource.altera.com, yvanderv@opensource.altera.com
Subject: Re: [PATCH v2 2/3] ARM: dts: socfpga: fpga bridges bindings docs
Message-ID: <20141027153205.GW10262@pengutronix.de>
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On Mon, Oct 27, 2014 at 05:05:29PM +0200, Pantelis Antoniou wrote:
> Hi Mark,
> 
> > On Oct 27, 2014, at 17:01 , Mark Brown <broonie@kernel.org> wrote:
> > 
> > On Mon, Oct 27, 2014 at 01:48:02PM +0200, Pantelis Antoniou wrote:
> >>> On Oct 24, 2014, at 02:51 , atull@opensource.altera.com wrote:
> > 
> >>> + - init-val         : 0 if driver should disable bridge at startup
> >>> +                      1 if driver should enable bridge at startup
> >>> +                      driver leaves bridge in current state if property not
> >>> +		      specified.
> > 
> >> Isn’t init-val a boolean property? It’s not named very well.
> > 
> > It's not boolean, it's tristate - turn on, turn off or don't touch.
> > 
> 
> I see. Even then ‘init-val’ is cryptic. I’d prefer two booleans,
> enable-at-startup; disable-at-startup.
> 
> >> Along with the label, is kinda hard to defend as configuration in DT.
> > 
> > Yeah...  presumably this decision would fall out of the users?
> 
> Well, it’s the user that should make the decision, but the driver should
> pick it up. This works but it’s not very nice.
> 

Hm, convince me why this AXI bus is so special, that I even need an
"init-val" property? Other buses don't have that.
Why don't I add a property "init-val" to my SPI buses, so I can enable
it in the DT and still have it in reset, just because....

The bridges on the SoCFPGA are buses, from the HPS to the FPGA. If I have
written firmware to the FPGA and I have subnodes on that bus, I have to
get it out of reset and probe everything. Normal procedure, no ?!


Regards,
Steffen

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