From: Lee Jones <lee.jones@linaro.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Damien Riegel <damien.riegel@savoirfairelinux.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-watchdog@vger.kernel.org, shawnguo@kernel.org,
kernel@pengutronix.de, wim@iguana.be, robh+dt@kernel.org,
sameo@linux.intel.com, dinh.linux@gmail.com, linux@roeck-us.net,
kernel@savoirfairelinux.com
Subject: Re: [PATCH v2 2/5] mfd: ts4800-syscon: add driver for TS-4800 syscon
Date: Tue, 3 Nov 2015 10:12:17 +0000 [thread overview]
Message-ID: <20151103101217.GE3503@x1> (raw)
In-Reply-To: <4911273.Q2mbQ2gvpn@wuerfel>
On Tue, 03 Nov 2015, Arnd Bergmann wrote:
> On Tuesday 03 November 2015 08:39:23 Lee Jones wrote:
> > On Tue, 03 Nov 2015, Lee Jones wrote:
> >
> > > On Mon, 02 Nov 2015, Damien Riegel wrote:
> > > > On Mon, Nov 02, 2015 at 09:12:53AM +0000, Lee Jones wrote:
> > > > > [Cc'ing Arnd]
> > > > >
> > > > > On Fri, 30 Oct 2015, Damien Riegel wrote:
> > > > > > On Fri, Oct 30, 2015 at 05:56:56PM +0000, Lee Jones wrote:
> > > > > > > On Thu, 29 Oct 2015, Damien Riegel wrote:
> > > > > > >
> > > > > > > > Driver for TS-4800 syscon. These registers belong to a FPGA that is
> > > > > > > > memory mapped and are used for counters, enable various IPs in the FPGA,
> > > > > > > > control LEDs, control IOs, etc.
> > > > > > > >
> > > > > > > > Currently, only the watchdog is handled.
> > > > > > >
> > > > > > > Why do you require your own syscon driver?
> > > > > > >
> > > > > > > What's wrong with the generic one?
> > > > > > >
> > > > > >
> > > > > > The generic one uses a regmap_config with reg_stride set to 4 and val_bits
> > > > > > to 32.
> > > > > >
> > > > > > TS-4800 syscon registers are 16-bit wide and must be accessed with 16
> > > > > > bit read and writes:
> > > > > > http://wiki.embeddedarm.com/wiki/TS-4800#Syscon
> > > > > >
> > > > > > I will address the other issues in the next version (split commit,
> > > > > > license issue, style, and superfluous remove).
> > > > >
> > > > > The Syscon driver was written to be generic so that each
> > > > > vendor/platform didn't require their own incarnation. How unique is
> > > > > the TS-4800?
> > > > >
> > > > > Perhaps it might be better to supply a generic 16 bit Syscon for
> > > > > devices akin to the TS-4800?
> > > >
> > > > The TS-4800 syscon could use a generic 16-bit syscon. There is nothing
> > > > specific that requires a driver besides that.
> > > >
> > > > We could add some optional properties to the generic syscon node to
> > > > configure reg_bits, val_bits, and reg_stride (and pad_bits ?). Would
> > > > that be a good solution ?
> > >
> > > Without looking at the ramifications of such an addition, the premise
> > > sounds good to me. So long as the current behaviour remains the
> > > default.
> >
> > Perhaps a "syscon-16bit" compatible might be in order?
> >
> >
>
> I think a 'buswidth=<16>;' property in addition to 'compatible="syscon"'
> is more in line with what other subsystems do.
Perfect. Are you happy coding this up Damien?
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2015-11-03 10:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 20:27 [PATCH v2 0/5] Add board support for TS-4800 Damien Riegel
2015-10-29 20:27 ` [PATCH v2 1/5] of: add vendor prefix for Technologic Systems Damien Riegel
2015-10-30 18:04 ` Lee Jones
2015-10-30 19:58 ` Damien Riegel
2015-11-02 9:13 ` Lee Jones
2015-10-29 20:27 ` [PATCH v2 2/5] mfd: ts4800-syscon: add driver for TS-4800 syscon Damien Riegel
2015-10-30 17:56 ` Lee Jones
2015-10-30 20:08 ` Damien Riegel
2015-11-02 9:12 ` Lee Jones
2015-11-02 18:13 ` Damien Riegel
2015-11-03 8:38 ` Lee Jones
2015-11-03 8:39 ` Lee Jones
2015-11-03 8:40 ` Arnd Bergmann
2015-11-03 10:12 ` Lee Jones [this message]
2015-11-03 10:48 ` Arnd Bergmann
2015-11-03 14:36 ` Damien Riegel
2015-10-29 20:27 ` [PATCH v2 3/5] watchdog: ts4800: add driver for TS-4800 watchdog Damien Riegel
2015-10-30 17:28 ` Lee Jones
2015-10-30 17:52 ` Lee Jones
2015-10-29 20:27 ` [PATCH v2 4/5] ARM: imx_v6_v7_defconfig: add TS-4800 watchdog and syscon Damien Riegel
2015-10-29 20:27 ` [PATCH v2 5/5] ARM: dts: TS-4800: add basic device tree Damien Riegel
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