From: Mark Brown <broonie@kernel.org>
To: Michael Walle <michael@walle.cc>
Cc: "Lee Jones" <lee.jones@linaro.org>,
"Andy Shevchenko" <andy.shevchenko@gmail.com>,
"Ranjani Sridharan" <ranjani.sridharan@linux.intel.com>,
david.m.ertman@intel.com, shiraz.saleem@intel.com,
"Rob Herring" <robh+dt@kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-hwmon@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-watchdog@vger.kernel.org,
"linux-arm Mailing List" <linux-arm-kernel@lists.infradead.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Bartosz Golaszewski" <bgolaszewski@baylibre.com>,
"Jean Delvare" <jdelvare@suse.com>,
"Guenter Roeck" <linux@roeck-us.net>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Wim Van Sebroeck" <wim@linux-watchdog.org>,
"Shawn Guo" <shawnguo@kernel.org>, "Li Yang" <leoyang.li@nxp.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Jason Cooper" <jason@lakedaemon.net>,
"Marc Zyngier" <maz@kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v4 02/11] mfd: Add support for Kontron sl28cpld management controller
Date: Tue, 9 Jun 2020 15:42:01 +0100 [thread overview]
Message-ID: <20200609144201.GK4583@sirena.org.uk> (raw)
In-Reply-To: <32287ac0488f7cbd5a7d1259c284e554@walle.cc>
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On Tue, Jun 09, 2020 at 04:38:31PM +0200, Michael Walle wrote:
> mfd-device@10 {
> compatible = "simple-regmap", "simple-mfd";
> reg = <10>;
> regmap,reg-bits = <8>;
> regmap,val-bits = <8>;
> sub-device@0 {
> compatible = "vendor,sub-device0";
> reg = <0>;
> };
A DT binding like this is not a good idea, encoding the details of the
register map into the DT binding makes it an ABI which is begging for
trouble. I'd also suggest that any device using a generic driver like
this should have a specific compatible string for the device so we can
go back and add quirks later if we need them.
> ...
> };
>
> Or if you just want the regmap:
>
> &soc {
> regmap: regmap@fff0000 {
> compatible = "simple-regmap";
> reg = <0xfff0000>;
> regmap,reg-bits = <16>;
> regmap,val-bits = <32>;
> };
>
> enet-which-needs-syscon-too@1000000 {
> vendor,ctrl-regmap = <®map>;
> };
> };
>
> Similar to the current syscon (which is MMIO only..).
>
> -michael
>
> >
> > I can't think of any reasons why not, off the top of my head.
> >
> > Does Regmap only deal with shared accesses from multiple devices
> > accessing a single register map, or can it also handle multiple
> > devices communicating over a single I2C channel?
> >
> > One for Mark perhaps.
> >
> > > > The issues I wish to resolve using 'simple-mfd' are when sub-devices
> > > > register maps overlap and intertwine.
> >
> > [...]
> >
> > > > > > > What do these bits configure?
> > > > >
> > > > > - hardware strappings which have to be there before the board powers
> > > > > up,
> > > > > like clocking mode for different SerDes settings
> > > > > - "keep-in-reset" bits for onboard peripherals if you want to save
> > > > > power
> > > > > - disable watchdog bits (there is a watchdog which is active right
> > > > > from
> > > > > the start and supervises the bootloader start and switches to
> > > > > failsafe
> > > > > mode if it wasn't successfully started)
> > > > > - special boot modes, like eMMC, etc.
> > > > >
> > > > > Think of it as a 16bit configuration word.
> > > >
> > > > And you wish for users to be able to view these at run-time?
> > >
> > > And esp. change them.
> > >
> > > > Can they adapt any of them on-the-fly or will the be RO?
> > >
> > > They are R/W but only will only affect the board behavior after a
> > > reset.
> >
> > I see. Makes sense. This is board controller territory. Perhaps
> > suitable for inclusion into drivers/soc or drivers/platform.
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next prev parent reply other threads:[~2020-06-09 14:42 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 21:10 [PATCH v4 00/11] Add support for Kontron sl28cpld Michael Walle
2020-06-04 21:10 ` [PATCH v4 01/11] dt-bindings: mfd: Add bindings for sl28cpld Michael Walle
2020-06-09 16:28 ` Rob Herring
2020-06-04 21:10 ` [PATCH v4 02/11] mfd: Add support for Kontron sl28cpld management controller Michael Walle
2020-06-05 6:57 ` Lee Jones
2020-06-05 9:51 ` Michael Walle
2020-06-05 10:50 ` Mark Brown
2020-06-05 20:07 ` Michael Walle
2020-06-06 11:46 ` Mark Brown
2020-06-06 12:45 ` Michael Walle
2020-06-08 8:28 ` Lee Jones
2020-06-08 10:02 ` Andy Shevchenko
2020-06-08 15:41 ` Michael Walle
2020-06-08 18:56 ` Lee Jones
2020-06-08 21:09 ` Michael Walle
2020-06-09 6:47 ` Lee Jones
2020-06-09 14:38 ` Michael Walle
2020-06-09 14:42 ` Mark Brown [this message]
2020-06-09 15:01 ` Michael Walle
2020-06-09 17:15 ` Rob Herring
2020-06-09 17:29 ` Mark Brown
2020-06-09 18:41 ` Lee Jones
2020-06-09 15:19 ` Lee Jones
2020-06-09 15:30 ` Michael Walle
2020-06-09 19:45 ` Lee Jones
2020-06-10 7:10 ` Michael Walle
2020-06-10 7:19 ` Lee Jones
2020-06-10 7:49 ` Michael Walle
2020-06-10 7:56 ` Lee Jones
2020-06-10 9:27 ` Michael Walle
2020-06-10 18:30 ` Lee Jones
2020-06-10 17:16 ` Rob Herring
2020-06-10 18:02 ` Lee Jones
2020-06-08 18:20 ` Lee Jones
2020-06-09 16:54 ` Rob Herring
2020-06-09 18:52 ` Lee Jones
2020-06-05 8:01 ` Andy Shevchenko
2020-06-05 8:02 ` Andy Shevchenko
2020-06-05 10:09 ` Michael Walle
2020-06-05 10:48 ` Andy Shevchenko
2020-06-05 11:51 ` Michael Walle
2020-06-04 21:10 ` [PATCH v4 03/11] irqchip: add sl28cpld interrupt controller support Michael Walle
2020-06-05 1:26 ` kernel test robot
2020-06-05 8:07 ` Andy Shevchenko
2020-06-08 15:12 ` kernel test robot
2020-06-04 21:10 ` [PATCH v4 04/11] watchdog: add support for sl28cpld watchdog Michael Walle
2020-06-05 8:14 ` Andy Shevchenko
2020-06-05 10:24 ` Michael Walle
2020-06-05 10:50 ` Andy Shevchenko
2020-06-05 13:52 ` Guenter Roeck
2020-06-05 14:09 ` Andy Shevchenko
2020-06-05 15:05 ` Guenter Roeck
2020-06-05 16:04 ` Andy Shevchenko
2020-06-05 16:34 ` Guenter Roeck
2020-06-04 21:10 ` [PATCH v4 05/11] pwm: add support for sl28cpld PWM controller Michael Walle
2020-06-05 8:15 ` Andy Shevchenko
2020-06-05 8:49 ` Lee Jones
2020-06-05 9:33 ` Andy Shevchenko
2020-06-05 11:39 ` Michael Walle
2020-06-05 18:17 ` Michael Walle
2020-06-08 7:46 ` Lee Jones
2020-06-04 21:10 ` [PATCH v4 06/11] gpio: add support for the sl28cpld GPIO controller Michael Walle
2020-06-05 12:00 ` Andy Shevchenko
2020-06-05 12:42 ` Michael Walle
2020-06-05 13:15 ` Andy Shevchenko
2020-06-05 18:44 ` Michael Walle
2020-06-05 21:19 ` Andy Shevchenko
2020-06-04 21:10 ` [PATCH v4 07/11] hwmon: add support for the sl28cpld hardware monitoring controller Michael Walle
2020-06-05 12:06 ` Andy Shevchenko
2020-06-04 21:10 ` [PATCH v4 08/11] arm64: dts: freescale: sl28: enable sl28cpld Michael Walle
2020-06-04 21:10 ` [PATCH v4 09/11] arm64: dts: freescale: sl28: map GPIOs to input events Michael Walle
2020-06-04 21:10 ` [PATCH v4 10/11] arm64: dts: freescale: sl28: enable LED support Michael Walle
2020-06-04 21:10 ` [PATCH v4 11/11] arm64: dts: freescale: sl28: enable fan support Michael Walle
2020-06-05 6:13 ` [PATCH v4 00/11] Add support for Kontron sl28cpld Lee Jones
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