linux-kernel - RE: [PATCH 4/4] Documentation: atmel-at91: add DT bindings for fast startup

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Date:	Mon, 1 Feb 2016 06:22:26 +0000
From:	"Yang, Wenyou" <Wenyou.Yang@...el.com>
To:	Rob Herring <robh@...nel.org>
CC:	"Ferre, Nicolas" <Nicolas.FERRE@...el.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Russell King <linux@....linux.org.uk>,
	"linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Brown <broonie@...nel.org>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH 4/4] Documentation: atmel-at91: add DT bindings for fast
 startup

Hi Rob,

Thank you for your review.

> -----Original Message-----
> From: Rob Herring [mailto:robh@...nel.org]
> Sent: 2016年1月30日 0:20
> To: Yang, Wenyou <Wenyou.Yang@...el.com>
> Cc: Ferre, Nicolas <Nicolas.FERRE@...el.com>; Alexandre Belloni
> <alexandre.belloni@...e-electrons.com>; Jean-Christophe Plagniol-Villard
> <plagnioj@...osoft.com>; Russell King <linux@....linux.org.uk>; linux-
> clk@...r.kernel.org; Pawel Moll <pawel.moll@....com>; Mark Brown
> <broonie@...nel.org>; Ian Campbell <ijc+devicetree@...lion.org.uk>; Kumar
> Gala <galak@...eaurora.org>; linux-arm-kernel@...ts.infradead.org; linux-
> kernel@...r.kernel.org; devicetree@...r.kernel.org
> Subject: Re: [PATCH 4/4] Documentation: atmel-at91: add DT bindings for fast
> startup
> 
> On Thu, Jan 28, 2016 at 06:19:16PM +0800, Wenyou Yang wrote:
> > Add DT bindings to configurate the PMC_FSMR and PMC_FSPR registers to
> > trigger a fast restart signal to PMC.
> >
> > Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
> > ---
> >
> >  .../devicetree/bindings/arm/atmel-pmc.txt          |   74
> ++++++++++++++++++++
> >  1 file changed, 74 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/arm/atmel-pmc.txt
> > b/Documentation/devicetree/bindings/arm/atmel-pmc.txt
> > index 795cc78..8d45ff9f 100644
> > --- a/Documentation/devicetree/bindings/arm/atmel-pmc.txt
> > +++ b/Documentation/devicetree/bindings/arm/atmel-pmc.txt
> > @@ -12,3 +12,77 @@ Examples:
> >  		compatible = "atmel,at91rm9200-pmc";
> >  		reg = <0xfffffc00 0x100>;
> >  	};
> > +
> > +PMC Fast Startup Signals
> > +
> > +The PMC Fast Start Signals are used as the wake up source to trigger
> > +the PMC to wake up the system from the ULP1 mode.
> > +
> > +required properties:
> > +- compatible: Should be "atmel,sama5d2-pmc-fast-startup".
> 
> Why the compatible? Does this correspond to some h/w block rather than features
> of the PMC? If it is simply because you want to have a separate driver, that is not
> a good reason.

The PMC is regarded as an MFD device.

The Fast Startup function is a sub-device, the driver access the register
through regmap returned from the syscon helper API syscon_node_to_regmap().

> 
> > +
> > +optional properties:
> > +- atmel,fast-startup-wake-up: boolean to enable the WKUP pin to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-secumod: boolean to enable the Security Mode to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu0: boolean to enable the PIOBU0 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu1: boolean to enable the PIOBU1 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu2: boolean to enable the PIOBU2 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu3: boolean to enable the PIOBU3 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu4: boolean to enable the PIOBU4 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu5: boolean to enable the PIOBU5 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu6: boolean to enable the PIOBU6 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-piobu7: boolean to enable the PIOBU7 Input to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-gmac-wol: boolean to enable the GMAC Wake-up On
> > +LAN
> > +  to trigger a fast restart signal to the PMC.
> > +- atmel,fast-startup-rtc-alarm: boolean to enable the RTC Alarm to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-usb-resume: boolean to enable the USB Resume to
> > +trigger
> > +  a fast restart signal to the PMC.
> > +- atmel,fast-startup-sdmmc-cd: boolean to enable the SDMMC Card
> > +Detect
> > +  to trigger a fast restart signal to the PMC.
> > +- atmel,fast-startup-rxlp-match: boolean to enable the Backuo UART
> > +Receive
> > +  Match Condition to trigger a fast restart signal to the PMC.
> > +- atmel,fast-startup-acc-comparison: boolean to enable the Analog
> > +Comparator
> > +  Controller (ACC) Comparison to to trigger a fast restart signal to the PMC.
> > +
> > +- atmel,fast-startup-wkup-pin-high: boolean to indicate if the WKUP
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> 
> Perhaps just make the above bool properties take a value to indicate high or low
> triggered.

Agreed. 

How about the following changes? And a more compact form.

atmel,fs-wkup-pin-level = <1>; to indicated the WKUP Pin is in the high level trigged.
atmel,fs-wkup-pin-level = <0>; to indicated the WKUP Pin is in the low level trigged.

> 
> > +- atmel,fast-startup-piobu0-high: boolean to indicate if the PIOBU0
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu1-high: boolean to indicate if the PIOBU1
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu2-high: boolean to indicate if the PIOBU2
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu3-high: boolean to indicate if the PIOBU3
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu4-high: boolean to indicate if the PIOBU4
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu5-high: boolean to indicate if the PIOBU5
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu6-high: boolean to indicate if the PIOBU6
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> > +- atmel,fast-startup-piobu7-high: boolean to indicate if the PIOBU7
> > +Pin is
> > +  in the high level to trigger fast restart signal, otherwise low level.
> 
> This would be a long list in the DT if you set all these properties.
> Perhaps this should all be expressed in a more compact form.
> 

Yes, change as above.

> > +
> > +Example:
> > +
> > +	pmc: pmc@...14000 {
> > +		compatible = "atmel,sama5d2-pmc";
> > +		reg = <0xf0014000 0x160>;
> > +
> > +		pmc_fast_restart {
> > +			compatible = "atmel,sama5d2-pmc-fast-startup";
> > +			atmel,fast-startup-wake-up;
> > +			atmel,fast-startup-rtc-alarm;
> > +		};
> > +	};
> > --
> > 1.7.9.5
> >


Best Regards,
Wenyou Yang