diff mbox series

[1/3,v3] dt-bindings: abx80x: Add autocal-filter property

Message ID 20200615105113.57770-1-kevin+linux@km6g.us
State Changes Requested
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Series [1/3,v3] dt-bindings: abx80x: Add autocal-filter property | expand

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Commit Message

Kevin P. Fleming June 15, 2020, 10:51 a.m. UTC
Add a property to allow control of the autocalibration filter
capacitor.

Signed-off-by: Kevin P. Fleming <kevin+linux@km6g.us>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
To: linux-rtc@vger.kernel.org
To: devicetree@vger.kernel.org
---
v3: corrected whitespace
 Documentation/devicetree/bindings/rtc/abracon,abx80x.txt | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Rob Herring July 13, 2020, 6:39 p.m. UTC | #1
On Mon, Jun 15, 2020 at 06:51:11AM -0400, Kevin P. Fleming wrote:
> Add a property to allow control of the autocalibration filter
> capacitor.
> 
> Signed-off-by: Kevin P. Fleming <kevin+linux@km6g.us>
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> To: linux-rtc@vger.kernel.org
> To: devicetree@vger.kernel.org
> ---
> v3: corrected whitespace
>  Documentation/devicetree/bindings/rtc/abracon,abx80x.txt | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> index 2405e35a1bc0f..1b606e33d1a83 100644
> --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> @@ -29,3 +29,11 @@ and valid to enable charging:
>   - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V)
>   - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output
>                            resistor, the other values are in kOhm.
> +
> +All of the devices can have a 47pf capacitor attached to increase the
> +autocalibration accuracy of their RC oscillators. To enable or disable usage
> +of the capacitor the following property can be defined:
> +
> + - "abracon,autocal-filter": should be <0> or <1>. 0 indicates that there
> +                             is no capacitor attached, 1 indicates that there
> +                             is a capacitor attached.

What does not present mean? If you don't have a defined meaning (such 
as maintain the default/bootloader initialized setting), then make this 
boolean.

Rob
Kevin P. Fleming July 13, 2020, 10:05 p.m. UTC | #2
On Mon, Jul 13, 2020 at 2:39 PM Rob Herring <robh@kernel.org> wrote:
>
> On Mon, Jun 15, 2020 at 06:51:11AM -0400, Kevin P. Fleming wrote:
> > Add a property to allow control of the autocalibration filter
> > capacitor.
> >
> > Signed-off-by: Kevin P. Fleming <kevin+linux@km6g.us>
> > Cc: Alessandro Zummo <a.zummo@towertech.it>
> > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > To: linux-rtc@vger.kernel.org
> > To: devicetree@vger.kernel.org
> > ---
> > v3: corrected whitespace
> >  Documentation/devicetree/bindings/rtc/abracon,abx80x.txt | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > index 2405e35a1bc0f..1b606e33d1a83 100644
> > --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > @@ -29,3 +29,11 @@ and valid to enable charging:
> >   - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V)
> >   - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output
> >                            resistor, the other values are in kOhm.
> > +
> > +All of the devices can have a 47pf capacitor attached to increase the
> > +autocalibration accuracy of their RC oscillators. To enable or disable usage
> > +of the capacitor the following property can be defined:
> > +
> > + - "abracon,autocal-filter": should be <0> or <1>. 0 indicates that there
> > +                             is no capacitor attached, 1 indicates that there
> > +                             is a capacitor attached.
>
> What does not present mean? If you don't have a defined meaning (such
> as maintain the default/bootloader initialized setting), then make this
> boolean.

That is the intended meaning (leave the current setting unmodified). I
can add that to the documentation so it is clear.
Alexandre Belloni July 26, 2020, 7:40 p.m. UTC | #3
Hi Rob,

On 13/07/2020 12:39:06-0600, Rob Herring wrote:
> On Mon, Jun 15, 2020 at 06:51:11AM -0400, Kevin P. Fleming wrote:
> > Add a property to allow control of the autocalibration filter
> > capacitor.
> > 
> > Signed-off-by: Kevin P. Fleming <kevin+linux@km6g.us>
> > Cc: Alessandro Zummo <a.zummo@towertech.it>
> > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > To: linux-rtc@vger.kernel.org
> > To: devicetree@vger.kernel.org
> > ---
> > v3: corrected whitespace
> >  Documentation/devicetree/bindings/rtc/abracon,abx80x.txt | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > index 2405e35a1bc0f..1b606e33d1a83 100644
> > --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> > @@ -29,3 +29,11 @@ and valid to enable charging:
> >   - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V)
> >   - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output
> >                            resistor, the other values are in kOhm.
> > +
> > +All of the devices can have a 47pf capacitor attached to increase the
> > +autocalibration accuracy of their RC oscillators. To enable or disable usage
> > +of the capacitor the following property can be defined:
> > +
> > + - "abracon,autocal-filter": should be <0> or <1>. 0 indicates that there
> > +                             is no capacitor attached, 1 indicates that there
> > +                             is a capacitor attached.
> 
> What does not present mean? If you don't have a defined meaning (such 
> as maintain the default/bootloader initialized setting), then make this 
> boolean.

We discussed that on the previous revision. Not present means keeping
the current value. Like most RTC registers, this is battery backed and
it is expected to persist across reboots. If it has ever been
initialized to a value, (e.g. by the bootloader), then we need a way to
have the driver not change it.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
index 2405e35a1bc0f..1b606e33d1a83 100644
--- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
+++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
@@ -29,3 +29,11 @@  and valid to enable charging:
  - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V)
  - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output
                           resistor, the other values are in kOhm.
+
+All of the devices can have a 47pf capacitor attached to increase the
+autocalibration accuracy of their RC oscillators. To enable or disable usage
+of the capacitor the following property can be defined:
+
+ - "abracon,autocal-filter": should be <0> or <1>. 0 indicates that there
+                             is no capacitor attached, 1 indicates that there
+                             is a capacitor attached.