On Mon, Mar 2, 2020 at 12:49 PM Rob Herring <robh@xxxxxxxxxx> wrote:
>
Rob,
Thanks for the review! Some questions below:
> On Mon, Feb 24, 2020 at 12:54:23PM -0800, Tim Harvey wrote:
> > This patch adds documentation of device-tree bindings for the
> > Gateworks System Controller (GSC).
> >
> > Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> > ---
> > v5:
> > - resolve dt_binding_check issues
> >
> > v4:
> > - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
> > - remove unncessary resolution/scaling properties for ADCs
> > - update to yaml
> > - remove watchdog
> >
> > v3:
> > - replaced _ with -
> > - remove input bindings
> > - added full description of hwmon
> > - fix unit address of hwmon child nodes
> > ---
> > .../devicetree/bindings/mfd/gateworks-gsc.yaml | 158 +++++++++++++++++++++
> > 1 file changed, 158 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
> > new file mode 100644
> > index 00000000..f7c1a05
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
> > @@ -0,0 +1,158 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mfd/gateworks-gsc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Gateworks System Controller multi-function device
> > +
> > +description: |
> > + The GSC is a Multifunction I2C slave device with the following submodules:
> > + - Watchdog Timer
> > + - GPIO
> > + - Pushbutton controller
> > + - Hardware Monitore with ADC's for temperature and voltage rails and
>
> typo
will fix
>
> > + fan controller
> > +
> > +maintainers:
> > + - Tim Harvey <tharvey@xxxxxxxxxxxxx>
> > + - Robert Jones <rjones@xxxxxxxxxxxxx>
> > +
> > +properties:
> > + $nodename:
> > + pattern: "gsc@[0-9a-f]{1,2}"
> > + compatible:
> > + const: gw,gsc
>
> That's not very specific.
>
Do you mean something like 'gw,system-controller' would be better
instead of the gsc abbreviation for 'Gateworks System Controller'?
> +
> > + reg:
> > + description: I2C device address
> > + maxItems: 1
> > +
> > + interrupts:
> > + maxItems: 1
> > +
> > + interrupt-controller: true
> > +
> > + "#interrupt-cells":
> > + const: 1
> > + description: The IRQ number
>
> description is wrong. You can just drop it.
>
ok
> > +
> > + hwmon:
>
> 'hwmon' is a Linux thing. I'm suspicious...
>
Yes, we've discussed this before and I understand that DT shouldn't
use terminology that is Linux specific (which is why I replaced
'hwmon' with 'adc' in the ADC nodes below) but I still see a long of
dt bindings in Documentation/devicetree/bindings with the word 'hwmon'
in them.
Perhaps this makes more sense?
adc {
compatible = "gw,gsc-adc";
#address-cells = <1>;
#size-cells = <0>;
channel@6 {
type = "gw,hwmon-temperature";
reg = <0x06>;
label = "temp";
};
...
};
> > + type: object
> > + description: Optional Hardware Monitoring module
> > +
> > + properties:
> > + compatible:
> > + const: gw,gsc-hwmon
> > +
> > + "#address-cells":
> > + const: 1
> > +
> > + "#size-cells":
> > + const: 0
> > +
> > + gw,fan-base:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + description: The fan controller base address
>
> Shouldn't this be described as a node in the DT or be implied by the
> compatible?
It does look out of place there. Would adding another subnode outside
of the (perhaps misnamed) 'hwmon' node make more sense?:
fan:
properties:
compatible: gw,gsc-fancontroller
reg:
description: address of the fan controller base register
maxItems: 1
>
> > +
> > + patternProperties:
> > + "^adc@[0-2]$":
>
> There's only one number space at any level. So if you ever need anything
> else at this level, it can't have an address. Just something to
> consider.
>
yes, one number space is ok if I understand what you mean but I meant
this to be "^adc@[0-9]+$" to support the number of ADC pins the part
supports.
> > + type: object
> > + description: |
> > + Properties for a single ADC which can report cooked values
> > + (ie temperature sensor based on thermister), raw values
> > + (ie voltage rail with a pre-scaling resistor divider).
> > +
> > + properties:
> > + reg:
> > + description: Register of the ADC
> > + maxItems: 1
> > +
> > + label:
> > + description: Name of the ADC input
> > +
> > + type:
>
> Very generic property name, but it's not generic. Needs a vendor prefix
> at least.
You mean the property name of 'type' is fine, but the values will need
to be vendor specific like 'gw,temperature', 'gw,voltage',
'gw,voltage-raw' or is it inappropriate to use 'type'?
>
> > + description: |
> > + temperature in C*10 (temperature),
> > + pre-scaled voltage value (voltage),
> > + or scaled based on an optional resistor divider and optional
> > + offset (voltage-raw)
> > + enum:
> > + - temperature
> > + - voltage
> > + - voltage-raw
> > +
> > + gw,voltage-divider:
> > + allOf:
> > + - $ref: /schemas/types.yaml#/definitions/uint32-array
> > + description: values of resistors for divider on raw ADC input
> > + items:
> > + - description: R1
> > + - description: R2
>
> Needs a standard unit suffix. With that, you can drop the type
> reference.
I understand the unit suffix but not sure what you mean by type
reference. Do you mean:
gw,voltage-divider-milli-ohms:
description: values of resistors for divider on raw ADC input
items:
- description: R1
- description: R2
>
> > +
> > + gw,voltage-offset:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + description: |
> > + A positive uV voltage offset to apply to a raw ADC
> > + (ie to compensate for a diode drop).
>
> Needs a unit suffix.
ok
Thanks!
Tim
