Hi Jonathan,
On Mon, 12 Oct 2020 15:39:23 +0100
Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote:
> On Mon, 12 Oct 2020 16:02:30 +0200
> Tomas Novotny <tomas@xxxxxxxxxx> wrote:
>
> > Hi Jonathan,
> >
> > On Sun, 11 Oct 2020 18:07:40 +0100
> > Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >
> > > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > >
> > > I'm not sure vdd-supply absolutely has to be provided if vref-supply
> > > is, but as the previous binding docs stated it was required it seems
> > > reasonable to leave it as such.
> >
> > Good catch. Vdd is useless on MCP4726 if Vref is specified. The driver
> > requires Vdd...
>
> The driver will get the regulator but as it's not via an optional
> call it the regulator core will provide a stub regulator.
> If the ref regulator is present, all that will happen with vdd is
> a regulator_enable() call which is fine with a stub regulator (it's
> a noop). So we should be good to update the binding to specify
> the requirement. Perhaps it's one to do as a follow up patch?
> Given any existing DT must be providing that regulator, there is
> no rush for us to fix it :)
ok, I see, I will handle with a follow up patch when this will be merged.
Thanks,
Tomas
> > How to proceed there?
> >
> > Thanks,
> >
> > Tomas
> >
> > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > > Cc: Tomas Novotny <tomas@xxxxxxxxxx>
> > > ---
> > > .../devicetree/bindings/iio/dac/mcp4725.txt | 35 ---------
> > > .../bindings/iio/dac/microchip,mcp4725.yaml | 71 +++++++++++++++++++
> > > 2 files changed, 71 insertions(+), 35 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/iio/dac/mcp4725.txt b/Documentation/devicetree/bindings/iio/dac/mcp4725.txt
> > > deleted file mode 100644
> > > index 1bc6c093fbfe..000000000000
> > > --- a/Documentation/devicetree/bindings/iio/dac/mcp4725.txt
> > > +++ /dev/null
> > > @@ -1,35 +0,0 @@
> > > -Microchip mcp4725 and mcp4726 DAC device driver
> > > -
> > > -Required properties:
> > > - - compatible: Must be "microchip,mcp4725" or "microchip,mcp4726"
> > > - - reg: Should contain the DAC I2C address
> > > - - vdd-supply: Phandle to the Vdd power supply. This supply is used as a
> > > - voltage reference on mcp4725. It is used as a voltage reference on
> > > - mcp4726 if there is no vref-supply specified.
> > > -
> > > -Optional properties (valid only for mcp4726):
> > > - - vref-supply: Optional phandle to the Vref power supply. Vref pin is
> > > - used as a voltage reference when this supply is specified.
> > > - - microchip,vref-buffered: Boolean to enable buffering of the external
> > > - Vref pin. This boolean is not valid without the vref-supply. Quoting
> > > - the datasheet: This is offered in cases where the reference voltage
> > > - does not have the current capability not to drop its voltage when
> > > - connected to the internal resistor ladder circuit.
> > > -
> > > -Examples:
> > > -
> > > - /* simple mcp4725 */
> > > - mcp4725@60 {
> > > - compatible = "microchip,mcp4725";
> > > - reg = <0x60>;
> > > - vdd-supply = <&vdac_vdd>;
> > > - };
> > > -
> > > - /* mcp4726 with the buffered external reference voltage */
> > > - mcp4726@60 {
> > > - compatible = "microchip,mcp4726";
> > > - reg = <0x60>;
> > > - vdd-supply = <&vdac_vdd>;
> > > - vref-supply = <&vdac_vref>;
> > > - microchip,vref-buffered;
> > > - };
> > > diff --git a/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml
> > > new file mode 100644
> > > index 000000000000..271998610ceb
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml
> > > @@ -0,0 +1,71 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/iio/dac/microchip,mcp4725.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Microchip mcp4725 and mcp4726 DAC
> > > +
> > > +maintainers:
> > > + - Tomas Novotny <tomas@xxxxxxxxxx>
> > > +
> > > +properties:
> > > + compatible:
> > > + enum:
> > > + - microchip,mcp4725
> > > + - microchip,mcp4726
> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + vdd-supply:
> > > + description: |
> > > + Provides both power and acts as the reference supply on the mcp4725.
> > > + For the mcp4726 it will be used as the reference voltage if vref-supply
> > > + is not provided.
> > > +
> > > + vref-supply:
> > > + description:
> > > + Vref pin is used as a voltage reference when this supply is specified.
> > > +
> > > + microchip,vref-buffered:
> > > + type: boolean
> > > + description: |
> > > + Enable buffering of the external Vref pin. This boolean is not valid
> > > + without the vref-supply. Quoting the datasheet: This is offered in
> > > + cases where the reference voltage does not have the current
> > > + capability not to drop its voltage when connected to the internal
> > > + resistor ladder circuit.
> > > +
> > > +allOf:
> > > + - if:
> > > + not:
> > > + properties:
> > > + compatible:
> > > + contains:
> > > + const: microchip,mcp4726
> > > + then:
> > > + properties:
> > > + vref-supply: false
> > > + microchip,vref-buffered: false
> > > +
> > > +required:
> > > + - compatible
> > > + - reg
> > > + - vdd-supply
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > + - |
> > > + i2c {
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > +
> > > + mcp4725@60 {
> > > + compatible = "microchip,mcp4725";
> > > + reg = <0x60>;
> > > + vdd-supply = <&vdac_vdd>;
> > > + };
> > > + };
> > > +...
>
>
