| Message ID | 20211012061704.284214-1-alexander.stein@ew.tq-group.com |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | [v2,1/2] dt-bindings: mtd: spi-nor: Add output-driver-strength property | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success | |
| robh/dt-meta-schema | success | |
| robh/dtbs-check | fail | build log |
Am 2021-10-12 08:17, schrieb Alexander Stein: > This property is for optimizing output voltage impedance and is > specific to each board. It overwrites the default set by the flash > device. Various flash devices support different impedances. > > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> > --- > Changes in v2: > * Updated the property description and the commit message accordingly > > Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > index ed590d7c6e37..4c3c506a8853 100644 > --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > @@ -72,6 +72,14 @@ properties: > be used on such systems, to denote the absence of a reliable > reset > mechanism. > > + output-driver-strength: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: > + Output driver strength in ohms which optimizes the impedance at > Vcc/2 > + output voltage. This property overwrites the default set by the > flash > + device. This is board specific and should be determined by the > + manufacturer. Various flash devices support different > impedances. Mh, this seems to be very tailored to this flash chip. Eg. the "Vcc/2", is this something specific to this flash or is this some kind of common usage? For example, Winbond flashes specifies the output driver strength in percent. Settings are 25%, 50%, 75%, 100% there. I'd have to ask a hardware guy, if one could convert between these two representations of the driver strength. Rob, do you know how is this case ususally handled? Can there be different properties, like: output-driver-strength-ohms output-driver-strength-percent or similar. -michael
diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml index ed590d7c6e37..4c3c506a8853 100644 --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml @@ -72,6 +72,14 @@ properties: be used on such systems, to denote the absence of a reliable reset mechanism. + output-driver-strength: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + Output driver strength in ohms which optimizes the impedance at Vcc/2 + output voltage. This property overwrites the default set by the flash + device. This is board specific and should be determined by the + manufacturer. Various flash devices support different impedances. + label: true partitions:
This property is for optimizing output voltage impedance and is specific to each board. It overwrites the default set by the flash device. Various flash devices support different impedances. Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> --- Changes in v2: * Updated the property description and the commit message accordingly Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 8 ++++++++ 1 file changed, 8 insertions(+)