On 10/4/21 2:15 PM, Alexander Stein wrote: > [You don't often get email from alexander.stein@xxxxxxxxxxxxxx. Learn why this is important at http://aka.ms/LearnAboutSenderIdentification.] > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > From: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> > > This property is for optimizing output voltage impedance and is > specific to each board. > > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> > --- > I checked Micron and Macronix datasheets. Both have similar but not > identical supported values. Also the register locations are different. > For those reasons I decided to specify the Ohms value directly and let > the device specfic driver figure out if it is supported where to write > it to. > BTW: Are the Ohm values and the corresponding register bits standardized > somewhere? Please check JEDEC Standard No. 216D.01, I see a SCCR Map which defines Output Driver Strength values. > > Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > index ed590d7c6e37..7d7f20a741b5 100644 > --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml > @@ -72,6 +72,12 @@ 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. > + > label: true > > partitions: > -- > 2.25.1 >
