From fc922946bfe20a22afe8977ad9d67fa73b7bb1c8 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 14 Jun 2022 10:46:10 +0200 Subject: [PATCH] dt-bindings: dp83867: add binding for io_impedance_ctrl nvmem cell We have a board where measurements indicate that the current three options - leaving IO_IMPEDANCE_CTRL at the reset value (which is factory calibrated to a value corresponding to approximately 50 ohms) or using one of the two boolean properties to set it to the min/max value - are too coarse. There is no fixed mapping from register values to values in the range 35-70 ohms; it varies from chip to chip, and even that target range is approximate. So add a DT binding for an nvmem cell which can be populated during production with a value suitable for each specific board. Reviewed-by: Rob Herring Reviewed-by: Andrew Lunn Signed-off-by: Rasmus Villemoes Signed-off-by: Jakub Kicinski --- .../devicetree/bindings/net/ti,dp83867.yaml | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.yaml b/Documentation/devicetree/bindings/net/ti,dp83867.yaml index 047d757e8d828..76ff08a477ba2 100644 --- a/Documentation/devicetree/bindings/net/ti,dp83867.yaml +++ b/Documentation/devicetree/bindings/net/ti,dp83867.yaml @@ -31,6 +31,16 @@ properties: reg: maxItems: 1 + nvmem-cells: + maxItems: 1 + description: + Nvmem data cell containing the value to write to the + IO_IMPEDANCE_CTRL field of the IO_MUX_CFG register. + + nvmem-cell-names: + items: + - const: io_impedance_ctrl + ti,min-output-impedance: type: boolean description: | @@ -42,9 +52,11 @@ properties: description: | MAC Interface Impedance control to set the programmable output impedance to a maximum value (70 ohms). - Note: ti,min-output-impedance and ti,max-output-impedance are mutually - exclusive. When both properties are present ti,max-output-impedance - takes precedence. + Note: Specifying an io_impedance_ctrl nvmem cell or one of the + ti,min-output-impedance, ti,max-output-impedance properties + are mutually exclusive. If more than one is present, an nvmem + cell takes precedence over ti,max-output-impedance, which in + turn takes precedence over ti,min-output-impedance. tx-fifo-depth: $ref: /schemas/types.yaml#/definitions/uint32 -- 2.39.5