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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2022-06-14 10:46:10 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-06-16 20:28:53 -0700 |
| commit | ab1e9de84aff0ca897dee5e4d6692ff46788697b (patch) | |
| tree | cdeb229faef06c4506d0dfdabccce059ae9111b7 /Documentation | |
| parent | 9cbc9911260f24cd3ce2bfb3bcdf4792366a5745 (diff) | |
| download | linux-stable-ab1e9de84aff0ca897dee5e4d6692ff46788697b.tar.gz linux-stable-ab1e9de84aff0ca897dee5e4d6692ff46788697b.tar.bz2 linux-stable-ab1e9de84aff0ca897dee5e4d6692ff46788697b.zip | |
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 <robh@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/net/ti,dp83867.yaml | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.yaml b/Documentation/devicetree/bindings/net/ti,dp83867.yaml index 047d757e8d82..76ff08a477ba 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 |