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    Subject[PATCH v4 1/5] dt-bindings: nvmem: new optional property wp-gpios
    Date
    Several memories have a write-protect pin, that when pulled high, it
    blocks the write operation.

    On some boards, this pin is connected to a GPIO and pulled high by
    default, which forces the user to manually change its state before
    writing.

    Instead of modifying all the memory drivers to check this pin, make
    the NVMEM subsystem check if the write-protect GPIO being passed
    through the nvmem_config or defined in the device tree and pull it
    low whenever writing to the memory.

    Add a new optional property to the device tree binding document, which
    allows to specify the GPIO line to which the write-protect pin is
    connected.

    Signed-off-by: Khouloud Touil <ktouil@baylibre.com>
    ---
    Documentation/devicetree/bindings/nvmem/nvmem.yaml | 11 +++++++++++
    1 file changed, 11 insertions(+)

    diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.yaml b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
    index 1c75a059206c..b43c6c65294e 100644
    --- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
    +++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
    @@ -34,6 +34,14 @@ properties:
    description:
    Mark the provider as read only.

    + wp-gpios:
    + description:
    + GPIO to which the write-protect pin of the chip is connected.
    + The write-protect GPIO is asserted, when it's driven high
    + (logical '1') to block the write operation. It's deasserted,
    + when it's driven low (logical '0') to allow writing.
    + maxItems: 1
    +
    patternProperties:
    "^.*@[0-9a-f]+$":
    type: object
    @@ -63,9 +71,12 @@ patternProperties:

    examples:
    - |
    + #include <dt-bindings/gpio/gpio.h>
    +
    qfprom: eeprom@700000 {
    #address-cells = <1>;
    #size-cells = <1>;
    + wp-gpios = <&gpio1 3 GPIO_ACTIVE_HIGH>;

    /* ... */

    --
    2.17.1
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