On Fri, Feb 10, 2017 at 12:43:48PM -0800, Matthias Kaehlcke wrote:
> The output voltage of a voltage controlled regulator can be controlled
> through the voltage of another regulator. The current version of this
> driver assumes that the output voltage is a linear function of the control
> voltage.
>
> Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> ---
> Note: The current version of the driver has a known limitation: If an
> input supply is configured besides the control supply the two regulators
> must have no common ancestor, otherwise the spinlock of the ancestor
> would be acquired twice by the core code. One possible solution would be
> to configure the control regulator through a string instead of a phandle,
> i.e. not specifying it as supply.
>
> .../devicetree/bindings/regulator/vctrl.txt | 56 +++
Please split bindings to separate patch.
> drivers/regulator/Kconfig | 7 +
> drivers/regulator/Makefile | 1 +
> drivers/regulator/vctrl-regulator.c | 525 +++++++++++++++++++++
> 4 files changed, 589 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/regulator/vctrl.txt
> create mode 100644 drivers/regulator/vctrl-regulator.c
>
> diff --git a/Documentation/devicetree/bindings/regulator/vctrl.txt b/Documentation/devicetree/bindings/regulator/vctrl.txt
> new file mode 100644
> index 000000000000..ba3c9b2f61b1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/vctrl.txt
> @@ -0,0 +1,56 @@
> +Bindings for Voltage controlled regulators
> +==========================================
> +
> +Required properties:
> +--------------------
> +- compatible : must be "vctrl-regulator".
> +- ctrl-supply: : a phandle for the regulator supplying the control
> + voltage.
> +- output-voltage-range : an array of two integer values specifying the range
> + (min/max) of the output voltage. The min/max voltage
> + constraints of the regulator (if specified) must not
> + exceed this range.
> +- ctrl-voltage-range : an array of two integer values specifying the range
> + (min/max) of the control voltage. The values of
> + ctrl-voltage-range and output-voltage-range are used
> + for the conversion between output and control voltage.
> + The min/max values of ctrl-voltage-range must specify
> + the control voltage needed to generate the min/max
> + output voltage.
> +
> +Optional properties:
> +--------------------
> +- ovp-threshold-percent : overvoltage protection (OVP) threshold of the
> + regulator in percent. Some regulators have an OVP
> + circuitry which shuts down the regulator when the
> + actual output voltage deviates beyond a certain
> + margin from the expected value for a given control
> + voltage. On larger voltage decreases this can occur
> + undesiredly since the output voltage does not adjust
> + inmediately to changes in the control voltage. To
> + avoid this situation the vctrl driver breaks down
> + larger voltage decreases into multiple steps, where
> + each step is within the OVP threshold.
> +- min-slew-down-rate : Describes how slowly the regulator voltage will decay
> + down in the worst case (lightest expected load).
> + Specified in uV / us (like main regulator ramp rate).
> + This value is required when ovp-threshold-percent is
> + specified.
Don't we have a standard prop for this or that's just for ramp? Perhaps
this should be common?
> +
> +Example:
> +
> + vctrl_reg {
Don't use '_' in node names.
> + compatible = "vctrl-regulator";
> + regulator-name = "vctrl_reg";
> +
> + ctrl-supply = <&ctrl_supply>;
> +
> + regulator-min-microvolt = <800000>;
> + regulator-max-microvolt = <1500000>;
> +
> + output-voltage-range = <800000 1500000>;
Why do you need both?
> + ctrl-voltage-range = <200000 500000>;
> +
> + slew-rate = <225>;
Not documented.
> + ovp-threshold-percent = <16>;
> + };
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