forked from Minki/linux
02258b8bcb
* Add support for continuous-voltage mode * Put more meat on the bones with regards to voltage-table mode * Sort out formatting for ease of consumption Cc: devicetree@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org>
72 lines
2.3 KiB
Plaintext
72 lines
2.3 KiB
Plaintext
Bindings for the Generic PWM Regulator
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======================================
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Currently supports 2 modes of operation:
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voltage-table: When in this mode, a voltage table (See below) of
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predefined voltage <=> duty-cycle values must be
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provided via DT. Limitations are that the regulator can
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only operate at the voltages supplied in the table.
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Intermediary duty-cycle values which would normally
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allow finer grained voltage selection are ignored and
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rendered useless. Although more control is given to
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the user if the assumptions made in continuous-voltage
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mode do not reign true.
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continuous-voltage: This mode uses the regulator's maximum and minimum
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supplied voltages specified in the
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regulator-{min,max}-microvolt properties to calculate
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appropriate duty-cycle values. This allows for a much
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more fine grained solution when compared with
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voltage-table mode above. This solution does make an
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assumption that a %50 duty-cycle value will cause the
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regulator voltage to run at half way between the
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supplied max_uV and min_uV values.
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Required properties:
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--------------------
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- compatible: Should be "pwm-regulator"
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- pwms: PWM specification (See: ../pwm/pwm.txt)
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One of these must be provided:
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- voltage-table: Voltage and Duty-Cycle table consisting of 2 cells
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First cell is voltage in microvolts (uV)
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Second cell is duty-cycle in percent (%)
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- max-duty-cycle: Maximum Duty-Cycle value -- this will normally be
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255 (0xff) for an 8 bit PWM device
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If both are provided, the current default is voltage-table mode.
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Any property defined as part of the core regulator binding can also be used.
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(See: ../regulator/regulator.txt)
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Continuous Voltage Example:
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pwm_regulator {
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compatible = "pwm-regulator;
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pwms = <&pwm1 0 8448 0>;
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regulator-min-microvolt = <1016000>;
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regulator-max-microvolt = <1114000>;
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regulator-name = "vdd_logic";
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max-duty-cycle = <255>; /* 8bit PWM */
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};
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Voltage Table Example:
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pwm_regulator {
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compatible = "pwm-regulator;
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pwms = <&pwm1 0 8448 0>;
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regulator-min-microvolt = <1016000>;
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regulator-max-microvolt = <1114000>;
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regulator-name = "vdd_logic";
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/* Voltage Duty-Cycle */
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voltage-table = <1114000 0>,
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<1095000 10>,
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<1076000 20>,
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<1056000 30>,
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<1036000 40>,
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<1016000 50>;
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};
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