summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/bindings/regulator/pwm-regulator.txt')
-rw-r--r--Documentation/devicetree/bindings/regulator/pwm-regulator.txt92
1 files changed, 92 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
new file mode 100644
index 000000000..3d78d507e
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
@@ -0,0 +1,92 @@
+Bindings for the Generic PWM Regulator
+======================================
+
+Currently supports 2 modes of operation:
+
+Voltage Table: When in this mode, a voltage table (See below) of
+ predefined voltage <=> duty-cycle values must be
+ provided via DT. Limitations are that the regulator can
+ only operate at the voltages supplied in the table.
+ Intermediary duty-cycle values which would normally
+ allow finer grained voltage selection are ignored and
+ rendered useless. Although more control is given to
+ the user if the assumptions made in continuous-voltage
+ mode do not reign true.
+
+Continuous Voltage: This mode uses the regulator's maximum and minimum
+ supplied voltages specified in the
+ regulator-{min,max}-microvolt properties to calculate
+ appropriate duty-cycle values. This allows for a much
+ more fine grained solution when compared with
+ voltage-table mode above. This solution does make an
+ assumption that a %50 duty-cycle value will cause the
+ regulator voltage to run at half way between the
+ supplied max_uV and min_uV values.
+
+Required properties:
+--------------------
+- compatible: Should be "pwm-regulator"
+
+- pwms: PWM specification (See: ../pwm/pwm.txt)
+
+Only required for Voltage Table Mode:
+- voltage-table: Voltage and Duty-Cycle table consisting of 2 cells
+ First cell is voltage in microvolts (uV)
+ Second cell is duty-cycle in percent (%)
+
+Optional properties for Continuous mode:
+- pwm-dutycycle-unit: Integer value encoding the duty cycle unit. If not
+ defined, <100> is assumed, meaning that
+ pwm-dutycycle-range contains values expressed in
+ percent.
+
+- pwm-dutycycle-range: Should contain 2 entries. The first entry is encoding
+ the dutycycle for regulator-min-microvolt and the
+ second one the dutycycle for regulator-max-microvolt.
+ Duty cycle values are expressed in pwm-dutycycle-unit.
+ If not defined, <0 100> is assumed.
+
+NB: To be clear, if voltage-table is provided, then the device will be used
+in Voltage Table Mode. If no voltage-table is provided, then the device will
+be used in Continuous Voltage Mode.
+
+Optional properties:
+--------------------
+- enable-gpios: GPIO to use to enable/disable the regulator
+
+Any property defined as part of the core regulator binding can also be used.
+(See: ../regulator/regulator.txt)
+
+Continuous Voltage With Enable GPIO Example:
+ pwm_regulator {
+ compatible = "pwm-regulator";
+ pwms = <&pwm1 0 8448 0>;
+ enable-gpios = <&gpio0 23 GPIO_ACTIVE_HIGH>;
+ regulator-min-microvolt = <1016000>;
+ regulator-max-microvolt = <1114000>;
+ regulator-name = "vdd_logic";
+ /* unit == per-mille */
+ pwm-dutycycle-unit = <1000>;
+ /*
+ * Inverted PWM logic, and the duty cycle range is limited
+ * to 30%-70%.
+ */
+ pwm-dutycycle-range = <700 300>; /* */
+ };
+
+Voltage Table Example:
+ pwm_regulator {
+ compatible = "pwm-regulator";
+ pwms = <&pwm1 0 8448 0>;
+ regulator-min-microvolt = <1016000>;
+ regulator-max-microvolt = <1114000>;
+ regulator-name = "vdd_logic";
+
+ /* Voltage Duty-Cycle */
+ voltage-table = <1114000 0>,
+ <1095000 10>,
+ <1076000 20>,
+ <1056000 30>,
+ <1036000 40>,
+ <1016000 50>;
+ };