This adds the binding document describing the three hardware blocks
related to the Light Pulse Generator found in a wide range of Qualcomm
PMICs.
Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org>
---
.../devicetree/bindings/leds/leds-qcom-lpg.txt | 194 +++++++++++++++++++++
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create mode 100644 Documentation/devicetree/bindings/leds/leds-qcom-lpg.txt
diff --git a/Documentation/devicetree/bindings/leds/leds-qcom-lpg.txt
b/Documentation/devicetree/bindings/leds/leds-qcom-lpg.txt
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+Binding for Qualcomm Light Pulse Generator
+
+The Qualcomm Light Pulse Generator consists of three different hardware blocks;
+a ramp generator with lookup table, the light pulse generator and a three
+channel current sink. These blocks are found in a wide range of Qualcomm PMICs.
+Each of these are described individually below.
+
+= Lookup Table (LUT)
+
+- compatible:
+ Usage: required
+ Value type: <stringlist>
+ Definition: must be "qcom,spmi-lpg-lut"
+
+- reg:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: base address of the LUT block
+
+- qcom,lut-size:
+ Usage: required
+ Value type: <u32>
+ Definition: number of elements available in the lookup table
+
+= Light Pulse Generator (LPG)
+The Light Pulse Generator can operate either as a standard PWM controller or in
+a more advanced lookup-table based mode. These are described separately below.
+
+- compatible:
+ Usage: required
+ Value type: <stringlist>
+ Definition: must be "qcom,spmi-lpg"
+
+- reg:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: base address of the LPG block
+
+== PWM mode
+
+- #pwm-cells:
+ Usage: required
+ Value type: <u32>
+ Definition: must be 1
+
+== Lookup-table mode
+
+- cell-index:
+ Usage: required, when referencing a LUT
+ Value type: <u32>
+ Definition: id of the LPG, used to associate the LPG with a particular
+ ramp generator in the LUT block
+
+- default-state:
+ Usage: optional
+ Value type: <string>
+ Definition: default state, as defined in common.txt
+
+- label:
+ Usage: optional
+ Value type: <string>
+ Definition: label of the LED, as defined in common.txt
+
+- linux,default-trigger:
+ Usage: optional
+ Value type: <string>
+ Definition: default trigger, as defined in common.txt
+
+- qcom,tri-led:
+ Usage: optional
+ Value type: <prop-encoded-array>
+ Definition: a phandle of a TRILED node and a single u32 denoting which
+ output channel to control
+
+- qcom,lut:
+ Usage: optional
+ Value type: <prop-encoded-array>
+ Definition: phandle of a LUT node
+
+- qcom,dtest:
+ Usage: optional
+ Value type: <prop-encoded-array>
+ Definition: configures the output into an internal test line of the
+ pmic. A first u32 defines which test line to use and the
+ second cell configures how the value should be outputed
+ (available lines and configuration differs between PMICs)
+
+- qcom,pattern:
+ Usage: optional
+ Value type: <u16-list>
+ Definition: list of 16 bit duty cycle values to make up the pattern to
+ be programmed into the LUT. Values should be in the range
+ [0,512).
+
+- qcom,pattern-length-ms:
+ Usage: optional
+ Value type: <u32>
+ Definition: duration, in milliseconds, of the ramp generator running
+ one pass over the defined pattern
+
+- qcom,pattern-pause-lo-ms:
+ Usage: optional
+ Value type: <u32>
+ Definition: duration, in milliseconds, for the ramp generator to pause
+ before iterating over the pattern
+
+- qcom,pattern-pause-hi-ms:
+ Usage: optional
+ Value type: <u32>
+ Definition: duration, in milliseconds, for the ramp generator to pause
+ after iterating over the pattern
+
+- qcom,pattern-ping-pong:
+ Usage: optional
+ Value type: <boolean>
+ Definition: denotes that the ramp generator should reverse direction
+ when reaching the end of the pattern, instead of wrapping
+ to the beginning
+
+- qcom,pattern-oneshot:
+ Usage: optional
+ Value type: <boolean>
+ Definition: denotes that the ramp generator should stop after a single
+ pass over the pattern
+
+- qcom,pattern-reverse:
+ Usage: optional
+ Value type: <boolean>
+ Definition: denotes that the ramp generator should operate backwards
+ over the pattern
+
+= LED Current Sink (TRILED)
+
+- compatible:
+ Usage: required
+ Value type: <stringlist>
+ Definition: must be "qcom,spmi-tri-led"
+
+- reg:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: base address of the TRILED block
+
+- qcom,power-source:
+ Usage: required
+ Value type: <u32>
+ Definition: power-source used to drive the output, as defined in the
+ datasheet
+
+= EXAMPLE:
+The following example defines a single output of the PMI8994, sinking current
+into a LED in a natural pulsating pattern:
+
+&spmi_bus {
+ pmic@3 {
+ compatible = "qcom,pmi8994", "qcom,spmi-pmic";
+ reg = <0x3 SPMI_USID>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pmi8994_lpg_lut: lpg-lut@b000 {
+ compatible = "qcom,spmi-lpg-lut";
+ reg = <0xb000>;
+
+ qcom,lut-size = <24>;
+ };
+
+ lpg@b200 {
+ compatible = "qcom,spmi-lpg";
+ reg = <0xb200>;
+
+ cell-index = <2>;
+
+ label = "lpg:green:user0";
+
+ qcom,tri-led = <&pmi8994_tri_led 1>;
+ qcom,lut = <&pmi8994_lpg_lut>;
+
+ qcom,pattern = /bits/ 16 <9 20 42 86 158 256 353
+ 425 469 491 502 507>;
+ qcom,pattern-length-ms = <1337>;
+ qcom,pattern-ping-pong;
+
+ default-state = "on";
+ };
+
+ pmi8994_tri_led: tri-led@d000 {
+ compatible = "qcom,spmi-tri-led";
+ reg = <0xd000>;
+
+ qcom,power-source = <1>;
+ };
+ };
+};
--
2.12.0
