[PATCH v2 1/3] dt-bindings: input: Add Qualcomm SPMI PMIC haptics

[Fenglin Wu]

Add binding document for the haptics module inside Qualcomm PMIC
PMIH0108.

Assisted-by: Claude:claude-4-6-sonnet
Signed-off-by: Fenglin Wu <fenglin.wu@xxxxxxxxxxxxxxxx>
---
 .../bindings/input/qcom,spmi-haptics.yaml          | 132 +++++++++++++++++++++
 1 file changed, 132 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/qcom,spmi-haptics.yaml b/Documentation/devicetree/bindings/input/qcom,spmi-haptics.yaml
new file mode 100644
index 000000000000..3764c3e113a3
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/qcom,spmi-haptics.yaml
@@ -0,0 +1,132 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/qcom,spmi-haptics.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Haptics device inside Qualcomm Technologies, Inc. PMIC
+
+maintainers:
+  - Fenglin Wu <fenglin.wu@xxxxxxxxxxxxxxxx>
+
+description: |
+  Certain Qualcomm PMICs integrate a haptics module, such as the HAP530_HV haptics
+  module in the PMIH0108 PMIC, which drives an LRA (Linear Resonant Actuator) with
+  an output voltage up to 10 V. Several play modes are supported in HAP530_HV:
+
+    DIRECT_PLAY: The hardware outputs sinusoidal waveforms whose period is
+      defined by lra-period-us and whose peak voltage is defined by vmax-microvolt.
+      The driving amplitude can be scaled in the range [0, 255] via a single
+      register byte.  Hardware-based LRA auto-resonance tracking is enabled by
+      default in this mode, allowing the haptics engine to follow the actual
+      resonant frequency of the LRA and update the driving period accordingly
+      to achieve stronger vibration magnitude.
+
+    FIFO: The hardware can play an arbitrary waveform composed of a sequence
+      of 8-bit samples at a configurable play rate.  Samples are pre-filled
+      into the internal FIFO memory of the haptics module and continuously
+      replenished via the FIFO-empty IRQ until all samples have been played.
+      An 8K-byte FIFO memory bank is available in the HAP530_HV haptics module,
+      shared between the FIFO and PAT_MEM play modes. The memory partition
+      between the two modes is configurable via registers, and FIFO mode always
+      uses the 1st partition starting from offset 0.
+
+    PAT_MEM: This mode is very similar to FIFO streaming mode but without the
+      data refilling capability. It is designed mainly for short, latency-critical
+      vibrations. The memory space for PAT_MEM mode must be reserved for dedicated
+      usage, and the waveform data should be preloaded and remain unchanged
+      thereafter. The haptics module can play the waveform data from the memory
+      region specified by the PAT_MEM play start address and length registers.
+
+    In either FIFO mode or PAT_MEM mode, the following play rates are supported:
+      -- 0(T_LRA): each FIFO byte drives one full sinusoidal cycle with the
+        period defined in lra-period-us.
+      -- 1/2/3(T_LRA_DIV_2/4/8): each FIFO byte drives a half/quarter/eighth
+        sinusoidal cycle with the period defined in lra-period-us.
+      -- 8/9/10/11/12/13(8KHz/16KHz/24KHz/32KHz/44.1KHz/48KHz): the FIFO
+        data is treated as PCM samples and drives the output with an
+        arbitrarily shaped waveform.  This mode is typically used to define
+        custom driving waveforms for specific vibration effects such as fast
+        attack, crisp brake, etc.
+
+    The drive voltage in FIFO or PAT_MEM mode can exceed the value defined in
+    vmax-mv to achieve a special vibration effect, but the waveform must be
+    short enough to prevent the LRA from being damaged by operating at an
+    overvoltage.
+
+    Also, hardware-based LRA auto-resonance tracking is normally disabled in
+    FIFO or PAT_MEM mode, as these modes are intended to drive arbitrary
+    waveforms that may not follow the resonant frequency; autonomous hardware
+    resonance correction would interfere with the intended output.
+
+properties:
+  compatible:
+    const: qcom,spmi-haptics
+
+  reg:
+    items:
+      - description: HAP_CFG module base address
+      - description: HAP_PTN module base address
+
+  reg-names:
+    items:
+      - const: cfg
+      - const: ptn
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-names:
+    items:
+      - const: fifo-empty
+
+  qcom,vmax-microvolt:
+    description:
+      Maximum allowed output driving voltage in microvolts, rounded to the
+      nearest 50,000 uV step. This is the peak driving voltage in DIRECT_PLAY
+      mode, which outputs sinusoidal waveforms. The value should be equal to
+      the square root of 2 times the Vrms voltage of the LRA.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 50000
+    maximum: 10000000
+    multipleOf: 50000
+
+  qcom,lra-period-us:
+    description:
+      LRA actuator initial resonance period in microseconds
+      (1,000,000 / resonant_freq_hz).  Used to configure T_LRA-based play
+      rates and the auto-resonance zero-crossing window. It could be also used
+      as the initial period if the LRA wants to be driven off resonance.
+    minimum: 5
+    maximum: 20475
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - interrupt-names
+  - qcom,vmax-microvolt
+  - qcom,lra-period-us
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    pmic {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        haptics@f000 {
+            compatible = "qcom,spmi-haptics";
+            reg = <0xf000>, <0xf100>;
+            reg-names = "cfg", "ptn";
+            interrupts = <0x7 0xf0 0x1 IRQ_TYPE_EDGE_RISING>;
+            interrupt-names = "fifo-empty";
+
+            qcom,vmax-microvolt = <1300000>;
+            qcom,lra-period-us = <5880>;
+        };
+    };

-- 
2.43.0