[PATCH v3 1/2] dt-bindings: sound: add Texas Instruments TAS2557

[Gianluca Boiano <morf3089@gmail.com>]

Document the TAS2557 mono Class-D smart amplifier with an integrated
DSP for speaker protection. The device is controlled over I2C and
receives audio over I2S/TDM (ASI). One node can describe either a
single mono device or, via a two-entry `reg`, a stereo pair sharing
one bus: the physical device at each `reg` index applies that half
(DEV_A/DEV_B) of a stereo-tuned firmware image, so no separate
channel-selection property is needed -- device order in `reg` is
the only configuration required, matching the convention already
used by ti,tas2781.yaml/ti,tas2563.yaml for the same TI firmware
toolchain. `ti,imon-slot-nos`/`ti,vmon-slot-nos` follow the same
per-index convention for the TDM sense-data slots. `reg` is capped
at two entries because the uCDSP firmware container only defines
mono or two-device (DEV_A/DEV_B) types -- there is no third slot to
extend into regardless of DT shape.

The on-chip DSP boots from a firmware image generated per speaker
design with the TI PurePath Console tuning tools; the optional
firmware-name property selects a board-specific image, shared by
every device in the group.

Addresses review from Krzysztof Kozlowski, who questioned a
per-node channel-selection property (an earlier ti,channel/
ti,audio-channel design) on the grounds that it doesn't scale and
isn't how other multi-device TI amplifiers in-tree solve the same
problem.

Signed-off-by: Gianluca Boiano <morf3089@gmail.com>
---
Changes in v3:
- single-node reg-array model (up to two devices), matching
  ti,tas2781.yaml; drop ti,channel, derive DEV_A/DEV_B from reg order
- rename ti,imon-slot-no/ti,vmon-slot-no to the plural
  ti,imon-slot-nos/ti,vmon-slot-nos arrays; firmware-name maxItems: 1

Changes in v2:
- add the four mandatory supplies to "required" (Wang Sen)

 .../devicetree/bindings/sound/ti,tas2557.yaml | 174 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 175 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/ti,tas2557.yaml

diff --git a/Documentation/devicetree/bindings/sound/ti,tas2557.yaml b/Documentation/devicetree/bindings/sound/ti,tas2557.yaml
new file mode 100644
index 000000000000..648ba605e0f4
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/ti,tas2557.yaml
@@ -0,0 +1,174 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2026 Gianluca Boiano <morf3089@gmail.com>
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/ti,tas2557.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments TAS2557 Mono Smart Amplifier
+
+maintainers:
+  - Gianluca Boiano <morf3089@gmail.com>
+
+description: |
+  The TAS2557 is a mono, digital-input Class-D amplifier with an
+  integrated DSP for speaker protection. Audio is carried over I2S/TDM
+  (ASI). The on-chip DSP boots from a firmware image that is generated
+  for a specific speaker design using the TI PurePath Console tuning
+  tools.
+
+  A single node describes either one physical TAS2557, or up to two of
+  them sharing one ASI bus and one reset/IRQ pair, using the same
+  reg-array convention as
+  Documentation/devicetree/bindings/sound/ti,tas2781.yaml. When two
+  devices are listed, `reg` carries both I2C addresses and the
+  physical device at each index is implicitly assigned one half of a
+  stereo-tuned firmware image: the device at index 0 is DEV_A and the
+  device at index 1 is DEV_B. No explicit channel-selection property
+  exists or is needed -- the order of addresses in `reg` is the only
+  configuration required. `ti,imon-slot-nos` and `ti,vmon-slot-nos`
+  follow the same indexing: the item at array index N sets the TDM TX
+  slot used by the device at the Nth `reg` entry.
+
+  The uCDSP firmware format defines only the DEV_A and DEV_B device
+  types, so `reg` (and the two TDM slot properties) cannot list more
+  than two entries, regardless of how many physical speakers the board
+  has.
+
+  Datasheet: https://www.ti.com/lit/gpn/tas2557
+
+allOf:
+  - $ref: dai-common.yaml#
+
+properties:
+  compatible:
+    const: ti,tas2557
+
+  reg:
+    minItems: 1
+    maxItems: 2
+    description:
+      I2C address of each physical device sharing this node. One
+      entry configures a single mono TAS2557. Two entries configure a
+      device pair; the device at index 0 is DEV_A and the device at
+      index 1 is DEV_B.
+
+  '#sound-dai-cells':
+    const: 0
+
+  reset-gpios:
+    maxItems: 1
+    description: GPIO connected to the active-low RESET pin.
+
+  interrupts:
+    maxItems: 1
+    description: Fault interrupt output (INT).
+
+  vbat-supply:
+    description: Battery/boost input supply (VBAT), 2.9 V to 5.5 V.
+
+  iovdd-supply:
+    description: Digital I/O supply, 1.62 V to 3.6 V.
+
+  avdd-supply:
+    description: Analog supply, 1.65 V to 1.95 V.
+
+  dvdd-supply:
+    description: Digital core supply, 1.65 V to 1.95 V.
+
+  ti,imon-slot-nos:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 1
+    maxItems: 2
+    items:
+      minimum: 0
+      maximum: 7
+    description:
+      TDM TX time slot(s) for current-sense data, one entry per `reg`
+      entry. The item at array index N configures the device at the
+      Nth `reg` entry.
+
+  ti,vmon-slot-nos:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 1
+    maxItems: 2
+    items:
+      minimum: 0
+      maximum: 7
+    description:
+      TDM TX time slot(s) for voltage-sense data, one entry per `reg`
+      entry. The item at array index N configures the device at the
+      Nth `reg` entry.
+
+  firmware-name:
+    maxItems: 1
+    description: |
+      Name of the DSP firmware image to load. Defaults to a name
+      derived from the silicon revision. A device pair shares one
+      image; each device's half of it is selected by its `reg` index,
+      not by this property.
+
+required:
+  - compatible
+  - reg
+  - '#sound-dai-cells'
+  - vbat-supply
+  - iovdd-supply
+  - avdd-supply
+  - dvdd-supply
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        audio-codec@4c {
+            compatible = "ti,tas2557";
+            reg = <0x4c>;
+            #sound-dai-cells = <0>;
+            reset-gpios = <&tlmm 77 GPIO_ACTIVE_LOW>;
+            interrupt-parent = <&tlmm>;
+            interrupts = <73 IRQ_TYPE_LEVEL_HIGH>;
+
+            vbat-supply = <&vph_pwr>;
+            iovdd-supply = <&vreg_l6b_1p8>;
+            avdd-supply = <&vreg_l6b_1p8>;
+            dvdd-supply = <&vreg_l6b_1p8>;
+
+            ti,imon-slot-nos = <0>;
+            ti,vmon-slot-nos = <2>;
+        };
+    };
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        audio-codec@4c {
+            compatible = "ti,tas2557";
+            reg = <0x4c>, <0x4d>;
+            #sound-dai-cells = <0>;
+            reset-gpios = <&tlmm 77 GPIO_ACTIVE_LOW>;
+            interrupt-parent = <&tlmm>;
+            interrupts = <73 IRQ_TYPE_LEVEL_HIGH>;
+
+            vbat-supply = <&vph_pwr>;
+            iovdd-supply = <&vreg_l6b_1p8>;
+            avdd-supply = <&vreg_l6b_1p8>;
+            dvdd-supply = <&vreg_l6b_1p8>;
+
+            ti,imon-slot-nos = <0 1>;
+            ti,vmon-slot-nos = <2 3>;
+            firmware-name = "tas2557-stereo.bin";
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 806bd2d80d15..44ece19d669f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26679,6 +26679,7 @@ M:	Sen Wang <sen@ti.com>
 L:	linux-sound@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/sound/ti,tas2552.yaml
+F:	Documentation/devicetree/bindings/sound/ti,tas2557.yaml
 F:	Documentation/devicetree/bindings/sound/ti,tas2562.yaml
 F:	Documentation/devicetree/bindings/sound/ti,tas2770.yaml
 F:	Documentation/devicetree/bindings/sound/ti,tas27xx.yaml
-- 
2.55.0