ASoC: Add support for GPIOs driven amplifiers

Herve Codina <herve.codina@bootlin.com> says:

On some embedded system boards, audio amplifiers are designed using
discrete components such as op-amp, several resistors and switches to
either adjust the gain (switching resistors) or fully switch the
audio signal path (mute and/or bypass features).

Those switches are usually driven by simple GPIOs.

This kind of amplifiers are not handled in ASoC and the fallback is to
let the user-space handle those GPIOs out of the ALSA world.

In order to have those kind of amplifiers fully integrated in the audio
stack, this series introduces the audio-gpio-amp to handle them.

This new ASoC component allows to have the amplifiers seen as ASoC
auxiliarty devices and so it allows to control them through audio mixer
controls.

In order to ease the review, I choose to split modifications related
to the merge of the gpio-audio-amp part into the simple-amplfier driver
in several commits.

Link: https://patch.msgid.link/20260513081702.317117-1-herve.codina@bootlin.com

Author: broonie

.mailmap

@@ -857,6 +857,7 @@ Tobias Klauser <tklauser@distanz.ch> <klto@zhaw.ch>
 Tobias Klauser <tklauser@distanz.ch> <tklauser@nuerscht.ch>
 Tobias Klauser <tklauser@distanz.ch> <tklauser@xenon.tklauser.home>
 Todor Tomov <todor.too@gmail.com> <todor.tomov@linaro.org>
+Tomasz Jeznach <tomasz.jeznach@linux.dev> <tjeznach@rivosinc.com>
 Tony Luck <tony.luck@intel.com>
 Trilok Soni <quic_tsoni@quicinc.com> <tsoni@codeaurora.org>
 TripleX Chung <xxx.phy@gmail.com> <triplex@zh-kernel.org>

Documentation/arch/riscv/cmodx.rst

@@ -21,13 +21,13 @@ call at each patchable function entry, and patches it dynamically at runtime to
 enable or disable the redirection. In the case of RISC-V, 2 instructions,
 AUIPC + JALR, are required to compose a function call. However, it is impossible
 to patch 2 instructions and expect that a concurrent read-side executes them
-without a race condition. This series makes atmoic code patching possible in
+without a race condition. This series makes atomic code patching possible in
 RISC-V ftrace. Kernel preemption makes things even worse as it allows the old
 state to persist across the patching process with stop_machine().
 
 In order to get rid of stop_machine() and run dynamic ftrace with full kernel
 preemption, we partially initialize each patchable function entry at boot-time,
-setting the first instruction to AUIPC, and the second to NOP. Now, atmoic
+setting the first instruction to AUIPC, and the second to NOP. Now, atomic
 patching is possible because the kernel only has to update one instruction.
 According to Ziccif, as long as an instruction is naturally aligned, the ISA
 guarantee an  atomic update.
@@ -36,8 +36,8 @@ By fixing down the first instruction, AUIPC, the range of the ftrace trampoline
 is limited to +-2K from the predetermined target, ftrace_caller, due to the lack
 of immediate encoding space in RISC-V. To address the issue, we introduce
 CALL_OPS, where an 8B naturally align metadata is added in front of each
-pacthable function. The metadata is resolved at the first trampoline, then the
-execution can be derect to another custom trampoline.
+patchable function. The metadata is resolved at the first trampoline, then the
+execution can be directed to another custom trampoline.
 
 CMODX in the User Space
 -----------------------

Documentation/arch/riscv/zicfilp.rst

@@ -78,7 +78,7 @@ the program.
 
 Per-task indirect branch tracking state can be monitored and
 controlled via the :c:macro:`PR_GET_CFI` and :c:macro:`PR_SET_CFI`
-``prctl()` arguments (respectively), by supplying
+``prctl()`` arguments (respectively), by supplying
 :c:macro:`PR_CFI_BRANCH_LANDING_PADS` as the second argument.  These
 are architecture-agnostic, and will return -EINVAL if the underlying
 functionality is not supported.

Documentation/devicetree/bindings/sound/gpio-audio-amp.yaml

@@ -0,0 +1,270 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/gpio-audio-amp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Audio amplifier driven by GPIOs
+
+maintainers:
+  - Herve Codina <herve.codina@bootlin.com>
+
+description: |
+  Audio GPIO amplifiers are driven by GPIO in order to control the gain value
+  of the amplifier, its mute function and/or its bypass function.
+
+  Those amplifiers are based on discrete components (analog switches, op-amps
+  and more) where some of them, mostly analog switches, are controlled by GPIOs
+  to adjust the gain value of the whole amplifier and/or to control
+  the mute and/or bypass function.
+
+  For instance, the following piece of hardware is a GPIO amplifier
+
+                                         +5VA
+                                           ^
+                                        |\ |
+                                        | \
+        Vin >---------------------------|+ \
+                                        |   +-------+-----> Vout
+                .--\/\/\/--+------------|- /        |
+                |          |            | /         |
+                v          |            |/ |        |
+               GND         o               v        |
+                            \             GND       |
+       gpio >----------->    \                      |
+                         o    o                     |
+                         |    |                     |
+                         |    '--\/\/\/--.          |
+                         |               +--\/\/\/--'
+                         '---------------'
+
+properties:
+  compatible:
+    oneOf:
+      - const: gpio-audio-amp-mono
+        description:
+          A single channel amplifier. All features apply to this sole channel.
+
+      - const: gpio-audio-amp-stereo
+        description:
+          A dual channel amplifier (left and right). All features apply to both
+          channels producing the same effect on both channels at the same time.
+
+  vdd-supply:
+    description: Main power supply of the amplifier
+
+  vddio-supply:
+    description: Power supply related to the control path
+
+  vdda1-supply:
+    description: Analog power supply
+
+  vdda2-supply:
+    description: Additional analog power supply
+
+  mute-gpios:
+    description: GPIO to control the mute function
+    maxItems: 1
+
+  bypass-gpios:
+    description: GPIO to control the bypass function
+    maxItems: 1
+
+  gain-gpios:
+    description: |
+      GPIOs to control the amplifier gain
+
+      The gain value is computed from GPIOs value from 0 to 2^N-1 with N the
+      number of GPIO described. The first GPIO described is the lsb of the gain
+      value.
+
+      For instance assuming 2 gpios
+         gain-gpios = <&gpio1 GPIO_ACTIVE_HIGH> <&gpio2 GPIO_ACTIVE_HIGH>;
+      The gain value will be the following:
+
+          gpio1 | gpio2 | gain
+          ------+-------+-----
+            0   |    0  | 0b00 -> 0
+            1   |    0  | 0b01 -> 1
+            0   |    1  | 0b10 -> 2
+            1   |    1  | 0b11 -> 3
+          ------+-------+-----
+
+      Note: The gain value, bits set to 1 or 0, indicate the state active (bit
+            set) or the state inactive (bit unset) of the related GPIO. The
+            physical voltage corresponding to this active/inactive state is
+            given by the GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags.
+
+    minItems: 1
+    maxItems: 16
+
+  gain-ranges:
+    $ref: /schemas/types.yaml#/definitions/int32-matrix
+    description: |
+      A list of one or more ranges of possible values. Each range is defined by
+      the first and last point in the range. Each point is defined by the pair
+      (GPIOs value, Gain in 0.01 dB unit).
+
+      Ranges can be contiguous or holes can be present between ranges if some
+      gpios value should not be used. Also in a range the first point and the
+      last point can be identical. In that case, the range contains only one
+      item, the given point.
+
+    items:
+      items:
+        - description: GPIOs value of the first point in the range
+        - description: Gain in 0.01 dB unit of the first point in the range
+        - description: GPIOs value of the last point in the range
+        - description: Gain in 0.01 dB unit of the last point in the range
+      description: |
+        A range defines a linear function (linear in dB) from the first point
+        to the last point, both included. The number of items in the range is
+          N = abs(first_point.gpio_value - last_point.gpio_value) + 1
+
+        It allows to define the gain range from the first_point.gain to
+        the last_point.gain, both points included.
+
+             Gain (0.01 dB unit)
+               ^
+               |                      last
+               +- - - - - - - - - - + point
+               |                 +  .
+               |              +     .
+               |           +        .
+               +- - - - +           .
+               |  first .           .
+               |  point .           .
+               |        .           .
+               +--------+-----------+---> gpios
+                                          value
+
+        Note: Even if first_point.gpio_value is lower than last_point.gpio_value
+              and first_point.gain is lower than last_point.gain in the above
+              graphic, all combination of values are supported leading to an
+              increasing or a decreasing linear segment.
+
+    minItems: 1
+    maxItems: 65536
+
+  gain-labels:
+    $ref: /schemas/types.yaml#/definitions/string-array
+    minItems: 2
+    maxItems: 65536
+    description: |
+      List of the gain labels attached to the combination of GPIOs controlling
+      the gain. The first label is related to the gain value 0, the second label
+      is related to the gain value 1 and so on.
+
+      With 2 GPIOs controlling the gain, GPIOs value can be 0, 1, 2 and 3.
+      Assuming that gain value set the hardware according to the following
+      table:
+
+         GPIOs | Hardware
+         value | amplification
+         ------+--------------
+           0   | Low
+           1   | Middle
+           2   | High
+           3   | Max
+         ------+--------------
+
+      The description using gain labels can be:
+        gain-labels = "Low", "Middle", "High", "Max";
+
+dependencies:
+  gain-ranges: [ gain-gpios ]
+  gain-labels: [ gain-gpios ]
+
+required:
+  - compatible
+  - vdd-supply
+
+anyOf:
+  - required:
+      - gain-gpios
+  - required:
+      - mute-gpios
+  - required:
+      - bypass-gpios
+
+allOf:
+  - $ref: component-common.yaml#
+  - if:
+      required:
+        - gain-ranges
+    then:
+      properties:
+        gain-labels: false
+  - if:
+      required:
+        - gain-labels
+    then:
+      properties:
+        gain-ranges: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    /* Gain controlled by gpios */
+    amplifier-0 {
+        compatible = "gpio-audio-amp-mono";
+        vdd-supply = <&regulator>;
+        gain-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>, <&gpio 1 GPIO_ACTIVE_HIGH>;
+    };
+
+    /* Gain controlled by gpio using a simple range on a stereo amplifier */
+    amplifier-1 {
+        compatible = "gpio-audio-amp-stereo";
+        vdd-supply = <&regulator>;
+        gain-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>, <&gpio 1 GPIO_ACTIVE_HIGH>;
+        gain-ranges = <0 (-300) 3 600>;
+    };
+
+    /* Gain controlled by gpio with labels */
+    amplifier-3 {
+        compatible = "gpio-audio-amp-mono";
+        vdd-supply = <&regulator>;
+        gain-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
+        gain-labels = "Low", "High";
+    };
+
+    /* A mutable stereo amplifier without any gain control */
+    amplifier-4 {
+        compatible = "gpio-audio-amp-stereo";
+        vdd-supply = <&regulator>;
+        mute-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
+    };
+
+    /*
+     * Several supplies, gain controlled using more complex ranges, mute and
+     * bypass.
+     *
+     * Assuming 3 gpios for controlling the gain with the following table
+     *   gpios value    Gain
+     *      0b000       Do not use (gpios value not allowed)
+     *      0b001       - 3dB
+     *      0b010       + 3dB
+     *      0b011       + 10dB
+     *      0b100       Do not use (gpios value not allowed)
+     *      0b101       + 6dB
+     *      0b110       + 7dB
+     *      0b111       + 8dB
+     */
+    amplifier-5 {
+        compatible = "gpio-audio-amp-mono";
+        vdd-supply = <&regulator>;
+        vddio-supply = <&regulator1>;
+        vdda1-supply = <&regulator2>;
+        gain-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>,
+                     <&gpio 1 GPIO_ACTIVE_HIGH>,
+                     <&gpio 2 GPIO_ACTIVE_HIGH>;
+        gain-ranges = <1 (-300) 2 300>,
+                      <3 1000   3 1000>,
+                      <5 600    7 800>;
+        mute-gpios = <&gpio 3 GPIO_ACTIVE_HIGH>;
+        bypass-gpios = <&gpio 4 GPIO_ACTIVE_HIGH>;
+    };
+...

Documentation/hwmon/sy7636a-hwmon.rst

@@ -22,5 +22,5 @@ The following sensors are supported
 sysfs-Interface
 ---------------
 
-temp0_input
+temp1_input
 	- Temperature of external NTC (milli-degree C)

Documentation/netlink/genetlink-c.yaml

@@ -69,6 +69,15 @@ properties:
         header:
           description: For C-compatible languages, header which already defines this value.
           type: string
+        scope:
+          description: |
+            Visibility of this definition. "uapi" (default) renders into
+            the uAPI header, "kernel" renders into the kernel-side
+            generated header, "user" renders into the user-side
+            generated header. When combined with `header:`, the
+            definition is not rendered, and the named header is
+            included only by code matching the scope.
+          enum: [ uapi, kernel, user ]
         type:
           enum: [ const, enum, flags ]
         doc:

Documentation/netlink/genetlink-legacy.yaml

@@ -83,6 +83,15 @@ properties:
         header:
           description: For C-compatible languages, header which already defines this value.
           type: string
+        scope:
+          description: |
+            Visibility of this definition. "uapi" (default) renders into
+            the uAPI header, "kernel" renders into the kernel-side
+            generated header, "user" renders into the user-side
+            generated header. When combined with `header:`, the
+            definition is not rendered, and the named header is
+            included only by code matching the scope.
+          enum: [ uapi, kernel, user ]
         type:
           enum: [ const, enum, flags, struct ] # Trim
         doc:

Documentation/netlink/genetlink.yaml

@@ -55,6 +55,15 @@ properties:
         header:
           description: For C-compatible languages, header which already defines this value.
           type: string
+        scope:
+          description: |
+            Visibility of this definition. "uapi" (default) renders into
+            the uAPI header, "kernel" renders into the kernel-side
+            generated header, "user" renders into the user-side
+            generated header. When combined with `header:`, the
+            definition is not rendered, and the named header is
+            included only by code matching the scope.
+          enum: [ uapi, kernel, user ]
         type:
           enum: [ const, enum, flags ]
         doc:

Documentation/netlink/netlink-raw.yaml

@@ -87,6 +87,15 @@ properties:
         header:
           description: For C-compatible languages, header which already defines this value.
           type: string
+        scope:
+          description: |
+            Visibility of this definition. "uapi" (default) renders into
+            the uAPI header, "kernel" renders into the kernel-side
+            generated header, "user" renders into the user-side
+            generated header. When combined with `header:`, the
+            definition is not rendered, and the named header is
+            included only by code matching the scope.
+          enum: [ uapi, kernel, user ]
         type:
           enum: [ const, enum, flags, struct ] # Trim
         doc: