[PATCH v5 0/2] iio: adc: Add support for Texas Instruments ADS112C04

[PATCH v5 0/2] iio: adc: Add support for Texas Instruments ADS112C04

[Kyle Hsieh]

This patch series introduces support for the Texas Instruments ADS112C04
Analog-to-Digital Converters.

The ADS112C04 (16-bit) is precision, low-power, delta-sigma ADCs with
an I2C interface. They feature a flexible input multiplexer supporting
single-ended and differential measurements, a programmable gain amplifier,
and an internal voltage reference.

Note: While this chip shares similarities with the ADS112C14 (currently 
being upstreamed by David Lechner), the register maps and feature sets 
are sufficiently different to warrant a separate driver. However, the
DT bindings and channel parsing logic have been aligned with the
ADS112C14 conventions.

This initial submission provides a minimal feature set (single-shot 
conversions and basic DRDY interrupt) covering current use cases.

Signed-off-by: Kyle Hsieh <kylehsieh1995@gmail.com>
---
Changes in v5:
- Addressed several suggestions from v1-v4 that I had missed in earlier
  revisions. Apologies for the churn this caused; I went back through
  all four threads as David asked.

- dt-bindings: iio: adc: ti,ads112c04:
  - No changes. Picked up David's Reviewed-by and Conor's Acked-by.

- iio: adc: ti-ads112c04:
  - Made the reference voltage per-channel, following the ADS112C14
    driver: reference-sources is parsed with
    fwnode_property_match_property_string() and stored per channel, and
    the CONFIG1 VREF field is now updated together with the MUX before
    each conversion. avdd is read with
    devm_regulator_get_enable_read_voltage() when a channel uses it.
  - Organised the register field macros indented under their register,
    and shortened CONFIG to CONF in the field names.
  - Spelled out all CONFIG0/CONFIG1 fields explicitly with FIELD_PREP()
    when initialising, rather than relying on implicit zeros.
  - Moved the internal reference macro to the top of the file with the
    other defines and renamed it to ADS112C04_INT_REF_mV.
  - Dropped disable_irq_nosync(); the handler only calls complete(),
    which is safe in a normal IRQ handler, so a threaded IRQ isn't
    needed. The bare `0` flags argument is now packed with the
    other arguments.
  - Fixed word-read byte ordering by using
    i2c_smbus_read_word_swapped().
  - Dropped the has_refp state member; it is passed as a function
    argument instead.
  - Added a REVISIT comment on spec->type for when
    ti,refp-refn-resistor-ohms is implemented.
  - Reduced the power-on reset delay from 50ms to 500us, per the
    datasheet.
  - Replaced the diff-channels if-else chain with a 4x4 lookup table
    indexed by [AINP][AINN].
  - Used wait_for_completion_timeout() directly in the if condition,
    swapped err/ret in ads112c04_wait_for_data(), made the channel
    index unsigned int with the assignment split out, stopped reusing
    pair[0] for single-channel, and used ARRAY_SIZE(pair).
  - Added ADS112C04_MAX_CHANNELS and used it in the bounds check.
  - Split reference-sources parsing into a helper to keep the call
    within the line length limit.
  - Updated the commit message to describe per-channel reference
    selection; refn-supply remains unsupported.
  - Switched the hardware reset to the reset controller framework
    (devm_reset_control_get_optional_exclusive()), which works with the
    existing reset-gpios property via the reset-gpio driver. The binding
    is unchanged.
- Link to v4: https://lore.kernel.org/r/20260811-ti-ads112c04-driver-v4-0-ae704ac17241@gmail.com

Changes in v4:
- dt-bindings: iio: adc: ti,ads112c04:
  - Fixed excitation-current-nanoamp to use single-entry list syntax
    (items: - enum: [...]) instead of combining maxItems: 1 with a
    mapping-style items, which failed dt_binding_check.
  - Widened excitation-channels to maximum: 5 to account for IDAC1/
    IDAC2 also being routable to REFP0/REFN0, and documented the
    mapping, per David Lechner.
  - Reduced excitation-current-nanoamp to a single entry, since the
    two IDAC outputs share one current setting, per David Lechner.
  - Changed burn-out-current-nanoamp to use `const: 10000`, per David
    Lechner.
  - Renamed reference-sources' internal enum value to "internal"
    (dropped voltage suffix, since there is only one internal
    reference), per David Lechner.

- iio: adc: ti-ads112c04:
  - Fixed word-read byte ordering by switching to
    i2c_smbus_read_word_swapped(), addressing a big-endian data
    corruption issue flagged by Sashiko AI review.
  - Masked the DRDY interrupt in the hardirq handler
    (disable_irq_nosync()) and re-enabled it once the conversion data
    is read, to avoid an interrupt storm on level-triggered DRDY
    configurations, without hardcoding the trigger type.
  - Reworked reference-sources handling in parse_channels(): it is now
    validated against the actually-selected refp-supply instead of
    being unconditionally rejected, per David Lechner.
  - Simplified regulator handling in probe() using
    devm_regulator_get_enable_read_voltage(), dropping the now-unused
    vref_reg field, per David Lechner.
  - Corrected the commit message to no longer claim refn-supply
    support, since it remains explicitly unsupported in probe().
- Added a MAINTAINERS entry for the new binding and driver.
- Link to v3: https://lore.kernel.org/r/20260805-ti-ads112c04-driver-v3-0-49f436829e01@gmail.com

Changes in v3:
- dt-bindings: iio: adc: ti,ads112c04:
  - Resolved dt_binding_check errors by removing redundant $ref for
    standard unit suffixes and fixing YAML array syntax.
  - Added full hardware capability descriptions (excitation-channels,
    excitation-current-nanoamp, burn-out-current-nanoamp,
    reference-sources) as suggested by David Lechner.
  - Restricted the reg maximum to 11 and updated the regex to
    ^channel@[0-9a-b]$ to accurately reflect the 12 possible MUX
    combinations.

- iio: adc: ti-ads112c04:
  - Transitioned all I2C read/write wrappers to use SMBus APIs
    (i2c_smbus_read_byte_data, i2c_smbus_read_word_data, etc.) to
    gracefully handle I2C errors, NACKs, and Repeated Starts, addressing
    feedback from Joshua Crofts and Jonathan Cameron.
  - Added forward compatibility checks in probe() and parse_channels()
    using dev_err_probe() to return -EOPNOTSUPP for unimplemented DT
    properties.
  - Reverted devm_request_irq() flags to 0 to let the driver inherit the
    trigger type strictly from the DT, per Jonathan Cameron's advice.
  - Reduced the data wait timeout to 100ms, reflecting the chip's slowest
    data rate of 20 SPS.
  - Fixed #include alphabetical sorting, grouped <linux/iio/*> headers,
    and added missing headers.
  - Fixed variable declaration ordering (reverse xmas tree) and updated
    variable naming to vref_mV (SI unit exception).
  - Optimized GPIO reset logic using GPIOD_OUT_HIGH.
- Link to v2: https://lore.kernel.org/r/20260731-ti-ads112c04-driver-v2-0-aab0168c3c01@gmail.com

Changes in v2:
- Replaced `vref-supply` with `refp-supply` and `refn-supply` to accurately reflect hardware.
- Refactored the driver to dynamically parse channel configurations and routing from DT child nodes.
- Modernized the driver using kernel macros.
- Handled endianness elegantly.
- Added hardware reset fallback logic.
- Inherited IRQ trigger type from device tree instead of hardcoding.
- Fixed a bug where the MUX software cache could desync from hardware if the I2C write failed.
- Added strict return value checking for all I2C writes during probe.
- Updated the `i2c_device_id` array to use C99 named initializers.
- Link to v1: https://lore.kernel.org/r/20260728-ti-ads112c04-driver-v1-0-475efe4e2b78@gmail.com

---
Kyle Hsieh (2):
      dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04
      iio: adc: ti-ads112c04: Add support for TI ADS112C04

 .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 148 ++++++
 MAINTAINERS                                        |   7 +
 drivers/iio/adc/Kconfig                            |  10 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/ti-ads112c04.c                     | 525 +++++++++++++++++++++
 5 files changed, 691 insertions(+)
---
base-commit: 350d1fb9204b13c5f95e511e98b8bcb47574d425
change-id: 20260724-ti-ads112c04-driver-be7e89047834

Best regards,
-- 
Kyle Hsieh <kylehsieh1995@gmail.com>

[PATCH v5 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[Kyle Hsieh]

Add device tree binding documentation for Texas Instruments ADS112C04
I2C Analog-to-Digital Converters.

These devices provide 4-channel, 16-bit delta-sigma ADCs with an I2C
interface, programmable gain amplifier (PGA), and data-ready (DRDY)
interrupt output.

The binding uses child nodes to dynamically define the connected
single-ended or differential channels.

Excitation current, burn-out current, and reference source properties
are also included to fully describe the chip's hardware capabilities,
aligned with the ti,ads112c14 binding conventions.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Kyle Hsieh <kylehsieh1995@gmail.com>
---
 .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 148 +++++++++++++++++++++
 MAINTAINERS                                        |   6 +
 2 files changed, 154 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
new file mode 100644
index 000000000000..68a0df21cedd
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
@@ -0,0 +1,148 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,ads112c04.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments ADS112C04 ADC
+
+maintainers:
+  - Kyle Hsieh <kylehsieh1995@gmail.com>
+
+description:
+  The ADS112C04 (16-bit) are precision analog-to-digital converters (ADCs)
+  with an I2C interface. They feature a flexible input multiplexer, a
+  low-noise programmable gain amplifier (PGA), two programmable excitation
+  current sources, a voltage reference, and a precision temperature sensor.
+
+properties:
+  compatible:
+    enum:
+      - ti,ads112c04
+
+  reg:
+    maxItems: 1
+    description: I2C address of the device.
+
+  interrupts:
+    maxItems: 1
+    description: Data ready (DRDY) interrupt output.
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  reset-gpios:
+    maxItems: 1
+    description: GPIO connected to the RESET pin. Active low.
+
+  avdd-supply: true
+  dvdd-supply: true
+
+  refp-supply: true
+  refn-supply: true
+
+  ti,refp-refn-resistor-ohms:
+    description: Resistance of the external resistor between REFP and REFN.
+
+patternProperties:
+  "^channel@[0-9a-b]$":
+    $ref: adc.yaml
+    unevaluatedProperties: false
+    properties:
+      reg:
+        items:
+          - maximum: 11
+
+      single-channel:
+        maximum: 3
+
+      diff-channels:
+        items:
+          maximum: 3
+
+      excitation-channels:
+        maxItems: 2
+        items:
+          maximum: 5
+        description:
+          Additionally to AIN0-AIN3, IDAC1/IDAC2 can also be routed to
+          REFP0 (4) and REFN0 (5).
+
+      excitation-current-nanoamp:
+        items:
+          - enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]
+
+      burn-out-current-nanoamp:
+        items:
+          - const: 10000
+
+      reference-sources:
+        items:
+          - enum: [internal, external, avdd]
+            default: internal
+
+    dependencies:
+      excitation-channels: [ excitation-current-nanoamp ]
+      excitation-current-nanoamp: [ excitation-channels ]
+
+    oneOf:
+      - required: [ single-channel ]
+      - required: [ diff-channels ]
+
+required:
+  - compatible
+  - reg
+  - avdd-supply
+  - dvdd-supply
+
+dependencies:
+  refn-supply: [ refp-supply ]
+
+oneOf:
+  - required:
+      - refp-supply
+  - required:
+      - ti,refp-refn-resistor-ohms
+  - properties:
+      refp-supply: false
+      refn-supply: false
+      ti,refp-refn-resistor-ohms: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@40 {
+            compatible = "ti,ads112c04";
+            reg = <0x40>;
+            interrupt-parent = <&gpio>;
+            interrupts = <12 IRQ_TYPE_EDGE_FALLING>;
+
+            reset-gpios = <&gpio 13 GPIO_ACTIVE_LOW>;
+            avdd-supply = <&vdd_3v3_reg>;
+            dvdd-supply = <&vdd_3v3_reg>;
+            refp-supply = <&vref_reg>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+                diff-channels = <0>, <1>;
+            };
+
+            channel@1 {
+                reg = <1>;
+                single-channel = <2>;
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 04fa5322d9f7..417d74b6d6cc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26987,6 +26987,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/adc/ti,ads1119.yaml
 F:	drivers/iio/adc/ti-ads1119.c
 
+TI ADS112C04 ADC DRIVER
+M:	Kyle Hsieh <kylehsieh1995@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
+
 TI ADS112C14 ADC DRIVER
 M:	David Lechner <dlechner@baylibre.com>
 L:	linux-iio@vger.kernel.org

-- 
2.34.1

Re: [PATCH v5 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `excitation-current-nanoamp` property incorrectly uses a YAML list for `items`, defining a 1-element tuple constraint instead of a generic array schema, which breaks configurations using dual excitation currents.
--

--- Patch [1]: [PATCH v5 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04 ---
commit 1aa9d5f5c579fdf57e652aeb671cbcbcce2eaa69
Author: Kyle Hsieh <kylehsieh1995@gmail.com>

dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

This commit adds device tree binding documentation for the Texas Instruments
ADS112C04 I2C Analog-to-Digital Converter. It includes properties for
describing the chip's channels, excitation currents, and reference sources.

> diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
[ ... ]
> +patternProperties:
> +  "^channel@[0-9a-b]$":
> +    $ref: adc.yaml
> +    unevaluatedProperties: false
> +    properties:
[ ... ]
> +      excitation-channels:
> +        maxItems: 2
> +        items:
> +          maximum: 5
> +        description:
> +          Additionally to AIN0-AIN3, IDAC1/IDAC2 can also be routed to
> +          REFP0 (4) and REFN0 (5).
> +
> +      excitation-current-nanoamp:
> +        items:
> +          - enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]

[Severity: Medium]
Will this correctly allow multiple excitation currents? The hyphen before enum
defines a 1-item tuple constraint instead of a generic schema constraint for
all array elements.

If a device tree configuration specifies two excitation channels and provides
two corresponding excitation currents, won't this schema enforce a maximum of
1 item and erroneously reject the valid configuration during dtbs_check?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260813-ti-ads112c04-driver-v5-0-79dff9e249cd@gmail.com?part=1

Re: [PATCH v5 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[Rob Herring]

On Thu, Aug 13, 2026 at 11:06:02AM +0800, Kyle Hsieh wrote:
> Add device tree binding documentation for Texas Instruments ADS112C04
> I2C Analog-to-Digital Converters.
> 
> These devices provide 4-channel, 16-bit delta-sigma ADCs with an I2C
> interface, programmable gain amplifier (PGA), and data-ready (DRDY)
> interrupt output.
> 
> The binding uses child nodes to dynamically define the connected
> single-ended or differential channels.
> 
> Excitation current, burn-out current, and reference source properties
> are also included to fully describe the chip's hardware capabilities,
> aligned with the ti,ads112c14 binding conventions.
> 
> Reviewed-by: David Lechner <dlechner@baylibre.com>
> Acked-by: Conor Dooley <conor.dooley@microchip.com>
> Signed-off-by: Kyle Hsieh <kylehsieh1995@gmail.com>
> ---
>  .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 148 +++++++++++++++++++++
>  MAINTAINERS                                        |   6 +
>  2 files changed, 154 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> new file mode 100644
> index 000000000000..68a0df21cedd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> @@ -0,0 +1,148 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/ti,ads112c04.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Texas Instruments ADS112C04 ADC
> +
> +maintainers:
> +  - Kyle Hsieh <kylehsieh1995@gmail.com>
> +
> +description:
> +  The ADS112C04 (16-bit) are precision analog-to-digital converters (ADCs)
> +  with an I2C interface. They feature a flexible input multiplexer, a
> +  low-noise programmable gain amplifier (PGA), two programmable excitation
> +  current sources, a voltage reference, and a precision temperature sensor.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - ti,ads112c04
> +
> +  reg:
> +    maxItems: 1
> +    description: I2C address of the device.
> +
> +  interrupts:
> +    maxItems: 1
> +    description: Data ready (DRDY) interrupt output.
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: GPIO connected to the RESET pin. Active low.
> +
> +  avdd-supply: true
> +  dvdd-supply: true
> +
> +  refp-supply: true
> +  refn-supply: true
> +
> +  ti,refp-refn-resistor-ohms:
> +    description: Resistance of the external resistor between REFP and REFN.
> +
> +patternProperties:
> +  "^channel@[0-9a-b]$":
> +    $ref: adc.yaml
> +    unevaluatedProperties: false
> +    properties:
> +      reg:
> +        items:
> +          - maximum: 11
> +
> +      single-channel:
> +        maximum: 3
> +
> +      diff-channels:
> +        items:
> +          maximum: 3
> +
> +      excitation-channels:
> +        maxItems: 2
> +        items:
> +          maximum: 5
> +        description:
> +          Additionally to AIN0-AIN3, IDAC1/IDAC2 can also be routed to
> +          REFP0 (4) and REFN0 (5).
> +
> +      excitation-current-nanoamp:
> +        items:
> +          - enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]

Drop 'items'. Just enum is enough.

> +
> +      burn-out-current-nanoamp:
> +        items:
> +          - const: 10000

Just 'const'

> +
> +      reference-sources:
> +        items:
> +          - enum: [internal, external, avdd]
> +            default: internal

default for an items entry doesn't make sense as the entry has to be 
present. Instead (at the same level as 'items'):

default: [ internal ]

> +
> +    dependencies:
> +      excitation-channels: [ excitation-current-nanoamp ]
> +      excitation-current-nanoamp: [ excitation-channels ]
> +
> +    oneOf:
> +      - required: [ single-channel ]
> +      - required: [ diff-channels ]
> +
> +required:
> +  - compatible
> +  - reg
> +  - avdd-supply
> +  - dvdd-supply
> +
> +dependencies:
> +  refn-supply: [ refp-supply ]
> +
> +oneOf:
> +  - required:
> +      - refp-supply

Just to make sure, refp-supply is allowed without refn-supply? If not, 
either this should be refn or the dependencies reversed.

Rob

Re: [PATCH v5 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[Kyle Hsieh]

On Fri, Aug 14, 2026 at 12:57 AM Rob Herring <robh@kernel.org> wrote:
>
> On Thu, Aug 13, 2026 at 11:06:02AM +0800, Kyle Hsieh wrote:
> > Add device tree binding documentation for Texas Instruments ADS112C04
> > I2C Analog-to-Digital Converters.
> >
> > These devices provide 4-channel, 16-bit delta-sigma ADCs with an I2C
> > interface, programmable gain amplifier (PGA), and data-ready (DRDY)
> > interrupt output.
> >
> > The binding uses child nodes to dynamically define the connected
> > single-ended or differential channels.
> >
> > Excitation current, burn-out current, and reference source properties
> > are also included to fully describe the chip's hardware capabilities,
> > aligned with the ti,ads112c14 binding conventions.
> >
> > Reviewed-by: David Lechner <dlechner@baylibre.com>
> > Acked-by: Conor Dooley <conor.dooley@microchip.com>
> > Signed-off-by: Kyle Hsieh <kylehsieh1995@gmail.com>
> > ---
> >  .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 148 +++++++++++++++++++++
> >  MAINTAINERS                                        |   6 +
> >  2 files changed, 154 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> > new file mode 100644
> > index 000000000000..68a0df21cedd
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> > @@ -0,0 +1,148 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/ti,ads112c04.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Texas Instruments ADS112C04 ADC
> > +
> > +maintainers:
> > +  - Kyle Hsieh <kylehsieh1995@gmail.com>
> > +
> > +description:
> > +  The ADS112C04 (16-bit) are precision analog-to-digital converters (ADCs)
> > +  with an I2C interface. They feature a flexible input multiplexer, a
> > +  low-noise programmable gain amplifier (PGA), two programmable excitation
> > +  current sources, a voltage reference, and a precision temperature sensor.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - ti,ads112c04
> > +
> > +  reg:
> > +    maxItems: 1
> > +    description: I2C address of the device.
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +    description: Data ready (DRDY) interrupt output.
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#size-cells":
> > +    const: 0
> > +
> > +  reset-gpios:
> > +    maxItems: 1
> > +    description: GPIO connected to the RESET pin. Active low.
> > +
> > +  avdd-supply: true
> > +  dvdd-supply: true
> > +
> > +  refp-supply: true
> > +  refn-supply: true
> > +
> > +  ti,refp-refn-resistor-ohms:
> > +    description: Resistance of the external resistor between REFP and REFN.
> > +
> > +patternProperties:
> > +  "^channel@[0-9a-b]$":
> > +    $ref: adc.yaml
> > +    unevaluatedProperties: false
> > +    properties:
> > +      reg:
> > +        items:
> > +          - maximum: 11
> > +
> > +      single-channel:
> > +        maximum: 3
> > +
> > +      diff-channels:
> > +        items:
> > +          maximum: 3
> > +
> > +      excitation-channels:
> > +        maxItems: 2
> > +        items:
> > +          maximum: 5
> > +        description:
> > +          Additionally to AIN0-AIN3, IDAC1/IDAC2 can also be routed to
> > +          REFP0 (4) and REFN0 (5).
> > +
> > +      excitation-current-nanoamp:
> > +        items:
> > +          - enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]
>
> Drop 'items'. Just enum is enough.
>
> > +
> > +      burn-out-current-nanoamp:
> > +        items:
> > +          - const: 10000
>
> Just 'const'
>
> > +
> > +      reference-sources:
> > +        items:
> > +          - enum: [internal, external, avdd]
> > +            default: internal
>
> default for an items entry doesn't make sense as the entry has to be
> present. Instead (at the same level as 'items'):
>
> default: [ internal ]
>

Will fix all three in v6, thanks.

> > +
> > +    dependencies:
> > +      excitation-channels: [ excitation-current-nanoamp ]
> > +      excitation-current-nanoamp: [ excitation-channels ]
> > +
> > +    oneOf:
> > +      - required: [ single-channel ]
> > +      - required: [ diff-channels ]
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - avdd-supply
> > +  - dvdd-supply
> > +
> > +dependencies:
> > +  refn-supply: [ refp-supply ]
> > +
> > +oneOf:
> > +  - required:
> > +      - refp-supply
>
> Just to make sure, refp-supply is allowed without refn-supply? If not,
> either this should be refn or the dependencies reversed.

Yes - refp-supply alone is valid when REFN is tied to AVSS/ground, which
is the common single-ended case (and what my board does). The
dependency is one-directional on purpose: refn-supply requires
refp-supply, but not the other way round.

Kyle Hsieh

[PATCH v5 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04

[Kyle Hsieh]

Add IIO driver support for the Texas Instruments ADS112C04 (16-bit)
delta-sigma ADCs.

The driver implements:
- Single-shot conversions using the IIO raw read interface.
- Dynamic parsing of single-ended and differential channels from
  device tree child nodes.
- Hardware interrupt support via the DRDY pin, falling back to
  software polling if no IRQ is provided.
- Per-channel reference source selection (internal 2.048V, external
  REFP/REFN, or AVDD) via the reference-sources device tree property.
  refn-supply is not yet supported.
- Hardware reset via the reset controller framework, falling back to
  the RESET command when no reset controller is present.

Signed-off-by: Kyle Hsieh <kylehsieh1995@gmail.com>
---
 MAINTAINERS                    |   1 +
 drivers/iio/adc/Kconfig        |  10 +
 drivers/iio/adc/Makefile       |   1 +
 drivers/iio/adc/ti-ads112c04.c | 525 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 537 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 417d74b6d6cc..f51fbda9d4b9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26992,6 +26992,7 @@ M:	Kyle Hsieh <kylehsieh1995@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
+F:	drivers/iio/adc/ti-ads112c04.c
 
 TI ADS112C14 ADC DRIVER
 M:	David Lechner <dlechner@baylibre.com>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 990e7b3e7212..037fc7df8415 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1817,6 +1817,16 @@ config TI_ADS1119
          This driver can also be built as a module. If so, the module will be
          called ti-ads1119.
 
+config TI_ADS112C04
+	tristate "Texas Instruments ADS112C04 ADC"
+	depends on I2C
+	help
+	  If you say yes here you get support for Texas Instruments
+	  ADS112C04 (16-bit) I2C analog to digital converters.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called ti-ads112c04.
+
 config TI_ADS112C14
 	tristate "Texas Instruments ADS112C14/ADS122C14"
 	depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index dcec0abb03b7..d8acf2831fd2 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -155,6 +155,7 @@ obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
 obj-$(CONFIG_TI_ADS1018) += ti-ads1018.o
 obj-$(CONFIG_TI_ADS1100) += ti-ads1100.o
 obj-$(CONFIG_TI_ADS1119) += ti-ads1119.o
+obj-$(CONFIG_TI_ADS112C04) += ti-ads112c04.o
 obj-$(CONFIG_TI_ADS112C14) += ti-ads112c14.o
 obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
 obj-$(CONFIG_TI_ADS1298) += ti-ads1298.o
diff --git a/drivers/iio/adc/ti-ads112c04.c b/drivers/iio/adc/ti-ads112c04.c
new file mode 100644
index 000000000000..c2995e94c4f8
--- /dev/null
+++ b/drivers/iio/adc/ti-ads112c04.c
@@ -0,0 +1,525 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Texas Instruments ADS112C04 16-bit I2C ADC driver
+ *
+ * Copyright (c) 2026 Kyle Hsieh <kylehsieh1995@gmail.com>
+ *
+ * Datasheet: https://www.ti.com/lit/ds/symlink/ads112c04.pdf
+ * Based on TI Reference Code and standard Linux IIO framework.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+#include <linux/iio/iio.h>
+
+#define ADS112C04_CMD_RESET		0x06
+#define ADS112C04_CMD_START_SYNC	0x08
+#define ADS112C04_CMD_RDATA		0x10
+#define ADS112C04_CMD_RREG(reg)		(0x20 | ((reg) << 2))
+#define ADS112C04_CMD_WREG(reg)		(0x40 | ((reg) << 2))
+
+#define ADS112C04_REG_CONFIG0			0x00
+#define   ADS112C04_CONF0_MUX			  GENMASK(7, 4)
+#define     ADS112C04_CONF0_MUX_AIN0_AIN1	    0
+#define     ADS112C04_CONF0_MUX_AIN_SINGLE_BASE	    8
+#define   ADS112C04_CONF0_GAIN			  GENMASK(3, 1)
+#define     ADS112C04_CONF0_GAIN_X1		    0
+#define   ADS112C04_CONF0_PGA_BYPASS		  BIT(0)
+
+#define ADS112C04_REG_CONFIG1			0x01
+#define   ADS112C04_CONF1_DR			  GENMASK(7, 5)
+#define     ADS112C04_CONF1_DR_20SPS		    0
+#define   ADS112C04_CONF1_MODE			  BIT(4)
+#define     ADS112C04_CONF1_MODE_NORMAL		    0
+#define   ADS112C04_CONF1_CM			  BIT(3)
+#define     ADS112C04_CONF1_CM_SINGLE_SHOT	    0
+#define   ADS112C04_CONF1_VREF			  GENMASK(2, 1)
+#define     ADS112C04_CONF1_VREF_INTERNAL	    0
+#define     ADS112C04_CONF1_VREF_EXTERNAL	    1
+#define     ADS112C04_CONF1_VREF_AVDD		    2
+#define   ADS112C04_CONF1_TS			  BIT(0)
+#define     ADS112C04_CONF1_TS_DISABLED		    0
+
+#define ADS112C04_REG_CONFIG2			0x02
+#define   ADS112C04_CONF2_DRDY			  BIT(7)
+
+#define ADS112C04_INT_REF_mV			2048
+
+#define ADS112C04_MAX_CHANNELS		12
+
+enum {
+	ADS112C04_VREF_SOURCE_INTERNAL,
+	ADS112C04_VREF_SOURCE_EXTERNAL,
+	ADS112C04_VREF_SOURCE_AVDD,
+};
+
+static const char * const ads112c04_vref_names[] = {
+	[ADS112C04_VREF_SOURCE_INTERNAL] = "internal",
+	[ADS112C04_VREF_SOURCE_EXTERNAL] = "external",
+	[ADS112C04_VREF_SOURCE_AVDD]     = "avdd",
+};
+
+static const u8 ads112c04_vref_reg_val[] = {
+	[ADS112C04_VREF_SOURCE_INTERNAL] = ADS112C04_CONF1_VREF_INTERNAL,
+	[ADS112C04_VREF_SOURCE_EXTERNAL] = ADS112C04_CONF1_VREF_EXTERNAL,
+	[ADS112C04_VREF_SOURCE_AVDD]     = ADS112C04_CONF1_VREF_AVDD,
+};
+
+/* Indexed by [AINP][AINN], -1 means the combination is not available. */
+static const s8 ads112c04_diff_mux[4][4] = {
+	{ -1,  0,  1,  2 },
+	{  3, -1,  4,  5 },
+	{ -1, -1, -1,  6 },
+	{ -1, -1,  7, -1 },
+};
+
+struct ads112c04_state {
+	struct i2c_client *client;
+	/* Protects concurrent ADC reads and device configuration */
+	struct mutex lock;
+	struct completion completion;
+	u32 avdd_mV;
+	u32 ext_ref_mV;
+	u8 *vref_source;	/* one entry per channel, indexed by scan order */
+	u8 config0;
+	u8 config1;
+};
+
+static int ads112c04_write_cmd(struct i2c_client *client, u8 cmd)
+{
+	return i2c_smbus_write_byte(client, cmd);
+}
+
+static int ads112c04_read_reg(struct i2c_client *client, u8 reg, u8 *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, ADS112C04_CMD_RREG(reg));
+	if (ret < 0)
+		return ret;
+
+	*val = ret;
+
+	return 0;
+}
+
+static int ads112c04_write_reg(struct i2c_client *client, u8 reg, u8 val)
+{
+	return i2c_smbus_write_byte_data(client, ADS112C04_CMD_WREG(reg), val);
+}
+
+static int ads112c04_wait_for_data(struct ads112c04_state *st)
+{
+	int ret, err;
+	u8 val;
+
+	if (st->client->irq > 0) {
+		/* Timeout is 100ms (slowest data rate is 20 SPS) */
+		if (!wait_for_completion_timeout(&st->completion, msecs_to_jiffies(100)))
+			return -ETIMEDOUT;
+
+		return 0;
+	}
+
+	ret = read_poll_timeout(ads112c04_read_reg, err,
+				(err < 0 || (val & ADS112C04_CONF2_DRDY)),
+				1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC, false,
+				st->client, ADS112C04_REG_CONFIG2, &val);
+	if (err < 0)
+		return err;
+
+	return ret;
+}
+
+static int ads112c04_read_data(struct ads112c04_state *st, int *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(st->client, ADS112C04_CMD_RDATA);
+	if (ret < 0)
+		return ret;
+
+	*val = sign_extend32(ret, 15);
+
+	return 0;
+}
+
+static int ads112c04_get_adc_result(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan,
+				    int *val)
+{
+	struct ads112c04_state *st = iio_priv(indio_dev);
+	unsigned int idx = chan - indio_dev->channels;
+	u8 new_config0, new_config1;
+	int ret;
+
+	new_config0 = st->config0;
+	FIELD_MODIFY(ADS112C04_CONF0_MUX, &new_config0, chan->address);
+
+	if (st->config0 != new_config0) {
+		ret = ads112c04_write_reg(st->client, ADS112C04_REG_CONFIG0,
+					  new_config0);
+		if (ret < 0)
+			return ret;
+
+		st->config0 = new_config0;
+	}
+
+	new_config1 = st->config1;
+	FIELD_MODIFY(ADS112C04_CONF1_VREF, &new_config1,
+		     ads112c04_vref_reg_val[st->vref_source[idx]]);
+
+	if (st->config1 != new_config1) {
+		ret = ads112c04_write_reg(st->client, ADS112C04_REG_CONFIG1,
+					  new_config1);
+		if (ret < 0)
+			return ret;
+
+		st->config1 = new_config1;
+	}
+
+	reinit_completion(&st->completion);
+
+	ret = ads112c04_write_cmd(st->client, ADS112C04_CMD_START_SYNC);
+	if (ret < 0)
+		return ret;
+
+	ret = ads112c04_wait_for_data(st);
+	if (ret < 0)
+		return ret;
+
+	return ads112c04_read_data(st, val);
+}
+
+static int ads112c04_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val, int *val2, long mask)
+{
+	struct ads112c04_state *st = iio_priv(indio_dev);
+	unsigned int idx = chan - indio_dev->channels;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&st->lock);
+		ret = ads112c04_get_adc_result(indio_dev, chan, val);
+		mutex_unlock(&st->lock);
+
+		if (ret < 0)
+			return ret;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		switch (st->vref_source[idx]) {
+		case ADS112C04_VREF_SOURCE_EXTERNAL:
+			*val = st->ext_ref_mV;
+			break;
+		case ADS112C04_VREF_SOURCE_AVDD:
+			*val = st->avdd_mV;
+			break;
+		default:
+			*val = ADS112C04_INT_REF_mV;
+			break;
+		}
+		*val2 = 15;
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static irqreturn_t ads112c04_irq_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct ads112c04_state *st = iio_priv(indio_dev);
+
+	complete(&st->completion);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info ads112c04_info = {
+	.read_raw = ads112c04_read_raw,
+};
+
+static int ads112c04_parse_vref_source(struct fwnode_handle *child)
+{
+	if (!fwnode_property_present(child, "reference-sources"))
+		return ADS112C04_VREF_SOURCE_INTERNAL;
+
+	return fwnode_property_match_property_string(child, "reference-sources",
+						    ads112c04_vref_names,
+						    ARRAY_SIZE(ads112c04_vref_names));
+}
+
+static int ads112c04_parse_channels(struct iio_dev *indio_dev,
+				    bool *need_avdd_ref, bool *need_ext_ref)
+{
+	struct device *dev = indio_dev->dev.parent;
+	struct ads112c04_state *st = iio_priv(indio_dev);
+	struct iio_chan_spec *channels;
+	u32 num_channels, pair[2], channel;
+	unsigned int i;
+	int ret;
+
+	num_channels = device_get_named_child_node_count(dev, "channel");
+	if (!num_channels)
+		return dev_err_probe(dev, -EINVAL, "no channel subnodes found\n");
+
+	if (num_channels > ADS112C04_MAX_CHANNELS)
+		return dev_err_probe(dev, -EINVAL,
+				     "num of channel nodes exceeds %d\n",
+				     ADS112C04_MAX_CHANNELS);
+
+	channels = devm_kcalloc(dev, num_channels, sizeof(*channels), GFP_KERNEL);
+	if (!channels)
+		return -ENOMEM;
+
+	st->vref_source = devm_kcalloc(dev, num_channels,
+				       sizeof(*st->vref_source), GFP_KERNEL);
+	if (!st->vref_source)
+		return -ENOMEM;
+
+	i = 0;
+	device_for_each_named_child_node_scoped(dev, child, "channel") {
+		struct iio_chan_spec *spec = &channels[i];
+
+		if (fwnode_property_present(child, "excitation-channels"))
+			return dev_err_probe(dev, -EOPNOTSUPP,
+					     "excitation-channels is not supported yet\n");
+
+		st->vref_source[i] = ADS112C04_VREF_SOURCE_INTERNAL;
+
+		if (fwnode_property_present(child, "reference-sources")) {
+			ret = ads112c04_parse_vref_source(child);
+			if (ret < 0)
+				return dev_err_probe(dev, ret,
+						     "invalid reference-sources value\n");
+
+			st->vref_source[i] = ret;
+		}
+
+		if (st->vref_source[i] == ADS112C04_VREF_SOURCE_EXTERNAL)
+			*need_ext_ref = true;
+		if (st->vref_source[i] == ADS112C04_VREF_SOURCE_AVDD)
+			*need_avdd_ref = true;
+
+		/*
+		 * REVISIT: when ti,refp-refn-resistor-ohms is implemented, a
+		 * channel using an external resistor reference is effectively
+		 * a resistance measurement and should use IIO_RESISTANCE.
+		 */
+		spec->type = IIO_VOLTAGE;
+		spec->indexed = 1;
+		spec->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE);
+
+		if (fwnode_property_present(child, "single-channel")) {
+			ret = fwnode_property_read_u32(child, "single-channel", &channel);
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "failed to read single-channel property\n");
+
+			if (channel > 3)
+				return dev_err_probe(dev, -EINVAL,
+						     "single-channel must be 0-3\n");
+
+			spec->channel = channel;
+			spec->address = ADS112C04_CONF0_MUX_AIN_SINGLE_BASE + channel;
+		} else if (fwnode_property_present(child, "diff-channels")) {
+			ret = fwnode_property_read_u32_array(child, "diff-channels",
+							     pair, ARRAY_SIZE(pair));
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "failed to read diff-channels property\n");
+
+			if (pair[0] > 3 || pair[1] > 3)
+				return dev_err_probe(dev, -EINVAL,
+						     "diff-channels must be 0-3\n");
+
+			spec->channel = pair[0];
+			spec->channel2 = pair[1];
+			spec->differential = 1;
+
+			if (ads112c04_diff_mux[pair[0]][pair[1]] < 0)
+				return dev_err_probe(dev, -EINVAL,
+						     "invalid diff-channels combination\n");
+
+			spec->address = ads112c04_diff_mux[pair[0]][pair[1]];
+		} else {
+			return dev_err_probe(dev, -EINVAL,
+					     "channel node must have single-channel or diff-channels\n");
+		}
+
+		i++;
+	}
+
+	indio_dev->channels = channels;
+	indio_dev->num_channels = i;
+
+	return 0;
+}
+
+static int ads112c04_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct iio_dev *indio_dev;
+	struct ads112c04_state *st;
+	struct reset_control *reset;
+	bool need_avdd_ref = false, need_ext_ref = false;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->client = client;
+
+	ret = devm_mutex_init(dev, &st->lock);
+	if (ret)
+		return ret;
+
+	init_completion(&st->completion);
+
+	indio_dev->name = "ads112c04";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ads112c04_info;
+
+	/* Forward compatibility checks for unimplemented DT properties */
+	if (device_property_present(dev, "refn-supply") ||
+	    device_property_present(dev, "ti,refp-refn-resistor-ohms"))
+		return dev_err_probe(dev, -EOPNOTSUPP,
+				     "refn-supply and external resistors are not supported yet\n");
+
+	ret = ads112c04_parse_channels(indio_dev, &need_avdd_ref, &need_ext_ref);
+	if (ret)
+		return ret;
+
+	if (need_avdd_ref) {
+		ret = devm_regulator_get_enable_read_voltage(dev, "avdd");
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "failed to get avdd voltage\n");
+
+		st->avdd_mV = ret / (MICRO / MILLI);
+	} else {
+		ret = devm_regulator_get_enable(dev, "avdd");
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to get avdd regulator\n");
+	}
+
+	ret = devm_regulator_get_enable(dev, "dvdd");
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get dvdd regulator\n");
+
+	if (device_property_present(dev, "refp-supply")) {
+		ret = devm_regulator_get_enable_read_voltage(dev, "refp");
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "failed to get refp voltage\n");
+
+		st->ext_ref_mV = ret / (MICRO / MILLI);
+	}
+
+	if (need_ext_ref && !st->ext_ref_mV)
+		return dev_err_probe(dev, -EINVAL,
+				     "external reference measurements require refp-supply\n");
+
+	/* Datasheet: POR releases ~500us after supplies are stable */
+	fsleep(500);
+
+	reset = devm_reset_control_get_optional_exclusive(dev, NULL);
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset), "failed to get reset\n");
+
+	if (reset) {
+		ret = reset_control_reset(reset);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to reset device\n");
+	} else {
+		ret = ads112c04_write_cmd(client, ADS112C04_CMD_RESET);
+		if (ret < 0)
+			return ret;
+	}
+
+	fsleep(1 * USEC_PER_MSEC);
+
+	/*
+	 * Initialize CONFIG0 with all fields explicit: gain of 1 with the PGA
+	 * bypassed, which allows full-scale single-ended measurements. The MUX
+	 * field is updated per channel before each conversion.
+	 */
+	st->config0 = FIELD_PREP(ADS112C04_CONF0_MUX,
+				 ADS112C04_CONF0_MUX_AIN0_AIN1) |
+		      FIELD_PREP(ADS112C04_CONF0_GAIN,
+				 ADS112C04_CONF0_GAIN_X1) |
+		      ADS112C04_CONF0_PGA_BYPASS;
+
+	ret = ads112c04_write_reg(client, ADS112C04_REG_CONFIG0, st->config0);
+	if (ret)
+		return ret;
+
+	st->config1 = FIELD_PREP(ADS112C04_CONF1_DR,
+				 ADS112C04_CONF1_DR_20SPS) |
+		      FIELD_PREP(ADS112C04_CONF1_MODE,
+				 ADS112C04_CONF1_MODE_NORMAL) |
+		      FIELD_PREP(ADS112C04_CONF1_CM,
+				 ADS112C04_CONF1_CM_SINGLE_SHOT) |
+		      FIELD_PREP(ADS112C04_CONF1_VREF,
+				 ADS112C04_CONF1_VREF_INTERNAL) |
+		      FIELD_PREP(ADS112C04_CONF1_TS,
+				 ADS112C04_CONF1_TS_DISABLED);
+
+	ret = ads112c04_write_reg(client, ADS112C04_REG_CONFIG1, st->config1);
+	if (ret)
+		return ret;
+
+	if (client->irq > 0) {
+		ret = devm_request_irq(dev, client->irq, ads112c04_irq_handler, 0,
+				       indio_dev->name, indio_dev);
+		if (ret)
+			return ret;
+	}
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct i2c_device_id ads112c04_id[] = {
+	{ .name = "ads112c04" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ads112c04_id);
+
+static const struct of_device_id ads112c04_of_match[] = {
+	{ .compatible = "ti,ads112c04" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ads112c04_of_match);
+
+static struct i2c_driver ads112c04_driver = {
+	.driver = {
+		.name = "ads112c04",
+		.of_match_table = ads112c04_of_match,
+	},
+	.probe = ads112c04_probe,
+	.id_table = ads112c04_id,
+};
+module_i2c_driver(ads112c04_driver);
+
+MODULE_AUTHOR("Kyle Hsieh <kylehsieh1995@gmail.com>");
+MODULE_DESCRIPTION("Texas Instruments ADS112C04 ADC driver");
+MODULE_LICENSE("GPL");

-- 
2.34.1

Re: [PATCH v5 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] Interrupt storm on level-triggered lines and probe failure on nested IRQs due to hardirq request.
- [High] Time-of-Check to Time-of-Use (TOCTOU) heap buffer overflow when parsing device tree channels.
- [Medium] Hardware state desynchronization causing silent data corruption after system suspend.
--

--- Patch [2]: [PATCH v5 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04 ---
commit 60ab1f79461d9cde81c399c16a9e8fc0068a1dee
Author: Kyle Hsieh <kylehsieh1995@gmail.com>

iio: adc: ti-ads112c04: Add support for TI ADS112C04

Add IIO driver support for the Texas Instruments ADS112C04 (16-bit)
delta-sigma ADCs.

> diff --git a/drivers/iio/adc/ti-ads112c04.c b/drivers/iio/adc/ti-ads112c04.c
> index 0000000000000..c2995e94c4f8d
> --- /dev/null
> +++ b/drivers/iio/adc/ti-ads112c04.c
> @@ -166,15 +166,15 @@ static int ads112c04_get_adc_result(struct iio_dev *indio_dev,
> +	unsigned int idx = chan - indio_dev->channels;
> +	u8 new_config0, new_config1;
> +	int ret;
> +
> +	new_config0 = st->config0;
> +	FIELD_MODIFY(ADS112C04_CONF0_MUX, &new_config0, chan->address);
> +
> +	if (st->config0 != new_config0) {
> +		ret = ads112c04_write_reg(st->client, ADS112C04_REG_CONFIG0,
> +					  new_config0);
> +		if (ret < 0)
> +			return ret;
> +
> +		st->config0 = new_config0;
> +	}

[Severity: Medium]
Could this caching logic lead to silent data corruption after a system
suspend?

The driver skips writing the configuration if it matches the cached
value. Since there are no PM suspend/resume hooks, if the system
enters suspend and power to the ADC is cut, the hardware resets to its
Power-On Reset (POR) state.

Upon resume, if a conversion is requested that matches the cached
configuration, the driver will skip the I2C write. The hardware will
remain in its POR state and return incorrect measurements.

[ ... ]

> @@ -203,9 +203,9 @@ static irqreturn_t ads112c04_irq_handler(int irq, void *private)
> +static irqreturn_t ads112c04_irq_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct ads112c04_state *st = iio_priv(indio_dev);
> +
> +	complete(&st->completion);
> +
> +	return IRQ_HANDLED;
> +}

[ ... ]

> @@ -223,31 +223,31 @@ static int ads112c04_parse_channels(struct iio_dev *indio_dev,
> +static int ads112c04_parse_channels(struct iio_dev *indio_dev,
> +				    bool *need_avdd_ref, bool *need_ext_ref)
> +{
> +	struct device *dev = indio_dev->dev.parent;
> +	struct ads112c04_state *st = iio_priv(indio_dev);
> +	struct iio_chan_spec *channels;
> +	u32 num_channels, pair[2], channel;
> +	unsigned int i;
> +	int ret;
> +
> +	num_channels = device_get_named_child_node_count(dev, "channel");
> +	if (!num_channels)
> +		return dev_err_probe(dev, -EINVAL, "no channel subnodes found\n");
> +
> +	if (num_channels > ADS112C04_MAX_CHANNELS)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "num of channel nodes exceeds %d\n",
> +				     ADS112C04_MAX_CHANNELS);
> +
> +	channels = devm_kcalloc(dev, num_channels, sizeof(*channels), GFP_KERNEL);
> +	if (!channels)
> +		return -ENOMEM;
> +
> +	st->vref_source = devm_kcalloc(dev, num_channels,
> +				       sizeof(*st->vref_source), GFP_KERNEL);
> +	if (!st->vref_source)
> +		return -ENOMEM;
> +
> +	i = 0;
> +	device_for_each_named_child_node_scoped(dev, child, "channel") {
> +		struct iio_chan_spec *spec = &channels[i];

[Severity: High]
Can this cause an out-of-bounds heap write?

The driver counts the number of child nodes to allocate the arrays, and
then iterates over the child nodes to populate them in two separate
traversals.

If a device tree overlay is applied concurrently between the count and
the iteration, the number of child nodes can increase, causing the loop
index 'i' to exceed num_channels.

[ ... ]

> @@ -493,5 +493,5 @@ static int ads112c04_probe(struct i2c_client *client)
> +	if (client->irq > 0) {
> +		ret = devm_request_irq(dev, client->irq, ads112c04_irq_handler, 0,
> +				       indio_dev->name, indio_dev);

[Severity: High]
Will this cause an interrupt storm if the DRDY interrupt is configured
as level-triggered?

Since this is requested as a hard IRQ via devm_request_irq(), the
handler completes the completion and returns IRQ_HANDLED without
clearing the hardware interrupt. The line will remain asserted.

Also, if the ADC is connected to a slow bus (like an I2C GPIO
expander) which provides a nested threaded IRQ, will this fail with
-EINVAL?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260813-ti-ads112c04-driver-v5-0-79dff9e249cd@gmail.com?part=2

Re: [PATCH v5 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04

[Andy Shevchenko]

On Thu, Aug 13, 2026 at 11:06:03AM +0800, Kyle Hsieh wrote:
> Add IIO driver support for the Texas Instruments ADS112C04 (16-bit)
> delta-sigma ADCs.
> 
> The driver implements:
> - Single-shot conversions using the IIO raw read interface.
> - Dynamic parsing of single-ended and differential channels from
>   device tree child nodes.
> - Hardware interrupt support via the DRDY pin, falling back to
>   software polling if no IRQ is provided.
> - Per-channel reference source selection (internal 2.048V, external
>   REFP/REFN, or AVDD) via the reference-sources device tree property.
>   refn-supply is not yet supported.
> - Hardware reset via the reset controller framework, falling back to
>   the RESET command when no reset controller is present.

...

> +static int ads112c04_wait_for_data(struct ads112c04_state *st)
> +{
> +	int ret, err;
> +	u8 val;
> +
> +	if (st->client->irq > 0) {
> +		/* Timeout is 100ms (slowest data rate is 20 SPS) */
> +		if (!wait_for_completion_timeout(&st->completion, msecs_to_jiffies(100)))
> +			return -ETIMEDOUT;
> +
> +		return 0;
> +	}
> +
> +	ret = read_poll_timeout(ads112c04_read_reg, err,
> +				(err < 0 || (val & ADS112C04_CONF2_DRDY)),

Better to split logically, also the outer parentheses are redundant.

	ret = read_poll_timeout(ads112c04_read_reg,
				err, err < 0 || (val & ADS112C04_CONF2_DRDY),

> +				1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC, false,
> +				st->client, ADS112C04_REG_CONFIG2, &val);
> +	if (err < 0)
> +		return err;
> +
> +	return ret;
> +}

...

> +	case IIO_CHAN_INFO_SCALE:
> +		switch (st->vref_source[idx]) {
> +		case ADS112C04_VREF_SOURCE_EXTERNAL:
> +			*val = st->ext_ref_mV;
> +			break;
> +		case ADS112C04_VREF_SOURCE_AVDD:
> +			*val = st->avdd_mV;
> +			break;
> +		default:
> +			*val = ADS112C04_INT_REF_mV;
> +			break;
> +		}
> +		*val2 = 15;

Seems like this being used in one of the above functions already. Perhaps you
want a defined constant? (I haven't checked if that 15 and this one are
semantically related, though.)

> +		return IIO_VAL_FRACTIONAL_LOG2;

...

With

	const char *sp = "single-channel", *dp = "diff-channels";

The below...

> +		if (fwnode_property_present(child, "single-channel")) {
> +			ret = fwnode_property_read_u32(child, "single-channel", &channel);
> +			if (ret)
> +				return dev_err_probe(dev, ret,
> +						     "failed to read single-channel property\n");
> +
> +			if (channel > 3)
> +				return dev_err_probe(dev, -EINVAL,
> +						     "single-channel must be 0-3\n");
> +
> +			spec->channel = channel;
> +			spec->address = ADS112C04_CONF0_MUX_AIN_SINGLE_BASE + channel;
> +		} else if (fwnode_property_present(child, "diff-channels")) {
> +			ret = fwnode_property_read_u32_array(child, "diff-channels",
> +							     pair, ARRAY_SIZE(pair));

+ array_size.h

> +			if (ret)
> +				return dev_err_probe(dev, ret,
> +						     "failed to read diff-channels property\n");
> +
> +			if (pair[0] > 3 || pair[1] > 3)
> +				return dev_err_probe(dev, -EINVAL,
> +						     "diff-channels must be 0-3\n");
> +
> +			spec->channel = pair[0];
> +			spec->channel2 = pair[1];
> +			spec->differential = 1;
> +
> +			if (ads112c04_diff_mux[pair[0]][pair[1]] < 0)
> +				return dev_err_probe(dev, -EINVAL,
> +						     "invalid diff-channels combination\n");
> +
> +			spec->address = ads112c04_diff_mux[pair[0]][pair[1]];
> +		} else {
> +			return dev_err_probe(dev, -EINVAL,
> +					     "channel node must have single-channel or diff-channels\n");
> +		}

...can be written as

		if (fwnode_property_present(child, sp)) {
			ret = fwnode_property_read_u32(child, sp, &channel);
			if (ret)
				return dev_err_probe(dev, ret, "failed to read %s property\n", sp);

			if (channel > 3)
				return dev_err_probe(dev, -EINVAL, "%s must be 0-3\n", sp);

			spec->channel = channel;
			spec->address = ADS112C04_CONF0_MUX_AIN_SINGLE_BASE + channel;
		} else if (fwnode_property_present(child, dp)) {
			ret = fwnode_property_read_u32_array(child, dp, pair, ARRAY_SIZE(pair));
			if (ret)
				return dev_err_probe(dev, ret, "failed to read %s property\n", dp);

			if (pair[0] > 3 || pair[1] > 3)
				return dev_err_probe(dev, -EINVAL, "%s must be 0-3\n", dp);

			spec->channel = pair[0];
			spec->channel2 = pair[1];
			spec->differential = 1;

			if (ads112c04_diff_mux[pair[0]][pair[1]] < 0)
				return dev_err_probe(dev, -EINVAL, "invalid %s combination\n", dp);

			spec->address = ads112c04_diff_mux[pair[0]][pair[1]];
		} else {
			return dev_err_probe(dev, -EINVAL,
					     "channel node must have %s or %s\n", sp, dp);
		}

(but it also makes sense to check with bloat-o-meter to see how much code is
 added and how much data space is saved).

...

> +	/* Datasheet: POR releases ~500us after supplies are stable */
> +	fsleep(500);
> +
> +	reset = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(reset))
> +		return dev_err_probe(dev, PTR_ERR(reset), "failed to get reset\n");
> +
> +	if (reset) {
> +		ret = reset_control_reset(reset);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "failed to reset device\n");
> +	} else {
> +		ret = ads112c04_write_cmd(client, ADS112C04_CMD_RESET);
> +		if (ret < 0)
> +			return ret;
> +	}

Also a comment here?

> +	fsleep(1 * USEC_PER_MSEC);

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 2/2] iio: adc: ti-ads112c04: Add support for TI ADS112C04

[Kyle Hsieh]

On Mon, Aug 17, 2026 at 3:12 PM Andy Shevchenko
<andriy.shevchenko@intel.com> wrote:
>
> On Thu, Aug 13, 2026 at 11:06:03AM +0800, Kyle Hsieh wrote:
> > Add IIO driver support for the Texas Instruments ADS112C04 (16-bit)
> > delta-sigma ADCs.
> >
> > The driver implements:
> > - Single-shot conversions using the IIO raw read interface.
> > - Dynamic parsing of single-ended and differential channels from
> >   device tree child nodes.
> > - Hardware interrupt support via the DRDY pin, falling back to
> >   software polling if no IRQ is provided.
> > - Per-channel reference source selection (internal 2.048V, external
> >   REFP/REFN, or AVDD) via the reference-sources device tree property.
> >   refn-supply is not yet supported.
> > - Hardware reset via the reset controller framework, falling back to
> >   the RESET command when no reset controller is present.
>
> ...
>
> > +static int ads112c04_wait_for_data(struct ads112c04_state *st)
> > +{
> > +     int ret, err;
> > +     u8 val;
> > +
> > +     if (st->client->irq > 0) {
> > +             /* Timeout is 100ms (slowest data rate is 20 SPS) */
> > +             if (!wait_for_completion_timeout(&st->completion, msecs_to_jiffies(100)))
> > +                     return -ETIMEDOUT;
> > +
> > +             return 0;
> > +     }
> > +
> > +     ret = read_poll_timeout(ads112c04_read_reg, err,
> > +                             (err < 0 || (val & ADS112C04_CONF2_DRDY)),
>
> Better to split logically, also the outer parentheses are redundant.

Fixed in v6.
>
>         ret = read_poll_timeout(ads112c04_read_reg,
>                                 err, err < 0 || (val & ADS112C04_CONF2_DRDY),
>
> > +                             1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC, false,
> > +                             st->client, ADS112C04_REG_CONFIG2, &val);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     return ret;
> > +}
>
> ...
>
> > +     case IIO_CHAN_INFO_SCALE:
> > +             switch (st->vref_source[idx]) {
> > +             case ADS112C04_VREF_SOURCE_EXTERNAL:
> > +                     *val = st->ext_ref_mV;
> > +                     break;
> > +             case ADS112C04_VREF_SOURCE_AVDD:
> > +                     *val = st->avdd_mV;
> > +                     break;
> > +             default:
> > +                     *val = ADS112C04_INT_REF_mV;
> > +                     break;
> > +             }
> > +             *val2 = 15;
>
> Seems like this being used in one of the above functions already. Perhaps you
> want a defined constant? (I haven't checked if that 15 and this one are
> semantically related, though.)

They are - both come from the 16-bit signed conversion result. Added
ADS112C04_RESOLUTION_BITS and used RESOLUTION_BITS - 1 in both places.
>
> > +             return IIO_VAL_FRACTIONAL_LOG2;
>
> ...
>
> With
>
>         const char *sp = "single-channel", *dp = "diff-channels";
>
> The below...
>
> > +             if (fwnode_property_present(child, "single-channel")) {
> > +                     ret = fwnode_property_read_u32(child, "single-channel", &channel);
> > +                     if (ret)
> > +                             return dev_err_probe(dev, ret,
> > +                                                  "failed to read single-channel property\n");
> > +
> > +                     if (channel > 3)
> > +                             return dev_err_probe(dev, -EINVAL,
> > +                                                  "single-channel must be 0-3\n");
> > +
> > +                     spec->channel = channel;
> > +                     spec->address = ADS112C04_CONF0_MUX_AIN_SINGLE_BASE + channel;
> > +             } else if (fwnode_property_present(child, "diff-channels")) {
> > +                     ret = fwnode_property_read_u32_array(child, "diff-channels",
> > +                                                          pair, ARRAY_SIZE(pair));
>
> + array_size.h

Added.
>
> > +                     if (ret)
> > +                             return dev_err_probe(dev, ret,
> > +                                                  "failed to read diff-channels property\n");
> > +
> > +                     if (pair[0] > 3 || pair[1] > 3)
> > +                             return dev_err_probe(dev, -EINVAL,
> > +                                                  "diff-channels must be 0-3\n");
> > +
> > +                     spec->channel = pair[0];
> > +                     spec->channel2 = pair[1];
> > +                     spec->differential = 1;
> > +
> > +                     if (ads112c04_diff_mux[pair[0]][pair[1]] < 0)
> > +                             return dev_err_probe(dev, -EINVAL,
> > +                                                  "invalid diff-channels combination\n");
> > +
> > +                     spec->address = ads112c04_diff_mux[pair[0]][pair[1]];
> > +             } else {
> > +                     return dev_err_probe(dev, -EINVAL,
> > +                                          "channel node must have single-channel or diff-channels\n");
> > +             }
>
> ...can be written as
>
>                 if (fwnode_property_present(child, sp)) {
>                         ret = fwnode_property_read_u32(child, sp, &channel);
>                         if (ret)
>                                 return dev_err_probe(dev, ret, "failed to read %s property\n", sp);
>
>                         if (channel > 3)
>                                 return dev_err_probe(dev, -EINVAL, "%s must be 0-3\n", sp);
>
>                         spec->channel = channel;
>                         spec->address = ADS112C04_CONF0_MUX_AIN_SINGLE_BASE + channel;
>                 } else if (fwnode_property_present(child, dp)) {
>                         ret = fwnode_property_read_u32_array(child, dp, pair, ARRAY_SIZE(pair));
>                         if (ret)
>                                 return dev_err_probe(dev, ret, "failed to read %s property\n", dp);
>
>                         if (pair[0] > 3 || pair[1] > 3)
>                                 return dev_err_probe(dev, -EINVAL, "%s must be 0-3\n", dp);
>
>                         spec->channel = pair[0];
>                         spec->channel2 = pair[1];
>                         spec->differential = 1;
>
>                         if (ads112c04_diff_mux[pair[0]][pair[1]] < 0)
>                                 return dev_err_probe(dev, -EINVAL, "invalid %s combination\n", dp);
>
>                         spec->address = ads112c04_diff_mux[pair[0]][pair[1]];
>                 } else {
>                         return dev_err_probe(dev, -EINVAL,
>                                              "channel node must have %s or %s\n", sp, dp);
>                 }
>
> (but it also makes sense to check with bloat-o-meter to see how much code is
>  added and how much data space is saved).
>

Applied - it also keeps the error messages in sync with the property
names automatically.
> ...
>
> > +     /* Datasheet: POR releases ~500us after supplies are stable */
> > +     fsleep(500);
> > +
> > +     reset = devm_reset_control_get_optional_exclusive(dev, NULL);
> > +     if (IS_ERR(reset))
> > +             return dev_err_probe(dev, PTR_ERR(reset), "failed to get reset\n");
> > +
> > +     if (reset) {
> > +             ret = reset_control_reset(reset);
> > +             if (ret)
> > +                     return dev_err_probe(dev, ret, "failed to reset device\n");
> > +     } else {
> > +             ret = ads112c04_write_cmd(client, ADS112C04_CMD_RESET);
> > +             if (ret < 0)
> > +                     return ret;
> > +     }
>
> Also a comment here?
>
> > +     fsleep(1 * USEC_PER_MSEC);
>

Added.

Thanks,
Kyle Hsieh