Max22007 dev

Documentation/devicetree/bindings/iio/dac/adi,max22007.yaml

@@ -0,0 +1,116 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/dac/adi,max22007.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX22007 DAC device driver
+
+maintainers:
+  - Janani Sunil <[email protected]>
+
+description:
+  The MAX22007 is a quad-channel, 12-bit digital-to-analog converter (DAC)
+  with integrated precision output amplifiers and current output capability.
+  Each channel can be independently configured for voltage or current output.
+  Datasheet available at https://www.analog.com/en/products/max22007.html
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: adi,max22007
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 500000
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  vdd-supply:
+    description: Low-Voltage Power Supply from +2.7V to +5.5V.
+
+  hvdd-supply:
+    description:
+      Positive High-Voltage Power Supply from +8V to (HVSS +24V) for
+      the Output Channels.
+
+  hvss-supply:
+    description:
+      Negative High-Voltage Power Supply from -2V to 0V for the Output Channels.
+
+  reset-gpios:
+    maxItems: 1
+    description:
+      GPIO used for hardware reset of the device.
+
+patternProperties:
+  "^channel@[0-3]$":
+    allOf:
+      - $ref: /schemas/iio/dac/dac.yaml#
+      - type: object
+        description:
+          Represents the external channels which are connected to the DAC.
+          Channels not specified in the device tree will be powered off.
+
+        properties:
+          reg:
+            description: Channel number
+            maxItems: 1
+
+          adi,type:
+            description: Channel output type.
+            $ref: /schemas/types.yaml#/definitions/string
+            enum: [voltage, current]
+
+        required:
+          - reg
+          - adi,type
+
+        unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+
+anyOf:
+  - required: [channel@0]
+  - required: [channel@1]
+  - required: [channel@2]
+  - required: [channel@3]
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        dac@0 {
+            compatible = "adi,max22007";
+            reg = <0>;
+            spi-max-frequency = <500000>;
+            reset-gpios = <&gpio 19 GPIO_ACTIVE_LOW>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+                adi,type = "voltage";
+            };
+
+            channel@1 {
+                reg = <1>;
+                adi,type = "current";
+            };
+        };
+    };
+...

Documentation/iio/index.rst

@@ -37,4 +37,5 @@ Industrial I/O Kernel Drivers
    adxl345
    bno055
    ep93xx_adc
+   max22007
    opt4060

Documentation/iio/max22007.rst

@@ -0,0 +1,145 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+===============
+MAX22007 driver
+===============
+
+Device driver for Analog Devices Inc. MAX22007 quad-channel industrial DAC.
+The module name is ``max22007``.
+
+Supported devices
+=================
+
+* `MAX22007 <https://www.analog.com/en/products/max22007.html>`_
+
+Wiring connections
+==================
+
+The MAX22007 uses a standard SPI interface.
+
+Device Tree Configuration
+=========================
+
+The device supports both global and per-channel configuration through device tree.
+
+Global Properties:
+
+* ``reset-gpios``: GPIO pin for hardware reset (optional, falls back to
+  software reset if not specified)
+* ``vdd-supply``: Low-Voltage Power Supply from +2.7V to +5.5V (optional)
+* ``hvdd-supply``: Positive High-Voltage Power Supply from +8V to (HVSS +24V)
+  for the Output Channels (optional)
+* ``hvss-supply``: Negative High-Voltage Power Supply from -2V to 0V for the
+  Output Channels (optional)
+
+Per-channel properties:
+
+* ``adi,type``: Specify the channel output type - must be either "voltage" or "current" (mandatory)
+
+Note: The driver operates in transparent mode (immediate register-to-output updates).
+Channel mode is determined by the ``adi,type`` property:
+
+* ``adi,type = "current"``: the channel operates in current mode
+* ``adi,type = "voltage"``: the channel operates in voltage mode
+
+Device attributes
+=================
+
+The MAX22007 driver provides IIO DAC interfaces that vary based on the
+configured channel mode. Each channel appears as a separate IIO device
+attribute:
+
+* ``out_voltage_raw`` (voltage mode channels)
+* ``out_current_raw`` (current mode channels)
+* ``out_voltage_scale`` / ``out_current_scale`` (channel scaling factors)
+* ``out_voltage_powerdown`` / ``out_current_powerdown`` (channel power control)
+
+The driver automatically configures the IIO channel type based on the configured
+channel mode from device tree.
+
+Power Mode Control
+==================
+
+Each channel provides standard IIO ``powerdown`` attributes for runtime power
+control:
+
+* Write ``1`` to power down (disable) the channel output
+* Write ``0`` to power up (enable) the channel output
+* Read the attribute to get the current power state (1=powered down, 0=powered up)
+
+This allows individual channels to be powered on/off independently for power
+management and safety purposes.
+
+Usage Examples
+==============
+
+Setting DAC output values:
+
+.. code-block:: bash
+
+   # Set channel 0 (voltage mode) to raw value 655 (≈2V)
+   # Output is updated immediately in transparent mode
+   echo 655 > /sys/bus/iio/devices/iio:deviceX/out_voltage0_raw
+
+   # Set channel 1 (current mode)
+   # Output is updated immediately in transparent mode
+   echo 1024 > /sys/bus/iio/devices/iio:deviceX/out_current1_raw
+
+Controlling channel power modes:
+
+.. code-block:: bash
+
+   # Enable channel 0 (power up)
+   echo 0 > /sys/bus/iio/devices/iio:deviceX/out_voltage0_powerdown
+
+   # Disable channel 1 (power down)
+   echo 1 > /sys/bus/iio/devices/iio:deviceX/out_current1_powerdown
+
+   # Check current power state (0=powered up, 1=powered down)
+   cat /sys/bus/iio/devices/iio:deviceX/out_voltage0_powerdown
+
+Reading channel values and scale factors:
+
+.. code-block:: bash
+
+   # Read raw DAC value
+   cat /sys/bus/iio/devices/iio:deviceX/out_voltage0_raw
+
+   # Read scale factor (volts per LSB)
+   cat /sys/bus/iio/devices/iio:deviceX/out_voltage0_scale
+
+Check available channels:
+
+.. code-block:: bash
+
+   ls /sys/bus/iio/devices/iio:deviceX/out_*_raw
+
+Scale Calculations
+==================
+
+The driver provides accurate scale factors based on the hardware configuration:
+
+**Voltage Mode:**
+
+- Scale = (5 × 2.5V) / 4096 = 0.003051757 V per LSB
+- Range: 0V to 12.5V over 12-bit (0-4095)
+- Formula: Output = Raw_Value × Scale
+
+**Current Mode:**
+
+- Scale = (2.5V / (2 × 50Ω)) / 4096 = 0.000006103515625 A per LSB
+- Range: 0A to 0.025A over 12-bit (0-4095)
+- Formula: Output = Raw_Value × Scale
+
+Driver Architecture
+===================
+
+The driver implements:
+
+* **CRC8 Error Checking**: Always-enabled CRC8 for SPI data integrity
+* **Channel Configuration**: Supports per-channel mode and power configuration
+
+Channel configuration (voltage/current mode) is set via the ``adi,type``
+device tree property and cannot be changed dynamically The driver requires
+proper device tree configuration with mandatory ``adi,type`` property for each
+channel.

MAINTAINERS

@@ -1593,6 +1593,15 @@ W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/dac/adi,ad9739a.yaml
 F:	drivers/iio/dac/ad9739a.c
 
+ANALOG DEVICES INC MAX22007 DRIVER
+M:	Janani Sunil <[email protected]>
+L:	[email protected]
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/iio/dac/adi,max22007.yaml
+F:	Documentation/iio/max22007.rst
+F:	drivers/iio/dac/max22007.c
+
 ANALOG DEVICES INC ADA4250 DRIVER
 M:	Antoniu Miclaus <[email protected]>
 L:	[email protected]

drivers/iio/dac/Kconfig

@@ -482,6 +482,19 @@ config MAX517
 	  This driver can also be built as a module.  If so, the module
 	  will be called max517.
 
+config MAX22007
+	tristate "Analog Devices MAX22007 DAC Driver"
+	depends on SPI
+	select REGMAP_SPI
+	select CRC8
+	help
+	  Say Y here if you want to build a driver for Analog Devices MAX22007.
+
+	  MAX22007 is a quad-channel, 12-bit, voltage-output digital to
+	  analog converter (DAC) with SPI interface.
+
+	  If compiled as a module, it will be called max22007.
+
 config MAX5522
 	tristate "Maxim MAX5522 DAC driver"
 	depends on SPI_MASTER

drivers/iio/dac/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_LTC2664) += ltc2664.o
 obj-$(CONFIG_LTC2688) += ltc2688.o
 obj-$(CONFIG_M62332) += m62332.o
 obj-$(CONFIG_MAX517) += max517.o
+obj-$(CONFIG_MAX22007) += max22007.o
 obj-$(CONFIG_MAX5522) += max5522.o
 obj-$(CONFIG_MAX5821) += max5821.o
 obj-$(CONFIG_MCP4725) += mcp4725.o