[PATCH v6 0/2] mfd: max597x: Add support for max597x

[PATCH v6 0/2] mfd: max597x: Add support for max597x

[Naresh Solanki]

max597x is multifunction device with hot swap controller, fault
protection & upto four indication leds.

max5978 has single hot swap controller whereas max5970 has two hot swap
controllers.

Changes in V6:
- Update missing vendor prefix
- Update indentation in example
Changes in V5:
- Fix dt schema error
Changes in V4:
- Add NULL entry for of_device_id
- Memory allocation check
Changes in V3:
- Address code review comment
Changes in V2:
- Update depends in Kconfig.

Marcello Sylvester Bauer (1):
  dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

Patrick Rudolph (1):
  mfd: max597x: Add support for MAX5970 and MAX5978

 .../bindings/mfd/maxim,max5970.yaml           | 164 ++++++++++++++++++
 drivers/mfd/Kconfig                           |  12 ++
 drivers/mfd/Makefile                          |   1 +
 drivers/mfd/max597x.c                         |  92 ++++++++++
 include/linux/mfd/max597x.h                   | 103 +++++++++++
 5 files changed, 372 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
 create mode 100644 drivers/mfd/max597x.c
 create mode 100644 include/linux/mfd/max597x.h


base-commit: 6b780408be034213edfb5946889882cb29f8f159
-- 
2.37.3

[PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Naresh Solanki]

From: Marcello Sylvester Bauer <sylv@sylv.io>

The MAX597x is a hot swap controller with configurable fault protection.
It also has 10bit ADC for current & voltage measurements.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
 .../bindings/mfd/maxim,max5970.yaml           | 164 ++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/maxim,max5970.yaml

diff --git a/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
new file mode 100644
index 000000000000..fc9d6d3647b3
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
@@ -0,0 +1,164 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/max5970.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Regulator for MAX5970 smart switch from Maxim Integrated.
+
+maintainers:
+  - Patrick Rudolph <patrick.rudolph@9elements.com>
+
+description: |
+  The smart switch provides no output regulation, but independent fault protection
+  and voltage and current sensing.
+  Programming is done through I2C bus.
+
+  Datasheets:
+    https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
+    https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
+
+properties:
+  compatible:
+    enum:
+      - maxim,max5970
+      - maxim,max5978
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  leds:
+    type: object
+    description:
+      Properties for single channel.
+
+    patternProperties:
+      "^led@[0-3]$":
+        $ref: /schemas/leds/common.yaml#
+        type: object
+
+    additionalProperties: true
+
+  vss1-supply:
+    description: Supply of the first channel.
+
+  vss2-supply:
+    description: Supply of the first channel.
+
+  "#io-channel-cells":
+    const: 1
+
+  regulators:
+    type: object
+    description:
+      Properties for single channel.
+
+    patternProperties:
+      "^(sw[0-1])$":
+        $ref: /schemas/regulator/regulator.yaml#
+        type: object
+
+      shunt-resistor-micro-ohms:
+        description: |
+          The value of curent sense resistor in microohms.
+          Must be specified for each channel.
+
+    additionalProperties: true
+
+required:
+  - compatible
+  - reg
+  - regulators
+  - vss1-supply
+
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - maxim,max5970
+    then:
+      properties:
+        io-channels:
+          items:
+            - description: voltage first channel
+            - description: current first channel
+            - description: voltage second channel
+            - description: current second channel
+          description: |
+            Voltage and current for first and second channel.
+      required:
+        - vss2-supply
+    else:
+      properties:
+        io-channels:
+          items:
+            - description: voltage first channel
+            - description: current first channel
+          description: |
+            Voltage and current for first channel.
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        regulator@3a {
+           compatible = "maxim,max5978";
+           reg = <0x3a>;
+           vss1-supply = <&p3v3>;
+
+           regulators {
+               sw0_ref_0: SW0 {
+                      regulator-compatible = "SW0";
+                      shunt-resistor-micro-ohms = <12000>;
+               };
+           };
+
+           leds {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               led@0 {
+                   reg = <0>;
+                   label = "led0";
+                   default-state = "on";
+               };
+               led@1 {
+                   reg = <1>;
+                   label = "led1";
+                   default-state = "on";
+               };
+           };
+        };
+    };
+
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        regulator@3a {
+            compatible = "maxim,max5970";
+            reg = <0x3a>;
+            vss1-supply = <&p3v3>;
+            vss2-supply = <&p5v>;
+
+            regulators {
+                sw0_ref_1: SW0 {
+                    regulator-compatible = "SW0";
+                    shunt-resistor-micro-ohms = <12000>;
+                };
+                sw1_ref_1: SW1 {
+                    regulator-compatible = "SW1";
+                    shunt-resistor-micro-ohms = <10000>;
+                };
+            };
+        };
+    };
+...
-- 
2.37.3

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Rob Herring]

On Thu, 03 Nov 2022 09:05:44 +0100, Naresh Solanki wrote:
> From: Marcello Sylvester Bauer <sylv@sylv.io>
> 
> The MAX597x is a hot swap controller with configurable fault protection.
> It also has 10bit ADC for current & voltage measurements.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---
>  .../bindings/mfd/maxim,max5970.yaml           | 164 ++++++++++++++++++
>  1 file changed, 164 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
./Documentation/devicetree/bindings/mfd/maxim,max5970.yaml: $id: relative path/filename doesn't match actual path or filename
	expected: http://devicetree.org/schemas/mfd/maxim,max5970.yaml#

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Krzysztof Kozlowski]

On 03/11/2022 04:05, Naresh Solanki wrote:
> From: Marcello Sylvester Bauer <sylv@sylv.io>
> 
> The MAX597x is a hot swap controller with configurable fault protection.
> It also has 10bit ADC for current & voltage measurements.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---
>  .../bindings/mfd/maxim,max5970.yaml           | 164 ++++++++++++++++++
>  1 file changed, 164 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
> new file mode 100644
> index 000000000000..fc9d6d3647b3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
> @@ -0,0 +1,164 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mfd/max5970.yaml#

Does not look like you tested the bindings. Please run `make
dt_binding_check` (see
Documentation/devicetree/bindings/writing-schema.rst for instructions).

> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Regulator for MAX5970 smart switch from Maxim Integrated.
> +
> +maintainers:
> +  - Patrick Rudolph <patrick.rudolph@9elements.com>
> +
> +description: |
> +  The smart switch provides no output regulation, but independent fault protection
> +  and voltage and current sensing.
> +  Programming is done through I2C bus.
> +
> +  Datasheets:
> +    https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
> +    https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - maxim,max5970
> +      - maxim,max5978
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  leds:
> +    type: object
> +    description:
> +      Properties for single channel.
> +
> +    patternProperties:
> +      "^led@[0-3]$":
> +        $ref: /schemas/leds/common.yaml#
> +        type: object
> +
> +    additionalProperties: true
> +
> +  vss1-supply:
> +    description: Supply of the first channel.
> +
> +  vss2-supply:
> +    description: Supply of the first channel.
> +
> +  "#io-channel-cells":
> +    const: 1
> +
> +  regulators:
> +    type: object
> +    description:
> +      Properties for single channel.
> +
> +    patternProperties:
> +      "^(sw[0-1])$":
> +        $ref: /schemas/regulator/regulator.yaml#
> +        type: object
> +
> +      shunt-resistor-micro-ohms:
> +        description: |
> +          The value of curent sense resistor in microohms.
> +          Must be specified for each channel.
> +
> +    additionalProperties: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - regulators
> +  - vss1-supply
> +
> +

Just one blank line.

> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          enum:
> +            - maxim,max5970
> +    then:
> +      properties:
> +        io-channels:
> +          items:
> +            - description: voltage first channel
> +            - description: current first channel
> +            - description: voltage second channel
> +            - description: current second channel
> +          description: |
> +            Voltage and current for first and second channel.
> +      required:
> +        - vss2-supply
> +    else:
> +      properties:
> +        io-channels:
> +          items:
> +            - description: voltage first channel
> +            - description: current first channel
> +          description: |
> +            Voltage and current for first channel.
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        regulator@3a {
> +           compatible = "maxim,max5978";
> +           reg = <0x3a>;
> +           vss1-supply = <&p3v3>;
> +
> +           regulators {
> +               sw0_ref_0: SW0 {

No improvements here.

Best regards,
Krzysztof

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Naresh Solanki]

Hi Krzysztof,

On 03-11-2022 06:43 pm, Krzysztof Kozlowski wrote:
>> +examples:
>> +  - |
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +        regulator@3a {
>> +           compatible = "maxim,max5978";
>> +           reg = <0x3a>;
>> +           vss1-supply = <&p3v3>;
>> +
>> +           regulators {
>> +               sw0_ref_0: SW0 {
> No improvements here.
I've addressed 4 space indentation, bindings are matched, compatible is 
moved to first, then reg then the rest.

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Krzysztof Kozlowski]

On 03/11/2022 13:53, Naresh Solanki wrote:
> Hi Krzysztof,
> 
> On 03-11-2022 06:43 pm, Krzysztof Kozlowski wrote:
>>> +examples:
>>> +  - |
>>> +    i2c {
>>> +        #address-cells = <1>;
>>> +        #size-cells = <0>;
>>> +        regulator@3a {
>>> +           compatible = "maxim,max5978";
>>> +           reg = <0x3a>;
>>> +           vss1-supply = <&p3v3>;
>>> +
>>> +           regulators {
>>> +               sw0_ref_0: SW0 {
>> No improvements here.
> I've addressed 4 space indentation, bindings are matched, compatible is 
> moved to first, then reg then the rest.

OK, so indeed there are improvements.

Yet still you did not improve the warnings coming from the binding -
this does not match your binding. Test the binding and you will see big
fat warning.

Best regards,
Krzysztof

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Naresh Solanki]

On 03-11-2022 11:31 pm, Krzysztof Kozlowski wrote:
> OK, so indeed there are improvements.
> 
> Yet still you did not improve the warnings coming from the binding -
> this does not match your binding. Test the binding and you will see big
> fat warning.
Not sure what I've missed but below is the output:
make dt_binding_check -j1 V=1
make -f ./scripts/Makefile.build obj=scripts/basic
make -f ./scripts/Makefile.build obj=scripts/dtc
make -f ./scripts/Makefile.build obj=Documentation/devicetree/bindings
   dt-extract-example 
Documentation/devicetree/bindings/mfd/maxim,max5970.yaml > 
Documentation/devicetree/bindings/mfd/maxim,max5970.example.dts
   gcc -E 
-Wp,-MMD,Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.pre.tmp 
-nostdinc -I./scripts/dtc/include-prefixes -undef -D__DTS__ -x 
assembler-with-cpp -o 
Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.dts.tmp 
Documentation/devicetree/bindings/mfd/maxim,max5970.example.dts ; 
./scripts/dtc/dtc -o 
Documentation/devicetree/bindings/mfd/maxim,max5970.example.dtb -b 0 
-iDocumentation/devicetree/bindings/mfd/ 
-i./scripts/dtc/include-prefixes -Wno-avoid_unnecessary_addr_size 
-Wno-graph_child_address -Wno-interrupt_provider 
-Wno-unique_unit_address -Wunique_unit_address_if_enabled -d 
Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.dtc.tmp 
Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.dts.tmp 
; cat 
Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.pre.tmp 
Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.dtc.tmp 
 > Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d ; 
dt-validate  -u ./Documentation/devicetree/bindings -p 
./Documentation/devicetree/bindings/processed-schema.json 
Documentation/devicetree/bindings/mfd/maxim,max5970.example.dtb || true

Didn't get any error or warning on example.
Made sure python package dt-schema is updated as well.

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Krzysztof Kozlowski]

On 03/11/2022 14:20, Naresh Solanki wrote:
> 
> 
> On 03-11-2022 11:31 pm, Krzysztof Kozlowski wrote:
>> OK, so indeed there are improvements.
>>
>> Yet still you did not improve the warnings coming from the binding -
>> this does not match your binding. Test the binding and you will see big
>> fat warning.
> Not sure what I've missed but below is the output:
> make dt_binding_check -j1 V=1
> make -f ./scripts/Makefile.build obj=scripts/basic
> make -f ./scripts/Makefile.build obj=scripts/dtc
> make -f ./scripts/Makefile.build obj=Documentation/devicetree/bindings
>    dt-extract-example 
> Documentation/devicetree/bindings/mfd/maxim,max5970.yaml > 
> Documentation/devicetree/bindings/mfd/maxim,max5970.example.dts
>    gcc -E 
> -Wp,-MMD,Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.pre.tmp 
> -nostdinc -I./scripts/dtc/include-prefixes -undef -D__DTS__ -x 
> assembler-with-cpp -o 
> Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.dts.tmp 
> Documentation/devicetree/bindings/mfd/maxim,max5970.example.dts ; 
> ./scripts/dtc/dtc -o 
> Documentation/devicetree/bindings/mfd/maxim,max5970.example.dtb -b 0 
> -iDocumentation/devicetree/bindings/mfd/ 
> -i./scripts/dtc/include-prefixes -Wno-avoid_unnecessary_addr_size 
> -Wno-graph_child_address -Wno-interrupt_provider 
> -Wno-unique_unit_address -Wunique_unit_address_if_enabled -d 
> Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.dtc.tmp 
> Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.dts.tmp 
> ; cat 
> Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.pre.tmp 
> Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d.dtc.tmp 
>  > Documentation/devicetree/bindings/mfd/.maxim_max5970.example.dtb.d ; 
> dt-validate  -u ./Documentation/devicetree/bindings -p 
> ./Documentation/devicetree/bindings/processed-schema.json 
> Documentation/devicetree/bindings/mfd/maxim,max5970.example.dtb || true
> 
> Didn't get any error or warning on example.
> Made sure python package dt-schema is updated as well.

Eh, true, but you have there "additionalProperties: true" which are not
allowed. This must be false and about leds I commented. False must be in
all other places as well.

Best regards,
Krzysztof

Re: [PATCH v6 1/2] dt-bindings: mfd: Add bindings for MAX5970 and MAX5978

[Naresh Solanki]

On 04-11-2022 01:56 am, Krzysztof Kozlowski wrote:
> Eh, true, but you have there "additionalProperties: true" which are not
> allowed. This must be false and about leds I commented. False must be in
> all other places as well.
Will fix in V8.

Thanks

[PATCH v6 2/2] mfd: max597x: Add support for MAX5970 and MAX5978

[Naresh Solanki]

From: Patrick Rudolph <patrick.rudolph@9elements.com>

Implement a regulator driver with IRQ support for fault management.
Written against documentation [1] and [2] and tested on real hardware.

Every channel has its own regulator supplies nammed 'vss1-supply' and
'vss2-supply'. The regulator supply is used to determine the output
voltage, as the smart switch provides no output regulation.
The driver requires the 'shunt-resistor-micro-ohms' property to be
present in Device Tree to properly calculate current related
values.

Datasheet links:
1: https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
2: https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
 drivers/mfd/Kconfig         |  12 +++++
 drivers/mfd/Makefile        |   1 +
 drivers/mfd/max597x.c       |  92 ++++++++++++++++++++++++++++++++
 include/linux/mfd/max597x.h | 103 ++++++++++++++++++++++++++++++++++++
 4 files changed, 208 insertions(+)
 create mode 100644 drivers/mfd/max597x.c
 create mode 100644 include/linux/mfd/max597x.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8b93856de432..416fe7986b7b 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -253,6 +253,18 @@ config MFD_MADERA_SPI
 	  Support for the Cirrus Logic Madera platform audio SoC
 	  core functionality controlled via SPI.
 
+config MFD_MAX597X
+	tristate "Maxim 597x Power Switch and Monitor"
+	depends on I2C
+	depends on OF
+	select MFD_CORE
+	select REGMAP_I2C
+	help
+	  This driver controls a Maxim 5970/5978 switch via I2C bus.
+	  The MAX5970/5978 is a smart switch with no output regulation, but
+	  fault protection and voltage and current monitoring capabilities.
+	  Also it supports upto 4 indication LEDs.
+
 config MFD_CS47L15
 	bool "Cirrus Logic CS47L15"
 	select PINCTRL_CS47L15
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 7ed3ef4a698c..819d711fa748 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -161,6 +161,7 @@ obj-$(CONFIG_MFD_DA9063)	+= da9063.o
 obj-$(CONFIG_MFD_DA9150)	+= da9150-core.o
 
 obj-$(CONFIG_MFD_MAX14577)	+= max14577.o
+obj-$(CONFIG_MFD_MAX597X)	+= max597x.o
 obj-$(CONFIG_MFD_MAX77620)	+= max77620.o
 obj-$(CONFIG_MFD_MAX77650)	+= max77650.o
 obj-$(CONFIG_MFD_MAX77686)	+= max77686.o
diff --git a/drivers/mfd/max597x.c b/drivers/mfd/max597x.c
new file mode 100644
index 000000000000..2c64edb6b6dd
--- /dev/null
+++ b/drivers/mfd/max597x.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Maxim MAX5970/MAX5978 MFD Driver
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max597x.h>
+#include <linux/regmap.h>
+
+static const struct regmap_config max597x_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX_REGISTERS,
+};
+
+static const struct mfd_cell max597x_cells[] = {
+	{ .name = "max597x-regulator", },
+	{ .name = "max597x-iio", },
+	{ .name = "max597x-led", },
+};
+
+static int max597x_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
+{
+	struct max597x_data *ddata;
+	enum max597x_chip_type chip = id->driver_data;
+
+	ddata = devm_kzalloc(&i2c->dev, sizeof(*ddata),	GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	/* Initialize num of switch based on chip type for later use by regulator
+	 * & iio cells
+	 */
+	switch (chip) {
+	case MAX597x_TYPE_MAX5970:
+		ddata->num_switches = MAX5970_NUM_SWITCHES;
+		break;
+	case MAX597x_TYPE_MAX5978:
+		ddata->num_switches = MAX5978_NUM_SWITCHES;
+		break;
+	}
+
+	ddata->regmap = devm_regmap_init_i2c(i2c, &max597x_regmap_config);
+	if (IS_ERR(ddata->regmap)) {
+		dev_err(&i2c->dev, "Failed to initialise regmap");
+		return -EINVAL;
+	}
+
+	/* IRQ used by regulator cell */
+	ddata->irq = i2c->irq;
+	ddata->dev = &i2c->dev;
+	i2c_set_clientdata(i2c, ddata);
+
+	return devm_mfd_add_devices(ddata->dev, PLATFORM_DEVID_AUTO,
+				    max597x_cells, ARRAY_SIZE(max597x_cells),
+				    NULL, 0, NULL);
+}
+
+static const struct i2c_device_id max597x_table[] = {
+	{ .name = "max5970", MAX597x_TYPE_MAX5970 },
+	{ .name = "max5978", MAX597x_TYPE_MAX5978 },
+};
+
+MODULE_DEVICE_TABLE(i2c, max597x_table);
+
+static const struct of_device_id max597x_of_match[] = {
+	{ .compatible = "maxim,max5970", .data = (void *)MAX597x_TYPE_MAX5970 },
+	{ .compatible = "maxim,max5978", .data = (void *)MAX597x_TYPE_MAX5978 },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, max597x_of_match);
+
+static struct i2c_driver max597x_driver = {
+	.id_table = max597x_table,
+	.driver = {
+		.name = "max597x",
+		.of_match_table = of_match_ptr(max597x_of_match),
+		},
+	.probe = max597x_probe,
+};
+
+module_i2c_driver(max597x_driver);
+
+MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
+MODULE_DESCRIPTION("MAX597X Power Switch and Monitor");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/max597x.h b/include/linux/mfd/max597x.h
new file mode 100644
index 000000000000..f88a57f0e4f2
--- /dev/null
+++ b/include/linux/mfd/max597x.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Maxim MAX5970/MAX5978 MFD Driver
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
+ */
+
+#ifndef MFD_MAX597X_H
+#define MFD_MAX597X_H
+
+#include <linux/device.h>
+#include <linux/regmap.h>
+
+/* Number of switch based on chip variant */
+#define MAX5970_NUM_SWITCHES 2
+#define MAX5978_NUM_SWITCHES 1
+/* Both chip variant have 4 indication LEDs used by LED cell */
+#define MAX597X_NUM_LEDS     4
+
+enum max597x_chip_type {
+	MAX597x_TYPE_MAX5978 = 1,
+	MAX597x_TYPE_MAX5970,
+};
+
+#define MAX5970_REG_CURRENT_L(ch)		(0x01 + (ch) * 4)
+#define MAX5970_REG_CURRENT_H(ch)		(0x00 + (ch) * 4)
+#define MAX5970_REG_VOLTAGE_L(ch)		(0x03 + (ch) * 4)
+#define MAX5970_REG_VOLTAGE_H(ch)		(0x02 + (ch) * 4)
+#define MAX5970_REG_MON_RANGE			0x18
+#define  MAX5970_MON_MASK				0x3
+#define  MAX5970_MON(reg, ch)		(((reg) >> ((ch) * 2)) & MAX5970_MON_MASK)
+#define  MAX5970_MON_MAX_RANGE_UV		16000000
+
+#define MAX5970_REG_CH_UV_WARN_H(ch)	(0x1A + (ch) * 10)
+#define MAX5970_REG_CH_UV_WARN_L(ch)	(0x1B + (ch) * 10)
+#define MAX5970_REG_CH_UV_CRIT_H(ch)	(0x1C + (ch) * 10)
+#define MAX5970_REG_CH_UV_CRIT_L(ch)	(0x1D + (ch) * 10)
+#define MAX5970_REG_CH_OV_WARN_H(ch)	(0x1E + (ch) * 10)
+#define MAX5970_REG_CH_OV_WARN_L(ch)	(0x1F + (ch) * 10)
+#define MAX5970_REG_CH_OV_CRIT_H(ch)	(0x20 + (ch) * 10)
+#define MAX5970_REG_CH_OV_CRIT_L(ch)	(0x21 + (ch) * 10)
+
+#define  MAX5970_VAL2REG_H(x)			(((x) >> 2) & 0xFF)
+#define  MAX5970_VAL2REG_L(x)			((x) & 0x3)
+
+#define MAX5970_REG_DAC_FAST(ch)		(0x2E + (ch))
+
+#define MAX5970_FAST2SLOW_RATIO			200
+
+#define MAX5970_REG_STATUS0				0x31
+#define  MAX5970_CB_IFAULTF(ch)			(1 << (ch))
+#define  MAX5970_CB_IFAULTS(ch)			(1 << ((ch) + 4))
+
+#define MAX5970_REG_STATUS1				0x32
+#define  STATUS1_PROT_MASK				0x3
+#define  STATUS1_PROT(reg) \
+	(((reg) >> 6) & STATUS1_PROT_MASK)
+#define  STATUS1_PROT_SHUTDOWN			0
+#define  STATUS1_PROT_CLEAR_PG			1
+#define  STATUS1_PROT_ALERT_ONLY		2
+
+#define MAX5970_REG_STATUS2				0x33
+#define  MAX5970_IRNG_MASK				0x3
+#define  MAX5970_IRNG(reg, ch)	\
+						(((reg) >> ((ch) * 2)) & MAX5970_IRNG_MASK)
+
+#define MAX5970_REG_STATUS3				0x34
+#define  MAX5970_STATUS3_ALERT			BIT(4)
+#define  MAX5970_STATUS3_PG(ch)			BIT(ch)
+
+#define MAX5970_REG_FAULT0				0x35
+#define  UV_STATUS_WARN(ch)				BIT(ch)
+#define  UV_STATUS_CRIT(ch)				BIT(ch + 4)
+
+#define MAX5970_REG_FAULT1				0x36
+#define  OV_STATUS_WARN(ch)				BIT(ch)
+#define  OV_STATUS_CRIT(ch)				BIT(ch + 4)
+
+#define MAX5970_REG_FAULT2				0x37
+#define  OC_STATUS_WARN(ch)				BIT(ch)
+
+#define MAX5970_REG_CHXEN				0x3b
+#define  CHXEN(ch)						(3 << (ch * 2))
+
+#define MAX5970_REG_LED_FLASH			0x43
+
+#define MAX_REGISTERS					0x49
+#define ADC_MASK						0x3FF
+
+struct max597x_data {
+	struct device *dev;
+	int irq;
+	int num_switches;
+	struct regmap *regmap;
+	/* Chip specific parameters needed by regulator & iio cells */
+	u32 irng[MAX5970_NUM_SWITCHES];
+	u32 mon_rng[MAX5970_NUM_SWITCHES];
+	u32 shunt_micro_ohms[MAX5970_NUM_SWITCHES];
+};
+
+#endif				/* _MAX597X_H */
-- 
2.37.3