Turris Omnia MCU driver

Add binding for cznic,turris-omnia-mcu, the device-tree node representing the system-controller features provided by the MCU on the Turris Omnia router.

Signed-off-by Marek Behún <[email protected]>

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +43 -0

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/cznic,turris-omnia-mcu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris Omnia MCU
+
+maintainers:
+  - Marek Behún <[email protected]>
+
+description:
+  The MCU on Turris Omnia acts as a system controller providing additional
+  GPIOs, interrupts, watchdog, system power off and wakeup configuration.
+
+properties:
+  compatible:
+    const: cznic,turris-omnia-mcu
+
+  reg:
+    description: MCU I2C slave address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - gpio-controller
+

Quoted 4 lines · Marek Behún

Add binding for cznic,turris-omnia-mcu, the device-tree node representing the system-controller features provided by the MCU on the Turris Omnia router.

Quoted 1 line

Signed-off-by Marek Behún <[email protected]>

Please use scripts/get_maintainers.pl to get a list of necessary people and lists to CC (and consider --no-git-fallback argument). It might happen, that command when run on an older kernel, gives you outdated entries. Therefore please be sure you base your patches on recent Linux kernel.

Quoted 6 lines

---
 .../bindings/arm/cznic,turris-omnia-mcu.yaml  | 72 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml

Quoted 5 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +0 -0

new file mode 100644
index 000000000000..055485847e71

ARM directory is only for top-level bindings, so this should go to soc.

Quoted 48 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +47 -0

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/cznic,turris-omnia-mcu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris Omnia MCU
+
+maintainers:
+  - Marek Behún <[email protected]>
+
+description:
+  The MCU on Turris Omnia acts as a system controller providing additional
+  GPIOs, interrupts, watchdog, system power off and wakeup configuration.
+
+properties:
+  compatible:
+    const: cznic,turris-omnia-mcu
+
+  reg:
+    description: MCU I2C slave address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - gpio-controller
+
+additionalProperties: false
+
+examples:
+  - |

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 53

Quoted 6 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +6 -0

+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ic: interrupt-controller {
+        interrupt-controller;
+        #interrupt-cells = <2>;
+    };  

Drop this node, not relevant.

Quoted 5 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +5 -0

+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 64

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Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +6 -0

+        system-controller@2a {
+            compatible = "cznic,turris-omnia-mcu";
+            reg = <0x2a>;
+
+            interrupt-parent = <&ic>;
+            interrupts = <11 IRQ_TYPE_NONE>;  

Are you sure interrupt is type none?

Hello Krzysztof,

thanks for the review.

Quoted 7 lines · On Thu, 24 Aug 2023 09:37:23 +0200 Krzysztof Kozlowski <[email protected]> wrote:

Quoted 5 lines · Marek Behún

Add binding for cznic,turris-omnia-mcu, the device-tree node representing the system-controller features provided by the MCU on the Turris Omnia router.

Signed-off-by Marek Behún <[email protected]>

Quoted 5 lines

Please use scripts/get_maintainers.pl to get a list of necessary people and lists to CC (and consider --no-git-fallback argument). It might happen, that command when run on an older kernel, gives you outdated entries. Therefore please be sure you base your patches on recent Linux kernel.

I shall do that.

Quoted 7 lines

Quoted 7 lines

---
 .../bindings/arm/cznic,turris-omnia-mcu.yaml  | 72 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml

Quoted 7 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml

Quoted 5 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +0 -0

new file mode 100644
index 000000000000..055485847e71

ARM directory is only for top-level bindings, so this should go to soc.

Hmm. The board uses a marvell SoC, but the board is from CZ.NIC (who does not create its own SoCs). So should this go into soc/marvell or soc/cznic?

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Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +47 -0

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/cznic,turris-omnia-mcu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris Omnia MCU
+
+maintainers:
+  - Marek Behún <[email protected]>
+
+description:
+  The MCU on Turris Omnia acts as a system controller providing additional
+  GPIOs, interrupts, watchdog, system power off and wakeup configuration.
+
+properties:
+  compatible:
+    const: cznic,turris-omnia-mcu
+
+  reg:
+    description: MCU I2C slave address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - gpio-controller
+
+additionalProperties: false
+
+examples:
+  - |

Quoted 8 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 53

Quoted 6 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +6 -0

+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ic: interrupt-controller {
+        interrupt-controller;
+        #interrupt-cells = <2>;
+    };  

Drop this node, not relevant.

Will the binding example compile without the ic node if the system-controller below uses it?

Quoted 14 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 64

Quoted 12 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +11 -0

+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        system-controller@2a {
+            compatible = "cznic,turris-omnia-mcu";
+            reg = <0x2a>;
+
+            interrupt-parent = <&ic>;
+            interrupts = <11 IRQ_TYPE_NONE>;  

Are you sure interrupt is type none?

The interrupt type is either LEVEL_LOW or EDGE_FALLING, depending on the version of the MCU firmware, so this has to be selected by the driver.

I tried setting LEVEL_LOW, since that is the one that is used by the newest MCU firmware. But then if the firmware is old and I want to select EDGE_FALLING in the driver when requesting the IRQ, it fails with message
type mismatch, failed to map hwirq-%lu for %s!
from
kernel/irq/irqdomain.c function irq_create_fwspec_mapping

I guess I can use irqd_set_trigger_type() before requesting the IRQ to avoid this error.

Should I use use LEVEL_LOW in the binding example and device-tree?

You replied only to me. Instead please reply-to-all to keep discussions public.

Quoted 7 lines

Quoted 3 lines

Quoted 1 line

+++ b/Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml

ARM directory is only for top-level bindings, so this should go to soc.

Hmm. The board uses a marvell SoC, but the board is from CZ.NIC (who does not create its own SoCs). So should this go into soc/marvell or soc/cznic?

Indeed and it is a dedicated MCU (some Cortex-M or similar, right?), so maybe arm is suitable at the end.

Quoted 11 lines

Quoted 10 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 53

Quoted 8 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +8 -0

+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ic: interrupt-controller {
+        interrupt-controller;
+        #interrupt-cells = <2>;
+    };    

Drop this node, not relevant.

Quoted 2 lines

Will the binding example compile without the ic node if the system-controller below uses it?

Yes.

Quoted 17 lines

Quoted 4 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml line 64

Quoted 2 lines

Documentation/devicetree/bindings/arm/cznic,turris-omnia-mcu.yaml new file +2 -0

+            interrupt-parent = <&ic>;
+            interrupts = <11 IRQ_TYPE_NONE>;    

Are you sure interrupt is type none?

The interrupt type is either LEVEL_LOW or EDGE_FALLING, depending on the version of the MCU firmware, so this has to be selected by the driver.

I tried setting LEVEL_LOW, since that is the one that is used by the newest MCU firmware. But then if the firmware is old and I want to select EDGE_FALLING in the driver when requesting the IRQ, it fails with message
type mismatch, failed to map hwirq-%lu for %s!
from
kernel/irq/irqdomain.c function irq_create_fwspec_mapping

Quoted 4 lines

I guess I can use irqd_set_trigger_type() before requesting the IRQ to avoid this error.

Should I use use LEVEL_LOW in the binding example and device-tree?

I guess in such case this NONE is okay

Turris Omnia's MCU provides various features that can be configured over I2C at address 0x2a. Add device-tree node.

Fixes 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")

Signed-off-by Marek Behún <[email protected]>

---
 .../dts/marvell/armada-385-turris-omnia.dts   | 24 ++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

arch/arm/boot/dts/marvell/armada-385-turris-omnia.dts +7 -1

index 2d8d319bec83..761147f5870f 100644
@@ -218,7 +218,24 @@ i2c@0 {
 			#size-cells = <0>;
 			reg = <0>;
 
-			/* STM32F0 command interface at address 0x2a */
+			mcu: system-controller@2a {
+				compatible = "cznic,turris-omnia-mcu";
+				reg = <0x2a>;
+
+				pinctrl-names = "default";
+				pinctrl-0 = <&mcu_pins>;
+