Convert the mtk-gce documentation from freeform text format to a
json-schema.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 .../bindings/mailbox/mediatek,gce-mbox.yaml   | 114 ++++++++++++++++++
 .../devicetree/bindings/mailbox/mtk-gce.txt   |  82 -------------
 2 files changed, 114 insertions(+), 82 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
 delete mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt

diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
new file mode 100644
index 000000000000..750391b4038c
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/mediatek,gce-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek Global Command Engine (GCE) mailbox
+
+maintainers:
+  - Houlong Wei <houlong.wei@mediatek.com>
+
+description: |
+  The Global Command Engine (GCE) is used to help read/write registers
+  with critical time limitation, such as updating display configuration
+  during the vblank.
+  The GCE can be used to implement the Command Queue (CMDQ) driver.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt6779-gce
+      - mediatek,mt8173-gce
+      - mediatek,mt8183-gce
+      - mediatek,mt8186-gce
+      - mediatek,mt8192-gce
+      - mediatek,mt8195-gce
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: gce
+
+  '#mbox-cells':
+    description: |
+      The first cell describes the mailbox channel, which is the GCE Thread ID;
+      The second cell describes the priority of the GCE thread.
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - '#mbox-cells'
+
+additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt8195-gce
+    then:
+      properties:
+        clocks:
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: gce0
+            - const: gce1
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/clock/mt8173-clk.h>
+    #include <dt-bindings/gce/mt8173-gce.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        gce: mailbox@10212000 {
+            compatible = "mediatek,mt8173-gce";
+            reg = <0 0x10212000 0 0x1000>;
+            interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>;
+            clocks = <&infracfg CLK_INFRA_GCE>;
+            clock-names = "gce";
+            #mbox-cells = <2>;
+        };
+
+        /* Client device using a GCE Thread */
+        mmsys: syscon@14000000 {
+            compatible = "mediatek,mt8173-mmsys", "syscon";
+            reg = <0 0x14000000 0 0x1000>;
+            mboxes = <&gce 0 CMDQ_THR_PRIO_HIGHEST>,
+                     <&gce 1 CMDQ_THR_PRIO_HIGHEST>;
+            mediatek,gce-client-reg = <&gce SUBSYS_1400XXXX 0 0x1000>;
+            #clock-cells = <1>;
+            #reset-cells = <1>;
+        };
+
+        /* Client device listening to specific GCE Events */
+        mutex: mutex@14020000 {
+            compatible = "mediatek,mt8173-disp-mutex";
+            reg = <0 0x14020000 0 0x1000>;
+            interrupts = <GIC_SPI 169 IRQ_TYPE_LEVEL_LOW>;
+            power-domains = <&spm 1>;
+            clocks = <&mmsys CLK_MM_MUTEX_32K>;
+            mediatek,gce-events = <CMDQ_EVENT_MUTEX0_STREAM_EOF>,
+                                  <CMDQ_EVENT_MUTEX1_STREAM_EOF>;
+        };
+    };
diff --git a/Documentation/devicetree/bindings/mailbox/mtk-gce.txt b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt
deleted file mode 100644
index c2aeba63bd47..000000000000
--- a/Documentation/devicetree/bindings/mailbox/mtk-gce.txt
+++ /dev/null
@@ -1,82 +0,0 @@
-MediaTek GCE
-===============
-
-The Global Command Engine (GCE) is used to help read/write registers with
-critical time limitation, such as updating display configuration during the
-vblank. The GCE can be used to implement the Command Queue (CMDQ) driver.
-
-CMDQ driver uses mailbox framework for communication. Please refer to
-mailbox.txt for generic information about mailbox device-tree bindings.
-
-Required properties:
-- compatible: can be "mediatek,mt8173-gce", "mediatek,mt8183-gce",
-  "mediatek,mt8186-gce", "mediatek,mt8192-gce", "mediatek,mt8195-gce" or
-  "mediatek,mt6779-gce".
-- reg: Address range of the GCE unit
-- interrupts: The interrupt signal from the GCE block
-- clock: Clocks according to the common clock binding
-- clock-names: Must be "gce" to stand for GCE clock
-- #mbox-cells: Should be 2.
-	<&phandle channel priority>
-	phandle: Label name of a gce node.
-	channel: Channel of mailbox. Be equal to the thread id of GCE.
-	priority: Priority of GCE thread.
-
-Required properties for a client device:
-- mboxes: Client use mailbox to communicate with GCE, it should have this
-  property and list of phandle, mailbox specifiers.
-Optional properties for a client device:
-- mediatek,gce-client-reg: Specify the sub-system id which is corresponding
-  to the register address, it should have this property and list of phandle,
-  sub-system specifiers.
-  <&phandle subsys_number start_offset size>
-  phandle: Label name of a gce node.
-  subsys_number: specify the sub-system id which is corresponding
-                 to the register address.
-  start_offset: the start offset of register address that GCE can access.
-  size: the total size of register address that GCE can access.
-
-Optional properties for a client mutex node:
-- mediatek,gce-events: GCE events used by clients. The event numbers are
-  defined in 'dt-bindings/gce/<chip>-gce.h'.
-
-Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h',
-'dt-bindings/gce/mt8183-gce.h', 'dt-bindings/gce/mt8186-gce.h'
-'dt-bindings/gce/mt8192-gce.h', 'dt-bindings/gce/mt8195-gce.h' or
-'dt-bindings/gce/mt6779-gce.h'.
-Such as sub-system ids, thread priority, event ids.
-
-Example:
-
-	gce: gce@10212000 {
-		compatible = "mediatek,mt8173-gce";
-		reg = <0 0x10212000 0 0x1000>;
-		interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>;
-		clocks = <&infracfg CLK_INFRA_GCE>;
-		clock-names = "gce";
-		#mbox-cells = <2>;
-	};
-
-Example for a client device:
-
-	mmsys: clock-controller@14000000 {
-		compatible = "mediatek,mt8173-mmsys";
-		mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST>,
-			 <&gce 1 CMDQ_THR_PRIO_LOWEST>;
-		mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF
-				CMDQ_EVENT_MUTEX1_STREAM_EOF>;
-		mediatek,gce-client-reg = <&gce SUBSYS_1400XXXX 0x3000 0x1000>,
-					  <&gce SUBSYS_1401XXXX 0x2000 0x100>;
-		...
-	};
-
-Example for a client mutex node:
-	mutex: mutex@14020000 {
-		compatible = "mediatek,mt8173-disp-mutex";
-		reg = <0 0x14020000 0 0x1000>;
-		interrupts = <GIC_SPI 169 IRQ_TYPE_LEVEL_LOW>;
-		power-domains = <&scpsys MT8173_POWER_DOMAIN_MM>;
-		clocks = <&mmsys CLK_MM_MUTEX_32K>;
-		mediatek,gce-events = <CMDQ_EVENT_MUTEX0_STREAM_EOF>,
-				      <CMDQ_EVENT_MUTEX1_STREAM_EOF>;
-	};
-- 
2.35.1

On 19/05/2022 12:18, AngeloGioacchino Del Regno wrote:
> Convert the mtk-gce documentation from freeform text format to a
> json-schema.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  .../bindings/mailbox/mediatek,gce-mbox.yaml   | 114 ++++++++++++++++++
>  .../devicetree/bindings/mailbox/mtk-gce.txt   |  82 -------------
>  2 files changed, 114 insertions(+), 82 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>  delete mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
> new file mode 100644
> index 000000000000..750391b4038c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
> @@ -0,0 +1,114 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/mediatek,gce-mbox.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek Global Command Engine (GCE) mailbox
> +
> +maintainers:
> +  - Houlong Wei <houlong.wei@mediatek.com>
> +
> +description: |
> +  The Global Command Engine (GCE) is used to help read/write registers
> +  with critical time limitation, such as updating display configuration
> +  during the vblank.
> +  The GCE can be used to implement the Command Queue (CMDQ) driver.

Mention the headers in description.

> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,mt6779-gce
> +      - mediatek,mt8173-gce
> +      - mediatek,mt8183-gce
> +      - mediatek,mt8186-gce
> +      - mediatek,mt8192-gce
> +      - mediatek,mt8195-gce
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    items:
> +      - const: gce
> +
> +  '#mbox-cells':
> +    description: |
> +      The first cell describes the mailbox channel, which is the GCE Thread ID;
> +      The second cell describes the priority of the GCE thread.
> +    const: 2
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - '#mbox-cells'
> +
> +additionalProperties: false
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          enum:
> +            - mediatek,mt8195-gce
> +    then:
> +      properties:
> +        clocks:
> +          maxItems: 2

Are you sure this works on mt8195-gce?

> +
> +        clock-names:
> +          items:
> +            - const: gce0
> +            - const: gce1
> +

Best regards,
Krzysztof

Il 20/05/22 10:15, Krzysztof Kozlowski ha scritto:
> On 19/05/2022 12:18, AngeloGioacchino Del Regno wrote:
>> Convert the mtk-gce documentation from freeform text format to a
>> json-schema.
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> ---
>>   .../bindings/mailbox/mediatek,gce-mbox.yaml   | 114 ++++++++++++++++++
>>   .../devicetree/bindings/mailbox/mtk-gce.txt   |  82 -------------
>>   2 files changed, 114 insertions(+), 82 deletions(-)
>>   create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>   delete mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>> new file mode 100644
>> index 000000000000..750391b4038c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>> @@ -0,0 +1,114 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/mailbox/mediatek,gce-mbox.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: MediaTek Global Command Engine (GCE) mailbox
>> +
>> +maintainers:
>> +  - Houlong Wei <houlong.wei@mediatek.com>
>> +
>> +description: |
>> +  The Global Command Engine (GCE) is used to help read/write registers
>> +  with critical time limitation, such as updating display configuration
>> +  during the vblank.
>> +  The GCE can be used to implement the Command Queue (CMDQ) driver.
> 
> Mention the headers in description.
> 

   Values for properties used by the GCE, such as sub-system IDs, thread

   priority and event IDs are defined in 'dt-bindings/gce/<chip>-gce.h'.

Would that be enough, or should I list all of the headers?

>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - mediatek,mt6779-gce
>> +      - mediatek,mt8173-gce
>> +      - mediatek,mt8183-gce
>> +      - mediatek,mt8186-gce
>> +      - mediatek,mt8192-gce
>> +      - mediatek,mt8195-gce
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 1
>> +
>> +  clock-names:
>> +    items:
>> +      - const: gce
>> +
>> +  '#mbox-cells':
>> +    description: |
>> +      The first cell describes the mailbox channel, which is the GCE Thread ID;
>> +      The second cell describes the priority of the GCE thread.
>> +    const: 2
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - clocks
>> +  - clock-names
>> +  - '#mbox-cells'
>> +
>> +additionalProperties: false
>> +
>> +allOf:
>> +  - if:
>> +      properties:
>> +        compatible:
>> +          enum:
>> +            - mediatek,mt8195-gce
>> +    then:
>> +      properties:
>> +        clocks:
>> +          maxItems: 2
> 
> Are you sure this works on mt8195-gce?
> 

Thanks for that, I've just rechecked the driver and.. no, that won't
work for MT8195: it's just one clock there (like the others) and the
clock names aren't even enforced, as the driver is always taking the
clock at index 0.

I got confused because the driver uses a slightly different kind of
logic when probing on SoCs with multiple mailboxes, specifically:
  - For single mailbox, having a clock with name "gce" is enforced
    as it's grabbing it with devm_clk_get(dev, clk_name), where the
    clock name is declared in a string called "clk_name";
  - For multiple mailboxes, it's looking for an of_alias, declared
    in an array of strings called "clk_names" and getting the clock
    with of_clk_get(node, 0).


So there comes my confusion, recapping:

static const char * const clk_name = "gce";
                  <- this is a clock name
static const char * const clk_names[] = { "gce0", "gce1" }; <- OF alias names


At this point, I think that the best idea would be to fix this issue
first... luckily there's no MT8195 devicetree upstream yet, so I would
technically not be breaking any ABI by changing it to be the same as
the others.

Easier explanation: plan is to change the driver such that we won't
need anything different from the others in this schema.

New version coming soon, then....

Regards,
Angelo

On 24/05/2022 14:18, AngeloGioacchino Del Regno wrote:
> Il 20/05/22 10:15, Krzysztof Kozlowski ha scritto:
>> On 19/05/2022 12:18, AngeloGioacchino Del Regno wrote:
>>> Convert the mtk-gce documentation from freeform text format to a
>>> json-schema.
>>>
>>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>>> ---
>>>   .../bindings/mailbox/mediatek,gce-mbox.yaml   | 114 ++++++++++++++++++
>>>   .../devicetree/bindings/mailbox/mtk-gce.txt   |  82 -------------
>>>   2 files changed, 114 insertions(+), 82 deletions(-)
>>>   create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>>   delete mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>> new file mode 100644
>>> index 000000000000..750391b4038c
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>> @@ -0,0 +1,114 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/mailbox/mediatek,gce-mbox.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek Global Command Engine (GCE) mailbox
>>> +
>>> +maintainers:
>>> +  - Houlong Wei <houlong.wei@mediatek.com>
>>> +
>>> +description: |
>>> +  The Global Command Engine (GCE) is used to help read/write registers
>>> +  with critical time limitation, such as updating display configuration
>>> +  during the vblank.
>>> +  The GCE can be used to implement the Command Queue (CMDQ) driver.
>>
>> Mention the headers in description.
>>
> 
>    Values for properties used by the GCE, such as sub-system IDs, thread
> 
>    priority and event IDs are defined in 'dt-bindings/gce/<chip>-gce.h'.
> 
> Would that be enough, or should I list all of the headers?

Yes.

> 
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - mediatek,mt6779-gce
>>> +      - mediatek,mt8173-gce
>>> +      - mediatek,mt8183-gce
>>> +      - mediatek,mt8186-gce
>>> +      - mediatek,mt8192-gce
>>> +      - mediatek,mt8195-gce
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    maxItems: 1
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: gce
>>> +
>>> +  '#mbox-cells':
>>> +    description: |
>>> +      The first cell describes the mailbox channel, which is the GCE Thread ID;
>>> +      The second cell describes the priority of the GCE thread.
>>> +    const: 2
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +  - interrupts
>>> +  - clocks
>>> +  - clock-names
>>> +  - '#mbox-cells'
>>> +
>>> +additionalProperties: false
>>> +
>>> +allOf:
>>> +  - if:
>>> +      properties:
>>> +        compatible:
>>> +          enum:
>>> +            - mediatek,mt8195-gce
>>> +    then:
>>> +      properties:
>>> +        clocks:
>>> +          maxItems: 2
>>
>> Are you sure this works on mt8195-gce?
>>
> 
> Thanks for that, I've just rechecked the driver and.. no, that won't
> work for MT8195: it's just one clock there (like the others) and the
> clock names aren't even enforced, as the driver is always taking the
> clock at index 0.

I was not thinking about driver, although it's nice that my review
helped in that. What I was mentioning, is your bindings behave correctly
for mediatek,mt8195-gce DTS? You have maxItems:1 and maxItems:2, so
usually it was failing, AFAIR.

The same with clock-names - I think the schema should fail here.


> 
> I got confused because the driver uses a slightly different kind of
> logic when probing on SoCs with multiple mailboxes, specifically:
>   - For single mailbox, having a clock with name "gce" is enforced
>     as it's grabbing it with devm_clk_get(dev, clk_name), where the
>     clock name is declared in a string called "clk_name";
>   - For multiple mailboxes, it's looking for an of_alias, declared
>     in an array of strings called "clk_names" and getting the clock
>     with of_clk_get(node, 0).
> 
> 
> So there comes my confusion, recapping:
> 
> static const char * const clk_name = "gce";
>                   <- this is a clock name
> static const char * const clk_names[] = { "gce0", "gce1" }; <- OF alias names
> 
> 
> At this point, I think that the best idea would be to fix this issue
> first... luckily there's no MT8195 devicetree upstream yet, so I would
> technically not be breaking any ABI by changing it to be the same as
> the others.

All this sounds a bit unrelated to the bindings. Anyway, gce for one
case and gce0+gce1 for other, are okay, although schema looks a bit more
complicated. See for example:
https://lore.kernel.org/linux-devicetree/20220523181836.2019180-8-dmitry.baryshkov@linaro.org/

Best regards,
Krzysztof

On 24/05/2022 14:18, AngeloGioacchino Del Regno wrote:
> Il 20/05/22 10:15, Krzysztof Kozlowski ha scritto:
>> On 19/05/2022 12:18, AngeloGioacchino Del Regno wrote:
>>> Convert the mtk-gce documentation from freeform text format to a
>>> json-schema.
>>>
>>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>>> ---
>>>   .../bindings/mailbox/mediatek,gce-mbox.yaml   | 114 ++++++++++++++++++
>>>   .../devicetree/bindings/mailbox/mtk-gce.txt   |  82 -------------
>>>   2 files changed, 114 insertions(+), 82 deletions(-)
>>>   create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>>   delete mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>> new file mode 100644
>>> index 000000000000..750391b4038c
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-mbox.yaml
>>> @@ -0,0 +1,114 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/mailbox/mediatek,gce-mbox.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek Global Command Engine (GCE) mailbox
>>> +
>>> +maintainers:
>>> +  - Houlong Wei <houlong.wei@mediatek.com>
>>> +
>>> +description: |
>>> +  The Global Command Engine (GCE) is used to help read/write registers
>>> +  with critical time limitation, such as updating display configuration
>>> +  during the vblank.
>>> +  The GCE can be used to implement the Command Queue (CMDQ) driver.
>>
>> Mention the headers in description.
>>
> 
>    Values for properties used by the GCE, such as sub-system IDs, thread
> 
>    priority and event IDs are defined in 'dt-bindings/gce/<chip>-gce.h'.
> 
> Would that be enough, or should I list all of the headers?

Yes.

> 
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - mediatek,mt6779-gce
>>> +      - mediatek,mt8173-gce
>>> +      - mediatek,mt8183-gce
>>> +      - mediatek,mt8186-gce
>>> +      - mediatek,mt8192-gce
>>> +      - mediatek,mt8195-gce
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    maxItems: 1
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: gce
>>> +
>>> +  '#mbox-cells':
>>> +    description: |
>>> +      The first cell describes the mailbox channel, which is the GCE Thread ID;
>>> +      The second cell describes the priority of the GCE thread.
>>> +    const: 2
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +  - interrupts
>>> +  - clocks
>>> +  - clock-names
>>> +  - '#mbox-cells'
>>> +
>>> +additionalProperties: false
>>> +
>>> +allOf:
>>> +  - if:
>>> +      properties:
>>> +        compatible:
>>> +          enum:
>>> +            - mediatek,mt8195-gce
>>> +    then:
>>> +      properties:
>>> +        clocks:
>>> +          maxItems: 2
>>
>> Are you sure this works on mt8195-gce?
>>
> 
> Thanks for that, I've just rechecked the driver and.. no, that won't
> work for MT8195: it's just one clock there (like the others) and the
> clock names aren't even enforced, as the driver is always taking the
> clock at index 0.

I was not thinking about driver, although it's nice that my review
helped in that. What I was mentioning, is your bindings behave correctly
for mediatek,mt8195-gce DTS? You have maxItems:1 and maxItems:2, so
usually it was failing, AFAIR.

The same with clock-names - I think the schema should fail here.


> 
> I got confused because the driver uses a slightly different kind of
> logic when probing on SoCs with multiple mailboxes, specifically:
>   - For single mailbox, having a clock with name "gce" is enforced
>     as it's grabbing it with devm_clk_get(dev, clk_name), where the
>     clock name is declared in a string called "clk_name";
>   - For multiple mailboxes, it's looking for an of_alias, declared
>     in an array of strings called "clk_names" and getting the clock
>     with of_clk_get(node, 0).
> 
> 
> So there comes my confusion, recapping:
> 
> static const char * const clk_name = "gce";
>                   <- this is a clock name
> static const char * const clk_names[] = { "gce0", "gce1" }; <- OF alias names
> 
> 
> At this point, I think that the best idea would be to fix this issue
> first... luckily there's no MT8195 devicetree upstream yet, so I would
> technically not be breaking any ABI by changing it to be the same as
> the others.

All this sounds a bit unrelated to the bindings. Anyway, gce for one
case and gce0+gce1 for other, are okay, although schema looks a bit more
complicated. See for example:
https://lore.kernel.org/linux-devicetree/20220523181836.2019180-8-dmitry.baryshkov@linaro.org/

Best regards,
Krzysztof