[PATCH v2 0/3] Add bindings for slave-specific SPI controller properties

[PATCH v2 0/3] Add bindings for slave-specific SPI controller properties

[Pratyush Yadav]

Hi,

This series adds bindings for slave-specific SPI controller properties.
See patch 1 for more info on the motivations behind this.

This is the best approach that I came up with with my limited knowledge
of JSON schema. It has some limitations that are mentioned in patch 1. I
don't know of any better ways to model this. Suggestions are welcome!

Changes in v2:
- Move other subnode properties listed in spi-controller.yaml to
  spi-slave-props.yaml
- Move the Cadence controller-specific properties out of
  spi-slave-props.yaml. They will be added in a separate file.
- Add a reference to spi-slave-props.yaml in spi-controller.yaml.
- Update description.

Pratyush Yadav (3):
  spi: dt-bindings: add schema listing slave-specific properties
  spi: dt-bindings: cdns,qspi-nor: Move slave-specific properties out
  dt-bindings: mtd: spi-nor: Add a reference to spi-slave-props.yaml

 .../bindings/mtd/jedec,spi-nor.yaml           |  3 +-
 .../spi/cdns,qspi-nor-slave-props.yaml        | 42 +++++++++
 .../bindings/spi/cdns,qspi-nor.yaml           | 33 -------
 .../bindings/spi/spi-controller.yaml          | 69 +-------------
 .../bindings/spi/spi-slave-props.yaml         | 93 +++++++++++++++++++
 5 files changed, 139 insertions(+), 101 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
 create mode 100644 Documentation/devicetree/bindings/spi/spi-slave-props.yaml

-- 
2.33.1.835.ge9e5ba39a7

[PATCH v2 1/3] spi: dt-bindings: add schema listing slave-specific properties

[Pratyush Yadav]

Many SPI controllers need to add properties to slave devices. This could
be the delay in clock or data lines, etc. These properties are
controller specific but need to be defined in the slave node because
they are per-slave and there can be multiple slaves attached to a
controller.

If these properties are not added to the slave binding, then the dtbs
check emits a warning. But these properties do not make much sense in
the slave binding because they are controller-specific and they will
just pollute every slave binding. So this binding is added to collect
all such properties from all such controllers. Slave bindings should
simply refer to this binding and they should be rid of the warnings.

There are some limitations with this approach. Firstly, there is no way
to specify required properties. The schema contains properties for all
controllers and there is no way to know which controller is being used.
Secondly, there is no way to restrict additional properties. Since this
schema will be used with an allOf operator, additionalProperties needs
to be true. In addition, the slave schema will have to set
unevaluatedProperties: false.

Despite these limitations, this appears to be the best solution to this
problem that doesn't involve modifying existing tools or schema specs.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>

---

Changes in v2:
- Move other subnode properties listed in spi-controller.yaml to
  spi-slave-props.yaml
- Move the Cadence controller-specific properties out of
  spi-slave-props.yaml. They will be added in a separate file.
- Add a reference to spi-slave-props.yaml in spi-controller.yaml.
- Update description.

 .../bindings/spi/spi-controller.yaml          | 69 +-------------
 .../bindings/spi/spi-slave-props.yaml         | 91 +++++++++++++++++++
 2 files changed, 93 insertions(+), 67 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-slave-props.yaml

diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml
index 8246891602e7..ff770657e214 100644
--- a/Documentation/devicetree/bindings/spi/spi-controller.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml
@@ -94,73 +94,8 @@ patternProperties:
   "^.*@[0-9a-f]+$":
     type: object
 
-    properties:
-      compatible:
-        description:
-          Compatible of the SPI device.
-
-      reg:
-        minItems: 1
-        maxItems: 256
-        items:
-          minimum: 0
-          maximum: 256
-        description:
-          Chip select used by the device.
-
-      spi-3wire:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          The device requires 3-wire mode.
-
-      spi-cpha:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          The device requires shifted clock phase (CPHA) mode.
-
-      spi-cpol:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          The device requires inverse clock polarity (CPOL) mode.
-
-      spi-cs-high:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          The device requires the chip select active high.
-
-      spi-lsb-first:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          The device requires the LSB first mode.
-
-      spi-max-frequency:
-        $ref: /schemas/types.yaml#/definitions/uint32
-        description:
-          Maximum SPI clocking speed of the device in Hz.
-
-      spi-rx-bus-width:
-        description:
-          Bus width to the SPI bus used for read transfers.
-          If 0 is provided, then no RX will be possible on this device.
-        $ref: /schemas/types.yaml#/definitions/uint32
-        enum: [0, 1, 2, 4, 8]
-        default: 1
-
-      spi-rx-delay-us:
-        description:
-          Delay, in microseconds, after a read transfer.
-
-      spi-tx-bus-width:
-        description:
-          Bus width to the SPI bus used for write transfers.
-          If 0 is provided, then no TX will be possible on this device.
-        $ref: /schemas/types.yaml#/definitions/uint32
-        enum: [0, 1, 2, 4, 8]
-        default: 1
-
-      spi-tx-delay-us:
-        description:
-          Delay, in microseconds, after a write transfer.
+    allOf:
+      - $ref: spi-slave-props.yaml
 
     required:
       - compatible
diff --git a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
new file mode 100644
index 000000000000..5166ec9b0353
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/spi-slave-props.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Slave-specific properties for a SPI bus.
+
+description: |
+  Many SPI controllers need to add properties to slave devices. They could be
+  common properties like spi-max-frequency, spi-cpha, etc. or they could be
+  controller specific like delay in clock or data lines, etc. These properties
+  need to be defined in the slave node because they are per-slave and there can
+  be multiple slaves attached to a controller. All those properties are listed
+  here. The controller specific properties should go in their own separate
+  schema that should be referenced from here.
+
+maintainers:
+  - Pratyush Yadav <p.yadav@ti.com>
+
+properties:
+  compatible:
+    description:
+      Compatible of the SPI device.
+
+  reg:
+    minItems: 1
+    maxItems: 256
+    items:
+      minimum: 0
+      maximum: 256
+    description:
+      Chip select used by the device.
+
+  spi-3wire:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The device requires 3-wire mode.
+
+  spi-cpha:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The device requires shifted clock phase (CPHA) mode.
+
+  spi-cpol:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The device requires inverse clock polarity (CPOL) mode.
+
+  spi-cs-high:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The device requires the chip select active high.
+
+  spi-lsb-first:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The device requires the LSB first mode.
+
+  spi-max-frequency:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Maximum SPI clocking speed of the device in Hz.
+
+  spi-rx-bus-width:
+    description:
+      Bus width to the SPI bus used for read transfers.
+      If 0 is provided, then no RX will be possible on this device.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1, 2, 4, 8]
+    default: 1
+
+  spi-rx-delay-us:
+    description:
+      Delay, in microseconds, after a read transfer.
+
+  spi-tx-bus-width:
+    description:
+      Bus width to the SPI bus used for write transfers.
+      If 0 is provided, then no TX will be possible on this device.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1, 2, 4, 8]
+    default: 1
+
+  spi-tx-delay-us:
+    description:
+      Delay, in microseconds, after a write transfer.
+
+# The controller specific properties go here.
+
+additionalProperties: true
-- 
2.33.1.835.ge9e5ba39a7

[PATCH v2 2/3] spi: dt-bindings: cdns,qspi-nor: Move slave-specific properties out

[Pratyush Yadav]

The spi-slave-props.yaml schema contains slave-specific properties
for SPI controllers that should be present in the slave node. Move
slave-specific properties to a separate file and refer to it in
spi-slave-props.yaml.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>

---

Changes in v2:
- New in v2.

 .../spi/cdns,qspi-nor-slave-props.yaml        | 42 +++++++++++++++++++
 .../bindings/spi/cdns,qspi-nor.yaml           | 33 ---------------
 .../bindings/spi/spi-slave-props.yaml         |  2 +
 3 files changed, 44 insertions(+), 33 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml

diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
new file mode 100644
index 000000000000..263382a5729a
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/cdns,qspi-nor-slave-props.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Slave-specific properties for the Cadence QSPI controller.
+
+description:
+  See spi-slave-props.yaml for more info.
+
+maintainers:
+  - Pratyush Yadav <p.yadav@ti.com>
+
+properties:
+  # cdns,qspi-nor.yaml
+  cdns,read-delay:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Delay for read capture logic, in clock cycles.
+
+  cdns,tshsl-ns:
+    description:
+      Delay in nanoseconds for the length that the master mode chip select
+      outputs are de-asserted between transactions.
+
+  cdns,tsd2d-ns:
+    description:
+      Delay in nanoseconds between one chip select being de-activated
+      and the activation of another.
+
+  cdns,tchsh-ns:
+    description:
+      Delay in nanoseconds between last bit of current transaction and
+      deasserting the device chip select (qspi_n_ss_out).
+
+  cdns,tslch-ns:
+    description:
+      Delay in nanoseconds between setting qspi_n_ss_out low and
+      first bit transfer.
+
+additionalProperties: true
diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
index ca155abbda7a..a439e3ed753f 100644
--- a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
+++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
@@ -86,39 +86,6 @@ properties:
     items:
       enum: [ qspi, qspi-ocp ]
 
-# subnode's properties
-patternProperties:
-  "@[0-9a-f]+$":
-    type: object
-    description:
-      Flash device uses the below defined properties in the subnode.
-
-    properties:
-      cdns,read-delay:
-        $ref: /schemas/types.yaml#/definitions/uint32
-        description:
-          Delay for read capture logic, in clock cycles.
-
-      cdns,tshsl-ns:
-        description:
-          Delay in nanoseconds for the length that the master mode chip select
-          outputs are de-asserted between transactions.
-
-      cdns,tsd2d-ns:
-        description:
-          Delay in nanoseconds between one chip select being de-activated
-          and the activation of another.
-
-      cdns,tchsh-ns:
-        description:
-          Delay in nanoseconds between last bit of current transaction and
-          deasserting the device chip select (qspi_n_ss_out).
-
-      cdns,tslch-ns:
-        description:
-          Delay in nanoseconds between setting qspi_n_ss_out low and
-          first bit transfer.
-
 required:
   - compatible
   - reg
diff --git a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
index 5166ec9b0353..4cc12a161da9 100644
--- a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
@@ -87,5 +87,7 @@ properties:
       Delay, in microseconds, after a write transfer.
 
 # The controller specific properties go here.
+allOf:
+  - $ref: cdns,qspi-nor-slave-props.yaml#
 
 additionalProperties: true
-- 
2.33.1.835.ge9e5ba39a7

[PATCH v2 3/3] dt-bindings: mtd: spi-nor: Add a reference to spi-slave-props.yaml

[Pratyush Yadav]

The spi-slave-props.yaml schema contains slave-specific properties
for SPI controllers that should be present in the slave node. Add a
reference to that so its constraints are followed.

additionalProperties: false cannot be used since it marks the controller
properties as unknown. Use unevaluatedProperties: false instead. This
has the side effect of allowing extra properties that are not specified
in the schema. The alternative is to list all the controller properties
in this schema but that would mean every slave binding would have to
repeat the same set of properties for each controller.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>

---

(no changes since v1)

 Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
index ed590d7c6e37..e69a8fbb91f1 100644
--- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
+++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
@@ -11,6 +11,7 @@ maintainers:
 
 allOf:
   - $ref: "mtd.yaml#"
+  - $ref: /schemas/spi/spi-slave-props.yaml#
 
 properties:
   compatible:
@@ -88,7 +89,7 @@ patternProperties:
   "^otp(-[0-9]+)?$":
     type: object
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
-- 
2.33.1.835.ge9e5ba39a7

Re: [PATCH v2 1/3] spi: dt-bindings: add schema listing slave-specific properties

[Rob Herring]

On Thu, Oct 28, 2021 at 06:15:16PM +0530, Pratyush Yadav wrote:
> Many SPI controllers need to add properties to slave devices. This could

Probably should replace 'slave' with 'peripheral' throughout[1]. 

> be the delay in clock or data lines, etc. These properties are
> controller specific but need to be defined in the slave node because
> they are per-slave and there can be multiple slaves attached to a
> controller.
> 
> If these properties are not added to the slave binding, then the dtbs
> check emits a warning. But these properties do not make much sense in
> the slave binding because they are controller-specific and they will
> just pollute every slave binding. So this binding is added to collect
> all such properties from all such controllers. Slave bindings should
> simply refer to this binding and they should be rid of the warnings.
> 
> There are some limitations with this approach. Firstly, there is no way
> to specify required properties. The schema contains properties for all
> controllers and there is no way to know which controller is being used.
> Secondly, there is no way to restrict additional properties. Since this
> schema will be used with an allOf operator, additionalProperties needs
> to be true. In addition, the slave schema will have to set
> unevaluatedProperties: false.
> 
> Despite these limitations, this appears to be the best solution to this
> problem that doesn't involve modifying existing tools or schema specs.
> 
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> 
> ---
> 
> Changes in v2:
> - Move other subnode properties listed in spi-controller.yaml to
>   spi-slave-props.yaml
> - Move the Cadence controller-specific properties out of
>   spi-slave-props.yaml. They will be added in a separate file.
> - Add a reference to spi-slave-props.yaml in spi-controller.yaml.
> - Update description.
> 
>  .../bindings/spi/spi-controller.yaml          | 69 +-------------
>  .../bindings/spi/spi-slave-props.yaml         | 91 +++++++++++++++++++
>  2 files changed, 93 insertions(+), 67 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml
> index 8246891602e7..ff770657e214 100644
> --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml
> +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml
> @@ -94,73 +94,8 @@ patternProperties:
>    "^.*@[0-9a-f]+$":
>      type: object
>  
> -    properties:
> -      compatible:
> -        description:
> -          Compatible of the SPI device.
> -
> -      reg:
> -        minItems: 1
> -        maxItems: 256
> -        items:
> -          minimum: 0
> -          maximum: 256
> -        description:
> -          Chip select used by the device.
> -
> -      spi-3wire:
> -        $ref: /schemas/types.yaml#/definitions/flag
> -        description:
> -          The device requires 3-wire mode.
> -
> -      spi-cpha:
> -        $ref: /schemas/types.yaml#/definitions/flag
> -        description:
> -          The device requires shifted clock phase (CPHA) mode.
> -
> -      spi-cpol:
> -        $ref: /schemas/types.yaml#/definitions/flag
> -        description:
> -          The device requires inverse clock polarity (CPOL) mode.
> -
> -      spi-cs-high:
> -        $ref: /schemas/types.yaml#/definitions/flag
> -        description:
> -          The device requires the chip select active high.
> -
> -      spi-lsb-first:
> -        $ref: /schemas/types.yaml#/definitions/flag
> -        description:
> -          The device requires the LSB first mode.
> -
> -      spi-max-frequency:
> -        $ref: /schemas/types.yaml#/definitions/uint32
> -        description:
> -          Maximum SPI clocking speed of the device in Hz.
> -
> -      spi-rx-bus-width:
> -        description:
> -          Bus width to the SPI bus used for read transfers.
> -          If 0 is provided, then no RX will be possible on this device.
> -        $ref: /schemas/types.yaml#/definitions/uint32
> -        enum: [0, 1, 2, 4, 8]
> -        default: 1
> -
> -      spi-rx-delay-us:
> -        description:
> -          Delay, in microseconds, after a read transfer.
> -
> -      spi-tx-bus-width:
> -        description:
> -          Bus width to the SPI bus used for write transfers.
> -          If 0 is provided, then no TX will be possible on this device.
> -        $ref: /schemas/types.yaml#/definitions/uint32
> -        enum: [0, 1, 2, 4, 8]
> -        default: 1
> -
> -      spi-tx-delay-us:
> -        description:
> -          Delay, in microseconds, after a write transfer.
> +    allOf:
> +      - $ref: spi-slave-props.yaml
>  
>      required:
>        - compatible
> diff --git a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> new file mode 100644
> index 000000000000..5166ec9b0353
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> @@ -0,0 +1,91 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/spi/spi-slave-props.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Slave-specific properties for a SPI bus.
> +
> +description: |

Don't need '|' if no formatting to preserve.

> +  Many SPI controllers need to add properties to slave devices. They could be
> +  common properties like spi-max-frequency, spi-cpha, etc. or they could be
> +  controller specific like delay in clock or data lines, etc. These properties
> +  need to be defined in the slave node because they are per-slave and there can
> +  be multiple slaves attached to a controller. All those properties are listed
> +  here. The controller specific properties should go in their own separate
> +  schema that should be referenced from here.
> +
> +maintainers:
> +  - Pratyush Yadav <p.yadav@ti.com>
> +
> +properties:
> +  compatible:
> +    description:
> +      Compatible of the SPI device.

You can drop 'compatible'.

> +
> +  reg:
> +    minItems: 1
> +    maxItems: 256
> +    items:
> +      minimum: 0
> +      maximum: 256
> +    description:
> +      Chip select used by the device.
> +
> +  spi-3wire:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      The device requires 3-wire mode.
> +
> +  spi-cpha:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      The device requires shifted clock phase (CPHA) mode.
> +
> +  spi-cpol:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      The device requires inverse clock polarity (CPOL) mode.
> +
> +  spi-cs-high:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      The device requires the chip select active high.
> +
> +  spi-lsb-first:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      The device requires the LSB first mode.
> +
> +  spi-max-frequency:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Maximum SPI clocking speed of the device in Hz.
> +
> +  spi-rx-bus-width:
> +    description:
> +      Bus width to the SPI bus used for read transfers.
> +      If 0 is provided, then no RX will be possible on this device.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 1, 2, 4, 8]
> +    default: 1
> +
> +  spi-rx-delay-us:
> +    description:
> +      Delay, in microseconds, after a read transfer.
> +
> +  spi-tx-bus-width:
> +    description:
> +      Bus width to the SPI bus used for write transfers.
> +      If 0 is provided, then no TX will be possible on this device.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 1, 2, 4, 8]
> +    default: 1
> +
> +  spi-tx-delay-us:
> +    description:
> +      Delay, in microseconds, after a write transfer.
> +
> +# The controller specific properties go here.
> +
> +additionalProperties: true
> -- 
> 2.33.1.835.ge9e5ba39a7
> 
> 

Re: [PATCH v2 2/3] spi: dt-bindings: cdns,qspi-nor: Move slave-specific properties out

[Rob Herring]

On Thu, Oct 28, 2021 at 06:15:17PM +0530, Pratyush Yadav wrote:
> The spi-slave-props.yaml schema contains slave-specific properties
> for SPI controllers that should be present in the slave node. Move
> slave-specific properties to a separate file and refer to it in
> spi-slave-props.yaml.

Other than s/slave/peripheral/, LGTM.

> 
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> 
> ---
> 
> Changes in v2:
> - New in v2.
> 
>  .../spi/cdns,qspi-nor-slave-props.yaml        | 42 +++++++++++++++++++
>  .../bindings/spi/cdns,qspi-nor.yaml           | 33 ---------------
>  .../bindings/spi/spi-slave-props.yaml         |  2 +
>  3 files changed, 44 insertions(+), 33 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
> 
> diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
> new file mode 100644
> index 000000000000..263382a5729a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-slave-props.yaml
> @@ -0,0 +1,42 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/spi/cdns,qspi-nor-slave-props.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Slave-specific properties for the Cadence QSPI controller.
> +
> +description:
> +  See spi-slave-props.yaml for more info.
> +
> +maintainers:
> +  - Pratyush Yadav <p.yadav@ti.com>
> +
> +properties:
> +  # cdns,qspi-nor.yaml
> +  cdns,read-delay:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Delay for read capture logic, in clock cycles.
> +
> +  cdns,tshsl-ns:
> +    description:
> +      Delay in nanoseconds for the length that the master mode chip select
> +      outputs are de-asserted between transactions.
> +
> +  cdns,tsd2d-ns:
> +    description:
> +      Delay in nanoseconds between one chip select being de-activated
> +      and the activation of another.
> +
> +  cdns,tchsh-ns:
> +    description:
> +      Delay in nanoseconds between last bit of current transaction and
> +      deasserting the device chip select (qspi_n_ss_out).
> +
> +  cdns,tslch-ns:
> +    description:
> +      Delay in nanoseconds between setting qspi_n_ss_out low and
> +      first bit transfer.
> +
> +additionalProperties: true
> diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
> index ca155abbda7a..a439e3ed753f 100644
> --- a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
> +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
> @@ -86,39 +86,6 @@ properties:
>      items:
>        enum: [ qspi, qspi-ocp ]
>  
> -# subnode's properties
> -patternProperties:
> -  "@[0-9a-f]+$":
> -    type: object
> -    description:
> -      Flash device uses the below defined properties in the subnode.
> -
> -    properties:
> -      cdns,read-delay:
> -        $ref: /schemas/types.yaml#/definitions/uint32
> -        description:
> -          Delay for read capture logic, in clock cycles.
> -
> -      cdns,tshsl-ns:
> -        description:
> -          Delay in nanoseconds for the length that the master mode chip select
> -          outputs are de-asserted between transactions.
> -
> -      cdns,tsd2d-ns:
> -        description:
> -          Delay in nanoseconds between one chip select being de-activated
> -          and the activation of another.
> -
> -      cdns,tchsh-ns:
> -        description:
> -          Delay in nanoseconds between last bit of current transaction and
> -          deasserting the device chip select (qspi_n_ss_out).
> -
> -      cdns,tslch-ns:
> -        description:
> -          Delay in nanoseconds between setting qspi_n_ss_out low and
> -          first bit transfer.
> -
>  required:
>    - compatible
>    - reg
> diff --git a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> index 5166ec9b0353..4cc12a161da9 100644
> --- a/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> +++ b/Documentation/devicetree/bindings/spi/spi-slave-props.yaml
> @@ -87,5 +87,7 @@ properties:
>        Delay, in microseconds, after a write transfer.
>  
>  # The controller specific properties go here.
> +allOf:
> +  - $ref: cdns,qspi-nor-slave-props.yaml#
>  
>  additionalProperties: true
> -- 
> 2.33.1.835.ge9e5ba39a7
> 
> 

Re: [PATCH v2 1/3] spi: dt-bindings: add schema listing slave-specific properties

[Rob Herring]

On Mon, Nov 08, 2021 at 12:04:55PM -0600, Rob Herring wrote:
> On Thu, Oct 28, 2021 at 06:15:16PM +0530, Pratyush Yadav wrote:
> > Many SPI controllers need to add properties to slave devices. This could
> 
> Probably should replace 'slave' with 'peripheral' throughout[1]. 

Forgot the link:

https://www.oshwa.org/a-resolution-to-redefine-spi-signal-names/