diff mbox series

[v2] dt-bindings: serial: Move omap-serial.txt to YAML schema

Message ID 20210610182227.2480-1-vigneshr@ti.com
State Accepted
Commit 1882441cd788a496b378f4d2684fa66cec195051
Headers show
Series [v2] dt-bindings: serial: Move omap-serial.txt to YAML schema | expand

Commit Message

Vignesh Raghavendra June 10, 2021, 6:22 p.m. UTC
Convert serial-omap.txt to YAML schema for better checks and documentation.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
---

v2:
*Drop reg-io-width and reg-shift as they are constant and documented in
 txt bindings (also not used by driver).
*Drop unused label in example.
*Rename file to 8250_omap.yaml to be more generic as IP is present in
varies families of TI SoCs.
*Add description for interrupt entries

 .../devicetree/bindings/serial/8250_omap.yaml | 118 ++++++++++++++++++
 .../bindings/serial/omap_serial.txt           |  40 ------
 2 files changed, 118 insertions(+), 40 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/serial/8250_omap.yaml
 delete mode 100644 Documentation/devicetree/bindings/serial/omap_serial.txt

Comments

Tony Lindgren June 11, 2021, 5:19 a.m. UTC | #1
* Vignesh Raghavendra <vigneshr@ti.com> [210610 18:22]:
> Convert serial-omap.txt to YAML schema for better checks and documentation.

Looks good to me thanks:

Acked-by: Tony Lindgren <tony@atomide.com>
Rob Herring June 18, 2021, 2:58 p.m. UTC | #2
On Thu, Jun 10, 2021 at 12:22 PM Vignesh Raghavendra <vigneshr@ti.com> wrote:
>
> Convert serial-omap.txt to YAML schema for better checks and documentation.
>
> Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
> ---
>
> v2:
> *Drop reg-io-width and reg-shift as they are constant and documented in
>  txt bindings (also not used by driver).
> *Drop unused label in example.
> *Rename file to 8250_omap.yaml to be more generic as IP is present in
> varies families of TI SoCs.
> *Add description for interrupt entries
>
>  .../devicetree/bindings/serial/8250_omap.yaml | 118 ++++++++++++++++++
>  .../bindings/serial/omap_serial.txt           |  40 ------
>  2 files changed, 118 insertions(+), 40 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/serial/8250_omap.yaml
>  delete mode 100644 Documentation/devicetree/bindings/serial/omap_serial.txt
>
> diff --git a/Documentation/devicetree/bindings/serial/8250_omap.yaml b/Documentation/devicetree/bindings/serial/8250_omap.yaml
> new file mode 100644
> index 000000000000..1c826fcf5828
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/8250_omap.yaml
> @@ -0,0 +1,118 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/serial/8250_omap.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Bindings for 8250 compliant UARTs on TI's OMAP2+ and K3 SoCs
> +
> +maintainers:
> +  - Vignesh Raghavendra <vigneshr@ti.com>
> +
> +allOf:
> +  - $ref: /schemas/serial/serial.yaml#
> +  - $ref: /schemas/serial/rs485.yaml#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - enum:
> +          - ti,am3352-uart
> +          - ti,am4372-uart
> +          - ti,am654-uart
> +          - ti,dra742-uart
> +          - ti,omap2-uart
> +          - ti,omap3-uart
> +          - ti,omap4-uart
> +      - items:
> +          - enum:
> +              - ti,am64-uart
> +              - ti,j721e-uart
> +          - const: ti,am654-uart
> +
> +  ti,hwmods:
> +    description:
> +      Must be "uart<n>", n being the instance number (1-based)
> +      This property is applicable only on legacy platforms mainly omap2/3
> +      and ti81xx and should not be used on other platforms.
> +    $ref: /schemas/types.yaml#/definitions/string
> +    deprecated: true
> +
> +  dmas:
> +    minItems: 1
> +    maxItems: 2
> +
> +  dma-names:
> +    items:
> +      - const: tx
> +      - const: rx
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 2
> +    description:
> +      First entry is module IRQ required for normal IO operation.
> +      Second entry is optional and corresponds to system wakeup IRQ
> +      where supported.

interrupts:
  minItems: 1
  items:
    - description: module IRQ required for normal IO operation
    - description: system wakeup IRQ

> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: fclk
> +
> +  rts-gpios: true
> +  cts-gpios: true
> +  dtr-gpios: true
> +  dsr-gpios: true
> +  rng-gpios: true
> +  dcd-gpios: true
> +  rs485-rts-delay: true
> +  rs485-rts-active-low: true
> +  rs485-rx-during-tx: true
> +  rs485-rts-active-high: true
> +  linux,rs485-enabled-at-boot-time: true
> +  rts-gpio: true
> +  power-domains: true
> +  clock-frequency: true
> +  current-speed: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +additionalProperties: false

Do you want to support serial attached devices? If so, you need:

unevaluatedProperties: false

You can also drop listing all the inherited properties from the
included schemas.

> +
> +if:
> +  properties:
> +    compatible:
> +      oneOf:
> +        - const: ti,omap2-uart
> +        - const: ti,omap3-uart
> +        - const: ti,omap4-uart
> +
> +then:
> +  properties:
> +    ti,hwmods:
> +      items:
> +        - pattern: "^uart([1-9])$"
> +
> +else:
> +  properties:
> +    ti,hwmods: false
> +
> +examples:
> +  - |
> +          serial@49042000 {
> +            compatible = "ti,omap3-uart";
> +            reg = <0x49042000 0x400>;
> +            interrupts = <80>;
> +            dmas = <&sdma 81 &sdma 82>;
> +            dma-names = "tx", "rx";
> +            ti,hwmods = "uart4";
> +            clock-frequency = <48000000>;
> +          };
> diff --git a/Documentation/devicetree/bindings/serial/omap_serial.txt b/Documentation/devicetree/bindings/serial/omap_serial.txt
> deleted file mode 100644
> index c2db8cabf2ab..000000000000
> --- a/Documentation/devicetree/bindings/serial/omap_serial.txt
> +++ /dev/null
> @@ -1,40 +0,0 @@
> -OMAP UART controller
> -
> -Required properties:
> -- compatible : should be "ti,am64-uart", "ti,am654-uart" for AM64 controllers
> -- compatible : should be "ti,j721e-uart", "ti,am654-uart" for J721E controllers
> -- compatible : should be "ti,am654-uart" for AM654 controllers
> -- compatible : should be "ti,omap2-uart" for OMAP2 controllers
> -- compatible : should be "ti,omap3-uart" for OMAP3 controllers
> -- compatible : should be "ti,omap4-uart" for OMAP4 controllers
> -- compatible : should be "ti,am4372-uart" for AM437x controllers
> -- compatible : should be "ti,am3352-uart" for AM335x controllers
> -- compatible : should be "ti,dra742-uart" for DRA7x controllers
> -- reg : address and length of the register space
> -- interrupts or interrupts-extended : Should contain the uart interrupt
> -                                      specifier or both the interrupt
> -                                      controller phandle and interrupt
> -                                      specifier.
> -- ti,hwmods : Must be "uart<n>", n being the instance number (1-based)
> -
> -Optional properties:
> -- clock-frequency : frequency of the clock input to the UART
> -- dmas : DMA specifier, consisting of a phandle to the DMA controller
> -         node and a DMA channel number.
> -- dma-names : "rx" for receive channel, "tx" for transmit channel.
> -- rs485-rts-delay, rs485-rx-during-tx, linux,rs485-enabled-at-boot-time: see rs485.txt
> -- rs485-rts-active-high: drive RTS high when sending (default is low).
> -- clocks: phandle to the functional clock as per
> -  Documentation/devicetree/bindings/clock/clock-bindings.txt
> -
> -Example:
> -
> -                uart4: serial@49042000 {
> -                        compatible = "ti,omap3-uart";
> -                        reg = <0x49042000 0x400>;
> -                        interrupts = <80>;
> -                        dmas = <&sdma 81 &sdma 82>;
> -                        dma-names = "tx", "rx";
> -                        ti,hwmods = "uart4";
> -                        clock-frequency = <48000000>;
> -                };
> --
> 2.32.0
>
Vignesh Raghavendra June 18, 2021, 3:22 p.m. UTC | #3
On 6/18/21 8:28 PM, Rob Herring wrote:
> On Thu, Jun 10, 2021 at 12:22 PM Vignesh Raghavendra <vigneshr@ti.com> wrote:

>>

>> Convert serial-omap.txt to YAML schema for better checks and documentation.

>>

>> Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

>> ---

>>

>> v2:

>> *Drop reg-io-width and reg-shift as they are constant and documented in

>>  txt bindings (also not used by driver).

>> *Drop unused label in example.

>> *Rename file to 8250_omap.yaml to be more generic as IP is present in

>> varies families of TI SoCs.

>> *Add description for interrupt entries

>>

>>  .../devicetree/bindings/serial/8250_omap.yaml | 118 ++++++++++++++++++

>>  .../bindings/serial/omap_serial.txt           |  40 ------

>>  2 files changed, 118 insertions(+), 40 deletions(-)

>>  create mode 100644 Documentation/devicetree/bindings/serial/8250_omap.yaml

>>  delete mode 100644 Documentation/devicetree/bindings/serial/omap_serial.txt

>>

>> diff --git a/Documentation/devicetree/bindings/serial/8250_omap.yaml b/Documentation/devicetree/bindings/serial/8250_omap.yaml

>> new file mode 100644

>> index 000000000000..1c826fcf5828

>> --- /dev/null

>> +++ b/Documentation/devicetree/bindings/serial/8250_omap.yaml

>> @@ -0,0 +1,118 @@

>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

>> +%YAML 1.2

>> +---

>> +$id: http://devicetree.org/schemas/serial/8250_omap.yaml#

>> +$schema: http://devicetree.org/meta-schemas/core.yaml#

>> +

>> +title: Bindings for 8250 compliant UARTs on TI's OMAP2+ and K3 SoCs

>> +

>> +maintainers:

>> +  - Vignesh Raghavendra <vigneshr@ti.com>

>> +

>> +allOf:

>> +  - $ref: /schemas/serial/serial.yaml#

>> +  - $ref: /schemas/serial/rs485.yaml#

>> +

>> +properties:

>> +  compatible:

>> +    oneOf:

>> +      - enum:

>> +          - ti,am3352-uart

>> +          - ti,am4372-uart

>> +          - ti,am654-uart

>> +          - ti,dra742-uart

>> +          - ti,omap2-uart

>> +          - ti,omap3-uart

>> +          - ti,omap4-uart

>> +      - items:

>> +          - enum:

>> +              - ti,am64-uart

>> +              - ti,j721e-uart

>> +          - const: ti,am654-uart

>> +

>> +  ti,hwmods:

>> +    description:

>> +      Must be "uart<n>", n being the instance number (1-based)

>> +      This property is applicable only on legacy platforms mainly omap2/3

>> +      and ti81xx and should not be used on other platforms.

>> +    $ref: /schemas/types.yaml#/definitions/string

>> +    deprecated: true

>> +

>> +  dmas:

>> +    minItems: 1

>> +    maxItems: 2

>> +

>> +  dma-names:

>> +    items:

>> +      - const: tx

>> +      - const: rx

>> +

>> +  reg:

>> +    maxItems: 1

>> +

>> +  interrupts:

>> +    minItems: 1

>> +    maxItems: 2

>> +    description:

>> +      First entry is module IRQ required for normal IO operation.

>> +      Second entry is optional and corresponds to system wakeup IRQ

>> +      where supported.

> 

> interrupts:

>   minItems: 1

>   items:

>     - description: module IRQ required for normal IO operation

>     - description: system wakeup IRQ

> 


OK, will send a follow up fix as the patch is already queued.

>> +

>> +  clocks:

>> +    maxItems: 1

>> +

>> +  clock-names:

>> +    const: fclk

>> +

>> +  rts-gpios: true

>> +  cts-gpios: true

>> +  dtr-gpios: true

>> +  dsr-gpios: true

>> +  rng-gpios: true

>> +  dcd-gpios: true

>> +  rs485-rts-delay: true

>> +  rs485-rts-active-low: true

>> +  rs485-rx-during-tx: true

>> +  rs485-rts-active-high: true

>> +  linux,rs485-enabled-at-boot-time: true

>> +  rts-gpio: true

>> +  power-domains: true

>> +  clock-frequency: true

>> +  current-speed: true

>> +

>> +required:

>> +  - compatible

>> +  - reg

>> +  - interrupts

>> +

>> +additionalProperties: false

> 

> Do you want to support serial attached devices? If so, you need:

> 

> unevaluatedProperties: false

> 


Yes, support for serial client devices is desired, but I see that with
"unevaluatedProperties: false" there are no warnings if DT has a
property not documented in the schema? Did I miss something?

> You can also drop listing all the inherited properties from the

> included schemas.


Yes, this can be done with "unevaluatedProperties: false".

Regards
Vignesh
Rob Herring June 18, 2021, 6:55 p.m. UTC | #4
On Fri, Jun 18, 2021 at 9:22 AM Vignesh Raghavendra <vigneshr@ti.com> wrote:
>
>
>
> On 6/18/21 8:28 PM, Rob Herring wrote:
> > On Thu, Jun 10, 2021 at 12:22 PM Vignesh Raghavendra <vigneshr@ti.com> wrote:
> >>
> >> Convert serial-omap.txt to YAML schema for better checks and documentation.
> >>
> >> Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
> >> ---
> >>
> >> v2:
> >> *Drop reg-io-width and reg-shift as they are constant and documented in
> >>  txt bindings (also not used by driver).
> >> *Drop unused label in example.
> >> *Rename file to 8250_omap.yaml to be more generic as IP is present in
> >> varies families of TI SoCs.
> >> *Add description for interrupt entries
> >>
> >>  .../devicetree/bindings/serial/8250_omap.yaml | 118 ++++++++++++++++++
> >>  .../bindings/serial/omap_serial.txt           |  40 ------
> >>  2 files changed, 118 insertions(+), 40 deletions(-)
> >>  create mode 100644 Documentation/devicetree/bindings/serial/8250_omap.yaml
> >>  delete mode 100644 Documentation/devicetree/bindings/serial/omap_serial.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/serial/8250_omap.yaml b/Documentation/devicetree/bindings/serial/8250_omap.yaml
> >> new file mode 100644
> >> index 000000000000..1c826fcf5828
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/serial/8250_omap.yaml
> >> @@ -0,0 +1,118 @@
> >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/serial/8250_omap.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: Bindings for 8250 compliant UARTs on TI's OMAP2+ and K3 SoCs
> >> +
> >> +maintainers:
> >> +  - Vignesh Raghavendra <vigneshr@ti.com>
> >> +
> >> +allOf:
> >> +  - $ref: /schemas/serial/serial.yaml#
> >> +  - $ref: /schemas/serial/rs485.yaml#
> >> +
> >> +properties:
> >> +  compatible:
> >> +    oneOf:
> >> +      - enum:
> >> +          - ti,am3352-uart
> >> +          - ti,am4372-uart
> >> +          - ti,am654-uart
> >> +          - ti,dra742-uart
> >> +          - ti,omap2-uart
> >> +          - ti,omap3-uart
> >> +          - ti,omap4-uart
> >> +      - items:
> >> +          - enum:
> >> +              - ti,am64-uart
> >> +              - ti,j721e-uart
> >> +          - const: ti,am654-uart
> >> +
> >> +  ti,hwmods:
> >> +    description:
> >> +      Must be "uart<n>", n being the instance number (1-based)
> >> +      This property is applicable only on legacy platforms mainly omap2/3
> >> +      and ti81xx and should not be used on other platforms.
> >> +    $ref: /schemas/types.yaml#/definitions/string
> >> +    deprecated: true
> >> +
> >> +  dmas:
> >> +    minItems: 1
> >> +    maxItems: 2
> >> +
> >> +  dma-names:
> >> +    items:
> >> +      - const: tx
> >> +      - const: rx
> >> +
> >> +  reg:
> >> +    maxItems: 1
> >> +
> >> +  interrupts:
> >> +    minItems: 1
> >> +    maxItems: 2
> >> +    description:
> >> +      First entry is module IRQ required for normal IO operation.
> >> +      Second entry is optional and corresponds to system wakeup IRQ
> >> +      where supported.
> >
> > interrupts:
> >   minItems: 1
> >   items:
> >     - description: module IRQ required for normal IO operation
> >     - description: system wakeup IRQ
> >
>
> OK, will send a follow up fix as the patch is already queued.
>
> >> +
> >> +  clocks:
> >> +    maxItems: 1
> >> +
> >> +  clock-names:
> >> +    const: fclk
> >> +
> >> +  rts-gpios: true
> >> +  cts-gpios: true
> >> +  dtr-gpios: true
> >> +  dsr-gpios: true
> >> +  rng-gpios: true
> >> +  dcd-gpios: true
> >> +  rs485-rts-delay: true
> >> +  rs485-rts-active-low: true
> >> +  rs485-rx-during-tx: true
> >> +  rs485-rts-active-high: true
> >> +  linux,rs485-enabled-at-boot-time: true
> >> +  rts-gpio: true
> >> +  power-domains: true
> >> +  clock-frequency: true
> >> +  current-speed: true
> >> +
> >> +required:
> >> +  - compatible
> >> +  - reg
> >> +  - interrupts
> >> +
> >> +additionalProperties: false
> >
> > Do you want to support serial attached devices? If so, you need:
> >
> > unevaluatedProperties: false
> >
>
> Yes, support for serial client devices is desired, but I see that with
> "unevaluatedProperties: false" there are no warnings if DT has a
> property not documented in the schema? Did I miss something?

Support for unevaluatedProperties is not yet implemented in the
underlying jsonschema package. So we get the default behavior for
unknown keywords which is a nop.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/serial/8250_omap.yaml b/Documentation/devicetree/bindings/serial/8250_omap.yaml
new file mode 100644
index 000000000000..1c826fcf5828
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/8250_omap.yaml
@@ -0,0 +1,118 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/8250_omap.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bindings for 8250 compliant UARTs on TI's OMAP2+ and K3 SoCs
+
+maintainers:
+  - Vignesh Raghavendra <vigneshr@ti.com>
+
+allOf:
+  - $ref: /schemas/serial/serial.yaml#
+  - $ref: /schemas/serial/rs485.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - ti,am3352-uart
+          - ti,am4372-uart
+          - ti,am654-uart
+          - ti,dra742-uart
+          - ti,omap2-uart
+          - ti,omap3-uart
+          - ti,omap4-uart
+      - items:
+          - enum:
+              - ti,am64-uart
+              - ti,j721e-uart
+          - const: ti,am654-uart
+
+  ti,hwmods:
+    description:
+      Must be "uart<n>", n being the instance number (1-based)
+      This property is applicable only on legacy platforms mainly omap2/3
+      and ti81xx and should not be used on other platforms.
+    $ref: /schemas/types.yaml#/definitions/string
+    deprecated: true
+
+  dmas:
+    minItems: 1
+    maxItems: 2
+
+  dma-names:
+    items:
+      - const: tx
+      - const: rx
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+    description:
+      First entry is module IRQ required for normal IO operation.
+      Second entry is optional and corresponds to system wakeup IRQ
+      where supported.
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: fclk
+
+  rts-gpios: true
+  cts-gpios: true
+  dtr-gpios: true
+  dsr-gpios: true
+  rng-gpios: true
+  dcd-gpios: true
+  rs485-rts-delay: true
+  rs485-rts-active-low: true
+  rs485-rx-during-tx: true
+  rs485-rts-active-high: true
+  linux,rs485-enabled-at-boot-time: true
+  rts-gpio: true
+  power-domains: true
+  clock-frequency: true
+  current-speed: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+if:
+  properties:
+    compatible:
+      oneOf:
+        - const: ti,omap2-uart
+        - const: ti,omap3-uart
+        - const: ti,omap4-uart
+
+then:
+  properties:
+    ti,hwmods:
+      items:
+        - pattern: "^uart([1-9])$"
+
+else:
+  properties:
+    ti,hwmods: false
+
+examples:
+  - |
+          serial@49042000 {
+            compatible = "ti,omap3-uart";
+            reg = <0x49042000 0x400>;
+            interrupts = <80>;
+            dmas = <&sdma 81 &sdma 82>;
+            dma-names = "tx", "rx";
+            ti,hwmods = "uart4";
+            clock-frequency = <48000000>;
+          };
diff --git a/Documentation/devicetree/bindings/serial/omap_serial.txt b/Documentation/devicetree/bindings/serial/omap_serial.txt
deleted file mode 100644
index c2db8cabf2ab..000000000000
--- a/Documentation/devicetree/bindings/serial/omap_serial.txt
+++ /dev/null
@@ -1,40 +0,0 @@ 
-OMAP UART controller
-
-Required properties:
-- compatible : should be "ti,am64-uart", "ti,am654-uart" for AM64 controllers
-- compatible : should be "ti,j721e-uart", "ti,am654-uart" for J721E controllers
-- compatible : should be "ti,am654-uart" for AM654 controllers
-- compatible : should be "ti,omap2-uart" for OMAP2 controllers
-- compatible : should be "ti,omap3-uart" for OMAP3 controllers
-- compatible : should be "ti,omap4-uart" for OMAP4 controllers
-- compatible : should be "ti,am4372-uart" for AM437x controllers
-- compatible : should be "ti,am3352-uart" for AM335x controllers
-- compatible : should be "ti,dra742-uart" for DRA7x controllers
-- reg : address and length of the register space
-- interrupts or interrupts-extended : Should contain the uart interrupt
-                                      specifier or both the interrupt
-                                      controller phandle and interrupt
-                                      specifier.
-- ti,hwmods : Must be "uart<n>", n being the instance number (1-based)
-
-Optional properties:
-- clock-frequency : frequency of the clock input to the UART
-- dmas : DMA specifier, consisting of a phandle to the DMA controller
-         node and a DMA channel number.
-- dma-names : "rx" for receive channel, "tx" for transmit channel.
-- rs485-rts-delay, rs485-rx-during-tx, linux,rs485-enabled-at-boot-time: see rs485.txt
-- rs485-rts-active-high: drive RTS high when sending (default is low).
-- clocks: phandle to the functional clock as per
-  Documentation/devicetree/bindings/clock/clock-bindings.txt
-
-Example:
-
-                uart4: serial@49042000 {
-                        compatible = "ti,omap3-uart";
-                        reg = <0x49042000 0x400>;
-                        interrupts = <80>;
-                        dmas = <&sdma 81 &sdma 82>;
-                        dma-names = "tx", "rx";
-                        ti,hwmods = "uart4";
-                        clock-frequency = <48000000>;
-                };