Message-ID: <6407d78e-8e97-4d83-89c2-fb4532f7861f@linaro.org>
Date: Sat, 17 Feb 2024 14:53:35 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Steven Niu <steven.niu.uj@...esas.com>, alexandre.belloni@...tlin.com,
 linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org,
 robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 devicetree@...r.kernel.org
Cc: zbigniew.lukwinski@...ux.intel.com
Subject: Re: [PATCH 1/2] dt-bindings: i3c-hub: Add Renesas RG3MxxB12A1 I3C HUB

On 17/02/2024 14:14, Steven Niu wrote:
> Document the Renesas RG3MxxB12A1 I3C HUB.
> 
> Signed-off-by: Steven Niu <steven.niu.uj@...esas.com>
> ---
>  .../devicetree/bindings/i3c/i3c-hub.yaml      | 400 ++++++++++++++++++
>  1 file changed, 400 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i3c/i3c-hub.yaml
> 
> diff --git a/Documentation/devicetree/bindings/i3c/i3c-hub.yaml b/Documentation/devicetree/bindings/i3c/i3c-hub.yaml
> new file mode 100644
> index 000000000000..8ff6ca172975
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i3c/i3c-hub.yaml

This does not match at all your device name. Filenames should use
compatibles.

This also sounds like some generic class of schema, but your short
commit msg does no explain here anything. I have no clue what you wanted
to achieve.


> @@ -0,0 +1,400 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/i3c/i3c-hub.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +

> +title: I3C HUB

No, you said it is Renesas device...


> +
> +maintainers:
> +  - Zbigniew Lukwinski <zbigniew.lukwinski@...ux.intel.com>
> +  - Steven Niu <steven.niu.uj@...esas.com>
> +
> +description: |
> +  I3C HUB is smart device which provides multiple functionality:
> +  * enabling voltage compatibility across I3C Controller and Target devices,
> +  * bus capacitance isolation
> +  * address conflict isolation
> +  * I3C port expansion
> +  * two controllers in a single I3C bus
> +  * I3C and SMBus device compatibility
> +  * GPIO expansion

All this only confuses me - do we talk about common schema or specific
device?

> +
> +  Having such big number of features, there is a need to have some DT knobs to tell the I3C HUB

No, there is no. Sorry, don't use such arguments and drop all unrelated
driver things like descriptions from binding.

Also, wrap it according to coding style.


> +  driver which features shall be enabled and how they shall be configured. I3C HUB driver read,
> +  validate DT knobs and set corresponding registers with the right way to satisfy user requests from
> +  DT.
> +
> +  All the DT properties for I3C HUB are located under dedicated (for I3C HUB) DT entry. I3C HUB DT
> +  entry structure is aligned with regular I3C device DT entry described in i3c.yaml.

Drop, instead describe hardware.

> +
> +allOf:
> +  - $ref: i3c.yaml#
> +
> +properties:
> +  $nodename:
> +    pattern: "^hub@0,0$"

No, why?

Where is compatible?

> +
> +  cp0-ldo-en:

No clue what's this... no vendor prefix, no ref, why is is a property of
a board.

> +    enum:
> +      - disabled
> +      - enabled
> +    description: |
> +      I3C HUB Controller Port 0 LDO disabling/enabling setting. If enabled, voltage produced by
> +      on-die LDO will be available externally on dedicated pin. This option could be used to supply
> +      external pull-up resistors or for any other purpose which does not cross LDO capabilities.

Wrap properly, as asked by Coding Style,

> +
> +      This property is optional. If not provided, LDO will be disabled.

Drop redundant sentence "This property is optional".

> +
> +  cp1-ldo-en:

Why is this a property of a board DTS?

> +    enum:
> +      - disabled
> +      - enabled
> +    description: |
> +      I3C HUB Controller Port 1 LDO disabling/enabling setting. If enabled, voltage produced by
> +      on-die LDO will be available externally on dedicated pin. This option could be used to supply
> +      external pull-up resistors or for any other purpose which does not cross LDO capabilities.
> +
> +      This property is optional. If not provided, LDO will be disabled.
> +
> +  tp0145-ldo-en:

Why is this a property of a board DTS?

> +    enum:
> +      - disabled
> +      - enabled
> +    description: |
> +      I3C HUB Target Ports 0/1/4/5 LDO disabling/enabling setting. If enabled, voltage produced by
> +      on-die LDO will be available externally on dedicated pin. This option could be used to supply
> +      external pull-up resistors or for any other purpose which does not cross LDO capabilities.
> +
> +      This property is optional. If not provided, LDO will be disabled.
> +
> +  tp2367-ldo-en:

None of these make sense to me, sorry.

> +    enum:
> +      - disabled
> +      - enabled
> +    description: |
> +      I3C HUB Target Ports 2/3/6/7 LDO disabling/enabling setting. If enabled, voltage produced by
> +      on-die LDO will be available externally on dedicated pin. This option could be used to supply
> +      external pull-up resistors or for any other purpose which does not cross LDO capabilities.
> +
> +      This property is optional. If not provided, LDO will be disabled.
> +
> +  cp0-ldo-volt:
> +    enum:
> +      - 1.0V
> +      - 1.1V
> +      - 1.2V
> +      - 1.8V
> +    description: |
> +      I3C HUB Controller Port 0 LDO setting to control the Controller Port 1 voltage level. This
> +      property is optional.
> +
> +      If not provided, LDO configuration is not modified in I3C HUB.
> +
> +  cp1-ldo-volt:
> +    enum:
> +      - 1.0V
> +      - 1.1V
> +      - 1.2V
> +      - 1.8V

OK, that's it. Sorry, stop reimplementing regulators as strings. Use
proper common property suffixes for properties.

> +    description: |
> +      I3C HUB Controller Port 1 LDO setting to control the Controller Port 1 voltage level. This
> +      property is optional.
> +
> +      If not provided, LDO configuration is not modified in I3C HUB.
> +
> +  tp0145-ldo-volt:
> +    enum:
> +      - disabled
> +      - 1.0V
> +      - 1.1V
> +      - 1.2V
> +      - 1.8V
> +    description: |
> +      I3C HUB Target Ports 0/1/4/5 LDO setting to control the Target Ports 0/1/4/5 voltage level.
> +
> +      If not provided, LDO configuration is not modified in I3C HUB.
> +
> +  tp2367-ldo-volt:
> +    enum:
> +      - disabled
> +      - 1.0V
> +      - 1.1V
> +      - 1.2V
> +      - 1.8V
> +    description: |
> +      I3C HUB Target Ports 2/3/6/7 LDO setting to control the Target Ports 2/3/6/7 voltage level.
> +
> +      If not provided, LDO configuration is not modified in I3C HUB.
> +
> +  tp0145-pullup:
> +    enum:
> +      - disabled
> +      - 250R
> +      - 500R
> +      - 1k
> +      - 2k
> +    description: |
> +      I3C HUB Target Ports 0/1/4/5 pull-up setting to control the Target Ports 0/1/4/5 pull-up
> +      resistance level.
> +
> +      This property is optional. If not provided, pull-up configuration is not modified in I3C HUB.
> +
> +  tp2367-pullup:
> +    enum:
> +      - disabled
> +      - 250R
> +      - 500R
> +      - 1k
> +      - 2k
> +    description: |
> +      I3C HUB Target Ports 2/3/6/7 pull-up setting to control the Target Ports 2/3/6/7 pull-up
> +      resistance level.
> +
> +      This property is optional. If not provided, pull-up configuration is not modified in I3C HUB.
> +
> +  cp0-io-strength:
> +    enum:
> +      - 20Ohms
> +      - 30Ohms
> +      - 40Ohms
> +      - 50Ohms
> +    description: |
> +      I3C HUB Controller Port 0 IO strength setting to control the Controller Port 0 output driver
> +      strength.
> +
> +      This property is optional. If not provided, IO strength configuration is not modified in I3C
> +      HUB.
> +
> +  cp1-io-strength:
> +    enum:
> +      - 20Ohms
> +      - 30Ohms
> +      - 40Ohms
> +      - 50Ohms
> +    description: |
> +      I3C HUB Controller Port 1 IO strength setting to control the Controller Port 1 output driver
> +      strength.
> +
> +      This property is optional. If not provided, IO strength configuration is not modified in I3C
> +      HUB.
> +
> +  tp0145-io-strength:
> +    enum:
> +      - 20Ohms
> +      - 30Ohms
> +      - 40Ohms
> +      - 50Ohms
> +    description: |
> +      I3C HUB Target Ports 0/1/4/5 IO strength setting to control the Target Ports 0/1/4/5 output
> +      driver strength.
> +
> +      This property is optional. If not provided, IO strength configuration is not modified in I3C
> +      HUB.
> +
> +  tp2367-io-strength:
> +    enum:
> +      - 20Ohms
> +      - 30Ohms
> +      - 40Ohms
> +      - 50Ohms
> +    description: |
> +      I3C HUB Target Ports 2/3/6/7 IO strength setting to control the Target Ports 2/3/6/7 output
> +      driver strength.
> +
> +      This property is optional. If not provided, IO strength configuration is not modified in I3C
> +      HUB.
> +
> +  id:
> +    enum:
> +      - 0
> +      - 1
> +      - 3

NAK, no ID properties.

You try to upstream some really non-upstream style of binding. One
looking like produced by vendor. Don't.


> +    description: |
> +      I3C HUB ID based on CSEL pin. There are three possible values:
> +      0 - CP0 is selected as primary Controller Port
> +      1 - Primary Controller Port is selected by software by writing the REG#56
> +      3 - CP1 is selected as primary Controller Port
> +
> +      I3C HUB driver reads CSEL pin status (REG#121[5:4]) and tries to find DT node with matching
> +      value in 'id' property.
> +
> +      This property is optional. If not provided, DT node can only be used by the I3C HUB driver if
> +      there is no others with matching 'id' or 'id-cp1'. If there is a multiple DT nodes with no
> +      'id' property - the first one will be chosen by I3C HUB driver. If there is a multiple DT
> +      nodes with matching 'id' property - the first one will be chosen by I3C HUB driver.
> +
> +      If both 'id' and 'id-cp1' are available, DT node will chosen only when both values match those
> +      read from I3C HUB.

All these redundant texts are no helping... Encode proper reliationships
in schema.


> +
> +  id-cp1:
> +    enum:
> +      - 0
> +      - 1
> +      - 2
> +      - 3
> +    description: |
> +      I3C HUB ID based on CP1 SDA and SCL pins state probed during power on.
> +
> +      I3C HUB driver reads CP1 SDA and SCL pin status and tries to find DT node with matching value
> +      in 'id-cp1' property.
> +
> +      This property is optional. If not provided, DT node can only be used by the I3C HUB
> +      driver if there is no others with matching 'id' or 'id-cp1'. If there is a multiple DT nodes
> +      with no 'id-cp1' property - the first one will be chosen by I3C HUB driver. If there is a
> +      multiple DT nodes with matching 'id-cp1' property - the first one will be chosen by I3C HUB
> +      driver.
> +
> +      If both 'id' and 'id-cp1' are available, DT node will chosen only when both values match those
> +      read from I3C HUB.
> +
> +patternProperties:
> +  "@[0-9]$":
> +    type: object
> +    description: |

Do not need '|' unless you need to preserve formatting.

> +      I3C HUB Target Port child, should be named: target-port@<target-port-id>
> +
> +    properties:
> +      mode:
> +        enum:
> +          - disabled
> +          - i3c
> +          - smbus
> +          - gpio
> +        description: |
> +          I3C HUB Target Port mode setting to control Target Port functionality.
> +
> +          This property is optional. If not provided, Target Port mode configuration is not modified
> +          in I3C HUB.

Not modified? What does it even mean? Not modified from what?

Missing default:

Anyway, now you implement pinctrl here. Sorry, this needs proper
justification but still half of these properties are a clear NAK.

> +
> +      pullup:
> +        enum:
> +          - disabled
> +          - enabled
> +        description: |
> +          I3C HUB Target Port pull-up setting to disable/enable Target Port pull-up.
> +
> +          This property is optional. If not provided, Target Port pull-up configuration is not
> +          modified in I3C HUB.
> +
> +      always-enable:
> +        type: boolean
> +        description: |
> +          I3C HUB Target Port settings to control the port enable/disable policy.
> +
> +          This property is optional. If not provided, Target Port is enabled only on accessing to
> +          the devices connected to it and the port is disabled automatically after the accessing
> +          is done. If provided, the Target Port is always enabled.
> +
> +    patternProperties:
> +      "@0,0$":
> +        type: object
> +        description: |
> +          Backend for handling SMBus mode, should be named: backend@0,0
> +          Adding this node installs the backed for handling SMBus Target mode communication.
> +
> +        properties:
> +          compatible:
> +            description:
> +              Compatible of the I2C/SMBus backend.
> +
> +          target-reg:
> +            description:
> +              Target address used for Target Port in the I3C HUB configured as SMBus Target mode.
> +
> +additionalProperties: true

NAK, please start from basics from example schema.


Best regards,
Krzysztof

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