[PATCH 0/2] i2c: rcar: add Gen5 support

[PATCH 0/2] i2c: rcar: add Gen5 support

[Wolfram Sang]

This small series adds support for the Renesas R-Car X5H SoC to the
i2c-rcar driver. Not much changes needed, only skip polling for reset.
And add some compatibles.

Tested with a Renesas R-Car Gen5 Ironhide board. Branch is here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/x5h/i2c-experimental

'dt_binding_check' also passed.

Happy hacking!


Minh Le (1):
  dt-bindings: i2c: rcar-i2c: Document R-Car X5H support

Wolfram Sang (1):
  i2c: rcar: add R-Car Gen5 support

 .../bindings/i2c/renesas,rcar-i2c.yaml        |  5 +++++
 drivers/i2c/busses/i2c-rcar.c                 | 22 ++++++++++++++-----
 2 files changed, 22 insertions(+), 5 deletions(-)

-- 
2.47.3

[PATCH 1/2] dt-bindings: i2c: rcar-i2c: Document R-Car X5H support

[Wolfram Sang]

From: Minh Le <minh.le.aj@renesas.com>

Document support for rcar-i2c on R8A78000 (X5H) SoCs.

Signed-off-by: Minh Le <minh.le.aj@renesas.com>
[wsa: fixed white space issues]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
index 6cc60c3f61cd..46b4bd16c593 100644
--- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
@@ -56,6 +56,11 @@ properties:
               - renesas,i2c-r8a779h0     # R-Car V4M
           - const: renesas,rcar-gen4-i2c # R-Car Gen4
 
+      - items:
+          - enum:
+              - renesas,i2c-r8a78000     # R-Car X5H
+          - const: renesas,rcar-gen5-i2c # R-Car Gen5
+
   reg:
     maxItems: 1
 
-- 
2.47.3

Re: [PATCH 1/2] dt-bindings: i2c: rcar-i2c: Document R-Car X5H support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The new `renesas,rcar-gen5-i2c` compatible string is missing from the `allOf` conditional block that requires the `resets` property, resulting in a Device Tree schema validation bypass.
--

--- Patch [1]: [PATCH 1/2] dt-bindings: i2c: rcar-i2c: Document R-Car X5H support ---
commit e3abab1fc2392666638c3324ed628bfe91397742
Author: Minh Le <minh.le.aj@renesas.com>

dt-bindings: i2c: rcar-i2c: Document R-Car X5H support

This commit adds documentation for the rcar-i2c on R8A78000 (X5H) SoCs.
It introduces the new Gen5 compatible strings.

> diff --git a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> index 6cc60c3f61cd6..46b4bd16c5937 100644
> --- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> @@ -56,6 +56,11 @@ properties:
>                - renesas,i2c-r8a779h0     # R-Car V4M
>            - const: renesas,rcar-gen4-i2c # R-Car Gen4
>  
> +      - items:
> +          - enum:
> +              - renesas,i2c-r8a78000     # R-Car X5H
> +          - const: renesas,rcar-gen5-i2c # R-Car Gen5

[Severity: Medium]
Will this schema fully validate the new hardware configurations? 

The new renesas,rcar-gen5-i2c string is defined here, but the allOf
conditional block for the resets property lower in the file only matches
Gen2, Gen3, and Gen4:

  - if:
      properties:
        compatible:
          contains:
            enum:
              - renesas,rcar-gen2-i2c
              - renesas,rcar-gen3-i2c
              - renesas,rcar-gen4-i2c
    then:
      required:
        - resets

Should renesas,rcar-gen5-i2c be added to this enum list so that missing reset
configurations are still caught by dt_binding_check?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260727113441.11193-4-wsa+renesas@sang-engineering.com?part=1

Re: [PATCH 1/2] dt-bindings: i2c: rcar-i2c: Document R-Car X5H support

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 183 bytes --]


> The new renesas,rcar-gen5-i2c string is defined here, but the allOf
> conditional block for the resets property lower in the file only matches
> Gen2, Gen3, and Gen4:

Sigh, yes.


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[PATCH 2/2] i2c: rcar: add R-Car Gen5 support

[Wolfram Sang]

To support the next generation of R-Car SoCs, we need to skip polling
the reset status. SCMI doesn't support it and the firmware must take
care of this anyhow. Other than that, the driver works fine as-is.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-rcar.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 5ce8f8e4856f..46508176712c 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -137,6 +137,7 @@ enum rcar_i2c_type {
 	I2C_RCAR_GEN2,
 	I2C_RCAR_GEN3,
 	I2C_RCAR_GEN4,
+	I2C_RCAR_GEN5,
 };
 
 struct rcar_i2c_priv {
@@ -900,8 +901,12 @@ static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
 	if (ret)
 		return ret;
 
-	return read_poll_timeout_atomic(reset_control_status, ret, ret == 0, 1,
-					100, false, priv->rstc);
+	/* SCMI based resets don't need to poll for success */
+	if (priv->devtype < I2C_RCAR_GEN5)
+		return read_poll_timeout_atomic(reset_control_status, ret, ret == 0,
+						1, 100, false, priv->rstc);
+
+	return 0;
 }
 
 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
@@ -1111,6 +1116,7 @@ static const struct of_device_id rcar_i2c_dt_ids[] = {
 	{ .compatible = "renesas,rcar-gen2-i2c", .data = (void *)I2C_RCAR_GEN2 },
 	{ .compatible = "renesas,rcar-gen3-i2c", .data = (void *)I2C_RCAR_GEN3 },
 	{ .compatible = "renesas,rcar-gen4-i2c", .data = (void *)I2C_RCAR_GEN4 },
+	{ .compatible = "renesas,rcar-gen5-i2c", .data = (void *)I2C_RCAR_GEN5 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
@@ -1194,9 +1200,15 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 			goto out_pm_put;
 		}
 
-		ret = reset_control_status(priv->rstc);
-		if (ret < 0)
-			goto out_pm_put;
+		/*
+		 * Gen5+ uses SCMI based reset which cannot report status.
+		 * Firmware has to ensure proper reset
+		 */
+		if (priv->devtype < I2C_RCAR_GEN5) {
+			ret = reset_control_status(priv->rstc);
+			if (ret < 0)
+				goto out_pm_put;
+		}
 
 		/* hard reset disturbs HostNotify local target, so disable it */
 		priv->flags &= ~ID_P_HOST_NOTIFY;
-- 
2.47.3