[PATCH v2 0/2] i2c: rtl9300: remove IO_MODE configuration

[PATCH v2 0/2] i2c: rtl9300: remove IO_MODE configuration

[Michael Zavertkin]

i2c driver for RTL9607C used to configure IO_MODE register. The register
is global and responsible for configuring SoC pins, therefore it should
belong to pinctrl driver.

SoC-specific pinctrl driver is WIP (waiting for these patches in OpenWRT),
but pinctrl-single could be used instead.

While added compatible realtek,rtl9607c-i2c relies on pinctrl driver,
old realtek,rtl9607-i2c left for backward compatibility.

Signed-off-by: Michael Zavertkin <misha.zavertkin@mail.ru>
---
Changes in v2:
- Backward compatibility achieved by adding new compatible value. Old
  one is marked as deprecated
- Link to v1: https://patch.msgid.link/cover.1791127538.git.misha.zavertkin@mail.ru
---
Michael Zavertkin (2):
  i2c: rtl9300: add realtek,rtl9607c-i2c compatible
  dt-bindings: i2c: rtl9300: add 'rtl9607c-i2c'

 .../bindings/i2c/realtek,rtl9301-i2c.yaml     | 20 ++++++++++++++++++-
 drivers/i2c/busses/i2c-rtl9300.c              | 15 ++++++++++----
 2 files changed, 30 insertions(+), 5 deletions(-)

-- 
2.54.0

[PATCH v2 1/2] i2c: rtl9300: add realtek,rtl9607c-i2c compatible

[Michael Zavertkin]

RTL9607C was already supported by realtek,rtl9607-i2c, which is
confusing, because there are another SoCs such as RTL9607F, RTL9607
(without letter) and a few more. So more correct compatible was added.

New compatible doesn't use IO_MODE_EN register, leaving it to pinctrl
driver. Old one left for backward compatibility.

Signed-off-by: Michael Zavertkin <misha.zavertkin@mail.ru>
---
 drivers/i2c/busses/i2c-rtl9300.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c
index 3a8225b0666c..22aa3b38458c 100644
--- a/drivers/i2c/busses/i2c-rtl9300.c
+++ b/drivers/i2c/busses/i2c-rtl9300.c
@@ -200,10 +200,12 @@ static int rtl9607_i2c_config_chan(struct rtl9300_i2c *i2c, struct rtl9300_i2c_c
 	if (ret)
 		return ret;
 
-	drv_data = device_get_match_data(i2c->dev);
-	ret = drv_data->select_scl(i2c, i2c->scl_num);
-	if (ret)
-		return ret;
+	if (device_is_compatible(i2c->dev, "realtek,rtl9607-i2c")) {
+		drv_data = device_get_match_data(i2c->dev);
+		ret = drv_data->select_scl(i2c, i2c->scl_num);
+		if (ret)
+			return ret;
+	}
 
 	i2c->sda_num = chan->sda_num;
 	return 0;
@@ -494,6 +496,10 @@ static int rtl9300_i2c_probe(struct platform_device *pdev)
 		scl_num = 0;
 	i2c->scl_num = (u8)scl_num;
 
+	if (device_is_compatible(i2c->dev, "realtek,rtl9607-i2c"))
+		dev_warn(dev, "Compatible 'realtek,rtl9607-i2c' is deprecated. "
+			      "Use 'realtek,rtl9607c-i2c' instead\n");
+
 	platform_set_drvdata(pdev, i2c);
 
 	drv_data = device_get_match_data(i2c->dev);
@@ -652,6 +658,7 @@ static const struct of_device_id i2c_rtl9300_dt_ids[] = {
 	{ .compatible = "realtek,rtl9312-i2c", .data = (void *) &rtl9310_i2c_drv_data },
 	{ .compatible = "realtek,rtl9313-i2c", .data = (void *) &rtl9310_i2c_drv_data },
 	{ .compatible = "realtek,rtl9607-i2c", .data = (void *) &rtl9607_i2c_drv_data },
+	{ .compatible = "realtek,rtl9607c-i2c", .data = (void *) &rtl9607_i2c_drv_data },
 	{}
 };
 MODULE_DEVICE_TABLE(of, i2c_rtl9300_dt_ids);
-- 
2.54.0

Re: [PATCH v2 1/2] i2c: rtl9300: add realtek,rtl9607c-i2c compatible

[Michael Zavertkin]

On Sat, Oct 10, 2026 at 06:45:14AM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] i2c: rtl9300: device_is_compatible check breaks DT fallback patterns
> --
> 
> commit 96f11e2144ef16398bba64fc512f5b346ab89571
> Author: Michael Zavertkin <misha.zavertkin@mail.ru>
> 
> i2c: rtl9300: add realtek,rtl9607c-i2c compatible
> 
> This commit adds support for the realtek,rtl9607c-i2c compatible string to 
> distinguish it from other RTL9607 variants. It avoids using the IO_MODE_EN 
> register on the new compatible by restricting the select_scl call and emits 
> a deprecation warning for the old compatible string.
> 
> > diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c
> > index 3a8225b0666c0..22aa3b38458c0 100644
> > --- a/drivers/i2c/busses/i2c-rtl9300.c
> > +++ b/drivers/i2c/busses/i2c-rtl9300.c
> > @@ -200,10 +200,12 @@ static int rtl9607_i2c_config_chan(struct rtl9300_i2c *i2c, struct rtl9300_i2c_c
> >  	if (ret)
> >  		return ret;
> >  
> > -	drv_data = device_get_match_data(i2c->dev);
> > -	ret = drv_data->select_scl(i2c, i2c->scl_num);
> > -	if (ret)
> > -		return ret;
> > +	if (device_is_compatible(i2c->dev, "realtek,rtl9607-i2c")) {
> > +		drv_data = device_get_match_data(i2c->dev);
> > +		ret = drv_data->select_scl(i2c, i2c->scl_num);
> > +		if (ret)
> > +			return ret;
> > +	}
> 
> [Severity: Medium]
> Will this check break device tree fallback patterns?
> 
> If a new device tree provides a fallback compatible list like 
> compatible = "realtek,rtl9607c-i2c", "realtek,rtl9607-i2c"; 
> device_is_compatible() will return true because the legacy string is still 
> present in the node.
> 
> If this happens, the driver will incorrectly execute the legacy select_scl 
> hardware configuration (modifying the IO_MODE_EN register) on RTL9607C 
> hardware, instead of delegating it to the pinctrl driver as intended.
> 
> Would it be safer to differentiate hardware capabilities based on the matched 
> driver data (for instance, pointing the new compatible to a struct without 
> a select_scl function) instead of dynamically searching the OF node for 
> deprecated strings?
> 
> >  	i2c->sda_num = chan->sda_num;
> >  	return 0;
> > @@ -494,6 +496,10 @@ static int rtl9300_i2c_probe(struct platform_device *pdev)
> >  		scl_num = 0;
> >  	i2c->scl_num = (u8)scl_num;
> >  
> > +	if (device_is_compatible(i2c->dev, "realtek,rtl9607-i2c"))
> > +		dev_warn(dev, "Compatible 'realtek,rtl9607-i2c' is deprecated. "
> > +			      "Use 'realtek,rtl9607c-i2c' instead\n");
> > +
> 
> [Severity: Medium]
> Does this also trigger an incorrect deprecation warning when fallback 
> compatibles are used?
> 
> Because device_is_compatible() matches any string in the list, providing a 
> valid fallback to support older kernels will falsely trigger this warning 
> even if "realtek,rtl9607c-i2c" is properly specified as the primary compatible 
> string.
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/cover.1791611999.git.misha.zavertkin@mail.ru?part=1

There is no device-embedded device tree files with this compatibles,
only embedded in kernel during build (OpenWRT approach), so fallback
compatibles isn't expected, and proper fallback support would look like
overkill right now.

[PATCH v2 2/2] dt-bindings: i2c: rtl9300: add 'rtl9607c-i2c'

[Michael Zavertkin]

Add realtek,rtl9607c-i2c compatible for RTL9607C SoC and mark
realtek,rtl9607-i2c as deprecated.

New compatible relies on pinctrl driver for correct pin assignment
instead of directly modifying IO_MODE register.

Signed-off-by: Michael Zavertkin <misha.zavertkin@mail.ru>
---
 .../bindings/i2c/realtek,rtl9301-i2c.yaml     | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i2c/realtek,rtl9301-i2c.yaml b/Documentation/devicetree/bindings/i2c/realtek,rtl9301-i2c.yaml
index 5873cfdc5b3e..7c00918f33c8 100644
--- a/Documentation/devicetree/bindings/i2c/realtek,rtl9301-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/realtek,rtl9301-i2c.yaml
@@ -36,7 +36,11 @@ properties:
       - enum:
           - realtek,rtl9301-i2c
           - realtek,rtl9310-i2c
-          - realtek,rtl9607-i2c
+          - realtek,rtl9607c-i2c
+      - const: realtek,rtl9607-i2c
+        deprecated: true
+        description: >
+          Use 'realtek,rtl9607c-i2c' instead
 
   reg:
     items:
@@ -57,6 +61,10 @@ properties:
   clocks:
     maxItems: 1
 
+  pinctrl-0: true
+
+  pinctrl-names: true
+
 patternProperties:
   '^i2c@[0-9ab]$':
     $ref: /schemas/i2c/i2c-controller.yaml
@@ -96,6 +104,16 @@ allOf:
       required:
         - realtek,scl
         - clocks
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: realtek,rtl9607c-i2c
+    then:
+      required:
+        - clocks
+        - pinctrl-0
+        - pinctrl-names
 
 required:
   - compatible
-- 
2.54.0

Re: [PATCH v2 2/2] dt-bindings: i2c: rtl9300: add 'rtl9607c-i2c'

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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