[PATCH 0/3] i2c: spacemit: add reset support

[PATCH 0/3] i2c: spacemit: add reset support

[Encrow Thorne]

Add reset control to SpacemiT K1 I2C.

Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
---
Encrow Thorne (3):
      dt-bindings: i2c: spacemit: add optional resets
      i2c: k1: add reset support
      riscv: dts: spacemit: add reset property

 Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml |  3 +++
 arch/riscv/boot/dts/spacemit/k1.dtsi                       |  2 ++
 drivers/i2c/busses/i2c-k1.c                                | 11 +++++++++++
 3 files changed, 16 insertions(+)
---
base-commit: 8fec172c82c2b5f6f8e47ab837c1dc91ee3d1b87
change-id: 20251104-i2c-k1_reset-support-12784e17bf83

Best regards,
-- 
Encrow Thorne <jyc0019@gmail.com>

[PATCH 1/3] dt-bindings: i2c: spacemit: add optional resets

[Encrow Thorne]

Add optional reset property for the SpacemiT K1 I2C.

Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
---
 Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
index b7220fff2235..3d4faec41abe 100644
--- a/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
@@ -27,6 +27,9 @@ properties:
       - description: I2C Functional Clock
       - description: APB Bus Clock
 
+  resets:
+    maxItems: 1
+
   clock-names:
     items:
       - const: func

-- 
2.25.1

Re: [PATCH 1/3] dt-bindings: i2c: spacemit: add optional resets

[Troy Mitchell]

On Wed, Nov 19, 2025 at 07:46:43PM +0800, Encrow Thorne wrote:
> Add optional reset property for the SpacemiT K1 I2C.
> 
> Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
>
Thanks.

Acked-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>

Re: [PATCH 1/3] dt-bindings: i2c: spacemit: add optional resets

[Krzysztof Kozlowski]

On Wed, Nov 19, 2025 at 07:46:43PM +0800, Encrow Thorne wrote:
> Add optional reset property for the SpacemiT K1 I2C.

Why? You just repeated diff and we can read the diff. Please explain WHY
you are doing things in terms of hardware.

> 
> Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
> ---
>  Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
> index b7220fff2235..3d4faec41abe 100644
> --- a/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
> @@ -27,6 +27,9 @@ properties:
>        - description: I2C Functional Clock
>        - description: APB Bus Clock
>  
> +  resets:
> +    maxItems: 1
> +

Completely misplaced. There are never random properties between xxx and
xxx-names.

Best regards,
Krzysztof

[PATCH 2/3] i2c: k1: add reset support

[Encrow Thorne]

Add reset control handling to the K1 I2C driver.

Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
---
 drivers/i2c/busses/i2c-k1.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
index 6b918770e612..64d817d8315d 100644
--- a/drivers/i2c/busses/i2c-k1.c
+++ b/drivers/i2c/busses/i2c-k1.c
@@ -10,6 +10,7 @@
  #include <linux/module.h>
  #include <linux/of_address.h>
  #include <linux/platform_device.h>
+ #include <linux/reset.h>
 
 /* spacemit i2c registers */
 #define SPACEMIT_ICR		 0x0		/* Control register */
@@ -113,6 +114,7 @@ struct spacemit_i2c_dev {
 	void __iomem *base;
 	int irq;
 	u32 clock_freq;
+	struct reset_control *resets;
 
 	struct i2c_msg *msgs;
 	u32 msg_num;
@@ -571,6 +573,15 @@ static int spacemit_i2c_probe(struct platform_device *pdev)
 	if (IS_ERR(clk))
 		return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock");
 
+	i2c->resets = devm_reset_control_get_optional(dev, NULL);
+	if (IS_ERR(i2c->resets))
+		return dev_err_probe(dev, PTR_ERR(i2c->resets),
+				    "failed to get reset\n");
+
+	reset_control_assert(i2c->resets);
+	udelay(2);
+	reset_control_deassert(i2c->resets);
+
 	spacemit_i2c_reset(i2c);
 
 	i2c_set_adapdata(&i2c->adapt, i2c);

-- 
2.25.1

Re: [PATCH 2/3] i2c: k1: add reset support

[Troy Mitchell]

Hi Encrow,

On Wed, Nov 19, 2025 at 07:46:44PM +0800, Encrow Thorne wrote:
> Add reset control handling to the K1 I2C driver.
> 
> Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
> ---
>  drivers/i2c/busses/i2c-k1.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
> index 6b918770e612..64d817d8315d 100644
> --- a/drivers/i2c/busses/i2c-k1.c
> +++ b/drivers/i2c/busses/i2c-k1.c
> @@ -10,6 +10,7 @@
>   #include <linux/module.h>
>   #include <linux/of_address.h>
>   #include <linux/platform_device.h>
> + #include <linux/reset.h>
>  
>  /* spacemit i2c registers */
>  #define SPACEMIT_ICR		 0x0		/* Control register */
> @@ -113,6 +114,7 @@ struct spacemit_i2c_dev {
>  	void __iomem *base;
>  	int irq;
>  	u32 clock_freq;
> +	struct reset_control *resets;
>  
>  	struct i2c_msg *msgs;
>  	u32 msg_num;
> @@ -571,6 +573,15 @@ static int spacemit_i2c_probe(struct platform_device *pdev)
>  	if (IS_ERR(clk))
>  		return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock");
>  
> +	i2c->resets = devm_reset_control_get_optional(dev, NULL);
> +	if (IS_ERR(i2c->resets))
> +		return dev_err_probe(dev, PTR_ERR(i2c->resets),
> +				    "failed to get reset\n");
Please align.

> +
> +	reset_control_assert(i2c->resets);
> +	udelay(2);
This seems to be a very small value. If this
has been verified multiple times?

                        - Troy
> +	reset_control_deassert(i2c->resets);
> +
>  	spacemit_i2c_reset(i2c);
>  
>  	i2c_set_adapdata(&i2c->adapt, i2c);
> 
> -- 
> 2.25.1
> 
> 

[PATCH 3/3] riscv: dts: spacemit: add reset property

[Encrow Thorne]

Add resets property to K1 I2C node.

Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
---
 arch/riscv/boot/dts/spacemit/k1.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/boot/dts/spacemit/k1.dtsi b/arch/riscv/boot/dts/spacemit/k1.dtsi
index af35f9cd6435..2b84dc276ace 100644
--- a/arch/riscv/boot/dts/spacemit/k1.dtsi
+++ b/arch/riscv/boot/dts/spacemit/k1.dtsi
@@ -468,6 +468,7 @@ i2c2: i2c@d4012000 {
 				 <&syscon_apbc CLK_TWSI2_BUS>;
 			clock-names = "func", "bus";
 			clock-frequency = <400000>;
+			resets = <&syscon_apbc RESET_TWSI2>;
 			interrupts = <38>;
 			status = "disabled";
 		};
@@ -481,6 +482,7 @@ i2c8: i2c@d401d800 {
 				 <&syscon_apbc CLK_TWSI8_BUS>;
 			clock-names = "func", "bus";
 			clock-frequency = <400000>;
+			resets = <&syscon_apbc RESET_TWSI8>;
 			interrupts = <19>;
 			status = "disabled";
 		};

-- 
2.25.1

Re: [PATCH 3/3] riscv: dts: spacemit: add reset property

[Troy Mitchell]

On Wed, Nov 19, 2025 at 07:46:45PM +0800, Encrow Thorne wrote:
> Add resets property to K1 I2C node.
> 
> Signed-off-by: Encrow Thorne <jyc0019@gmail.com>
> ---
>  arch/riscv/boot/dts/spacemit/k1.dtsi | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/riscv/boot/dts/spacemit/k1.dtsi b/arch/riscv/boot/dts/spacemit/k1.dtsi
> index af35f9cd6435..2b84dc276ace 100644
> --- a/arch/riscv/boot/dts/spacemit/k1.dtsi
> +++ b/arch/riscv/boot/dts/spacemit/k1.dtsi
> @@ -468,6 +468,7 @@ i2c2: i2c@d4012000 {
>  				 <&syscon_apbc CLK_TWSI2_BUS>;
>  			clock-names = "func", "bus";
>  			clock-frequency = <400000>;
> +			resets = <&syscon_apbc RESET_TWSI2>;
>  			interrupts = <38>;
>  			status = "disabled";
>  		};
> @@ -481,6 +482,7 @@ i2c8: i2c@d401d800 {
>  				 <&syscon_apbc CLK_TWSI8_BUS>;
>  			clock-names = "func", "bus";
>  			clock-frequency = <400000>;
> +			resets = <&syscon_apbc RESET_TWSI8>;
>  			interrupts = <19>;
>  			status = "disabled";
>  		};
Since this patch has been merged [1], you can add resets property in all
i2c node.

                                    - Troy

Link: https://lore.kernel.org/all/176294559674.467363.5417599191009488468.b4-ty@gentoo.org/ [1]
> 
> -- 
> 2.25.1
> 
>