[PATCH 0/3] mmc: sdhci-of-k1: add reset support

[PATCH 0/3] mmc: sdhci-of-k1: add reset support

[Yixun Lan]

This series try to add reset support explicitly to SpacemiT SDHCI controller.
Previous it works well for eMMC due to it's already initialized at brom or
bootloader phase.
  The controller has two reset lines, one connect to AXI bus which shared by
all controllers, while another one connect to individual controller separately.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
---
Yixun Lan (3):
      dt-bindings: mmc: spacemit,sdhci: add reset support
      mmc: sdhci-of-k1: add reset support
      riscv: dts: spacemit: sdhci: add reset support

 .../devicetree/bindings/mmc/spacemit,sdhci.yaml      | 14 ++++++++++++++
 arch/riscv/boot/dts/spacemit/k1.dtsi                 |  3 +++
 drivers/mmc/host/sdhci-of-k1.c                       | 20 ++++++++++++++++++++
 3 files changed, 37 insertions(+)
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251221-07-k1-sdhci-reset-1990d1170437

Best regards,
-- 
Yixun Lan

[PATCH 1/3] dt-bindings: mmc: spacemit,sdhci: add reset support

[Yixun Lan]

The SpacemiT SDHCI controller has two reset lines, one connect to AXI bus
which shared by all controllers, while another one connect to individual
controller separately.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
---
 Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
index 13d9382058fb..322c69b056f4 100644
--- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
@@ -32,12 +32,24 @@ properties:
       - const: core
       - const: io
 
+  resets:
+    items:
+      - description: axi reset, connect to AXI bus, shared by all controllers
+      - description: sdh reset, connect to individual controller separately
+
+  reset-names:
+    items:
+      - const: axi
+      - const: sdh
+
 required:
   - compatible
   - reg
   - interrupts
   - clocks
   - clock-names
+  - resets
+  - reset-names
 
 unevaluatedProperties: false
 
@@ -50,4 +62,6 @@ examples:
       interrupt-parent = <&plic>;
       clocks = <&clk_apmu 10>, <&clk_apmu 13>;
       clock-names = "core", "io";
+      resets = <&syscon_apmu 2>, <&syscon_apmu 5>;
+      reset-names = "axi", "sdh";
     };

-- 
2.52.0

Re: [PATCH 1/3] dt-bindings: mmc: spacemit,sdhci: add reset support

[Krzysztof Kozlowski]

On Sun, Dec 21, 2025 at 04:20:26PM +0800, Yixun Lan wrote:
> The SpacemiT SDHCI controller has two reset lines, one connect to AXI bus
> which shared by all controllers, while another one connect to individual
> controller separately.
> 
> Signed-off-by: Yixun Lan <dlan@gentoo.org>
> ---
>  Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> index 13d9382058fb..322c69b056f4 100644
> --- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> +++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> @@ -32,12 +32,24 @@ properties:
>        - const: core
>        - const: io
>  
> +  resets:
> +    items:
> +      - description: axi reset, connect to AXI bus, shared by all controllers
> +      - description: sdh reset, connect to individual controller separately
> +
> +  reset-names:
> +    items:
> +      - const: axi
> +      - const: sdh
> +
>  required:
>    - compatible
>    - reg
>    - interrupts
>    - clocks
>    - clock-names
> +  - resets
> +  - reset-names

This is an ABI break without mentioning in commit msg and without any
justification.

Best regards,
Krzysztof

Re: [PATCH 1/3] dt-bindings: mmc: spacemit,sdhci: add reset support

[Yixun Lan]

Hi Krzysztof, 

On 16:09 Sun 21 Dec     , Krzysztof Kozlowski wrote:
> On Sun, Dec 21, 2025 at 04:20:26PM +0800, Yixun Lan wrote:
> > The SpacemiT SDHCI controller has two reset lines, one connect to AXI bus
> > which shared by all controllers, while another one connect to individual
> > controller separately.
> > 
> > Signed-off-by: Yixun Lan <dlan@gentoo.org>
> > ---
> >  Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > index 13d9382058fb..322c69b056f4 100644
> > --- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > @@ -32,12 +32,24 @@ properties:
> >        - const: core
> >        - const: io
> >  
> > +  resets:
> > +    items:
> > +      - description: axi reset, connect to AXI bus, shared by all controllers
> > +      - description: sdh reset, connect to individual controller separately
> > +
> > +  reset-names:
> > +    items:
> > +      - const: axi
> > +      - const: sdh
> > +
> >  required:
> >    - compatible
> >    - reg
> >    - interrupts
> >    - clocks
> >    - clock-names
> > +  - resets
> > +  - reset-names
> 
> This is an ABI break without mentioning in commit msg and without any
> justification.
> 
Indeed, this will introduce a breakage when combining new kernel + old dtb

Since in current case, the eMMC works fine without reset line operation,
I then would make this property optional (drop it from 'required' section)
and switch to use devm_reset_control_get_optional_xx() API in driver code

Does this looks good to you?

-- 
Yixun Lan (dlan)

Re: [PATCH 1/3] dt-bindings: mmc: spacemit,sdhci: add reset support

[Krzysztof Kozlowski]

On 22/12/2025 03:12, Yixun Lan wrote:
>>>  required:
>>>    - compatible
>>>    - reg
>>>    - interrupts
>>>    - clocks
>>>    - clock-names
>>> +  - resets
>>> +  - reset-names
>>
>> This is an ABI break without mentioning in commit msg and without any
>> justification.
>>
> Indeed, this will introduce a breakage when combining new kernel + old dtb
> 
> Since in current case, the eMMC works fine without reset line operation,
> I then would make this property optional (drop it from 'required' section)
> and switch to use devm_reset_control_get_optional_xx() API in driver code
> 
> Does this looks good to you?
> 

Yes

Best regards,
Krzysztof

[PATCH 2/3] mmc: sdhci-of-k1: add reset support

[Yixun Lan]

The SDHCI controller of SpacemiT K1 SoC requires two resets, add
support to explicitly request the reset line and deassert during
initialization phase.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
---
 drivers/mmc/host/sdhci-of-k1.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index 0cc97e23a2f9..f8330cff5b2a 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/reset.h>
 #include <linux/platform_device.h>
 
 #include "sdhci.h"
@@ -223,6 +224,21 @@ static inline int spacemit_sdhci_get_clocks(struct device *dev,
 	return 0;
 }
 
+static inline int spacemit_sdhci_get_resets(struct device *dev)
+{
+	struct reset_control *rst;
+
+	rst = devm_reset_control_get_shared_deasserted(dev, "axi");
+	if (IS_ERR(rst))
+		return PTR_ERR(rst);
+
+	rst = devm_reset_control_get_exclusive_deasserted(dev, "sdh");
+	if (IS_ERR(rst))
+		return PTR_ERR(rst);
+
+	return 0;
+}
+
 static const struct sdhci_ops spacemit_sdhci_ops = {
 	.get_max_clock		= spacemit_sdhci_clk_get_max_clock,
 	.reset			= spacemit_sdhci_reset,
@@ -284,6 +300,10 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_pltfm;
 
+	ret = spacemit_sdhci_get_resets(dev);
+	if (ret)
+		goto err_pltfm;
+
 	ret = sdhci_add_host(host);
 	if (ret)
 		goto err_pltfm;

-- 
2.52.0

[PATCH 3/3] riscv: dts: spacemit: sdhci: add reset support

[Yixun Lan]

Request two reset line explicitly for SDHCI controller.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
---
 arch/riscv/boot/dts/spacemit/k1.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/riscv/boot/dts/spacemit/k1.dtsi b/arch/riscv/boot/dts/spacemit/k1.dtsi
index 7818ca4979b6..7dd41d6dcb85 100644
--- a/arch/riscv/boot/dts/spacemit/k1.dtsi
+++ b/arch/riscv/boot/dts/spacemit/k1.dtsi
@@ -984,6 +984,9 @@ emmc: mmc@d4281000 {
 				clocks = <&syscon_apmu CLK_SDH_AXI>,
 					 <&syscon_apmu CLK_SDH2>;
 				clock-names = "core", "io";
+				resets = <&syscon_apmu RESET_SDH_AXI>,
+					 <&syscon_apmu RESET_SDH2>;
+				reset-names = "axi", "sdh";
 				interrupts = <101>;
 				status = "disabled";
 			};

-- 
2.52.0