[PATCH v4 0/2] dt-bindings: mmc: st,sdhci: convert STMicroelectronics SDHCI-ST MMC/SD Controller controller binding to YAML

[PATCH v4 0/2] dt-bindings: mmc: st,sdhci: convert STMicroelectronics SDHCI-ST MMC/SD Controller controller binding to YAML

[Charan Pedumuru]

This patch series converts the legacy text-based Device Tree binding for
STMicroelectronics SDHCI-ST MMC/SD controller to DT schema (YAML) format.

Note:
The patch "dt-bindings: mmc: st,sdhci: convert to DT schema"
depends on the patch "arm: dts: st: align node patterns with established
convention". If the DT schema patch is applied before the DTS
cleanup patch, `dtbs_check` will fail due to the presence of the removed
properties in the existing DTS.

Signed-off-by: Charan Pedumuru <charan.pedumuru@gmail.com>
---
Changes in v4:
- st,sdhci: Add minItems: 1 to clock-names and reg-names to allow single-entry
  configurations, fixing dtbs_check failures on nodes that omit the
  optional 'icn' clock or 'top-mmc-delay' register region.
- st,sdhci: Modify the commit message to explain the changes.
- Link to v3: https://patch.msgid.link/20260508-st-mmc-v3-0-81c329ed28e8@gmail.com

Changes in v3:
- st,sdhci: Edit description of reg property. Modify reg-names. Add
  "minItems" for clocks and clock-names properties.
- Modify the commit message to match with the updated changes.
- Link to v2: https://patch.msgid.link/20260503-st-mmc-v2-0-11ae3216d2ce@gmail.com

Changes in v2:
- Fix node name in DTS for the MMC to match with the estableshed convention.
- st,sdhci: drop unnecessary properties, modify "reg", "reg-names" and
  "clock-names" properties, include an allOf with $ref to mmc-controller.
- Link to v1: https://patch.msgid.link/20260409-st-mmc-v1-1-4c54321c3535@gmail.com

---
Charan Pedumuru (2):
      arm: dts: st: align node patterns with established convention
      dt-bindings: mmc: st,sdhci: Convert to DT schema

 Documentation/devicetree/bindings/mmc/sdhci-st.txt | 110 ---------------------
 .../devicetree/bindings/mmc/st,sdhci.yaml          |  92 +++++++++++++++++
 arch/arm/boot/dts/st/stih407-family.dtsi           |   4 +-
 3 files changed, 94 insertions(+), 112 deletions(-)
---
base-commit: cf2cd8efd046c561191b8541d32a8bfe845bf06b
change-id: 20260327-st-mmc-c906ad95ff83

Best regards,
--  
Charan Pedumuru <charan.pedumuru@gmail.com>

[PATCH v4 1/2] arm: dts: st: align node patterns with established convention

[Charan Pedumuru]

Update ST MMC DTS node patterns to match established convention.

Signed-off-by: Charan Pedumuru <charan.pedumuru@gmail.com>
---
 arch/arm/boot/dts/st/stih407-family.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boot/dts/st/stih407-family.dtsi b/arch/arm/boot/dts/st/stih407-family.dtsi
index 3e6a0542e3ae..08acba209c56 100644
--- a/arch/arm/boot/dts/st/stih407-family.dtsi
+++ b/arch/arm/boot/dts/st/stih407-family.dtsi
@@ -596,7 +596,7 @@ spi@9542000 {
 			status = "disabled";
 		};
 
-		mmc0: sdhci@9060000 {
+		mmc0: mmc@9060000 {
 			compatible = "st,sdhci-stih407", "st,sdhci";
 			status = "disabled";
 			reg = <0x09060000 0x7ff>, <0x9061008 0x20>;
@@ -611,7 +611,7 @@ mmc0: sdhci@9060000 {
 			bus-width = <8>;
 		};
 
-		mmc1: sdhci@9080000 {
+		mmc1: mmc@9080000 {
 			compatible = "st,sdhci-stih407", "st,sdhci";
 			status = "disabled";
 			reg = <0x09080000 0x7ff>;

-- 
2.54.0

[PATCH v4 2/2] dt-bindings: mmc: st,sdhci: Convert to DT schema

[Charan Pedumuru]

Convert STMicroelectronics sdhci-st MMC/SD controller binding to
DT schema.

The 'icn' clock and 'top-mmc-delay' register region are optional in
the text binding and remain so in the YAML schema. minItems: 1 is
set on clock-names and reg-names to match the flexibility of their
paired clocks and reg properties, preserving compatibility with
existing in-tree DTS nodes that provide only a single clock or
register entry.

Signed-off-by: Charan Pedumuru <charan.pedumuru@gmail.com>
---
 Documentation/devicetree/bindings/mmc/sdhci-st.txt | 110 ---------------------
 .../devicetree/bindings/mmc/st,sdhci.yaml          |  92 +++++++++++++++++
 2 files changed, 92 insertions(+), 110 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-st.txt b/Documentation/devicetree/bindings/mmc/sdhci-st.txt
deleted file mode 100644
index ccf82b4ee838..000000000000
--- a/Documentation/devicetree/bindings/mmc/sdhci-st.txt
+++ /dev/null
@@ -1,110 +0,0 @@
-* STMicroelectronics sdhci-st MMC/SD controller
-
-This file documents the differences between the core properties in
-Documentation/devicetree/bindings/mmc/mmc.txt and the properties
-used by the sdhci-st driver.
-
-Required properties:
-- compatible:		Must be "st,sdhci" and it can be compatible to "st,sdhci-stih407"
-			to set the internal glue logic used for configuring the MMC
-			subsystem (mmcss) inside the FlashSS (available in STiH407 SoC
-			family).
-
-- clock-names:		Should be "mmc" and "icn".  (NB: The latter is not compulsory)
-			See: Documentation/devicetree/bindings/resource-names.txt
-- clocks:		Phandle to the clock.
-			See: Documentation/devicetree/bindings/clock/clock-bindings.txt
-
-- interrupts:		One mmc interrupt should be described here.
-- interrupt-names:	Should be "mmcirq".
-
-- pinctrl-names:	A pinctrl state names "default" must be defined.
-- pinctrl-0:		Phandle referencing pin configuration of the sd/emmc controller.
-			See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
-
-- reg:			This must provide the host controller base address and it can also
-			contain the FlashSS Top register for TX/RX delay used by the driver
-			to configure DLL inside the flashSS, if so reg-names must also be
-			specified.
-
-Optional properties:
-- reg-names:		Should be "mmc" and "top-mmc-delay". "top-mmc-delay" is optional
-			for eMMC on stih407 family silicon to configure DLL inside FlashSS.
-
-- non-removable:	Non-removable slot. Also used for configuring mmcss in STiH407 SoC
-			family.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-- bus-width:		Number of data lines.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-- max-frequency:	Can be 200MHz, 100MHz or 50MHz (default) and used for
-			configuring the CCONFIG3 in the mmcss.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-- resets:		Phandle and reset specifier pair to softreset line of HC IP.
-			See: Documentation/devicetree/bindings/reset/reset.txt
-
-- vqmmc-supply:		Phandle to the regulator dt node, mentioned as the vcc/vdd
-			supply in eMMC/SD specs.
-
-- sd-uhs-sdr50:	To enable the SDR50 in the mmcss.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-- sd-uhs-sdr104:	To enable the SDR104 in the mmcss.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-- sd-uhs-ddr50:		To enable the DDR50 in the mmcss.
-			See:  Documentation/devicetree/bindings/mmc/mmc.txt.
-
-Example:
-
-/* Example stih416e eMMC configuration */
-
-mmc0: sdhci@fe81e000 {
-	compatible	= "st,sdhci";
-	reg		= <0xfe81e000 0x1000>;
-	interrupts	= <GIC_SPI 127 IRQ_TYPE_NONE>;
-	interrupt-names	= "mmcirq";
-	pinctrl-names	= "default";
-	pinctrl-0	= <&pinctrl_mmc0>;
-	clock-names	= "mmc";
-	clocks		= <&clk_s_a1_ls 1>;
-	bus-width	= <8>
-
-/* Example SD stih407 family configuration */
-
-mmc1: sdhci@9080000 {
-	compatible	= "st,sdhci-stih407", "st,sdhci";
-	reg		= <0x09080000 0x7ff>;
-	reg-names	= "mmc";
-	interrupts	= <GIC_SPI 90 IRQ_TYPE_NONE>;
-	interrupt-names	= "mmcirq";
-	pinctrl-names	= "default";
-	pinctrl-0	= <&pinctrl_sd1>;
-	clock-names	= "mmc";
-	clocks		= <&clk_s_c0_flexgen CLK_MMC_1>;
-	resets		= <&softreset STIH407_MMC1_SOFTRESET>;
-	bus-width	= <4>;
-};
-
-/* Example eMMC stih407 family configuration */
-
-mmc0: sdhci@9060000 {
-	compatible	= "st,sdhci-stih407", "st,sdhci";
-	reg		= <0x09060000 0x7ff>, <0x9061008 0x20>;
-	reg-names	= "mmc", "top-mmc-delay";
-	interrupts	= <GIC_SPI 92 IRQ_TYPE_NONE>;
-	interrupt-names	= "mmcirq";
-	pinctrl-names	= "default";
-	pinctrl-0	= <&pinctrl_mmc0>;
-	clock-names	= "mmc";
-	clocks		= <&clk_s_c0_flexgen CLK_MMC_0>;
-	vqmmc-supply	= <&vmmc_reg>;
-	max-frequency	= <200000000>;
-	bus-width	= <8>;
-	non-removable;
-	sd-uhs-sdr50;
-	sd-uhs-sdr104;
-	sd-uhs-ddr50;
-};
diff --git a/Documentation/devicetree/bindings/mmc/st,sdhci.yaml b/Documentation/devicetree/bindings/mmc/st,sdhci.yaml
new file mode 100644
index 000000000000..0bf4fc3ca699
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/st,sdhci.yaml
@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/st,sdhci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics SDHCI-ST MMC/SD Controller
+
+maintainers:
+  - Peter Griffin <peter.griffin@linaro.org>
+
+description:
+  The STMicroelectronics SDHCI-ST MMC/SD host controller is compliant with
+  the SD Host Controller Interface (SDHCI) specification and is used to
+  interface with MMC, SD and SDIO cards. The ST SDHCI controller extends the
+  standard SDHCI capabilities with platform-specific configurations such as
+  additional register regions, clock inputs, and delay control mechanisms
+  required for signal timing adjustments to support high-speed modes across
+  different ST SoCs.
+
+allOf:
+  - $ref: mmc-controller.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - const: st,sdhci
+      - items:
+          - const: st,sdhci-stih407
+          - const: st,sdhci
+
+  reg:
+    minItems: 1
+    items:
+      - description: MMC controller base registers
+      - description: FlashSS Top registers for TX/RX DLL delay configuration
+
+  reg-names:
+    minItems: 1
+    items:
+      - const: mmc
+      - const: top-mmc-delay
+
+  clocks:
+    minItems: 1
+    items:
+      - description: Clock for the MMC controller
+      - description: Interconnect (ICN) clock
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: mmc
+      - const: icn
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-names:
+    const: mmcirq
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+  - interrupt-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/stih407-clks.h>
+    mmc@9060000 {
+        compatible = "st,sdhci-stih407", "st,sdhci";
+        reg = <0x09060000 0x7ff>, <0x9061008 0x20>;
+        reg-names = "mmc", "top-mmc-delay";
+        interrupts = <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "mmcirq";
+        pinctrl-names = "default";
+        pinctrl-0 = <&pinctrl_mmc0>;
+        clock-names = "mmc", "icn";
+        clocks = <&clk_s_c0_flexgen CLK_MMC_0>,
+                 <&clk_s_c0_flexgen CLK_RX_ICN_HVA>;
+        bus-width = <8>;
+    };
+...

-- 
2.54.0

Re: [PATCH v4 2/2] dt-bindings: mmc: st,sdhci: Convert to DT schema

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] The DT schema fails to conditionally require `reg-names` when multiple `reg` entries are provided, which can lead to silent runtime misconfiguration.
- [Medium] The YAML schema loses the original specific allowed values constraint for `max-frequency`.
--

commit e2c333948a6b09aa2bb42febade330d8715b076f
Author: Charan Pedumuru <charan.pedumuru@gmail.com>

dt-bindings: mmc: st,sdhci: Convert to DT schema

This commit converts the STMicroelectronics sdhci-st MMC/SD controller
binding from a text format to a YAML DT schema. It preserves the flexibility
of optional clocks and registers from the original binding.

> diff --git a/Documentation/devicetree/bindings/mmc/st,sdhci.yaml b/Documentation/devicetree/bindings/mmc/st,sdhci.yaml
> new file mode 100644
> index 0000000000000..0bf4fc3ca699f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/st,sdhci.yaml

[ ... ]

> +allOf:
> +  - $ref: mmc-controller.yaml#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: st,sdhci
> +      - items:
> +          - const: st,sdhci-stih407
> +          - const: st,sdhci

[Severity: Medium]
Is this a regression from the strict constraints of the text binding?

The original text binding restricted max-frequency to 200000000, 100000000,
or 50000000, which matches the driver's behavior in sdhci-st.c. Since this
new YAML schema omits max-frequency entirely, it falls back to the generic
mmc-controller.yaml which permits any integer.

Should this explicitly define max-frequency under properties with an enum
constraint to prevent unsupported frequencies from passing validation and
silently falling back to 50MHz at runtime?

> +
> +  reg:
> +    minItems: 1
> +    items:
> +      - description: MMC controller base registers
> +      - description: FlashSS Top registers for TX/RX DLL delay configuration
> +
> +  reg-names:
> +    minItems: 1
> +    items:
> +      - const: mmc
> +      - const: top-mmc-delay

[Severity: Medium]
Does this omission create a regression where the schema validation silently
accepts an invalid device tree?

The previous text binding explicitly stated that if the FlashSS Top register
is provided, reg-names must also be specified.

Without an allOf conditional block making reg-names required when the reg
property contains two items, won't the schema validation pass even if
reg-names is missing? If the driver relies on
devm_platform_ioremap_resource_byname() for top-mmc-delay, could this result
in a silent runtime misconfiguration?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260613-st-mmc-v4-0-b3c385617c16@gmail.com?part=2

Re: [PATCH v4 1/2] arm: dts: st: align node patterns with established convention

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Renaming 'sdhci@...' nodes to 'mmc@...' in the base dtsi file leaves overrides in derived dtsi and dts files orphaned, causing node duplication and completely breaking MMC functionality.
--

commit 40b6fa41749cf01adbee4227ca47061d9fbb6688
Author: Charan Pedumuru <charan.pedumuru@gmail.com>

arm: dts: st: align node patterns with established convention

This commit updates ST MMC DTS node patterns to match established convention
by renaming the base sdhci nodes to mmc.

> diff --git a/arch/arm/boot/dts/st/stih407-family.dtsi b/arch/arm/boot/dts/st/stih407-family.dtsi
> index 3e6a0542e3aea..08acba209c564 100644
> --- a/arch/arm/boot/dts/st/stih407-family.dtsi
> +++ b/arch/arm/boot/dts/st/stih407-family.dtsi
> @@ -596,7 +596,7 @@ spi@9542000 {
>  			status = "disabled";
>  		};
>  
> -		mmc0: sdhci@9060000 {
> +		mmc0: mmc@9060000 {

[Severity: High]
Does renaming these base nodes to mmc@... leave downstream overrides
orphaned?

Looking at board files like arch/arm/boot/dts/st/stih410-b2260.dts and
arch/arm/boot/dts/st/stih418-b2199.dts, there are still overrides using
the old names:

mmc0: sdhci@9060000 {
        pinctrl-0 = <&pinctrl_sd0>;
        bus-width = <4>;
        status = "okay";
};

Because the base node is renamed here without updating the downstream files,
will the DTC compiler treat the downstream overrides as new node declarations
rather than property merges?

This would leave the base mmc@9060000 node disabled, while the new
sdhci@9060000 node would lack essential properties like compatible and reg,
preventing the kernel from binding the MMC driver to the hardware.

>  			compatible = "st,sdhci-stih407", "st,sdhci";
>  			status = "disabled";
>  			reg = <0x09060000 0x7ff>, <0x9061008 0x20>;

[ ... ]

> -		mmc1: sdhci@9080000 {
> +		mmc1: mmc@9080000 {

[Severity: High]
Are there similar orphaned overrides for this node?

Checking arch/arm/boot/dts/st/stih418-b2199.dts, it appears this node is
also overridden using the old name:

mmc1: sdhci@9080000 {
        status = "okay";
};

Would this result in the same missing compatible properties and disabled
base node?

>  			compatible = "st,sdhci-stih407", "st,sdhci";
>  			status = "disabled";
>  			reg = <0x09080000 0x7ff>;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260613-st-mmc-v4-0-b3c385617c16@gmail.com?part=1