[PATCH RFC v2 0/2] mmc: sdhci-pxav3: pinctrl setting for fast bus clocks

[PATCH RFC v2 0/2] mmc: sdhci-pxav3: pinctrl setting for fast bus clocks

[Duje Mihanović]

Hello,

This small series adds a pinctrl setting for fast MMC bus clocks to the
pxav3 driver. On bus clocks above 100 MHz, driving the data pins at a
higher current helps maintain signal quality.

This series is related to Marvell PXA1908 SoC support; the latest
version of that patchset (v16 as of now) can be found at
https://lore.kernel.org/20250708-pxa1908-lkml-v16-0-b4392c484180@dujemihanovic.xyz

The series is RFC because of the following:
* I'm unsure whether setting pinctrl-{names,1} to true in the top level
  of the binding is correct.
* Other mainline MMC drivers select between default and UHS states based
  on the signal voltage. The PXA1908 vendor kernel does it based on the
  bus clock. I followed the vendor kernel, but do not know whether this
  is bad practice and therefore the other mainline drivers should be
  followed instead.

Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
---
Changes in v2:
- Address maintainer comments:
  - Newline between properties in if:
  - Don't try to lookup pinstates if pinctrl is NULL
  - Only change pinstates if both are valid
  - Replace dev_warn() with dev_dbg()
- Link to v1: https://lore.kernel.org/r/20250718-pxav3-uhs-v1-0-2e451256f1f6@dujemihanovic.xyz

---
Duje Mihanović (2):
      dt-bindings: mmc: sdhci-pxa: add state_uhs pinctrl
      mmc: sdhci-pxav3: add state_uhs pinctrl setting

 .../devicetree/bindings/mmc/sdhci-pxa.yaml         | 47 +++++++++++++++++-----
 drivers/mmc/host/sdhci-pxav3.c                     | 31 +++++++++++++-
 include/linux/platform_data/pxa_sdhci.h            |  7 ++++
 3 files changed, 74 insertions(+), 11 deletions(-)
---
base-commit: 038d61fd642278bab63ee8ef722c50d10ab01e8f
change-id: 20250718-pxav3-uhs-d956bfed13f0

Best regards,
-- 
Duje Mihanović <duje@dujemihanovic.xyz>

[PATCH RFC v2 1/2] dt-bindings: mmc: sdhci-pxa: add state_uhs pinctrl

[Duje Mihanović]

On the pxav3 controller, increasing the drive strength of the data pins
might be required to maintain stability on fast bus clocks (above 100
MHz). Add a state_uhs pinctrl to allow this.

The existing state_cmd_gpio pinctrl is changed to apply only on pxav1 as
it's unneeded on the other controllers.

Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
---
Changes in v2:
- Newlines between properties in if:
---
 .../devicetree/bindings/mmc/sdhci-pxa.yaml         | 47 +++++++++++++++++-----
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-pxa.yaml b/Documentation/devicetree/bindings/mmc/sdhci-pxa.yaml
index 4869ddef36fd89265a1bfe96bb9663b553ac5084..fba1cc50fdf07cc25d42f45512c385a9b8207b9b 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-pxa.yaml
+++ b/Documentation/devicetree/bindings/mmc/sdhci-pxa.yaml
@@ -30,6 +30,41 @@ allOf:
           maxItems: 1
         reg-names:
           maxItems: 1
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: mrvl,pxav1-mmc
+    then:
+      properties:
+        pinctrl-names:
+          description:
+            Optional for supporting PXA168 SDIO IRQ errata to switch CMD pin between
+            SDIO CMD and GPIO mode.
+          items:
+            - const: default
+            - const: state_cmd_gpio
+
+        pinctrl-1:
+          description:
+            Should switch CMD pin to GPIO mode as a high output.
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: mrvl,pxav3-mmc
+    then:
+      properties:
+        pinctrl-names:
+          description:
+            Optional for increasing stability of the controller at fast bus clocks.
+          items:
+            - const: default
+            - const: state_uhs
+
+        pinctrl-1:
+          description:
+            Should switch the drive strength of the data pins to high.
 
 properties:
   compatible:
@@ -62,21 +97,13 @@ properties:
       - const: io
       - const: core
 
-  pinctrl-names:
-    description:
-      Optional for supporting PXA168 SDIO IRQ errata to switch CMD pin between
-      SDIO CMD and GPIO mode.
-    items:
-      - const: default
-      - const: state_cmd_gpio
+  pinctrl-names: true
 
   pinctrl-0:
     description:
       Should contain default pinctrl.
 
-  pinctrl-1:
-    description:
-      Should switch CMD pin to GPIO mode as a high output.
+  pinctrl-1: true
 
   mrvl,clk-delay-cycles:
     description: Specify a number of cycles to delay for tuning.

-- 
2.50.1

Re: [PATCH RFC v2 1/2] dt-bindings: mmc: sdhci-pxa: add state_uhs pinctrl

[Rob Herring (Arm)]

On Fri, 01 Aug 2025 16:14:15 +0200, Duje Mihanović wrote:
> On the pxav3 controller, increasing the drive strength of the data pins
> might be required to maintain stability on fast bus clocks (above 100
> MHz). Add a state_uhs pinctrl to allow this.
> 
> The existing state_cmd_gpio pinctrl is changed to apply only on pxav1 as
> it's unneeded on the other controllers.
> 
> Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
> ---
> Changes in v2:
> - Newlines between properties in if:
> ---
>  .../devicetree/bindings/mmc/sdhci-pxa.yaml         | 47 +++++++++++++++++-----
>  1 file changed, 37 insertions(+), 10 deletions(-)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

[PATCH RFC v2 2/2] mmc: sdhci-pxav3: add state_uhs pinctrl setting

[Duje Mihanović]

Different bus clocks require different pinctrl states to remain stable.
Add support for selecting between a default and UHS state according to
the bus clock.

Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
---
Changes in v2:
- Don't attempt to lookup pinstates if getting pinctrl fails
- Only select pinstates if both of them are valid
- dev_warn() -> dev_dbg()
---
 drivers/mmc/host/sdhci-pxav3.c          | 31 ++++++++++++++++++++++++++++++-
 include/linux/platform_data/pxa_sdhci.h |  7 +++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
index 3fb56face3d81259b693c8569682d05c95be2880..fc6018de92fb19f028b776df0f87937846621e95 100644
--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -20,9 +20,11 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/mbus.h>
+#include <linux/units.h>
 
 #include "sdhci.h"
 #include "sdhci-pltfm.h"
@@ -313,8 +315,23 @@ static void pxav3_set_power(struct sdhci_host *host, unsigned char mode,
 		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
 }
 
+static void pxav3_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
+	struct sdhci_pxa_platdata *pdata = pdev->dev.platform_data;
+
+	if (!(IS_ERR(pdata->pinctrl) || IS_ERR(pdata->pins_default) || !IS_ERR(pdata->pins_uhs))) {
+		if (clock < 100 * HZ_PER_MHZ)
+			pinctrl_select_state(pdata->pinctrl, pdata->pins_default);
+		else
+			pinctrl_select_state(pdata->pinctrl, pdata->pins_uhs);
+	}
+
+	sdhci_set_clock(host, clock);
+}
+
 static const struct sdhci_ops pxav3_sdhci_ops = {
-	.set_clock = sdhci_set_clock,
+	.set_clock = pxav3_set_clock,
 	.set_power = pxav3_set_power,
 	.platform_send_init_74_clocks = pxav3_gen_init_74_clocks,
 	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
@@ -441,6 +458,18 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
 			host->mmc->pm_caps |= pdata->pm_caps;
 	}
 
+	pdata->pinctrl = devm_pinctrl_get(dev);
+	if (!IS_ERR(pdata->pinctrl)) {
+		pdata->pins_default = pinctrl_lookup_state(pdata->pinctrl, "default");
+		if (IS_ERR(pdata->pins_default))
+			dev_dbg(dev, "could not get default state: %ld\n",
+					PTR_ERR(pdata->pins_default));
+		pdata->pins_uhs = pinctrl_lookup_state(pdata->pinctrl, "state_uhs");
+		if (IS_ERR(pdata->pins_uhs))
+			dev_dbg(dev, "could not get uhs state: %ld\n", PTR_ERR(pdata->pins_uhs));
+	} else
+		dev_dbg(dev, "could not get pinctrl handle: %ld\n", PTR_ERR(pdata->pinctrl));
+
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, PXAV3_RPM_DELAY_MS);
diff --git a/include/linux/platform_data/pxa_sdhci.h b/include/linux/platform_data/pxa_sdhci.h
index 899457cee425d33f82606f0b8c280003bc73d48d..540aa36db11243719707bdf22db23a8e2035674d 100644
--- a/include/linux/platform_data/pxa_sdhci.h
+++ b/include/linux/platform_data/pxa_sdhci.h
@@ -35,6 +35,9 @@
  * @quirks: quirks of platfrom
  * @quirks2: quirks2 of platfrom
  * @pm_caps: pm_caps of platfrom
+ * @pinctrl: pinctrl handle
+ * @pins_default: default pinctrl state
+ * @pins_uhs: pinctrl state for fast (>100 MHz) bus clocks
  */
 struct sdhci_pxa_platdata {
 	unsigned int	flags;
@@ -47,5 +50,9 @@ struct sdhci_pxa_platdata {
 	unsigned int	quirks;
 	unsigned int	quirks2;
 	unsigned int	pm_caps;
+
+	struct pinctrl	     *pinctrl;
+	struct pinctrl_state *pins_default;
+	struct pinctrl_state *pins_uhs;
 };
 #endif /* _PXA_SDHCI_H_ */

-- 
2.50.1

Re: [PATCH RFC v2 2/2] mmc: sdhci-pxav3: add state_uhs pinctrl setting

[Adrian Hunter]

On 01/08/2025 17:14, Duje Mihanović wrote:
> Different bus clocks require different pinctrl states to remain stable.
> Add support for selecting between a default and UHS state according to
> the bus clock.
> 
> Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
> ---
> Changes in v2:
> - Don't attempt to lookup pinstates if getting pinctrl fails
> - Only select pinstates if both of them are valid
> - dev_warn() -> dev_dbg()
> ---
>  drivers/mmc/host/sdhci-pxav3.c          | 31 ++++++++++++++++++++++++++++++-
>  include/linux/platform_data/pxa_sdhci.h |  7 +++++++
>  2 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
> index 3fb56face3d81259b693c8569682d05c95be2880..fc6018de92fb19f028b776df0f87937846621e95 100644
> --- a/drivers/mmc/host/sdhci-pxav3.c
> +++ b/drivers/mmc/host/sdhci-pxav3.c
> @@ -20,9 +20,11 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/pm.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/mbus.h>
> +#include <linux/units.h>
>  
>  #include "sdhci.h"
>  #include "sdhci-pltfm.h"
> @@ -313,8 +315,23 @@ static void pxav3_set_power(struct sdhci_host *host, unsigned char mode,
>  		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
>  }
>  
> +static void pxav3_set_clock(struct sdhci_host *host, unsigned int clock)
> +{
> +	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
> +	struct sdhci_pxa_platdata *pdata = pdev->dev.platform_data;
> +
> +	if (!(IS_ERR(pdata->pinctrl) || IS_ERR(pdata->pins_default) || !IS_ERR(pdata->pins_uhs))) {
> +		if (clock < 100 * HZ_PER_MHZ)
> +			pinctrl_select_state(pdata->pinctrl, pdata->pins_default);
> +		else
> +			pinctrl_select_state(pdata->pinctrl, pdata->pins_uhs);
> +	}
> +
> +	sdhci_set_clock(host, clock);
> +}

Really pinctrl et al should be in struct sdhci_pxa not pdata.  Also
it is neater to set pinctrl_state pointers to NULL when there is no
valid value, so this could become:

static void pxav3_set_clock(struct sdhci_host *host, unsigned int clock)
{
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct sdhci_pxa *pxa = sdhci_pltfm_priv(pltfm_host);
	struct pinctrl_state *pins = clock < 100 * HZ_PER_MHZ ? pxa->pins_default : pxa->pins_uhs;

	if (pins)
		pinctrl_select_state(pxa->pinctrl, pins);

	sdhci_set_clock(host, clock);
}

> +
>  static const struct sdhci_ops pxav3_sdhci_ops = {
> -	.set_clock = sdhci_set_clock,
> +	.set_clock = pxav3_set_clock,
>  	.set_power = pxav3_set_power,
>  	.platform_send_init_74_clocks = pxav3_gen_init_74_clocks,
>  	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
> @@ -441,6 +458,18 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
>  			host->mmc->pm_caps |= pdata->pm_caps;
>  	}
>  
> +	pdata->pinctrl = devm_pinctrl_get(dev);
> +	if (!IS_ERR(pdata->pinctrl)) {
> +		pdata->pins_default = pinctrl_lookup_state(pdata->pinctrl, "default");
> +		if (IS_ERR(pdata->pins_default))
> +			dev_dbg(dev, "could not get default state: %ld\n",
> +					PTR_ERR(pdata->pins_default));
> +		pdata->pins_uhs = pinctrl_lookup_state(pdata->pinctrl, "state_uhs");
> +		if (IS_ERR(pdata->pins_uhs))
> +			dev_dbg(dev, "could not get uhs state: %ld\n", PTR_ERR(pdata->pins_uhs));
> +	} else
> +		dev_dbg(dev, "could not get pinctrl handle: %ld\n", PTR_ERR(pdata->pinctrl));
> +

To make the code neater, perhaps add a helper like:

static struct pinctrl_state *pxav3_pinctrl_state(struct device *dev, struct pinctrl *pinctrl,
						 const char *name)
{
	struct pinctrl_state *pins = pinctrl_lookup_state(pinctrl, name);

	if (IS_ERR(pins)) {
		dev_dbg(dev, "could not get pinctrl state '%s', error %ld\n", name, PTR_ERR(pins));
		return NULL;
	}

	return pins;
}

Then it could be like:

	pxa->pinctrl = devm_pinctrl_get(dev);
	if (IS_ERR(pxa->pinctrl)) {
		dev_dbg(dev, "could not get pinctrl handle: %ld\n", PTR_ERR(pxa->pinctrl));
	} else {
		pxa->pins_default = pxav3_pinctrl_state(dev, pxa->pinctrl, "default");
		if (pxa->pins_default)
			pxa->pins_uhs = pxav3_pinctrl_state(dev, pxa->pinctrl, "state_uhs");
	}

>  	pm_runtime_get_noresume(&pdev->dev);
>  	pm_runtime_set_active(&pdev->dev);
>  	pm_runtime_set_autosuspend_delay(&pdev->dev, PXAV3_RPM_DELAY_MS);
> diff --git a/include/linux/platform_data/pxa_sdhci.h b/include/linux/platform_data/pxa_sdhci.h
> index 899457cee425d33f82606f0b8c280003bc73d48d..540aa36db11243719707bdf22db23a8e2035674d 100644
> --- a/include/linux/platform_data/pxa_sdhci.h
> +++ b/include/linux/platform_data/pxa_sdhci.h
> @@ -35,6 +35,9 @@
>   * @quirks: quirks of platfrom
>   * @quirks2: quirks2 of platfrom
>   * @pm_caps: pm_caps of platfrom
> + * @pinctrl: pinctrl handle
> + * @pins_default: default pinctrl state
> + * @pins_uhs: pinctrl state for fast (>100 MHz) bus clocks
>   */
>  struct sdhci_pxa_platdata {
>  	unsigned int	flags;
> @@ -47,5 +50,9 @@ struct sdhci_pxa_platdata {
>  	unsigned int	quirks;
>  	unsigned int	quirks2;
>  	unsigned int	pm_caps;
> +
> +	struct pinctrl	     *pinctrl;
> +	struct pinctrl_state *pins_default;
> +	struct pinctrl_state *pins_uhs;

Move to struct sdhci_pxa

>  };
>  #endif /* _PXA_SDHCI_H_ */
>