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[PATCH 03/10] mmc: sdhci-of-k1: add regulator framework support

Iker Pedrosa posted 10 patches 1 month, 1 week ago
There is a newer version of this series
[PATCH 03/10] mmc: sdhci-of-k1: add regulator framework support
Posted by Iker Pedrosa 1 month, 1 week ago 
Add regulator framework support for voltage switching operations. This
enables proper PMIC control for UHS voltage switching between 3.3V and
1.8V signaling levels.

- Add regulator supply parsing
- Implement voltage switching callback
- Enable mmc regulator framework integration

Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
 drivers/mmc/host/sdhci-of-k1.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index b703b78282ed8d89183c816477c149c0a565618a..c260cb89704ae7a25bec0f07831d495553405bbd 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -216,6 +216,12 @@ static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
 			       SPACEMIT_SDHC_PHY_CTRL_REG);
 }
 
+static int spacemit_sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
+						      struct mmc_ios *ios)
+{
+	return sdhci_start_signal_voltage_switch(mmc, ios);
+}
+
 static inline int spacemit_sdhci_get_clocks(struct device *dev,
 					    struct sdhci_pltfm_host *pltfm_host)
 {
@@ -291,6 +297,12 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
 
 	host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
 
+	ret = mmc_regulator_get_supply(host->mmc);
+	if (ret)
+		dev_warn(dev, "Failed to get regulators: %d\n", ret);
+
+	host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
+
 	ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
 	if (ret)
 		goto err_pltfm;

-- 
2.53.0
Re: [PATCH 03/10] mmc: sdhci-of-k1: add regulator framework support
Posted by Yixun Lan 1 month ago 
Hi IKer,

On 16:13 Mon 02 Mar     , Iker Pedrosa wrote:
> Add regulator framework support for voltage switching operations. This
> enables proper PMIC control for UHS voltage switching between 3.3V and
> 1.8V signaling levels.
> 
> - Add regulator supply parsing
> - Implement voltage switching callback
> - Enable mmc regulator framework integration
> 
> Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> ---
>  drivers/mmc/host/sdhci-of-k1.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> index b703b78282ed8d89183c816477c149c0a565618a..c260cb89704ae7a25bec0f07831d495553405bbd 100644
> --- a/drivers/mmc/host/sdhci-of-k1.c
> +++ b/drivers/mmc/host/sdhci-of-k1.c
> @@ -216,6 +216,12 @@ static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
>  			       SPACEMIT_SDHC_PHY_CTRL_REG);
>  }
>  
> +static int spacemit_sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
> +						      struct mmc_ios *ios)
> +{
> +	return sdhci_start_signal_voltage_switch(mmc, ios);
> +}
I'd suggest to implement voltage_switch() instead of start_signal_voltage_switch(),
and put the pinctrl state switch here, which will be called by
start_signal_voltage_switch(), see drivers/mmc/host/sdhci.c for more detail

sdhci_start_signal_voltage_switch() -> voltage_switch()

static const struct sdhci_ops spacemit_sdhci_ops = {
..
	.voltage_switch         = spacemit_sdhci_voltage_switch,
..

> +
>  static inline int spacemit_sdhci_get_clocks(struct device *dev,
>  					    struct sdhci_pltfm_host *pltfm_host)
>  {
> @@ -291,6 +297,12 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
>  
>  	host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
>  
..
> +	ret = mmc_regulator_get_supply(host->mmc);
I think this is unnecessary which already handled in core framework, see
spacemit_sdhci_probbe() -> sdhci_add_host() -> sdhci_setup_host()

https://github.com/torvalds/linux/blob/v7.0-rc3/drivers/mmc/host/sdhci.c#L4289

> +	if (ret)
> +		dev_warn(dev, "Failed to get regulators: %d\n", ret);
> +
> +	host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
> +
with above, this line can be dropped too

>  	ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
>  	if (ret)
>  		goto err_pltfm;
> 
> -- 
> 2.53.0
> 

-- 
Yixun Lan (dlan)
Re: [PATCH 03/10] mmc: sdhci-of-k1: add regulator framework support
Posted by Yao Zi 1 month, 1 week ago 
On Mon, Mar 02, 2026 at 04:13:24PM +0100, Iker Pedrosa wrote:
> Add regulator framework support for voltage switching operations. This
> enables proper PMIC control for UHS voltage switching between 3.3V and
> 1.8V signaling levels.
> 
> - Add regulator supply parsing
> - Implement voltage switching callback
> - Enable mmc regulator framework integration
> 
> Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> ---
>  drivers/mmc/host/sdhci-of-k1.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

It seems PATCH 4 should be squashed into this one, or the functionality
of voltage switching isn't really complete.

> diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> index b703b78282ed8d89183c816477c149c0a565618a..c260cb89704ae7a25bec0f07831d495553405bbd 100644
> --- a/drivers/mmc/host/sdhci-of-k1.c
> +++ b/drivers/mmc/host/sdhci-of-k1.c

...

> @@ -291,6 +297,12 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
>  
>  	host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
>  
> +	ret = mmc_regulator_get_supply(host->mmc);
> +	if (ret)
> +		dev_warn(dev, "Failed to get regulators: %d\n", ret);
> +
> +	host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;

Why not assign start_signal_voltage_switch in the declaration of
spacemit_sdhci_ops?

>  	ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
>  	if (ret)
>  		goto err_pltfm;
> 
> -- 
> 2.53.0

Best regards,
Yao Zi
Re: [PATCH 03/10] mmc: sdhci-of-k1: add regulator framework support
Posted by Iker Pedrosa 1 month ago 
El mar, 3 mar 2026 a las 5:11, Yao Zi (<me@ziyao.cc>) escribió:
>
> On Mon, Mar 02, 2026 at 04:13:24PM +0100, Iker Pedrosa wrote:
> > Add regulator framework support for voltage switching operations. This
> > enables proper PMIC control for UHS voltage switching between 3.3V and
> > 1.8V signaling levels.
> >
> > - Add regulator supply parsing
> > - Implement voltage switching callback
> > - Enable mmc regulator framework integration
> >
> > Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> > ---
> >  drivers/mmc/host/sdhci-of-k1.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
>
> It seems PATCH 4 should be squashed into this one, or the functionality
> of voltage switching isn't really complete.

That makes sense. I'm still learning the best way to structure these
series for the kernel, so I appreciate the guidance. I'll squash patch
4 into this one for v2 to ensure the voltage switching logic is
atomic.

>
> > diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> > index b703b78282ed8d89183c816477c149c0a565618a..c260cb89704ae7a25bec0f07831d495553405bbd 100644
> > --- a/drivers/mmc/host/sdhci-of-k1.c
> > +++ b/drivers/mmc/host/sdhci-of-k1.c
>
> ...
>
> > @@ -291,6 +297,12 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
> >
> >       host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
> >
> > +     ret = mmc_regulator_get_supply(host->mmc);
> > +     if (ret)
> > +             dev_warn(dev, "Failed to get regulators: %d\n", ret);
> > +
> > +     host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
>
> Why not assign start_signal_voltage_switch in the declaration of
> spacemit_sdhci_ops?

You're right, that’s much cleaner. I'll move the assignment into the
spacemit_sdhci_ops declaration for v2. Thanks for the suggestion!

>
> >       ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
> >       if (ret)
> >               goto err_pltfm;
> >
> > --
> > 2.53.0
>
> Best regards,
> Yao Zi
>

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