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

Yixun Lan
2026-03-09T06:34:25Z

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)