Re: [RFC PATCH v3.1 14/27] mmc: sdhci-uhs2: skip signal_voltage_switch()

Adrian Hunter
2020-11-26T08:17:35Z

On 6/11/20 4:27 am, AKASHI Takahiro wrote:
> For UHS2, the signal voltage is supplied by vdd2 which is already 1.8v,
> so no voltage switch required.
>
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
> drivers/mmc/host/sdhci-uhs2.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index 2bf78cc4e9ed..1eca89359351 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -178,6 +178,29 @@ void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> }
> EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);
>
> +/*****************************************************************************\
> + * *
> + * MMC callbacks *
> + * *
> +\*****************************************************************************/
> +
> +static int sdhci_uhs2_start_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> +
> + /*
> + * For UHS2, the signal voltage is supplied by vdd2 which is
> + * already 1.8v so no voltage switch required.
> + */
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->version >= SDHCI_SPEC_400 &&
> + host->mmc->flags & MMC_UHS2_SUPPORT)

Could this be the same helper function suggested elsewhere i.e.

if (!sdhci_uhs2_mode(host))

> + return 0;
> +
> + return sdhci_start_signal_voltage_switch(mmc, ios);
> +}
> +
> /*****************************************************************************\
> * *
> * Driver init/exit *
> @@ -186,6 +209,9 @@ EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);
>
> static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
> {
> + host->mmc_host_ops.start_signal_voltage_switch =
> + sdhci_uhs2_start_signal_voltage_switch;
> +
> return 0;
> }
>
>