[PATCH] mmc: mmci: stm32: check when the voltage switch procedure should be done

[Ulf Hansson]

On Thu, 1 Jul 2021 at 16:34, Yann Gautier <yann.gautier at foss.st.com> wrote:
>
> From: Christophe Kerello <christophe.kerello at foss.st.com>
>
> If the card has not been power cycled, it may still be using 1.8V
> signaling. This situation is detected in mmc_sd_init_card function and
> should be handled in mmci stm32 variant.
> The host->pwr_reg variable is also correctly protected with spin locks.
>
> Fixes: 94b94a93e355 ("mmc: mmci_sdmmc: Implement signal voltage callbacks")
>
> Signed-off-by: Christophe Kerello <christophe.kerello at foss.st.com>
> Signed-off-by: Yann Gautier <yann.gautier at foss.st.com>

Applied for fixes and by adding stable tag, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/mmci_stm32_sdmmc.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
> index 51db30acf4dc..fdaa11f92fe6 100644
> --- a/drivers/mmc/host/mmci_stm32_sdmmc.c
> +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
> @@ -479,8 +479,9 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
>         u32 status;
>         int ret = 0;
>
> -       if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
> -               spin_lock_irqsave(&host->lock, flags);
> +       spin_lock_irqsave(&host->lock, flags);
> +       if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 &&
> +           host->pwr_reg & MCI_STM32_VSWITCHEN) {
>                 mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
>                 spin_unlock_irqrestore(&host->lock, flags);
>
> @@ -492,9 +493,11 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
>
>                 writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
>                                host->base + MMCICLEAR);
> +               spin_lock_irqsave(&host->lock, flags);
>                 mmci_write_pwrreg(host, host->pwr_reg &
>                                   ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
>         }
> +       spin_unlock_irqrestore(&host->lock, flags);
>
>         return ret;
>  }
> --
> 2.17.1
>