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SubjectRe: [PATCH 8/9] mmc: mmci: sdmmc: add voltage switch functions
On Fri, 10 Jan 2020 at 14:49, Ludovic Barre <ludovic.barre@st.com> wrote:
>
> To prepare the voltage switch procedure, the VSWITCHEN bit must be
> set before sending the cmd11.
> To confirm completion of voltage switch, the VSWEND flag must be
> checked.
>
> Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
> ---
> drivers/mmc/host/mmci.h | 4 +++
> drivers/mmc/host/mmci_stm32_sdmmc.c | 40 ++++++++++++++++++++++++++++-
> 2 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> index c04a144259a2..3634f98ad2d8 100644
> --- a/drivers/mmc/host/mmci.h
> +++ b/drivers/mmc/host/mmci.h
> @@ -165,6 +165,7 @@
> /* Extended status bits for the STM32 variants */
> #define MCI_STM32_BUSYD0 BIT(20)
> #define MCI_STM32_BUSYD0END BIT(21)
> +#define MCI_STM32_VSWEND BIT(25)
>
> #define MMCICLEAR 0x038
> #define MCI_CMDCRCFAILCLR (1 << 0)
> @@ -182,6 +183,9 @@
> #define MCI_ST_SDIOITC (1 << 22)
> #define MCI_ST_CEATAENDC (1 << 23)
> #define MCI_ST_BUSYENDC (1 << 24)
> +/* Extended clear bits for the STM32 variants */
> +#define MCI_STM32_VSWENDC BIT(25)
> +#define MCI_STM32_CKSTOPC BIT(26)
>
> #define MMCIMASK0 0x03c
> #define MCI_CMDCRCFAILMASK (1 << 0)
> diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
> index 10059fa19f4a..9f43cf947c5f 100644
> --- a/drivers/mmc/host/mmci_stm32_sdmmc.c
> +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
> @@ -263,7 +263,9 @@ static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
> struct mmc_ios ios = host->mmc->ios;
> struct sdmmc_dlyb *dlyb = host->variant_priv;
>
> - pwr = host->pwr_reg_add;
> + /* adds OF options and preserves voltage switch bits */
> + pwr = host->pwr_reg_add |
> + (host->pwr_reg & (MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
>
> sdmmc_dlyb_input_ck(dlyb);
>
> @@ -454,6 +456,40 @@ static int sdmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
> return sdmmc_dlyb_phase_tuning(host, opcode);
> }
>
> +static void sdmmc_prep_vswitch(struct mmci_host *host)
> +{
> + /* clear the voltage switch completion flag */
> + writel_relaxed(MCI_STM32_VSWENDC, host->base + MMCICLEAR);
> + /* enable Voltage switch procedure */
> + mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCHEN);
> +}
> +
> +static int sdmmc_vswitch(struct mmci_host *host, struct mmc_ios *ios)
> +{
> + unsigned long flags;
> + u32 status;
> + int ret = 0;
> +
> + if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
> + spin_lock_irqsave(&host->lock, flags);
> + mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + /* wait voltage switch completion while 10ms */
> + ret = readl_relaxed_poll_timeout(host->base + MMCISTATUS,
> + status,
> + (status & MCI_STM32_VSWEND),
> + 10, 10000);
> +
> + writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
> + host->base + MMCICLEAR);
> + mmci_write_pwrreg(host, host->pwr_reg &
> + ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
> + }

Don't you need to manage things when resetting to
MMC_SIGNAL_VOLTAGE_330, which for example happens during a card
removal or at system suspend/resume?

> +
> + return ret;
> +}
> +
> static struct mmci_host_ops sdmmc_variant_ops = {
> .validate_data = sdmmc_idma_validate_data,
> .prep_data = sdmmc_idma_prep_data,
> @@ -465,6 +501,8 @@ static struct mmci_host_ops sdmmc_variant_ops = {
> .set_clkreg = mmci_sdmmc_set_clkreg,
> .set_pwrreg = mmci_sdmmc_set_pwrreg,
> .busy_complete = sdmmc_busy_complete,
> + .prep_volt_switch = sdmmc_prep_vswitch,
> + .volt_switch = sdmmc_vswitch,
> };
>
> void sdmmc_variant_init(struct mmci_host *host)
> --
> 2.17.1
>

Kind regards
Uffe

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