[PATCH v3 1/2] mmc: host: dw_mmc: support setting f_min from host drivers

[Ulf Hansson]

On Sat, 5 Mar 2022 at 22:58, Peter Geis <pgwipeout at gmail.com> wrote:
>
> Host drivers may not be able to support frequencies as low as dw-mmc
> supports. Unfortunately f_min isn't available when the drv_data->init
> function is called, as the mmc_host struct hasn't been set up yet.
>
> Support the host drivers saving the requested minimum frequency, so we
> can later set f_min when it is available.
>
> Signed-off-by: Peter Geis <pgwipeout at gmail.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/dw_mmc.c | 7 ++++++-
>  drivers/mmc/host/dw_mmc.h | 2 ++
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 42bf8a2287ba..0d90d0201759 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2898,7 +2898,12 @@ static int dw_mci_init_slot_caps(struct dw_mci_slot *slot)
>         if (host->pdata->caps2)
>                 mmc->caps2 = host->pdata->caps2;
>
> -       mmc->f_min = DW_MCI_FREQ_MIN;
> +       /* if host has set a minimum_freq, we should respect it */
> +       if (host->minimum_speed)
> +               mmc->f_min = host->minimum_speed;
> +       else
> +               mmc->f_min = DW_MCI_FREQ_MIN;
> +
>         if (!mmc->f_max)
>                 mmc->f_max = DW_MCI_FREQ_MAX;
>
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 7f1e38621d13..4ed81f94f7ca 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -99,6 +99,7 @@ struct dw_mci_dma_slave {
>   * @bus_hz: The rate of @mck in Hz. This forms the basis for MMC bus
>   *     rate and timeout calculations.
>   * @current_speed: Configured rate of the controller.
> + * @minimum_speed: Stored minimum rate of the controller.
>   * @fifoth_val: The value of FIFOTH register.
>   * @verid: Denote Version ID.
>   * @dev: Device associated with the MMC controller.
> @@ -201,6 +202,7 @@ struct dw_mci {
>
>         u32                     bus_hz;
>         u32                     current_speed;
> +       u32                     minimum_speed;
>         u32                     fifoth_val;
>         u16                     verid;
>         struct device           *dev;
> --
> 2.25.1
>