On 22 September 2017 at 13:22, Fabrizio Castro
<fabrizio.castro@xxxxxxxxxxxxxx> wrote:
> mmc_regulator_get_supply returns -EPROBE_DEFER if either vmmc or
> vqmmc regulators had their probing deferred.
> vqmmc regulator is needed by UHS to work properly, therefore this
> patch checks the value returned by mmc_regulator_get_supply to
> make sure we have a reference to both vmmc and vqmmc (if found in
> the DT).
>
> Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx>
Thanks, applied for next!
Kind regards
Uffe
> ---
>
> I believe this patch is in order for UHS to work properly on the RZ/G1 platforms
> as the signal voltage needs to be switched from 3.3V to 1.8V, and therefore we
> need to make sure we hold a reference to vqmmc. Without this patch there is a
> chance that the regulator driver gets probed later on and therefore we end up
> without control over the power regulator. I have seen an RZ/G1E based platform
> failing the transition to UHS because of this.
> However, there are side effects to it as the mmc devices will be enumerated
> in a different order (due to -EPROBE_DEFER), this means this patch would likely
> break existing platforms.
> Please, let me know your comments.
>
> drivers/mmc/host/tmio_mmc_core.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
> index 88a9435..3df0413 100644
> --- a/drivers/mmc/host/tmio_mmc_core.c
> +++ b/drivers/mmc/host/tmio_mmc_core.c
> @@ -1153,8 +1153,11 @@ static int tmio_mmc_init_ocr(struct tmio_mmc_host *host)
> {
> struct tmio_mmc_data *pdata = host->pdata;
> struct mmc_host *mmc = host->mmc;
> + int err;
>
> - mmc_regulator_get_supply(mmc);
> + err = mmc_regulator_get_supply(mmc);
> + if (err)
> + return err;
>
> /* use ocr_mask if no regulator */
> if (!mmc->ocr_avail)
> --
> 2.7.4
>
