On Friday 07 of June 2013 10:28:29 Doug Anderson wrote:
> It is possible to specify a regulator that should be turned on when
> dw_mmc is probed.  At the moment dw_mmc will fail to use the regulator
> properly if the regulator probes after dw_mmc.  Fix this problem by
> honoring EPROBE_DEFER.
> 
> At the same time move the regulator code out of the slot init code.
> We only specify one regulator for the whole device

A question just out of curiousity: Is it really correct to have one vmmc 
regulator for the whole device, instead of one regulator per slot?

This might be something obvious, but I don't know any details about 
dw_mmc, so sorry if it's the case.

Best regards,
Tomasz

> and other parts of
> the code (like suspend/resume) assume that the regulator has only been
> enabled once.
> 
> Signed-off-by: Doug Anderson <diand...@chromium.org>
> ---
> Changes in v2:
> - Avoid hackery to detect regulators that will never show up.
> - Move regulator out of slot init--it doesn't belong there.
> 
>  .../devicetree/bindings/mmc/synopsis-dw-mshc.txt   |  4 +++
>  drivers/mmc/host/dw_mmc.c                          | 40
> ++++++++++++---------- 2 files changed, 25 insertions(+), 19
> deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt index
> 726fd21..d5cc94e 100644
> --- a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> @@ -55,6 +55,9 @@ Optional properties:
> 
>  * broken-cd: as documented in mmc core bindings.
> 
> +* vmmc-supply: The phandle to the regulator to use for vmmc.  If this
> is +  specified we'll defer probe until we can find this regulator. +
>  Aliases:
> 
>  - All the MSHC controller nodes should be represented in the aliases
> node using @@ -79,6 +82,7 @@ board specific portions as listed below.
>               broken-cd;
>               fifo-depth = <0x80>;
>               card-detect-delay = <200>;
> +             vmmc-supply = <&buck8>;
> 
>               slot@0 {
>                       reg = <0>;
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index bc3a1bc..ab5642d 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1895,7 +1895,7 @@ static int dw_mci_init_slot(struct dw_mci *host,
> unsigned int id) struct mmc_host *mmc;
>       struct dw_mci_slot *slot;
>       const struct dw_mci_drv_data *drv_data = host->drv_data;
> -     int ctrl_id, ret;
> +     int ctrl_id;
>       u8 bus_width;
> 
>       mmc = mmc_alloc_host(sizeof(struct dw_mci_slot), host->dev);
> @@ -1985,19 +1985,6 @@ static int dw_mci_init_slot(struct dw_mci *host,
> unsigned int id) #endif /* CONFIG_MMC_DW_IDMAC */
>       }
> 
> -     host->vmmc = devm_regulator_get(mmc_dev(mmc), "vmmc");
> -     if (IS_ERR(host->vmmc)) {
> -             pr_info("%s: no vmmc regulator found\n", 
mmc_hostname(mmc));
> -             host->vmmc = NULL;
> -     } else {
> -             ret = regulator_enable(host->vmmc);
> -             if (ret) {
> -                     dev_err(host->dev,
> -                             "failed to enable regulator: %d\n", ret);
> -                     goto err_setup_bus;
> -             }
> -     }
> -
>       if (dw_mci_get_cd(mmc))
>               set_bit(DW_MMC_CARD_PRESENT, &slot->flags);
>       else
> @@ -2023,10 +2010,6 @@ static int dw_mci_init_slot(struct dw_mci *host,
> unsigned int id) queue_work(host->card_workqueue, &host->card_work);
> 
>       return 0;
> -
> -err_setup_bus:
> -     mmc_free_host(mmc);
> -     return -EINVAL;
>  }
> 
>  static void dw_mci_cleanup_slot(struct dw_mci_slot *slot, unsigned int
> id) @@ -2229,11 +2212,29 @@ int dw_mci_probe(struct dw_mci *host)
>               }
>       }
> 
> +     host->vmmc = devm_regulator_get(host->dev, "vmmc");
> +     if (IS_ERR(host->vmmc)) {
> +             ret = PTR_ERR(host->vmmc);
> +             if (ret == -EPROBE_DEFER)
> +                     goto err_clk_ciu;
> +
> +             dev_info(host->dev, "no vmmc regulator found: %d\n", ret);
> +             host->vmmc = NULL;
> +     } else {
> +             ret = regulator_enable(host->vmmc);
> +             if (ret) {
> +                     if (ret != -EPROBE_DEFER)
> +                             dev_err(host->dev,
> +                                     "regulator_enable fail: %d\n", 
ret);
> +                     goto err_clk_ciu;
> +             }
> +     }
> +
>       if (!host->bus_hz) {
>               dev_err(host->dev,
>                       "Platform data must supply bus speed\n");
>               ret = -ENODEV;
> -             goto err_clk_ciu;
> +             goto err_regulator;
>       }
> 
>       host->quirks = host->pdata->quirks;
> @@ -2378,6 +2379,7 @@ err_dmaunmap:
>       if (host->use_dma && host->dma_ops->exit)
>               host->dma_ops->exit(host);
> 
> +err_regulator:
>       if (host->vmmc)
>               regulator_disable(host->vmmc);
--
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