On 10/23/2012 01:18 AM, Pavan Kunapuli wrote:
> vmmc and vqmmc regulators control the voltage to
> the host and device. Defer the probe if either of
> them is not registered.
>
> Signed-off-by: Pavan Kunapuli <pkunap...@nvidia.com>
> ---
> drivers/mmc/host/sdhci.c | 25 ++++++++++++++++++++++---
> 1 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
> !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
> mmc->caps |= MMC_CAP_NEEDS_POLL;
>
> - /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> + /*
> + * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> + * vqmmc regulator should be present. If it's not present,
> + * assume the regulator driver registration is not yet done and
> + * defer the probe.
> + */
> host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
> if (IS_ERR(host->vqmmc)) {
> - pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> + pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> host->vqmmc = NULL;
> + return -EPROBE_DEFER;
> }
Right now, the regulator is optional, and any failure to acquire the
regulator is just ignored.
Instead, I think the behaviour we want is:
Attempt to get regulator.
1) If no error -> OK
2) If deferred probe error -> return -EPROBE_DEFER
3) If any other error -> ignore it
Assuming that regulator_get() can explicitly detect and return the
difference between cases (1) and (2) above. If it can't, it seems like
it should be able to.
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