[PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[pkunapuli@nvidia.com (Pavan Kunapuli)]

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 <pkunapuli@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;
 	}
 	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
 		regulator_enable(host->vqmmc);
@@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
 
 	ocr_avail = 0;
 
+	/*
+	 * vmmc regulator should be present. If it's not present,
+	 * assume the regulator driver registration is not yet done
+	 * and defer the probe.
+	 */
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
 	if (IS_ERR(host->vmmc)) {
-		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
+		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
 		host->vmmc = NULL;
+		ret = -EPROBE_DEFER;
+		goto vmmc_err;
 	} else
 		regulator_enable(host->vmmc);
 
@@ -3121,7 +3134,13 @@ reset:
 untasklet:
 	tasklet_kill(&host->card_tasklet);
 	tasklet_kill(&host->finish_tasklet);
+vmmc_err:
+	if (host->vqmmc) {
+		if (regulator_is_enabled(host->vqmmc))
+			regulator_disable(host->vqmmc);
 
+		regulator_put(host->vqmmc);
+	}
 	return ret;
 }
 
-- 
1.7.1.1