linux-kernel - [PATCH AUTOSEL 4.9 15/34] mmc: sdhci: do not try to use 3.3V signaling if not supported

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Message-ID: <20180915013422.180023-15-alexander.levin@microsoft.com>
Date:   Sat, 15 Sep 2018 01:34:34 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Stefan Agner <stefan@...er.ch>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.9 15/34] mmc: sdhci: do not try to use 3.3V
 signaling if not supported

From: Stefan Agner <stefan@...er.ch>

[ Upstream commit 1b5190c2e74c47ebe4bcecf7a072358ad9f1feaa ]

For eMMC devices it is valid to only support 1.8V signaling. When
vqmmc is set to a fixed 1.8V regulator the stack tries to set 3.3V
initially and prints the following warning:
   mmc1: Switching to 3.3V signalling voltage failed

Clear the MMC_SIGNAL_VOLTAGE_330 flag in case 3.3V is signaling is
not available. This prevents the stack from even trying to use
3.3V signaling and avoids the above warning.

Signed-off-by: Stefan Agner <stefan@...er.ch>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/mmc/host/sdhci.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 44ea9d88651f..6bf58d27b6fc 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3328,14 +3328,21 @@ int sdhci_setup_host(struct sdhci_host *host)
 	    mmc_gpio_get_cd(host->mmc) < 0)
 		mmc->caps |= MMC_CAP_NEEDS_POLL;
 
-	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
 	if (!IS_ERR(mmc->supply.vqmmc)) {
 		ret = regulator_enable(mmc->supply.vqmmc);
+
+		/* If vqmmc provides no 1.8V signalling, then there's no UHS */
 		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
 						    1950000))
 			host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
 					 SDHCI_SUPPORT_SDR50 |
 					 SDHCI_SUPPORT_DDR50);
+
+		/* In eMMC case vqmmc might be a fixed 1.8V regulator */
+		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 2700000,
+						    3600000))
+			host->flags &= ~SDHCI_SIGNALING_330;
+
 		if (ret) {
 			pr_warn("%s: Failed to enable vqmmc regulator: %d\n",
 				mmc_hostname(mmc), ret);
-- 
2.17.1