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    Subject[PATCH 4.18 183/235] mmc: sdhci: do not try to use 3.3V signaling if not supported
    Date
    4.18-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Stefan Agner <stefan@agner.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@agner.ch>
    Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/mmc/host/sdhci.c | 9 ++++++++-
    1 file changed, 8 insertions(+), 1 deletion(-)

    --- a/drivers/mmc/host/sdhci.c
    +++ b/drivers/mmc/host/sdhci.c
    @@ -3734,14 +3734,21 @@ int sdhci_setup_host(struct sdhci_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);

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