From: Kevin Liu <kl...@marvell.com>

Add the function since MMC 1.8v signal voltage switch don't need
the same switch sequence requirements as SD/SDIO.

Signed-off-by: Kevin Liu <kl...@marvell.com>
---
 drivers/mmc/host/sdhci.c |   46 +++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 45 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 14ec904..50e7a54 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1794,6 +1794,46 @@ static int sdhci_do_1_8v_signal_voltage_switch(struct 
sdhci_host *host,
        return -EAGAIN;
 }
 
+static int sdhci_mmc_do_1_8v_signal_voltage_switch(struct sdhci_host *host,
+                                               u16 ctrl)
+{
+       int ret;
+
+       if (host->vqmmc) {
+               ret = regulator_set_voltage(host->vqmmc, 1700000, 1950000);
+               if (ret) {
+                       pr_warning("%s: Switching to 1.8V signalling voltage "
+                                  " failed\n", mmc_hostname(host->mmc));
+                       return -EIO;
+               }
+       }
+
+       /*
+        * May need to apply soc/platfrom settings for the
+        * voltage switch
+        */
+       if (host->ops->signal_voltage_switch)
+               host->ops->signal_voltage_switch(host,
+                               host->mmc->ios.signal_voltage);
+
+       /* Enable 1.8V Signal Enable in the Host Control2 register */
+       ctrl |= SDHCI_CTRL_VDD_180;
+       sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+       /* Wait for 5ms */
+       usleep_range(5000, 5500);
+
+       /* 1.8V regulator output should be stable within 5 ms */
+       ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+       if (ctrl & SDHCI_CTRL_VDD_180)
+               return 0;
+
+       pr_warning("%s: 1.8V regulator output did not became stable\n",
+                  mmc_hostname(host->mmc));
+
+       return -EIO;
+}
+
 static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
                                                struct mmc_ios *ios)
 {
@@ -1814,8 +1854,12 @@ static int sdhci_do_start_signal_voltage_switch(struct 
sdhci_host *host,
        if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
                return sdhci_do_3_3v_signal_voltage_switch(host, ctrl);
        else if (!(ctrl & SDHCI_CTRL_VDD_180) &&
-                       (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180))
+               (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180))
                return sdhci_do_1_8v_signal_voltage_switch(host, ctrl);
+       else if (!(ctrl & SDHCI_CTRL_VDD_180) &&
+               (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_MMC_180))
+               return sdhci_mmc_do_1_8v_signal_voltage_switch(host,
+                       ctrl);
        else
                /* No signal voltage switch required */
                return 0;
-- 
1.7.0.4

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