mmc: sdhci-sprd: Add start_signal_voltage_switch ops

For Spreadtrum SD host controller, we can not use standard SD registers
to change and detect the I/O voltage signals, since our voltage regulator
for I/O is fixed in hardware, and no signals were connected to the SD
controller. Thus add Spreadtrum specific voltage switch ops to change
voltage instead of using standard SD host registers.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
index 024c3c5..8b23c88 100644 (file)
--- a/drivers/mmc/host/sdhci-sprd.c
+++ b/drivers/mmc/host/sdhci-sprd.c
@@ -403,6 +403,22 @@ static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
        sdhci_request(mmc, mrq);
 }
 
+static int sdhci_sprd_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+       int ret;
+
+       if (!IS_ERR(mmc->supply.vqmmc)) {
+               ret = mmc_regulator_set_vqmmc(mmc, ios);
+               if (ret) {
+                       pr_err("%s: Switching signalling voltage failed\n",
+                              mmc_hostname(mmc));
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+
 static void sdhci_sprd_hs400_enhanced_strobe(struct mmc_host *mmc,
                                             struct mmc_ios *ios)
 {
@@ -470,6 +486,14 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
        host->mmc_host_ops.request = sdhci_sprd_request;
        host->mmc_host_ops.hs400_enhanced_strobe =
                sdhci_sprd_hs400_enhanced_strobe;
+       /*
+        * We can not use the standard ops to change and detect the voltage
+        * signal for Spreadtrum SD host controller, since our voltage regulator
+        * for I/O is fixed in hardware, that means we do not need control
+        * the standard SD host controller to change the I/O voltage.
+        */
+       host->mmc_host_ops.start_signal_voltage_switch =
+               sdhci_sprd_voltage_switch;
 
        host->mmc->caps = MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
                MMC_CAP_ERASE | MMC_CAP_CMD23;