On 25/07/18 15:23, Vijay Viswanath wrote:

Hi Adrian,


On 7/25/2018 5:23 PM, Adrian Hunter wrote:

quoted

On 20/07/18 13:46, Vijay Viswanath wrote:

quoted

Some controllers can have internal mechanism to inform the SW that it
is ready for voltage switching. For such controllers, changing voltage
before the HW is ready can result in various issues.

During setup/cleanup of host, check whether regulator enable/disable
was already done by platform driver.

Signed-off-by: Vijay Viswanath <redacted>
---
  drivers/mmc/host/sdhci.c | 21 ++++++++++++++++-----
  1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1c828e0..494a1e2 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c

@@ -3472,6 +3472,7 @@ int sdhci_setup_host(struct sdhci_host *host)

      unsigned int override_timeout_clk;
      u32 max_clk;
      int ret;
+    bool enable_vqmmc = false;
        WARN_ON(host == NULL);
      if (host == NULL)

@@ -3485,7 +3486,12 @@ int sdhci_setup_host(struct sdhci_host *host)

       * the host can take the appropriate action if regulators are not
       * available.
       */
-    ret = mmc_regulator_get_supply(mmc);
+    if (!mmc->supply.vmmc) {
+        ret = mmc_regulator_get_supply(mmc);
+        enable_vqmmc  = true;
+    } else {
+        ret = 0;
+    }
      if (ret)
          return ret;

Why not

    if (!mmc->supply.vmmc) {
        ret = mmc_regulator_get_supply(mmc);
          if (ret)
               return ret;
        enable_vqmmc  = true;
    }

looks neater. Will do.

quoted

quoted

  @@ -3736,7 +3742,10 @@ int sdhci_setup_host(struct sdhci_host *host)
        /* 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 (enable_vqmmc)
+            ret = regulator_enable(mmc->supply.vqmmc);

Please introduce host->vqmmc_enabled = !ret;

Any reason to introduce vqmmc_enabled variable in sdhci_host structure ? We
can get around with a local variable and using regulator_is_enabled API.

regulator_enable() uses reference counting, so we have to use
regulator_disable() exactly the same number of times that we use
regulator_enable().

quoted

quoted

+        else
+            ret = 0;
          if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
                              1950000))
              host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |

@@ -3984,7 +3993,7 @@ int sdhci_setup_host(struct sdhci_host *host)

      return 0;
    unreg:
-    if (!IS_ERR(mmc->supply.vqmmc))
+    if (!IS_ERR(mmc->supply.vqmmc) && enable_vqmmc)

And just make this

    if (host->vqmmc_enabled)

quoted

          regulator_disable(mmc->supply.vqmmc);
  undma:
      if (host->align_buffer)

@@ -4002,7 +4011,8 @@ void sdhci_cleanup_host(struct sdhci_host *host)

  {
      struct mmc_host *mmc = host->mmc;
  -    if (!IS_ERR(mmc->supply.vqmmc))
+    if (!IS_ERR(mmc->supply.vqmmc) &&
+            (regulator_is_enabled(mmc->supply.vqmmc) > 0))

    if (host->vqmmc_enabled)

quoted

          regulator_disable(mmc->supply.vqmmc);
        if (host->align_buffer)

@@ -4135,7 +4145,8 @@ void sdhci_remove_host(struct sdhci_host *host, int

dead)
        tasklet_kill(&host->finish_tasklet);
  -    if (!IS_ERR(mmc->supply.vqmmc))
+    if (!IS_ERR(mmc->supply.vqmmc) &&
+            (regulator_is_enabled(mmc->supply.vqmmc) > 0))

    if (host->vqmmc_enabled)

quoted

          regulator_disable(mmc->supply.vqmmc);
        if (host->align_buffer)

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Thanks,
Vijay