mmc: core: add the capability for broken voltage

There is an understood mismatch between the voltage the host controller is
set to and the voltage supplied to the card by a fixed voltage regulator.
Teaching the driver to accept the mismatch is overly complicated.  Instead
just accept the regulator's voltage.

This patch adds MMC_CAP2_BROKEN_VOLTAGE.

If the voltage didn't satisfy between min_uV and max_uV, try to change
the voltage in core.c.  When changing the voltage, maybe use
regulator_set_voltage().

In regulator_set_voltage(), check the below condition.

	/* sanity check */
	if (!rdev->desc->ops->set_voltage &&
	    !rdev->desc->ops->set_voltage_sel) {
		ret = -EINVAL;
		goto out;
	}

If some board should use the fixed-regulator, always return -EINVAL.
Then, eMMC didn't initialize always.

So if use a fixed-regulator, we need to add the MMC_CAP2_BROKEN_VOLTAGE.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index b3063b741df3..18661554e79c 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1131,6 +1131,10 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc,
                  * might not allow this operation
                  */
                 voltage = regulator_get_voltage(supply);
+
+                if (mmc->caps2 & MMC_CAP2_BROKEN_VOLTAGE)
+                        min_uV = max_uV = voltage;
+
                 if (voltage < 0)
                         result = voltage;
                 else if (voltage < min_uV || voltage > max_uV)