mmc: core: add the capability for broken voltage
authorJaehoon Chung <jh80.chung@samsung.com>
Mon, 16 Jan 2012 08:49:01 +0000 (17:49 +0900)
committerChris Ball <cjb@laptop.org>
Tue, 14 Feb 2012 01:39:01 +0000 (20:39 -0500)
commit6e8201f57c9359c9c5dc8f9805c15a4392492a10
treec936936d165e2fd134d657e569754460acebb26e
parent7488e924b55002e70f6d8d181f146edac3006b9f
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>
drivers/mmc/core/core.c
include/linux/mmc/host.h