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mmc: core: Prevent eMMC VCC supply to be cut from late init 

For eMMC cards that has been initialized from a bootloader,
the VCC voltage supply must not be cut in an uncontrolled
manner, without first sending SLEEP or POWEROFF_NOTIFY.

The regulator_init_complete late initcall, may cut the VCC
regulator if it's reference counter is zero. To be able to
prevent the regulator from being cut, mmc_start_host, which
should execute at device init and thus before late init,
calls mmc_power_up. Then the host driver is able to increase
the reference to the regulator.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Ulf Hansson 2012-05-09 16:15:26 +02:00 committed by Chris Ball
parent 95dcc2cb6c
commit fa5501890d
1 changed files with 15 additions and 3 deletions
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18
drivers/mmc/core/core.c
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@ -42,6 +42,7 @@
#include "sdio_ops.h"
static struct workqueue_struct *workqueue;
static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
/*
* Enabling software CRCs on the data blocks can be a significant (30%)
@ -1157,6 +1158,9 @@ static void mmc_power_up(struct mmc_host *host)
{
int bit;
if (host->ios.power_mode == MMC_POWER_ON)
return;
mmc_host_clk_hold(host);
/* If ocr is set, we use it */
@ -1199,6 +1203,10 @@ static void mmc_power_up(struct mmc_host *host)
void mmc_power_off(struct mmc_host *host)
{
int err = 0;
if (host->ios.power_mode == MMC_POWER_OFF)
return;
mmc_host_clk_hold(host);
host->ios.clock = 0;
@ -2005,7 +2013,6 @@ EXPORT_SYMBOL(mmc_detect_card_removed);
void mmc_rescan(struct work_struct *work)
{
static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
struct mmc_host *host =
container_of(work, struct mmc_host, detect.work);
int i;
@ -2044,8 +2051,12 @@ void mmc_rescan(struct work_struct *work)
*/
mmc_bus_put(host);
if (host->ops->get_cd && host->ops->get_cd(host) == 0)
if (host->ops->get_cd && host->ops->get_cd(host) == 0) {
mmc_claim_host(host);
mmc_power_off(host);
mmc_release_host(host);
goto out;
}
mmc_claim_host(host);
for (i = 0; i < ARRAY_SIZE(freqs); i++) {
@ -2063,7 +2074,8 @@ void mmc_rescan(struct work_struct *work)
void mmc_start_host(struct mmc_host *host)
{
mmc_power_off(host);
host->f_init = max(freqs[0], host->f_min);
mmc_power_up(host);
mmc_detect_change(host, 0);
}