diff options
| author | Ulf Hansson <ulf.hansson@linaro.org> | 2013-09-16 11:28:42 +0200 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2013-10-30 20:26:30 -0400 |
| commit | ce69d37b7d8fa692c45d71d94aa0c921859b82ce (patch) | |
| tree | aef1e93b62424f07b72ddd322a64e6435b27d932 /drivers/mmc/core/sd.c | |
| parent | 6904115095ad60ced638eb1e36e0e4e5e7de00b0 (diff) | |
mmc: core: Prevent violation of specs while initializing cards
According to eMMC/SD/SDIO specs, the VDD (VCC) voltage level must be
maintained during the initialization sequence. If we want/need to tune
the voltage level, a complete power cycle of the card must be executed.
Most host drivers conforms to the specifications by only allowing to
change VDD voltage level at the MMC_POWER_UP state, but some also cares
about MMC_POWER_ON state, which they should'nt. This patch will not
break those drivers, but they could clean up code to better reflect
what is expected from the protocol layer.
A big re-work of the mmc_select_voltage function is done to only change
VDD voltage level if the host supports MMC_CAP2_FULL_PWR_CYCLE.
Otherwise only validation of the host and card ocr mask will be done.
A very nice side-effect of this patch is that we now don't need to
reset the negotiated ocr mask at the mmc_power_off function, since now
it will actually reflect the present voltage level, which safely can be
used at the next power up and re-initialization. Moreover, we then only
need to execute mmc_select_voltage from the attach sequence.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc/core/sd.c')
| -rw-r--r-- | drivers/mmc/core/sd.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index 398065c57edf..53db60a76dae 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -1103,7 +1103,6 @@ static int mmc_sd_resume(struct mmc_host *host) mmc_claim_host(host); mmc_power_up(host, host->card->ocr); - mmc_select_voltage(host, host->card->ocr); err = mmc_sd_init_card(host, host->card->ocr, host->card); mmc_release_host(host); |