On Fri, Sep 22, 2017 at 11:38:40AM +0200, Ulf Hansson wrote: > On 21 September 2017 at 19:47, Kyle Roeschley <kyle.roeschley@xxxxxx> wrote: > > The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be > > lowered to less than 0.5V for a minimum of 1 ms when powering off a > > card. Increase our wait to 10 ms so that voltage has time to drain down > > to 0.5V and cards can power off correctly. > > > > Signed-off-by: Kyle Roeschley <kyle.roeschley@xxxxxx> > > --- > > drivers/mmc/core/core.c | 10 ++++------ > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > > index 66c9cf49ad2f..38630246de26 100644 > > --- a/drivers/mmc/core/core.c > > +++ b/drivers/mmc/core/core.c > > @@ -1679,18 +1679,16 @@ void mmc_power_off(struct mmc_host *host) > > mmc_set_initial_state(host); > > > > /* > > - * Some configurations, such as the 802.11 SDIO card in the OLPC > > - * XO-1.5, require a short delay after poweroff before the card > > - * can be successfully turned on again. > > + * The SD spec requires at least 1 ms with Vdd at less than 0.5 V > > + * before a card can be re-powered, but we need to wait longer so that > > + * the voltage has time to drain. > > */ > > - mmc_delay(1); > > + mmc_delay(10); > > No, this isn't the proper place of adding more "magic" delays. > > Instead, make sure the related ->set_ios() callback in the mmc host > driver deals with this instead. In case it uses an external regulator, > via the regulator API, then this is something that should be > controlled with the definition of the regulator. > Thanks for pointing me in the right direction, I'll reimplement the fix there. -- Kyle Roeschley Software Engineer National Instruments -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
