On Tue, May 4, 2021 at 6:12 PM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > After the eMMC sleep command (CMD5) has been sent, the card start signals > busy on the DAT0 line, which can be monitored to understand when it's > allowed to proceed to power off the VCC regulator. > > When MMC_CAP_WAIT_WHILE_BUSY isn't supported by the host the DAT0 line > isn't being monitored for busy completion, but instead we are waiting a > fixed period of time. The time corresponds to the sleep timeout that is > specified in the EXT_CSD register of the eMMC card. This is many cases > suboptimal, as the timeout corresponds to the worst case scenario. > > To improve the situation add support for HW busy polling through the > ->card_busy() host ops, when the host supports this. > > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Yours, Linus Walleij
