From: Ye Li ye.li@nxp.com
We meet SD initialization issue with some UHS-I SD cards on iMX8MM/iMX93/iMX91 EVK. When sending operation condition to card, the OCR does not return correct status. We find it is the issue in MMC power cycle after below commit applied: 4fcba5d (regulator: implement basic reference counter)
When SD startup, the sequence of MMC power cycle is: mmc_power_init(get vmmc_supply dev) -> mmc_power_off -> udelay(2000) -> mmc_power_on
Before the commit, as a fixed regulator, the GPIO is set as: GPIO inactive (in mmc_power_init) -> GPIO inactive and delay off-on-delay-us (in mmc_power_off) -> udelay(2000) -> GPIO active (in mmc_power_on)
After the commit: GPIO inactive (in mmc_power_init) -> enable_count is 0, regulator_set_enable returns -EALREADY, GPIO is inactive but NO delay (in mmc_power_off) -> udelay(2000) -> GPIO active (in mmc_power_on)
Because the lost of off-on-delay-us, the SD card is not completely power off. To fix the issue, add the delay after the GPIO setting in regulator_common_of_to_plat which is called in device probing. So in mmc_power_init, after GPIO is set to default inactive, the off-on-delay-us is applied.
Fixes: 4fcba5d556b ("regulator: implement basic reference counter") Signed-off-by: Ye Li ye.li@nxp.com Reviewed-by: Peng Fan peng.fan@nxp.com Signed-off-by: Peng Fan peng.fan@nxp.com --- drivers/power/regulator/regulator_common.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/power/regulator/regulator_common.c b/drivers/power/regulator/regulator_common.c index e3565d32a01..2192e900697 100644 --- a/drivers/power/regulator/regulator_common.c +++ b/drivers/power/regulator/regulator_common.c @@ -45,6 +45,12 @@ int regulator_common_of_to_plat(struct udevice *dev, dev_read_u32_default(dev, "u-boot,off-on-delay-us", 0); }
+ if ((flags & GPIOD_IS_OUT_ACTIVE) && plat->startup_delay_us) + udelay(plat->startup_delay_us); + + if (!(flags & GPIOD_IS_OUT_ACTIVE) && plat->off_on_delay_us) + udelay(plat->off_on_delay_us); + return 0; }