mmc: fsl_esdhc: workaround for hardware 3.3v IO reliability issue
When eSDHC operates at 3.3v, damage can accumulate in an internal
level shifter at a higher than expected rate. The faster the interface
runs, the more damage accumulates. This issue now is found on LX2160A
eSDHC1 for only SD card.
The hardware workaround is recommended to use an on-board level shifter
that is 1.8v on SoC side and 3.3v on SD card side.
For boards without hardware workaround, this option could be enabled,
ensuring 1.8v IO voltage and disabling eSDHC if no card.
This option assumes no hotplug, and u-boot has to make all the way to
to linux to use 1.8v UHS-I speed mode if has card.
If you do not want the workaround for better user experience, of course
you can choose to not select it running eSDHC in unsafe mode.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 3c4f057..8f56572 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -727,6 +727,21 @@
This selects support for the eSDHC (Enhanced Secure Digital Host
Controller) found on numerous Freescale/NXP SoCs.
+config FSL_ESDHC_33V_IO_RELIABILITY_WORKAROUND
+ bool "enable eSDHC workaround for 3.3v IO reliability issue"
+ depends on FSL_ESDHC && DM_MMC
+ default n
+ help
+ When eSDHC operates at 3.3v, damage can accumulate in an internal
+ level shifter at a higher than expected rate. The faster the interface
+ runs, the more damage accumulates. This issue now is found on LX2160A
+ eSDHC1 for only SD card. The hardware workaround is recommended to use
+ an on-board level shifter that is 1.8v on SoC side and 3.3v on SD card
+ side. For boards without hardware workaround, this option could be
+ enabled, ensuring 1.8v IO voltage and disabling eSDHC if no card.
+ This option assumes no hotplug, and u-boot has to make all the way to
+ to linux to use 1.8v UHS-I speed mode if has card.
+
config FSL_ESDHC_IMX
bool "Freescale/NXP i.MX eSDHC controller support"
help