It's complicated to support SD UHS-I and eMMC HS200 for eSDHC because
there're many differences between eSDHC and SD/eMMC spec. Several
differences as below must be considered:
1. Peripheral clock must be used instead of platform clock.
- eSDHC could select peripheral clock or platform clock as its clock
source. According to RM, UHS-I/HS200 must use peripheral clock since
it supports higher frequency than platform clock.
- Patch 1 is to support this.
2. Signal voltage switching requires a control circuit out of eSDHC.
- eSDHC supports signal voltage switch from 3.3v to 1.8v by
eSDHC_PROCTL[VOLT_SEL] bit. This bit changes the value of output
signal SDHC_VS, and there must be a control circuit out of eSDHC
to change the signal voltage according to SDHC_VS output signal.
- Patch 2 is to support this.
3. eSDHC uses tuning block for tuning procedure.
- Tuning clock control register must be configured before tuning.
- Patch 3 is to support this.
4. Delay is needed between tuning cycles for HS200 tuning.
- Once a patch removed mdelay between tuning cycles.
But eSDHC needs it.
- Patch 4 and patch 5 is to support this.
Adrian Hunter (1):
mmc: sdhci: Control the delay between tuning commands
Yangbo Lu (4):
mmc: sdhci-of-esdhc: add peripheral clock support
mmc: sdhci-of-esdhc: add support for signal voltage switch
mmc: sdhci-of-esdhc: add tuning support
mmc: sdhci-of-esdhc: add delay between tuning cycles
drivers/mmc/host/sdhci-esdhc.h | 7 ++
drivers/mmc/host/sdhci-of-esdhc.c | 168 +++++++++++++++++++++++++++++++++++++-
drivers/mmc/host/sdhci.c | 11 ++-
drivers/mmc/host/sdhci.h | 2 +
4 files changed, 183 insertions(+), 5 deletions(-)
--
2.1.0.27.g96db324
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