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| author | Loic Poulain <loic.poulain@linaro.org> | 2018-12-04 13:25:32 +0100 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2018-12-17 08:26:24 +0100 |
| commit | a89e7bcb18081c611eb6cf50edd440fa4983a71a (patch) | |
| tree | bbee0cc5a3e892b9bebb1f0ca279e3c4dc7a0b24 /include/linux/mmc | |
| parent | c5413ad815a675b5c98a002353d8e96b44b164e9 (diff) | |
| download | linux-a89e7bcb18081c611eb6cf50edd440fa4983a71a.tar.gz linux-a89e7bcb18081c611eb6cf50edd440fa4983a71a.tar.bz2 linux-a89e7bcb18081c611eb6cf50edd440fa4983a71a.zip | |
mmc: sdhci-msm: Disable CDR function on TX
The Clock Data Recovery (CDR) circuit allows to automatically adjust
the RX sampling-point/phase for high frequency cards (SDR104, HS200...).
CDR is automatically enabled during DLL configuration.
However, according to the APQ8016 reference manual, this function
must be disabled during TX and tuning phase in order to prevent any
interferences during tuning challenges and unexpected phase alteration
during TX transfers.
This patch enables/disables CDR according to the current transfer mode.
This fixes sporadic write transfer issues observed with some SDR104 and
HS200 cards.
Inspired by sdhci-msm downstream patch:
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/432516/
Reported-by: Leonid Segal <leonid.s@variscite.com>
Reported-by: Manabu Igusa <migusa@arrowjapan.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'include/linux/mmc')
0 files changed, 0 insertions, 0 deletions