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mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time problem
authorTrac Hoang <trac.hoang@broadcom.com>
Thu, 9 May 2019 17:24:26 +0000 (10:24 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 31 May 2019 13:46:01 +0000 (06:46 -0700)
commit227e01537baf7d8d5b14bd889540d5eb649ab66c
treee54a4cc9a3ff8544d2c302bd7e03b086745fbe86
parent792d65fc49a79b7cb3686c23dc17be91b154781d
mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time problem

commit b7dfa695afc40d5396ed84b9f25aa3754de23e39 upstream.

The iproc host eMMC/SD controller hold time does not meet the
specification in the HS50 mode. This problem can be mitigated
by disabling the HISPD bit; thus forcing the controller output
data to be driven on the falling clock edges rather than the
rising clock edges.

This change applies only to the Cygnus platform.

Stable tag (v4.12+) chosen to assist stable kernel maintainers so that
the change does not produce merge conflicts backporting to older kernel
versions. In reality, the timing bug existed since the driver was first
introduced but there is no need for this driver to be supported in kernel
versions that old.

Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Trac Hoang <trac.hoang@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/mmc/host/sdhci-iproc.c