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From:   Scott Branden <scott.branden@broadcom.com>
To:     Adrian Hunter <adrian.hunter@intel.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Ray Jui <rjui@broadcom.com>,
        Scott Branden <sbranden@broadcom.com>,
        Stefan Wahren <stefan.wahren@i2se.com>
Cc:     BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
        linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, Trac Hoang <trac.hoang@broadcom.com>,
        Scott Branden <scott.branden@broadcom.com>
Subject: [PATCH 1/2] mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time problem
Date:   Mon,  6 May 2019 10:01:14 -0700
Message-Id: <20190506170115.10840-2-scott.branden@broadcom.com>
In-Reply-To: <20190506170115.10840-1-scott.branden@broadcom.com>
References: <20190506170115.10840-1-scott.branden@broadcom.com>
Sender: linux-kernel-owner@vger.kernel.org
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From: Trac Hoang <trac.hoang@broadcom.com>

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.

Fixes: c833e92bbb60 ("mmc: sdhci-iproc: support standard byte register accesses")
Signed-off-by: Trac Hoang <trac.hoang@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
---
 drivers/mmc/host/sdhci-iproc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 9d12c06c7fd6..9d4071c41c94 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -196,7 +196,8 @@ static const struct sdhci_ops sdhci_iproc_32only_ops = {
 };
 
 static const struct sdhci_pltfm_data sdhci_iproc_cygnus_pltfm_data = {
-	.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
+	.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
+		  SDHCI_QUIRK_NO_HISPD_BIT,
 	.quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN | SDHCI_QUIRK2_HOST_OFF_CARD_ON,
 	.ops = &sdhci_iproc_32only_ops,
 };
-- 
2.17.1