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* [PATCH] mmc: sdhci-s3c: Fix mmc card I/O problem
@ 2011-08-26  9:28 ` Girish K S
  0 siblings, 0 replies; 6+ messages in thread
From: Girish K S @ 2011-08-26  9:28 UTC (permalink / raw)
  To: linux-mmc
  Cc: linux-arm-kernel, cjb, ben-linux, kgene.kim, patches,
	linux-samsung-soc, Girish K S

This patch fixes the problem in sdhci-s3c host driver for
Samsung Soc's. During the card identification stage the
mmc core driver enumerates for the best bus width in combination
with the highest available data rate. It starts enumerating from
the highest bus width (8) to lowest bus width (1).

In case of few MMC cards the 4-bit bus enumeration fails and tries
the 1-bit bus enumeration. When switched to 1-bit bus mode the host driver
has to clear the previous bus width setting and apply the new setting.

The current patch will clear the previous bus mode and apply the new
mode setting.

Signed-off-by: Girish K S <girish.shivananjappa@linaro.org>
---
 drivers/mmc/host/sdhci-s3c.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
index 2bd7bf4..fe886d6 100644
--- a/drivers/mmc/host/sdhci-s3c.c
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -302,6 +302,8 @@ static int sdhci_s3c_platform_8bit_width(struct sdhci_host *host, int width)
 		ctrl &= ~SDHCI_CTRL_8BITBUS;
 		break;
 	default:
+		ctrl &= ~SDHCI_CTRL_4BITBUS;
+		ctrl &= ~SDHCI_CTRL_8BITBUS;
 		break;
 	}
 
-- 
1.7.1

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2011-08-28 18:11 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-08-26  9:28 [PATCH] mmc: sdhci-s3c: Fix mmc card I/O problem Girish K S
2011-08-26  9:28 ` Girish K S
2011-08-26 10:46 ` Jaehoon Chung
2011-08-26 10:46   ` Jaehoon Chung
2011-08-28 18:11 ` Chris Ball
2011-08-28 18:11   ` Chris Ball

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