From bb5e9a408dc5d0e88fd8f10db6ae37a33f4d912e Mon Sep 17 00:00:00 2001 From: Dong Aisheng Date: Mon, 21 Oct 2013 16:54:40 +0800 Subject: [PATCH] mmc: sdhci-esdhc-imx: add delay line setting support The DLL(Delay Line) is newly added to assist in sampling read data. The DLL provides the ability to programmatically select a quantized delay (in fractions of the clock period) regardless of on-chip variations such as process, voltage and temperature (PVT). This patch adds a user interface to set slave delay line via device tree. It's usually used in high speed mode like mmc DDR mode when the signal quality is not good caused by board design, e.g. the signal path is too long. User can manually set delay line to find a suitable data sampling window for card to work properly. Signed-off-by: Dong Aisheng Acked-by: Shawn Guo Signed-off-by: Chris Ball --- drivers/mmc/host/sdhci-esdhc-imx.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index ccec0e32590f..6c3a56414187 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -54,6 +54,11 @@ #define ESDHC_DLL_OVERRIDE_VAL_SHIFT 9 #define ESDHC_DLL_OVERRIDE_EN_SHIFT 8 +/* dll control register */ +#define ESDHC_DLL_CTRL 0x60 +#define ESDHC_DLL_OVERRIDE_VAL_SHIFT 9 +#define ESDHC_DLL_OVERRIDE_EN_SHIFT 8 + /* tune control register */ #define ESDHC_TUNE_CTRL_STATUS 0x68 #define ESDHC_TUNE_CTRL_STEP 1 -- 2.39.5