From cd587096c0e2b85a67e77721a753679bac89b394 Mon Sep 17 00:00:00 2001 From: "Hebbar, Gururaja" Date: Mon, 19 Nov 2012 21:59:58 +0530 Subject: mmc: omap_hsmmc: Enable HSPE bit for high speed cards HSMMC IP on AM33xx need a special setting to handle High-speed cards. Other platforms like TI81xx, OMAP4 may need this as-well. This depends on the HSMMC IP timing closure done for the high speed cards. From AM335x TRM (SPRUH73F - 18.3.12 Output Signals Generation): The MMC/SD/SDIO output signals can be driven on either falling edge or rising edge depending on the SD_HCTL[2] HSPE bit. This feature allows to reach better timing performance, and thus to increase data transfer frequency. There are few pre-requisites for enabling the HSPE bit - Controller should support High-Speed-Enable Bit and - Controller should not be using DDR Mode and - Controller should advertise that it supports High Speed in capabilities register and - MMC/SD clock coming out of controller > 25MHz Signed-off-by: Hebbar, Gururaja Signed-off-by: Venkatraman S Signed-off-by: Chris Ball --- Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt') diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt index be76a23b34c..ed271fc255b 100644 --- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt @@ -19,6 +19,7 @@ ti,dual-volt: boolean, supports dual voltage cards "supply-name" examples are "vmmc", "vmmc_aux" etc ti,non-removable: non-removable slot (like eMMC) ti,needs-special-reset: Requires a special softreset sequence +ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed Example: mmc1: mmc@0x4809c000 { -- cgit v1.2.3