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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 <gururaja.hebbar@ti.com> Signed-off-by: Venkatraman S <svenkatr@ti.com> Signed-off-by: Chris Ball <cjb@laptop.org>
34 lines
1.1 KiB
Plaintext
34 lines
1.1 KiB
Plaintext
* TI Highspeed MMC host controller for OMAP
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The Highspeed MMC Host Controller on TI OMAP family
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provides an interface for MMC, SD, and SDIO types of memory cards.
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This file documents differences between the core properties described
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by mmc.txt and the properties used by the omap_hsmmc driver.
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Required properties:
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- compatible:
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Should be "ti,omap2-hsmmc", for OMAP2 controllers
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Should be "ti,omap3-hsmmc", for OMAP3 controllers
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Should be "ti,omap4-hsmmc", for OMAP4 controllers
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- ti,hwmods: Must be "mmc<n>", n is controller instance starting 1
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Optional properties:
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ti,dual-volt: boolean, supports dual voltage cards
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<supply-name>-supply: phandle to the regulator device tree node
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"supply-name" examples are "vmmc", "vmmc_aux" etc
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ti,non-removable: non-removable slot (like eMMC)
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ti,needs-special-reset: Requires a special softreset sequence
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ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed
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Example:
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mmc1: mmc@0x4809c000 {
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compatible = "ti,omap4-hsmmc";
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reg = <0x4809c000 0x400>;
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ti,hwmods = "mmc1";
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ti,dual-volt;
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bus-width = <4>;
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vmmc-supply = <&vmmc>; /* phandle to regulator node */
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ti,non-removable;
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};
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