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Add device tree based discovery support for Samsung's sdhci controller. Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
54 lines
2.1 KiB
Plaintext
54 lines
2.1 KiB
Plaintext
* Samsung's SDHCI Controller device tree bindings
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Samsung's SDHCI controller is used as a connectivity interface with external
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MMC, SD and eMMC storage mediums. This file documents differences between the
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core mmc properties described by mmc.txt and the properties used by the
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Samsung implmentation of the SDHCI controller.
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Note: The mmc core bindings documentation states that if none of the core
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card-detect bindings are used, then the standard sdhci card detect mechanism
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is used. The Samsung's SDHCI controller bindings extends this as listed below.
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[A] The property "samsung,cd-pinmux-gpio" can be used as stated in the
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"Optional Board Specific Properties" section below.
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[B] If core card-detect bindings and "samsung,cd-pinmux-gpio" property
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is not specified, it is assumed that there is no card detection
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mechanism used.
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Required SoC Specific Properties:
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- compatible: should be one of the following
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- "samsung,s3c6410-sdhci": For controllers compatible with s3c6410 sdhci
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controller.
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- "samsung,exynos4210-sdhci": For controllers compatible with Exynos4 sdhci
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controller.
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Required Board Specific Properties:
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- gpios: Should specify the gpios used for clock, command and data lines. The
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gpio specifier format depends on the gpio controller.
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Optional Board Specific Properties:
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- samsung,cd-pinmux-gpio: Specifies the card detect line that is routed
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through a pinmux to the card-detect pin of the card slot. This property
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should be used only if none of the mmc core card-detect properties are
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used.
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Example:
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sdhci@12530000 {
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compatible = "samsung,exynos4210-sdhci";
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reg = <0x12530000 0x100>;
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interrupts = <0 75 0>;
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bus-width = <4>;
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cd-gpios = <&gpk2 2 2 3 3>;
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gpios = <&gpk2 0 2 0 3>, /* clock line */
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<&gpk2 1 2 0 3>, /* command line */
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<&gpk2 3 2 3 3>, /* data line 0 */
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<&gpk2 4 2 3 3>, /* data line 1 */
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<&gpk2 5 2 3 3>, /* data line 2 */
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<&gpk2 6 2 3 3>; /* data line 3 */
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};
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Note: This example shows both SoC specific and board specific properties
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in a single device node. The properties can be actually be seperated
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into SoC specific node and board specific node.
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