summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/mmc/samsung-sdhci.txt53
1 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
new file mode 100644
index 000000000000..630a7d7f4718
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
@@ -0,0 +1,53 @@
+* Samsung's SDHCI Controller device tree bindings
+
+Samsung's SDHCI controller is used as a connectivity interface with external
+MMC, SD and eMMC storage mediums. This file documents differences between the
+core mmc properties described by mmc.txt and the properties used by the
+Samsung implmentation of the SDHCI controller.
+
+Note: The mmc core bindings documentation states that if none of the core
+card-detect bindings are used, then the standard sdhci card detect mechanism
+is used. The Samsung's SDHCI controller bindings extends this as listed below.
+
+[A] The property "samsung,cd-pinmux-gpio" can be used as stated in the
+ "Optional Board Specific Properties" section below.
+
+[B] If core card-detect bindings and "samsung,cd-pinmux-gpio" property
+ is not specified, it is assumed that there is no card detection
+ mechanism used.
+
+Required SoC Specific Properties:
+- compatible: should be one of the following
+ - "samsung,s3c6410-sdhci": For controllers compatible with s3c6410 sdhci
+ controller.
+ - "samsung,exynos4210-sdhci": For controllers compatible with Exynos4 sdhci
+ controller.
+
+Required Board Specific Properties:
+- gpios: Should specify the gpios used for clock, command and data lines. The
+ gpio specifier format depends on the gpio controller.
+
+Optional Board Specific Properties:
+- samsung,cd-pinmux-gpio: Specifies the card detect line that is routed
+ through a pinmux to the card-detect pin of the card slot. This property
+ should be used only if none of the mmc core card-detect properties are
+ used.
+
+Example:
+ sdhci@12530000 {
+ compatible = "samsung,exynos4210-sdhci";
+ reg = <0x12530000 0x100>;
+ interrupts = <0 75 0>;
+ bus-width = <4>;
+ cd-gpios = <&gpk2 2 2 3 3>;
+ gpios = <&gpk2 0 2 0 3>, /* clock line */
+ <&gpk2 1 2 0 3>, /* command line */
+ <&gpk2 3 2 3 3>, /* data line 0 */
+ <&gpk2 4 2 3 3>, /* data line 1 */
+ <&gpk2 5 2 3 3>, /* data line 2 */
+ <&gpk2 6 2 3 3>; /* data line 3 */
+ };
+
+ Note: This example shows both SoC specific and board specific properties
+ in a single device node. The properties can be actually be seperated
+ into SoC specific node and board specific node.