[PATCH v2 1/4] Documentation: mmc: Document mmc aliases

[Douglas Anderson]

From: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>

Now, index of mmc/mmcblk devices is allocated in accordance with probing
time.  If want to use the mmcblk1 for some device, it can use alias.

aliases {
	mmc0 = &mmc0;	/* mmc0/mmcblk0 for eMMC */
	mmc1 = &mmc2;	/* mmc1/mmcblk1 for SD */
	mmc2 = &mmc1;	/* mmc2/mmcblk2 for SDIO*/
};

If there are no corresponding values, it might be allocated with
existing scheme.

Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
[dianders: just bindings now; mention mmc not just mmcblk]
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
Changes in v2: None

 Documentation/devicetree/bindings/mmc/mmc.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index ed23b9bedfdc..4b5c23e61adb 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -71,6 +71,10 @@ Optional SDIO properties:
 - wakeup-source: Enables wake up of host system on SDIO IRQ assertion
 		 (Legacy property supported: "enable-sdio-wakeup")
 
+Aliases (Optional):
+- If you want to use the fixed index for devices like mmcX / mmcblkX, should
+be represented in the aliases node using following format "mmc(X)".
+(X is an unique number for the alias.)
 
 MMC power sequences:
 --------------------
@@ -145,3 +149,10 @@ mmc3: mmc@01c12000 {
 		interrupt-names = "host-wake";
 	};
 };
+
+Example with aliases nodes:
+
+aliases {
+	mmc0 = &mmc0;	/* Fixed to mmc0/mmcblk0 for &mmc0 */
+	mmc1 = &mmc2;	/* Fixed to mmc1/mmcblk1 for &mmc2 */
+};
-- 
2.8.0.rc3.226.g39d4020