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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
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Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+* Freescale Enhanced Secure Digital Host Controller (eSDHC) for i.MX
+
+The Enhanced Secure Digital Host Controller on Freescale i.MX family
+provides an interface for MMC, SD, and SDIO types of memory cards.
+
+This file documents differences between the core properties described
+by mmc.txt and the properties used by the sdhci-esdhc-imx driver.
+
+Required properties:
+- compatible : Should be "fsl,<chip>-esdhc", the supported chips include
+ "fsl,imx25-esdhc"
+ "fsl,imx35-esdhc"
+ "fsl,imx51-esdhc"
+ "fsl,imx53-esdhc"
+ "fsl,imx6q-usdhc"
+ "fsl,imx6sl-usdhc"
+ "fsl,imx6sx-usdhc"
+ "fsl,imx7d-usdhc"
+
+Optional properties:
+- fsl,wp-controller : Indicate to use controller internal write protection
+- fsl,delay-line : Specify the number of delay cells for override mode.
+ This is used to set the clock delay for DLL(Delay Line) on override mode
+ to select a proper data sampling window in case the clock quality is not good
+ due to signal path is too long on the board. Please refer to eSDHC/uSDHC
+ chapter, DLL (Delay Line) section in RM for details.
+- voltage-ranges : Specify the voltage range in case there are software
+ transparent level shifters on the outputs of the controller. Two cells are
+ required, first cell specifies minimum slot voltage (mV), second cell
+ specifies maximum slot voltage (mV). Several ranges could be specified.
+- fsl,tuning-start-tap: Specify the start dealy cell point when send first CMD19
+ in tuning procedure.
+- fsl,tuning-step: Specify the increasing delay cell steps in tuning procedure.
+ The uSDHC use one delay cell as default increasing step to do tuning process.
+ This property allows user to change the tuning step to more than one delay
+ cells which is useful for some special boards or cards when the default
+ tuning step can't find the proper delay window within limited tuning retries.
+
+Examples:
+
+esdhc@70004000 {
+ compatible = "fsl,imx51-esdhc";
+ reg = <0x70004000 0x4000>;
+ interrupts = <1>;
+ fsl,wp-controller;
+};
+
+esdhc@70008000 {
+ compatible = "fsl,imx51-esdhc";
+ reg = <0x70008000 0x4000>;
+ interrupts = <2>;
+ cd-gpios = <&gpio1 6 0>; /* GPIO1_6 */
+ wp-gpios = <&gpio1 5 0>; /* GPIO1_5 */
+};