Documentation/devicetree/bindings/mmc/mmc.txt - linux - Git at Google

 These properties are common to multiple MMC host controllers. Any host
 that requires the respective functionality should implement them using
 these definitions.

 Interpreted by the OF core:
 - reg: Registers location and length.
 - interrupts: Interrupts used by the MMC controller.

 Card detection:
 If no property below is supplied, host native card detect is used.
 Only one of the properties in this section should be supplied:
   - broken-cd: There is no card detection available; polling must be used.
   - cd-gpios: Specify GPIOs for card detection, see gpio binding
   - non-removable: non-removable slot (like eMMC); assume always present.

 Optional properties:
 - bus-width: Number of data lines, can be <1>, <4>, or <8>.  The default
   will be <1> if the property is absent.
 - wp-gpios: Specify GPIOs for write protection, see gpio binding
 - cd-inverted: when present, polarity on the CD line is inverted. See the note
   below for the case, when a GPIO is used for the CD line
 - wp-inverted: when present, polarity on the WP line is inverted. See the note
   below for the case, when a GPIO is used for the WP line
 - disable-wp: When set no physical WP line is present. This property should
   only be specified when the controller has a dedicated write-protect
   detection logic. If a GPIO is always used for the write-protect detection
   logic it is sufficient to not specify wp-gpios property in the absence of a WP
   line.
 - max-frequency: maximum operating clock frequency
 - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
   this system, even if the controller claims it is.
 - cap-sd-highspeed: SD high-speed timing is supported
 - cap-mmc-highspeed: MMC high-speed timing is supported
 - sd-uhs-sdr12: SD UHS SDR12 speed is supported
 - sd-uhs-sdr25: SD UHS SDR25 speed is supported
 - sd-uhs-sdr50: SD UHS SDR50 speed is supported
 - sd-uhs-sdr104: SD UHS SDR104 speed is supported
 - sd-uhs-ddr50: SD UHS DDR50 speed is supported
 - cap-power-off-card: powering off the card is safe
 - cap-mmc-hw-reset: eMMC hardware reset is supported
 - cap-sdio-irq: enable SDIO IRQ signalling on this interface
 - full-pwr-cycle: full power cycle of the card is supported
 - mmc-ddr-3_3v: eMMC high-speed DDR mode(3.3V I/O) is supported
 - mmc-ddr-1_8v: eMMC high-speed DDR mode(1.8V I/O) is supported
 - mmc-ddr-1_2v: eMMC high-speed DDR mode(1.2V I/O) is supported
 - mmc-hs200-1_8v: eMMC HS200 mode(1.8V I/O) is supported
 - mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported
 - mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported
 - mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported
 - mmc-hs400-enhanced-strobe: eMMC HS400 enhanced strobe mode is supported
 - dsr: Value the card's (optional) Driver Stage Register (DSR) should be
   programmed with. Valid range: [0 .. 0xffff].
 - no-sdio: controller is limited to send sdio cmd during initialization
 - no-sd: controller is limited to send sd cmd during initialization
 - no-mmc: controller is limited to send mmc cmd during initialization
 - fixed-emmc-driver-type: for non-removable eMMC, enforce this driver type.
   The value <n> is the driver type as specified in the eMMC specification
   (table 206 in spec version 5.1).

 *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
 polarity properties, we have to fix the meaning of the "normal" and "inverted"
 line levels. We choose to follow the SDHCI standard, which specifies both those
 lines as "active low." Therefore, using the "cd-inverted" property means, that
 the CD line is active high, i.e. it is high, when a card is inserted. Similar
 logic applies to the "wp-inverted" property.

 CD and WP lines can be implemented on the hardware in one of two ways: as GPIOs,
 specified in cd-gpios and wp-gpios properties, or as dedicated pins. Polarity of
 dedicated pins can be specified, using *-inverted properties. GPIO polarity can
 also be specified using the GPIO_ACTIVE_LOW flag. This creates an ambiguity
 in the latter case. We choose to use the XOR logic for GPIO CD and WP lines.
 This means, the two properties are "superimposed," for example leaving the
 GPIO_ACTIVE_LOW flag clear and specifying the respective *-inverted property
 property results in a double-inversion and actually means the "normal" line
 polarity is in effect.

 Optional SDIO properties:
 - keep-power-in-suspend: Preserves card power during a suspend/resume cycle
 - wakeup-source: Enables wake up of host system on SDIO IRQ assertion
 		 (Legacy property supported: "enable-sdio-wakeup")

 MMC power
 ---------

 Controllers may implement power control from both the connected cards and
 the IO signaling (for example to change to high-speed 1.8V signalling). If
 the system supports this, then the following two properties should point
 to valid regulator nodes:

 - vqmmc-supply: supply node for IO line power
 - vmmc-supply: supply node for card's power


 MMC power sequences:
 --------------------

 System on chip designs may specify a specific MMC power sequence. To
 successfully detect an (e)MMC/SD/SDIO card, that power sequence must be
 maintained while initializing the card.

 Optional property:
 - mmc-pwrseq: phandle to the MMC power sequence node. See "mmc-pwrseq-*"
 	for documentation of MMC power sequence bindings.


 Use of Function subnodes
 ------------------------

 On embedded systems the cards connected to a host may need additional
 properties. These can be specified in subnodes to the host controller node.
 The subnodes are identified by the standard 'reg' property.
 Which information exactly can be specified depends on the bindings for the
 SDIO function driver for the subnode, as specified by the compatible string.

 Required host node properties when using function subnodes:
 - #address-cells: should be one. The cell is the slot id.
 - #size-cells: should be zero.

 Required function subnode properties:
 - reg: Must contain the SDIO function number of the function this subnode
        describes. A value of 0 denotes the memory SD function, values from
        1 to 7 denote the SDIO functions.

 Optional function subnode properties:
 - compatible: name of SDIO function following generic names recommended practice


 Examples
 --------

 Basic example:

 sdhci@ab000000 {
 	compatible = "sdhci";
 	reg = <0xab000000 0x200>;
 	interrupts = <23>;
 	bus-width = <4>;
 	cd-gpios = <&gpio 69 0>;
 	cd-inverted;
 	wp-gpios = <&gpio 70 0>;
 	max-frequency = <50000000>;
 	keep-power-in-suspend;
 	wakeup-source;
 	mmc-pwrseq = <&sdhci0_pwrseq>
 }

 Example with sdio function subnode:

 mmc3: mmc@1c12000 {
 	#address-cells = <1>;
 	#size-cells = <0>;

 	pinctrl-names = "default";
 	pinctrl-0 = <&mmc3_pins_a>;
 	vmmc-supply = <&reg_vmmc3>;
 	bus-width = <4>;
 	non-removable;
 	mmc-pwrseq = <&sdhci0_pwrseq>

 	brcmf: bcrmf@1 {
 		reg = <1>;
 		compatible = "brcm,bcm43xx-fmac";
 		interrupt-parent = <&pio>;
 		interrupts = <10 8>; /* PH10 / EINT10 */
 		interrupt-names = "host-wake";
 	};
 };
	These properties are common to multiple MMC host controllers. Any host
	that requires the respective functionality should implement them using
	these definitions.

	Interpreted by the OF core:
	- reg: Registers location and length.
	- interrupts: Interrupts used by the MMC controller.

	Card detection:
	If no property below is supplied, host native card detect is used.
	Only one of the properties in this section should be supplied:
	- broken-cd: There is no card detection available; polling must be used.
	- cd-gpios: Specify GPIOs for card detection, see gpio binding
	- non-removable: non-removable slot (like eMMC); assume always present.

	Optional properties:
	- bus-width: Number of data lines, can be <1>, <4>, or <8>. The default
	will be <1> if the property is absent.
	- wp-gpios: Specify GPIOs for write protection, see gpio binding
	- cd-inverted: when present, polarity on the CD line is inverted. See the note
	below for the case, when a GPIO is used for the CD line
	- wp-inverted: when present, polarity on the WP line is inverted. See the note
	below for the case, when a GPIO is used for the WP line
	- disable-wp: When set no physical WP line is present. This property should
	only be specified when the controller has a dedicated write-protect
	detection logic. If a GPIO is always used for the write-protect detection
	logic it is sufficient to not specify wp-gpios property in the absence of a WP
	line.
	- max-frequency: maximum operating clock frequency
	- no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
	this system, even if the controller claims it is.
	- cap-sd-highspeed: SD high-speed timing is supported
	- cap-mmc-highspeed: MMC high-speed timing is supported
	- sd-uhs-sdr12: SD UHS SDR12 speed is supported
	- sd-uhs-sdr25: SD UHS SDR25 speed is supported
	- sd-uhs-sdr50: SD UHS SDR50 speed is supported
	- sd-uhs-sdr104: SD UHS SDR104 speed is supported
	- sd-uhs-ddr50: SD UHS DDR50 speed is supported
	- cap-power-off-card: powering off the card is safe
	- cap-mmc-hw-reset: eMMC hardware reset is supported
	- cap-sdio-irq: enable SDIO IRQ signalling on this interface
	- full-pwr-cycle: full power cycle of the card is supported
	- mmc-ddr-3_3v: eMMC high-speed DDR mode(3.3V I/O) is supported
	- mmc-ddr-1_8v: eMMC high-speed DDR mode(1.8V I/O) is supported
	- mmc-ddr-1_2v: eMMC high-speed DDR mode(1.2V I/O) is supported
	- mmc-hs200-1_8v: eMMC HS200 mode(1.8V I/O) is supported
	- mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported
	- mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported
	- mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported
	- mmc-hs400-enhanced-strobe: eMMC HS400 enhanced strobe mode is supported
	- dsr: Value the card's (optional) Driver Stage Register (DSR) should be
	programmed with. Valid range: [0 .. 0xffff].
	- no-sdio: controller is limited to send sdio cmd during initialization
	- no-sd: controller is limited to send sd cmd during initialization
	- no-mmc: controller is limited to send mmc cmd during initialization
	- fixed-emmc-driver-type: for non-removable eMMC, enforce this driver type.
	The value <n> is the driver type as specified in the eMMC specification
	(table 206 in spec version 5.1).

	NOTE on CD and WP polarity. To use common for all SD/MMC host controllers line
	polarity properties, we have to fix the meaning of the "normal" and "inverted"
	line levels. We choose to follow the SDHCI standard, which specifies both those
	lines as "active low." Therefore, using the "cd-inverted" property means, that
	the CD line is active high, i.e. it is high, when a card is inserted. Similar
	logic applies to the "wp-inverted" property.

	CD and WP lines can be implemented on the hardware in one of two ways: as GPIOs,
	specified in cd-gpios and wp-gpios properties, or as dedicated pins. Polarity of
	dedicated pins can be specified, using *-inverted properties. GPIO polarity can
	also be specified using the GPIO_ACTIVE_LOW flag. This creates an ambiguity
	in the latter case. We choose to use the XOR logic for GPIO CD and WP lines.
	This means, the two properties are "superimposed," for example leaving the
	GPIO_ACTIVE_LOW flag clear and specifying the respective *-inverted property
	property results in a double-inversion and actually means the "normal" line
	polarity is in effect.

	Optional SDIO properties:
	- keep-power-in-suspend: Preserves card power during a suspend/resume cycle
	- wakeup-source: Enables wake up of host system on SDIO IRQ assertion
	(Legacy property supported: "enable-sdio-wakeup")

	MMC power
	---------

	Controllers may implement power control from both the connected cards and
	the IO signaling (for example to change to high-speed 1.8V signalling). If
	the system supports this, then the following two properties should point
	to valid regulator nodes:

	- vqmmc-supply: supply node for IO line power
	- vmmc-supply: supply node for card's power


	MMC power sequences:
	--------------------

	System on chip designs may specify a specific MMC power sequence. To
	successfully detect an (e)MMC/SD/SDIO card, that power sequence must be
	maintained while initializing the card.

	Optional property:
	- mmc-pwrseq: phandle to the MMC power sequence node. See "mmc-pwrseq-*"
	for documentation of MMC power sequence bindings.


	Use of Function subnodes
	------------------------

	On embedded systems the cards connected to a host may need additional
	properties. These can be specified in subnodes to the host controller node.
	The subnodes are identified by the standard 'reg' property.
	Which information exactly can be specified depends on the bindings for the
	SDIO function driver for the subnode, as specified by the compatible string.

	Required host node properties when using function subnodes:
	- #address-cells: should be one. The cell is the slot id.
	- #size-cells: should be zero.

	Required function subnode properties:
	- reg: Must contain the SDIO function number of the function this subnode
	describes. A value of 0 denotes the memory SD function, values from
	1 to 7 denote the SDIO functions.

	Optional function subnode properties:
	- compatible: name of SDIO function following generic names recommended practice


	Examples
	--------

	Basic example:

	sdhci@ab000000 {
	compatible = "sdhci";
	reg = <0xab000000 0x200>;
	interrupts = <23>;
	bus-width = <4>;
	cd-gpios = <&gpio 69 0>;
	cd-inverted;
	wp-gpios = <&gpio 70 0>;
	max-frequency = <50000000>;
	keep-power-in-suspend;
	wakeup-source;
	mmc-pwrseq = <&sdhci0_pwrseq>
	}

	Example with sdio function subnode:

	mmc3: mmc@1c12000 {
	#address-cells = <1>;
	#size-cells = <0>;

	pinctrl-names = "default";
	pinctrl-0 = <&mmc3_pins_a>;
	vmmc-supply = <&reg_vmmc3>;
	bus-width = <4>;
	non-removable;
	mmc-pwrseq = <&sdhci0_pwrseq>

	brcmf: bcrmf@1 {
	reg = <1>;
	compatible = "brcm,bcm43xx-fmac";
	interrupt-parent = <&pio>;
	interrupts = <10 8>; /* PH10 / EINT10 */
	interrupt-names = "host-wake";
	};
	};