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author | Sascha Hauer <s.hauer@pengutronix.de> | 2014-06-30 11:07:24 +0200 |
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committer | Ulf Hansson <ulf.hansson@linaro.org> | 2015-01-19 09:56:26 +0100 |
commit | a31edf1e582111f05fb8315da9dd118c837bede5 (patch) | |
tree | dd9b22fc3771e1044de7e6f1b7546f488cbd9f43 /Documentation/devicetree/bindings/mmc | |
parent | 9b449e99924f1530d9dae8de52392582a6ce8972 (diff) | |
download | op-kernel-dev-a31edf1e582111f05fb8315da9dd118c837bede5.zip op-kernel-dev-a31edf1e582111f05fb8315da9dd118c837bede5.tar.gz |
mmc: Add SDIO function subnode DT documentation
While SDIO devices are runtime probable they sometimes need nonprobable
additional information on embedded systems, like an additional gpio
interrupt or a clock. This binding describes how to add child nodes to the
devicetree to supply this information.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[hdegoede@redhat.com: Documented the need for #address- and #size-cells]
[hdegoede@redhat.com: Added a real world example]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'Documentation/devicetree/bindings/mmc')
-rw-r--r-- | Documentation/devicetree/bindings/mmc/mmc.txt | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt index b52628b..bac1311 100644 --- a/Documentation/devicetree/bindings/mmc/mmc.txt +++ b/Documentation/devicetree/bindings/mmc/mmc.txt @@ -64,7 +64,31 @@ Optional SDIO properties: - keep-power-in-suspend: Preserves card power during a suspend/resume cycle - enable-sdio-wakeup: Enables wake up of host system on SDIO IRQ assertion -Example: + +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: +- compatible: name of SDIO function following generic names recommended practice +- 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. + + +Examples +-------- + +Basic example: sdhci@ab000000 { compatible = "sdhci"; @@ -78,3 +102,25 @@ sdhci@ab000000 { keep-power-in-suspend; enable-sdio-wakeup; } + +Example with sdio function subnode: + +mmc3: mmc@01c12000 { + #address-cells = <1>; + #size-cells = <0>; + + pinctrl-names = "default"; + pinctrl-0 = <&mmc3_pins_a>; + vmmc-supply = <®_vmmc3>; + bus-width = <4>; + non-removable; + status = "okay"; + + brcmf: bcrmf@1 { + reg = <1>; + compatible = "brcm,bcm43xx-fmac"; + interrupt-parent = <&pio>; + interrupts = <10 8>; /* PH10 / EINT10 */ + interrupt-names = "host-wake"; + }; +}; |