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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-11 11:30:41 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-11 11:30:41 -0800 |
commit | b58ed041a360ed051fab17e4d9b0f451c6fedba7 (patch) | |
tree | c21db4bc5042821cae320213652b2dbec880a58d /Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt | |
parent | 259cdbee2094d28b72f0f3d77bc9203d682994ff (diff) | |
parent | 58fea354d887fddddd342a8d14b02069161ca904 (diff) |
Merge tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux-2.6
Pull device tree changes from Grant Likely:
"Here are the DT changes I've got queued up for v3.8. As described
below, there are a lot of bug fixes here and documentation updates but
nothing major:
Bug fixes, little cleanups, and documentation changes. The most
invasive thing here touches a bunch of the arch directories to use a
common build rule for .dtb files. There are no major changes to
functionality here other than a few new helper functions."
* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux-2.6: (34 commits)
arm64: Fix the dtbs target building
mtd: nand: davinci: fix the binding documentation
rtc: rtc-mv: Add the device tree binding documentation
devicetree/bindings: Move gpio-leds binding into leds directory
of/vendor-prefixes: add Imagination Technologies
microblaze: use new common dtc rule
c6x: use new common dtc rule
openrisc: use new common dtc rule
arm64: Add dtbs target for building all the enabled dtb files
arm64: use new common dtc rule
ARM: dt: change .dtb build rules to build in dts directory
kbuild: centralize .dts->.dtb rule
Fix build when CONFIG_W1_MASTER_GPIO=m b exporting "allnodes"
of/spi: Honour "status=disabled" property of device
of_mdio: Honour "status=disabled" property of device
of_i2c: Honour "status=disabled" property of device
powerpc: Fix fallout from device_node->name constification
of: add 'const' for of_parse_phandle parameter *np
Documentation: correct of_platform_populate() argument list
script: dtc: clean generated files
...
Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt')
-rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt b/Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt new file mode 100644 index 00000000000..569b1624851 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-pxa-pci-ce4100.txt @@ -0,0 +1,93 @@ +CE4100 I2C +---------- + +CE4100 has one PCI device which is described as the I2C-Controller. This +PCI device has three PCI-bars, each bar contains a complete I2C +controller. So we have a total of three independent I2C-Controllers +which share only an interrupt line. +The driver is probed via the PCI-ID and is gathering the information of +attached devices from the devices tree. +Grant Likely recommended to use the ranges property to map the PCI-Bar +number to its physical address and to use this to find the child nodes +of the specific I2C controller. This were his exact words: + + Here's where the magic happens. Each entry in + ranges describes how the parent pci address space + (middle group of 3) is translated to the local + address space (first group of 2) and the size of + each range (last cell). In this particular case, + the first cell of the local address is chosen to be + 1:1 mapped to the BARs, and the second is the + offset from be base of the BAR (which would be + non-zero if you had 2 or more devices mapped off + the same BAR) + + ranges allows the address mapping to be described + in a way that the OS can interpret without + requiring custom device driver code. + +This is an example which is used on FalconFalls: +------------------------------------------------ + i2c-controller@b,2 { + #address-cells = <2>; + #size-cells = <1>; + compatible = "pci8086,2e68.2", + "pci8086,2e68", + "pciclass,ff0000", + "pciclass,ff00"; + + reg = <0x15a00 0x0 0x0 0x0 0x0>; + interrupts = <16 1>; + + /* as described by Grant, the first number in the group of + * three is the bar number followed by the 64bit bar address + * followed by size of the mapping. The bar address + * requires also a valid translation in parents ranges + * property. + */ + ranges = <0 0 0x02000000 0 0xdffe0500 0x100 + 1 0 0x02000000 0 0xdffe0600 0x100 + 2 0 0x02000000 0 0xdffe0700 0x100>; + + i2c@0 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "intel,ce4100-i2c-controller"; + + /* The first number in the reg property is the + * number of the bar + */ + reg = <0 0 0x100>; + + /* This I2C controller has no devices */ + }; + + i2c@1 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "intel,ce4100-i2c-controller"; + reg = <1 0 0x100>; + + /* This I2C controller has one gpio controller */ + gpio@26 { + #gpio-cells = <2>; + compatible = "ti,pcf8575"; + reg = <0x26>; + gpio-controller; + }; + }; + + i2c@2 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "intel,ce4100-i2c-controller"; + reg = <2 0 0x100>; + + gpio@26 { + #gpio-cells = <2>; + compatible = "ti,pcf8575"; + reg = <0x26>; + gpio-controller; + }; + }; + }; |