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author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-12-15 14:52:16 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-12-15 14:52:16 -0300 |
commit | 8d91c1e411f55d7ea91b1183a2e9f8088fb4d5be (patch) | |
tree | e9891aa6c295060d065adffd610c4f49ecf884f3 /Documentation/devicetree/bindings/i2c/i2c.txt | |
parent | a71852147516bc1cb5b0b3cbd13639bfd4022dc8 (diff) |
Linux-libre 4.3.2-gnu
Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c.txt')
-rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c.txt | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt new file mode 100644 index 000000000..8a99150ac --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c.txt @@ -0,0 +1,45 @@ +Generic device tree bindings for I2C busses +=========================================== + +This document describes generic bindings which can be used to describe I2C +busses in a device tree. + +Required properties +------------------- + +- #address-cells - should be <1>. Read more about addresses below. +- #size-cells - should be <0>. +- compatible - name of I2C bus controller following generic names + recommended practice. + +For other required properties e.g. to describe register sets, +clocks, etc. check the binding documentation of the specific driver. + +The cells properties above define that an address of children of an I2C bus +are described by a single value. This is usually a 7 bit address. However, +flags can be attached to the address. I2C_TEN_BIT_ADDRESS is used to mark a 10 +bit address. It is needed to avoid the ambiguity between e.g. a 7 bit address +of 0x50 and a 10 bit address of 0x050 which, in theory, can be on the same bus. +Another flag is I2C_OWN_SLAVE_ADDRESS to mark addresses on which we listen to +be devices ourselves. + +Optional properties +------------------- + +These properties may not be supported by all drivers. However, if a driver +wants to support one of the below features, it should adapt the bindings below. + +- clock-frequency - frequency of bus clock in Hz. +- wakeup-source - device can be used as a wakeup source. + +- interrupts - interrupts used by the device. +- interrupt-names - "irq" and "wakeup" names are recognized by I2C core, + other names are left to individual drivers. + +Binding may contain optional "interrupts" property, describing interrupts +used by the device. I2C core will assign "irq" interrupt (or the very first +interrupt if not using interrupt names) as primary interrupt for the slave. + +Also, if device is marked as a wakeup source, I2C core will set up "wakeup" +interrupt for the device. If "wakeup" interrupt name is not present in the +binding, then primary interrupt will be used as wakeup interrupt. |