From 7a59b00a0906945f7fe25a10332ac0820491a0c3 Mon Sep 17 00:00:00 2001 From: Wolfram Sang <wsa+renesas@sang-engineering.com> Date: Sat, 8 Aug 2015 13:35:18 +0200 Subject: [PATCH] i2c: dt: describe generic bindings Start a new file which describes the generic bindings used for I2C with device tree. So we have a central place to look for them, increase visibility of them, and hopefully reduce the amount of custom properties introduced. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> --- Documentation/devicetree/bindings/i2c/i2c.txt | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt new file mode 100644 index 00000000000000..1175efed4a41b5 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c.txt @@ -0,0 +1,33 @@ +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, interrupts, +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. -- GitLab