7a59b00a09
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>
34 lines
1.3 KiB
Plaintext
34 lines
1.3 KiB
Plaintext
Generic device tree bindings for I2C busses
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===========================================
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This document describes generic bindings which can be used to describe I2C
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busses in a device tree.
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Required properties
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-------------------
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- #address-cells - should be <1>. Read more about addresses below.
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- #size-cells - should be <0>.
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- compatible - name of I2C bus controller following generic names
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recommended practice.
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For other required properties e.g. to describe register sets, interrupts,
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clocks, etc. check the binding documentation of the specific driver.
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The cells properties above define that an address of children of an I2C bus
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are described by a single value. This is usually a 7 bit address. However,
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flags can be attached to the address. I2C_TEN_BIT_ADDRESS is used to mark a 10
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bit address. It is needed to avoid the ambiguity between e.g. a 7 bit address
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of 0x50 and a 10 bit address of 0x050 which, in theory, can be on the same bus.
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Another flag is I2C_OWN_SLAVE_ADDRESS to mark addresses on which we listen to
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be devices ourselves.
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Optional properties
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-------------------
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These properties may not be supported by all drivers. However, if a driver
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wants to support one of the below features, it should adapt the bindings below.
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- clock-frequency - frequency of bus clock in Hz
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- wakeup-source - device can be used as a wakeup source.
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