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authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-09 02:16:26 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-09 02:16:26 +0300
commitacceba598eda9817bc187f3a683a2d2ee7e7fbc7 (patch)
tree761b3950789d5eee179b75ecdafafc988ee42a46 /Documentation/devicetree/bindings/i2c/i2c.txt
parentc19176154b464c861e49355eff636aa6896735b5 (diff)
parent5a73882fd2c3a86b502d54da532d373a1f2db15e (diff)
downloadlinux-acceba598eda9817bc187f3a683a2d2ee7e7fbc7.tar.xz
Merge branch 'i2c/for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang: "Features: - new drivers: Renesas EMEV2, register based MUX, NXP LPC2xxx - core: scans DT and assigns wakeup interrupts. no driver changes needed. - core: some refcouting issues fixed and better API for that - core: new helper function for best effort block read emulation - slave framework: proper DT bindings and userspace instantiation - some bigger work for xiic, pxa, omap drivers .. and quite a number of smaller driver fixes, cleanups, improvements" * 'i2c/for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (65 commits) i2c: mux: reg Change ioread endianness for readback i2c: mux: reg: fix compilation warnings i2c: mux: reg: simplify register size checking i2c: muxes: fix leaked i2c adapter device node references i2c: allow specifying separate wakeup interrupt in device tree of/irq: export of_get_irq_byname() i2c: xgene-slimpro: dma_mapping_error() doesn't return an error code i2c: Replace I2C_CROS_EC_TUNNEL dependency eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated i2c: core: Add support for best effort block read emulation i2c: lpc2k: add driver i2c: mux: Add register-based mux i2c-mux-reg i2c: dt: describe generic bindings i2c: slave: print warning if slave flag not set i2c: support 10 bit and slave addresses in sysfs 'new_device' i2c: take address space into account when checking for used addresses i2c: apply DT flags when probing i2c: make address check indpendent from client struct i2c: rename address check functions i2c: apply address offset for slaves, too ...
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+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.