On Wed, Apr 15, 2020 at 12:51:00PM +0200, Wolfram Sang wrote: > Some bindings are for the bus master, some are for the slaves. > Regroup them and give them seperate headings to make it clear. > Also, remove references to "generic names" which is for nodes and not > for compatibles. ^ This last sentence is the change since V1. Thanks to Rob for the suggestion! > > Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c.txt | 66 +++++++++++-------- > 1 file changed, 39 insertions(+), 27 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index 9a53df4243c6..819436b48fae 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > @@ -2,32 +2,26 @@ Generic device tree bindings for I2C busses > =========================================== > > This document describes generic bindings which can be used to describe I2C > -busses in a device tree. > +busses and their child devices in a device tree. > > -Required properties > -------------------- > +Required properties (per bus) > +----------------------------- > > - #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. > +- compatible - name of I2C bus controller > > 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. > +are described by a single value. > > -Optional properties > -------------------- > +Optional properties (per bus) > +----------------------------- > > 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. > +wants to support one of the below features, it should adapt these bindings. > > - clock-frequency > frequency of bus clock in Hz. > @@ -73,31 +67,49 @@ wants to support one of the below features, it should adapt the bindings below. > i2c bus clock frequency (clock-frequency). > Specified in Hz. > > -- interrupts > - interrupts used by the device. > - > -- interrupt-names > - "irq", "wakeup" and "smbus_alert" names are recognized by I2C core, > - other names are left to individual drivers. > - > -- host-notify > - device uses SMBus host notify protocol instead of interrupt line. > - > - multi-master > states that there is another master active on this bus. The OS can use > this information to adapt power management to keep the arbitration awake > all the time, for example. > > -- wakeup-source > - device can be used as a wakeup source. > +Required properties (per child device) > +-------------------------------------- > + > +- compatible > + name of I2C slave device > > - reg > - I2C slave addresses > + One or many I2C slave addresses. These are usually a 7 bit addresses. > + However, flags can be attached to an 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 (per child device) > +-------------------------------------- > + > +These properties may not be supported by all drivers. However, if a driver > +wants to support one of the below features, it should adapt these bindings. > + > +- host-notify > + device uses SMBus host notify protocol instead of interrupt line. > + > +- interrupts > + interrupts used by the device. > + > +- interrupt-names > + "irq", "wakeup" and "smbus_alert" names are recognized by I2C core, > + other names are left to individual drivers. > > - reg-names > Names of map programmable addresses. > It can contain any map needing another address than default one. > > +- wakeup-source > + device can be used as a wakeup source. > + > 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. > -- > 2.20.1 >
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