Merge branch 'i2c/for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

  - address-width: number of address bits (one of 8, 16).

  - num-addresses: total number of i2c slave addresses this device takes

Example:

eeprom@52 {

	reg = <0x52>;

	pagesize = <32>;

	wp-gpios = <&gpio1 3 0>;

	num-addresses = <8>;

};

      "mediatek,mt6589-i2c": for MediaTek MT6589

      "mediatek,mt7622-i2c": for MediaTek MT7622

      "mediatek,mt7623-i2c", "mediatek,mt6577-i2c": for MediaTek MT7623

      "mediatek,mt7629-i2c", "mediatek,mt2712-i2c": for MediaTek MT7629

      "mediatek,mt8173-i2c": for MediaTek MT8173

  - reg: physical base address of the controller and dma base, length of memory

    mapped region.

i2c Controller on XScale platforms such as IOP3xx and IXP4xx

Required properties:

- compatible : Must be one of

  "intel,iop3xx-i2c"

  "intel,ixp4xx-i2c";

- reg

- #address-cells = <1>;

- #size-cells = <0>;

Optional properties:

- Child nodes conforming to i2c bus binding

Example:

i2c@c8011000 {

	compatible = "intel,ixp4xx-i2c";

	reg = <0xc8011000 0x18>;

	interrupts = <33 IRQ_TYPE_LEVEL_LOW>;

};

	case is when the length of an SMBus block data response

	(from the SMBus slave) is outside the range 1-32 bytes.

ESHUTDOWN

	Returned when a transfer was requested using an adapter

	which is already suspended.

ETIMEDOUT

	This is returned by drivers when an operation took too much

	time, and was aborted before it completed.

=========================

Linux I2C fault injection

=========================

driven I2C bus. Each subdirectory will contain files to trigger the fault

injection. They will be described now along with their intended use-cases.

Wire states

===========

"scl"

-----

core (see 'struct bus_recovery_info'). However, the bus recovery will not

succeed because SDA is still pinned low until you manually release it again

with "echo 1 > sda". A test with an automatic release can be done with the

following class of fault injectors.

"incomplete transfers" class of fault injectors.

Introduction to incomplete transfers

------------------------------------

Incomplete transfers

====================

The following fault injectors create situations where SDA will be held low by a

device. Bus recovery should be able to fix these situations. But please note:

additional STOP conditions to ensure the bus has been released. Otherwise

random data will be written to a device!

Lost arbitration

================

Here, we want to simulate the condition where the master under test loses the

bus arbitration against another master in a multi-master setup.

"lose_arbitration"

------------------

This file is write only and you need to write the duration of the arbitration

intereference (in µs, maximum is 100ms). The calling process will then sleep

and wait for the next bus clock. The process is interruptible, though.

Arbitration lost is achieved by waiting for SCL going down by the master under

test and then pulling SDA low for some time. So, the I2C address sent out

should be corrupted and that should be detected properly. That means that the

address sent out should have a lot of '1' bits to be able to detect corruption.

There doesn't need to be a device at this address because arbitration lost

should be detected beforehand. Also note, that SCL going down is monitored

using interrupts, so the interrupt latency might cause the first bits to be not

corrupted. A good starting point for using this fault injector on an otherwise

idle bus is:

# echo 200 > lose_arbitration &

# i2cget -y <bus_to_test> 0x3f

Panic during transfer

=====================

This fault injector will create a Kernel panic once the master under test

started a transfer. This usually means that the state machine of the bus master

driver will be ungracefully interrupted and the bus may end up in an unusual

state. Use this to check if your shutdown/reboot/boot code can handle this

scenario.

"inject_panic"

--------------

This file is write only and you need to write the delay between the detected

start of a transmission and the induced Kernel panic (in µs, maximum is 100ms).

The calling process will then sleep and wait for the next bus clock. The

process is interruptible, though.

Start of a transfer is detected by waiting for SCL going down by the master

under test.  A good starting point for using this fault injector is:

# echo 0 > inject_panic &

# i2cget -y <bus_to_test> <some_address>

Note that there doesn't need to be a device listening to the address you are

using. Results may vary depending on that, though.