diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/eeprom/at24.txt | 3 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-mtk.txt | 1 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-xscale.txt | 20 | ||||
| -rw-r--r-- | Documentation/i2c/fault-codes | 4 | ||||
| -rw-r--r-- | Documentation/i2c/gpio-fault-injection | 61 |
5 files changed, 86 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt b/Documentation/devicetree/bindings/eeprom/at24.txt index f9a7c984274c..0e456bbc1213 100644 --- a/Documentation/devicetree/bindings/eeprom/at24.txt +++ b/Documentation/devicetree/bindings/eeprom/at24.txt @@ -75,6 +75,8 @@ Optional properties: - address-width: number of address bits (one of 8, 16). + - num-addresses: total number of i2c slave addresses this device takes + Example: eeprom@52 { @@ -82,4 +84,5 @@ eeprom@52 { reg = <0x52>; pagesize = <32>; wp-gpios = <&gpio1 3 0>; + num-addresses = <8>; }; diff --git a/Documentation/devicetree/bindings/i2c/i2c-mtk.txt b/Documentation/devicetree/bindings/i2c/i2c-mtk.txt index e199695b1c96..ee4c32454198 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-mtk.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-mtk.txt @@ -10,6 +10,7 @@ Required properties: "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. diff --git a/Documentation/devicetree/bindings/i2c/i2c-xscale.txt b/Documentation/devicetree/bindings/i2c/i2c-xscale.txt new file mode 100644 index 000000000000..dcc8390e0d24 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-xscale.txt @@ -0,0 +1,20 @@ +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>; +}; diff --git a/Documentation/i2c/fault-codes b/Documentation/i2c/fault-codes index 47c25abb7d52..0cee0fc545b4 100644 --- a/Documentation/i2c/fault-codes +++ b/Documentation/i2c/fault-codes @@ -112,6 +112,10 @@ EPROTO 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. diff --git a/Documentation/i2c/gpio-fault-injection b/Documentation/i2c/gpio-fault-injection index a4ce62090fd5..c87f416d53dd 100644 --- a/Documentation/i2c/gpio-fault-injection +++ b/Documentation/i2c/gpio-fault-injection @@ -1,3 +1,4 @@ +========================= Linux I2C fault injection ========================= @@ -13,6 +14,9 @@ mounted at /sys/kernel/debug. There will be a separate subdirectory per GPIO 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" ----- @@ -34,10 +38,10 @@ I2C specification version 4, section 3.1.16) using the helpers of the Linux I2C 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: @@ -79,3 +83,54 @@ This is why bus recovery (up to 9 clock pulses) must either check SDA or send 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. |