diff options
Diffstat (limited to 'Documentation/devicetree/bindings/i2c')
5 files changed, 151 insertions, 5 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt new file mode 100644 index 00000000000..1ac8ea8ade1 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt @@ -0,0 +1,80 @@ +GPIO-based I2C Arbitration Using a Challenge & Response Mechanism +================================================================= +This uses GPIO lines and a challenge & response mechanism to arbitrate who is +the master of an I2C bus in a multimaster situation. + +In many cases using GPIOs to arbitrate is not needed and a design can use +the standard I2C multi-master rules. Using GPIOs is generally useful in +the case where there is a device on the bus that has errata and/or bugs +that makes standard multimaster mode not feasible. + + +Algorithm: + +All masters on the bus have a 'bus claim' line which is an output that the +others can see. These are all active low with pull-ups enabled. We'll +describe these lines as: + +- OUR_CLAIM: output from us signaling to other hosts that we want the bus +- THEIR_CLAIMS: output from others signaling that they want the bus + +The basic algorithm is to assert your line when you want the bus, then make +sure that the other side doesn't want it also. A detailed explanation is best +done with an example. + +Let's say we want to claim the bus. We: +1. Assert OUR_CLAIM. +2. Waits a little bit for the other sides to notice (slew time, say 10 + microseconds). +3. Check THEIR_CLAIMS. If none are asserted then the we have the bus and we are + done. +4. Otherwise, wait for a few milliseconds and see if THEIR_CLAIMS are released. +5. If not, back off, release the claim and wait for a few more milliseconds. +6. Go back to 1 (until retry time has expired). + + +Required properties: +- compatible: i2c-arb-gpio-challenge +- our-claim-gpio: The GPIO that we use to claim the bus. +- their-claim-gpios: The GPIOs that the other sides use to claim the bus. + Note that some implementations may only support a single other master. +- Standard I2C mux properties. See mux.txt in this directory. +- Single I2C child bus node at reg 0. See mux.txt in this directory. + +Optional properties: +- slew-delay-us: microseconds to wait for a GPIO to go high. Default is 10 us. +- wait-retry-us: we'll attempt another claim after this many microseconds. + Default is 3000 us. +- wait-free-us: we'll give up after this many microseconds. Default is 50000 us. + + +Example: + i2c@12CA0000 { + compatible = "acme,some-i2c-device"; + #address-cells = <1>; + #size-cells = <0>; + }; + + i2c-arbitrator { + compatible = "i2c-arb-gpio-challenge"; + #address-cells = <1>; + #size-cells = <0>; + + i2c-parent = <&{/i2c@12CA0000}>; + + our-claim-gpio = <&gpf0 3 1>; + their-claim-gpios = <&gpe0 4 1>; + slew-delay-us = <10>; + wait-retry-us = <3000>; + wait-free-us = <50000>; + + i2c@0 { + reg = <0>; + #address-cells = <1>; + #size-cells = <0>; + + i2c@52 { + // Normal I2C device + }; + }; + }; diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt index 7a3fe9e5f4c..4e1c8ac01eb 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt @@ -3,10 +3,13 @@ Required properties: - compatible: Should be "fsl,<chip>-i2c" - reg: Should contain registers location and length -- interrupts: Should contain ERROR and DMA interrupts +- interrupts: Should contain ERROR interrupt number - clock-frequency: Desired I2C bus clock frequency in Hz. Only 100000Hz and 400000Hz modes are supported. -- fsl,i2c-dma-channel: APBX DMA channel for the I2C +- dmas: DMA specifier, consisting of a phandle to DMA controller node + and I2C DMA channel ID. + Refer to dma.txt and fsl-mxs-dma.txt for details. +- dma-names: Must be "rx-tx". Examples: @@ -15,7 +18,8 @@ i2c0: i2c@80058000 { #size-cells = <0>; compatible = "fsl,imx28-i2c"; reg = <0x80058000 2000>; - interrupts = <111 68>; + interrupts = <111>; clock-frequency = <100000>; - fsl,i2c-dma-channel = <6>; + dmas = <&dma_apbx 6>; + dma-names = "rx-tx"; }; diff --git a/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt b/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt index f98d4c5b5cc..296eb453612 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt @@ -26,7 +26,7 @@ Required for all cases except "samsung,s3c2440-hdmiphy-i2c": - pinctrl-names: Should contain only one value - "default". Optional properties: - - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not + - samsung,i2c-slave-addr: Slave address in multi-master environment. If not specified, default value is 0. - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not specified, the default value in Hz is 100000. diff --git a/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt new file mode 100644 index 00000000000..ef77cc7a0e4 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt @@ -0,0 +1,60 @@ +NVIDIA Tegra20/Tegra30/Tegra114 I2C controller driver. + +Required properties: +- compatible : should be: + "nvidia,tegra114-i2c" + "nvidia,tegra30-i2c" + "nvidia,tegra20-i2c" + "nvidia,tegra20-i2c-dvc" + Details of compatible are as follows: + nvidia,tegra20-i2c-dvc: Tegra20 has specific I2C controller called as DVC I2C + controller. This only support master mode of I2C communication. Register + interface/offset and interrupts handling are different than generic I2C + controller. Driver of DVC I2C controller is only compatible with + "nvidia,tegra20-i2c-dvc". + nvidia,tegra20-i2c: Tegra20 has 4 generic I2C controller. This can support + master and slave mode of I2C communication. The i2c-tegra driver only + support master mode of I2C communication. Driver of I2C controller is + only compatible with "nvidia,tegra20-i2c". + nvidia,tegra30-i2c: Tegra30 has 5 generic I2C controller. This controller is + very much similar to Tegra20 I2C controller with additional feature: + Continue Transfer Support. This feature helps to implement M_NO_START + as per I2C core API transfer flags. Driver of I2C controller is + compatible with "nvidia,tegra30-i2c" to enable the continue transfer + support. This is also compatible with "nvidia,tegra20-i2c" without + continue transfer support. + nvidia,tegra114-i2c: Tegra114 has 5 generic I2C controller. This controller is + very much similar to Tegra30 I2C controller with some hardware + modification: + - Tegra30/Tegra20 I2C controller has 2 clock source called div-clk and + fast-clk. Tegra114 has only one clock source called as div-clk and + hence clock mechanism is changed in I2C controller. + - Tegra30/Tegra20 I2C controller has enabled per packet transfer by + default and there is no way to disable it. Tegra114 has this + interrupt disable by default and SW need to enable explicitly. + Due to above changes, Tegra114 I2C driver makes incompatible with + previous hardware driver. Hence, tegra114 I2C controller is compatible + with "nvidia,tegra114-i2c". +- reg: Should contain I2C controller registers physical address and length. +- interrupts: Should contain I2C controller interrupts. +- address-cells: Address cells for I2C device address. +- size-cells: Size of the I2C device address. +- clocks: Clock ID as per + Documentation/devicetree/bindings/clock/tegra<chip-id>.txt + for I2C controller. +- clock-names: Name of the clock: + Tegra20/Tegra30 I2C controller: "div-clk and "fast-clk". + Tegra114 I2C controller: "div-clk". + +Example: + + i2c@7000c000 { + compatible = "nvidia,tegra20-i2c"; + reg = <0x7000c000 0x100>; + interrupts = <0 38 0x04>; + #address-cells = <1>; + #size-cells = <0>; + clocks = <&tegra_car 12>, <&tegra_car 124>; + clock-names = "div-clk", "fast-clk"; + status = "disabled"; + }; diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt index 446859fcdca..ad6a73852f0 100644 --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt @@ -35,6 +35,8 @@ fsl,mc13892 MC13892: Power Management Integrated Circuit (PMIC) for i.MX35/51 fsl,mma8450 MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer fsl,mpr121 MPR121: Proximity Capacitive Touch Sensor Controller fsl,sgtl5000 SGTL5000: Ultra Low-Power Audio Codec +infineon,slb9635tt Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz) +infineon,slb9645tt Infineon SLB9645 I2C TPM (new protocol, max 400khz) maxim,ds1050 5 Bit Programmable, Pulse-Width Modulator maxim,max1237 Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs maxim,max6625 9-Bit/12-Bit Temperature Sensors with I²C-Compatible Serial Interface |