Add documentation for device tree binding of NVIDIA's Tegra i2c
controller driver.
Describing all compatible values used for diffenent Tegra SoCs
in details in this documentation.
Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
---
.../devicetree/bindings/i2c/nvidia,tegra20-i2c.txt | 99 ++++++++++++++++++++
1 files changed, 99 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt
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 0000000..e390ce8
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt
@@ -0,0 +1,99 @@
+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".
+
+
+Typical i2c node for Tegra20:
+ 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";
+ };
+
+Typical dvc-i2c node for Tegra20:
+ i2c@7000d000 {
+ compatible = "nvidia,tegra20-i2c-dvc";
+ reg = <0x7000d000 0x200>;
+ interrupts = <0 53 0x04>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ clocks = <&tegra_car 47>, <&tegra_car 124>;
+ clock-names = "div-clk", "fast-clk";
+ status = "disabled";
+ };
+
+Typical i2c node for Tegra30:
+ i2c@7000c000 {
+ compatible = "nvidia,tegra30-i2c", "nvidia,tegra20-i2c";
+ reg = <0x7000c000 0x100>;
+ interrupts = <0 38 0x04>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ clocks = <&tegra_car 12>, <&tegra_car 182>;
+ clock-names = "div-clk", "fast-clk";
+ status = "disabled";
+ };
+
+Typical i2c node for Tegra114:
+ i2c@7000c000 {
+ compatible = "nvidia,tegra114-i2c";
+ reg = <0x7000c000 0x100>;
+ interrupts = <0 38 0x04>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+ clocks = <&tegra_car 12>;
+ clock-names = "div-clk";
+ };
--
1.7.1.1
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