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-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-rk3x.txt14
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
index dde6c22ce91a..f0d71bc52e64 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
@@ -21,6 +21,17 @@ Required on RK3066, RK3188 :
Optional properties :
- clock-frequency : SCL frequency to use (in Hz). If omitted, 100kHz is used.
+ - i2c-scl-rising-time-ns : Number of nanoseconds the SCL signal takes to rise
+ (t(r) in I2C specification). If not specified this is assumed to be
+ the maximum the specification allows(1000 ns for Standard-mode,
+ 300 ns for Fast-mode) which might cause slightly slower communication.
+ - i2c-scl-falling-time-ns : Number of nanoseconds the SCL signal takes to fall
+ (t(f) in the I2C specification). If not specified this is assumed to
+ be the maximum the specification allows (300 ns) which might cause
+ slightly slower communication.
+ - i2c-sda-falling-time-ns : Number of nanoseconds the SDA signal takes to fall
+ (t(f) in the I2C specification). If not specified we'll use the SCL
+ value since they are the same in nearly all cases.
Example:
@@ -39,4 +50,7 @@ i2c0: i2c@2002d000 {
clock-names = "i2c";
clocks = <&cru PCLK_I2C0>;
+
+ i2c-scl-rising-time-ns = <800>;
+ i2c-scl-falling-time-ns = <100>;
};