Thread (18 messages) 18 messages, 11 authors, 2014-03-05

Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

From: Mark Rutland <mark.rutland@arm.com>
Date: 2014-02-21 11:01:43
Also in: linux-arm-kernel, linux-arm-msm, linux-i2c, lkml

On Fri, Feb 21, 2014 at 12:38:09AM +0000, Bjorn Andersson wrote:
quoted hunk ↗ jump to hunk
From: "Ivan T. Ivanov" <redacted>

The Qualcomm Universal Peripherial (QUP) wraps I2C mini-core and
provide input and output FIFO's for it. I2C controller can operate
as master with supported bus speeds of 100Kbps and 400Kbps.

Signed-off-by: Ivan T. Ivanov <redacted>
[bjorn: reformulated part of binding description
        added version to compatible
        cleaned up example]
Signed-off-by: Bjorn Andersson <redacted>
---
 .../devicetree/bindings/i2c/qcom,i2c-qup.txt       |   44 ++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
new file mode 100644
index 0000000..38d505f
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
@@ -0,0 +1,44 @@
+Qualcomm Universal Peripheral (QUP) I2C controller
+
+Required properties:
+ - compatible: Should be
+		"qcom,i2c-qup-v1.1.1" for 8660, 8960 and 8064.
+		"qcom,i2c-qup-v2.1.1" for 8974 v1.
+		"qcom,i2c-qup-v2.2.1" for 8974 v2 and later.
+ - reg: Should contain QUP register address and length.
+ - interrupts: Should contain I2C interrupt.
+
+ - clocks: Should contain the core clock and the AHB clock.
+ - clock-names: Should be "core" for the core clock and "iface" for the
+                AHB clock.
Could you please describe clocks in terms of clock-names? It makes the
relationship clearer, and avoids redundancy (which makes extending the
bindnig easier):

- clocks: A list of phandles + clock-specifiers, one for each entry in
  clock-names.
- clock-names: should contain:
  * "core" for the core clock
  * "iface" for the AHB clock

Cheers,
Mark.
+
+ - #address-cells: Should be <1> Address cells for i2c device address
+ - #size-cells: Should be <0> as i2c addresses have no size component
+
+Optional properties:
+ - clock-frequency: Should specify the desired i2c bus clock frequency in Hz,
+                    defaults to 100kHz if omitted.
+
+Child nodes should conform to i2c bus binding.
+
+Example:
+
+ i2c@f9924000 {
+ 	compatible = "qcom,i2c-qup-v2.2.1";
+ 	reg = <0xf9924000 0x1000>;
+ 	interrupts = <0 96 0>;
+
+ 	clocks = <&gcc GCC_BLSP1_QUP2_I2C_APPS_CLK>, <&gcc GCC_BLSP1_AHB_CLK>;
+ 	clock-names = "core", "iface";
+
+ 	clock-frequency = <355000>;
+
+ 	#address-cells = <1>;
+ 	#size-cells = <0>;
+
+ 	dummy@60 {
+ 		compatible = "dummy";
+ 		reg = <0x60>;
+ 	};
+ };
+
-- 
1.7.9.5
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