[PATCH 2/4] devicetree: serial: Document msm_serial bindings
From: Kumar Gala <hidden>
Date: 2013-08-20 14:41:21
Also in:
linux-arm-msm, linux-serial, lkml
On Aug 19, 2013, at 4:39 PM, Stephen Boyd wrote:
quoted hunk ↗ jump to hunk
The msm serial device bindings were added to the DTS files but never documented. Let's document them now and also fix things up so that it's clearer what hardware is supported. Instead of using hsuart (for high speed uart), let's use uartdm because that matches the actual name of the hardware. Also, let's add the version information in case we need to differentiate between different versions of the hardware in the future. Cc: David Brown <redacted> Cc: <redacted> Signed-off-by: Stephen Boyd <redacted> --- .../devicetree/bindings/serial/msm_serial.txt | 82 ++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 Documentation/devicetree/bindings/serial/msm_serial.txtdiff --git a/Documentation/devicetree/bindings/serial/msm_serial.txt b/Documentation/devicetree/bindings/serial/msm_serial.txt new file mode 100644 index 0000000..a6efac3 --- /dev/null +++ b/Documentation/devicetree/bindings/serial/msm_serial.txt@@ -0,0 +1,82 @@ +* MSM Serial UART and UARTDM + +There are two MSM serial hardware designs. UARTDM is designed for use with a +dma engine in high-speed use cases and the non-DM design is for lower speed use +cases. The two designs are mostly compatible from a software perspective except +the non-DM design can only read and write one character at a time and so the +register layout differs slightly.
I think you split this into two binding spec docs, one for each type of uart.
+ +UART +---- +Required properties: +- compatible: Should contain "qcom,msm-uart" +- reg: Should contain UART register location and length. The first
first? is there more than one reg region?
+ register shall specify the main control registers +- interrupts: Should contain UART interrupt. +- clocks: Should contain the core clock. +- clock-names: Should be "core_clk". + +Optional properties: +- dmas: Should contain dma specifiers for transmit and receive +- dma-names: Should contain "tx" for transmit and "rx" for receive
confused, above you say the non-DM doesn't support DMA so, why the optional props?
+
+Example:
+
+A uart device with dma capabilities.
+
+serial at a9c00000 {
+ compatible = "qcom,msm-uart";
+ reg = <0xa9c00000 0x1000>;
+ interrupts = <11>;
+ clocks = <&uart_cxc>;
+ clock-names = "core_clk";
+ dmas = <&dma0 0>, <&dma0 1>;
+ dma-names = "tx", "rx";
+};
+
+UARTDM
+------
+Required properties:
+- compatible: Should contain at least "qcom,msm-uartdm".
+ A more specific property should be specified as follows depending
+ on the version:
+ "qcom,msm-uartdm-v1.1"
+ "qcom,msm-uartdm-v1.2"
+ "qcom,msm-uartdm-v1.3"
+ "qcom,msm-uartdm-v1.4"
+- reg: Should contain UART register locations and lengths. The first
+ register shall specify the main control registers. An optional second
+ register location shall specify the GSBI control region.Is GSBI region existing tied to particular versions (if so can we say that) reg-names?
+- interrupts: Should contain UART interrupt. +- clocks: Should contain the core clock and the ahb clock.
nit, ahb in caps?
+- clock-names: Should be "core_clk" for the core clock and "iface_clk" for the
+ ahb clock.
+
+Optional properties:
+- dmas: Should contain dma specifiers for transmit and receive channels
+- dma-names: Should contain "tx" for transmit and "rx" for receive channels
+
+Examples:
+
+A uartdm v1.4 device with dma capabilities.
+
+serial at f991e000 {
+ compatible = "qcom,msm-uartdm-v1.4", "qcom,msm-uartdm";
+ reg = <0xf991e000 0x1000>;
+ interrupts = <0 108 0x0>;
+ clocks = <&blsp1_uart2_apps_cxc>, <&blsp1_ahb_cxc>;
+ clock-names = "core_clk", "iface_clk";
+ dmas = <&dma0 0>, <&dma0 1>;
+ dma-names = "tx", "rx";
+};
+
+A uartdm v1.3 device without dma capabilities.
+
+serial at 19c40000 {
+ compatible = "qcom,msm-uartdm-v1.3", "qcom,msm-uartdm";
+ reg = <0x19c40000 0x1000>,
+ <0x19c00000 0x1000>;
+ interrupts = <0 195 0x0>;
+ clocks = <&gsbi5_uart_cxc>, <&gsbi5_ahb_cxc>;
+ clock-names = "core_clk", "iface_clk";
+};
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