dt-bindings: cpufreq_trace: Introduce bindings for cpufreq-hw debug/trace

Qualcomm Technologies, Inc. CPUFREQ Hardware Debug Trace Bindings

--------------------------------------------------------------------

CPUFREQ Trace provide the support to capture CPUFREQ_HW debug and trace.

CPUFREQ HW debug and trace is used by Qualcomm Technologies, Inc. (QTI)  to

capture trace packets from various clock domains. If applicable trace mode

could be set to periodic or xor. Also, it enables the print for CPUFREQ_HW debug

registers.

Required Properties:

- compatible: shall contain the following:

		"qcom,cpufreq-hw-debug-trace" or "qcom,cpufreq-hw-epss-debug".

- reg: shall contain base register location and length.

- reg-names: shall contain the frequency domain name.

Optional Properties:

- qcom,freq-hw-domain: phandle to the frequency domain device node.

Usage :

The following debug node would get created under qcom-cpufreq-hw directory.

== Trace Enable/Debug ==

- clock_domain_packet_sel

Function:	Set and clear clock domain and trace packet

Input:		echo 1 2 1 > clock_domain_packet_sel (domain 1, packet 2, set)

		echo 1 2 1 > clock_domain_packet_sel (domain 1, packet 2, clear)

- clock_timer

Function:	Enable/Disable Clock Timer

Input:		echo 0 > clk_timer;

		echo 1 > clk_timer;

		cat clk_timer;

- trace_enable

Function:	Enable and disable global trace

Input:		echo 1 > trace_enable

		echo 0 > trace_enable

		cat trace_enable

- trace_type

Function:	Set trace type to XOR or PERIODIC

Input:		echo xor >  trace_type;

		echo periodic >  trace_type;

		cat trace_type;

- print_cpufreq_trace_regs

Function:	Print cpufreq hw trace registers

Input:		cat print_cpufreq_trace_regs

== CPUFREQ-HW Register ==

- print_cpufreq_debug_regs

Function:	Print cpufreq hardware debug registers

Input:		cat print_cpufreq_debug_regs

Example:

	cpufreq_hw_trace: qcom,cpufreq-hw-trace {

		compatible = "qcom,cpufreq-hw-trace";

		reg = <0x18320000 0x800>;

		reg-names = "domain-top";

		qcom,freq-hw-domain = <&cpufreq_hw 0>, <&cpufreq_hw 1>,

					<&cpufreq_hw 2>;

	};