metag: init common clk and use "core" clk (caa279dd) · Commits · 戴 / test

Documentation/devicetree/bindings/metag/meta.txt

0 → 100644

+30 −0

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		* Meta Processor Binding

		This binding specifies what properties must be available in the device tree
		representation of a Meta Processor Core, which is the root node in the tree.

		Required properties:

		- compatible: Specifies the compatibility list for the Meta processor.
		The type shall be <string> and the value shall include "img,meta".

		Optional properties:

		- clocks: Clock consumer specifiers as described in
		Documentation/devicetree/bindings/clock/clock-bindings.txt

		- clock-names: Clock consumer names as described in
		Documentation/devicetree/bindings/clock/clock-bindings.txt.

		Clocks are identified by name. Valid clocks are:

		- "core": The Meta core clock from which the Meta timers are derived.

		* Examples

		/ {
		compatible = "toumaz,tz1090", "img,meta";

		clocks = <&meta_core_clk>;
		clock-names = "core";
		};

arch/metag/include/asm/clock.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -19,6 +19,8 @@
		* core frequency will be determined like this:
		* Meta 1: based on loops_per_jiffy.
		* Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
		* If a "core" clock is provided by the device tree, it
		* will override this function.
		*/
		struct meta_clock_desc {
		unsigned long (*get_core_freq)(void);
		@@ -26,6 +28,12 @@ struct meta_clock_desc {

		extern struct meta_clock_desc _meta_clock;

		/*
		* Perform platform clock initialisation, reading clocks from device tree etc.
		* Only accessible during boot.
		*/
		void init_metag_clocks(void);

		/*
		* Set up the default clock, ensuring all callbacks are valid - only accessible
		* during boot.

arch/metag/kernel/clock.c

+56 −1

Original line number	Diff line number	Diff line
		@@ -8,8 +8,10 @@
		* published by the Free Software Foundation.
		*/

		#include <linux/clk.h>
		#include <linux/delay.h>
		#include <linux/io.h>
		#include <linux/of.h>

		#include <asm/param.h>
		#include <asm/clock.h>
		@@ -34,8 +36,61 @@ static unsigned long get_core_freq_default(void)
		#endif
		}

		static struct clk *clk_core;

		/* Clk based get_core_freq callback. */
		static unsigned long get_core_freq_clk(void)
		{
		return clk_get_rate(clk_core);
		}

		/**
		* init_metag_core_clock() - Set up core clock from devicetree.
		*
		* Checks to see if a "core" clock is provided in the device tree, and overrides
		* the get_core_freq callback to use it.
		*/
		static void __init init_metag_core_clock(void)
		{
		/*
		* See if a core clock is provided by the devicetree (and
		* registered by the init callback above).
		*/
		struct device_node *node;
		node = of_find_compatible_node(NULL, NULL, "img,meta");
		if (!node) {
		pr_warn("%s: no compatible img,meta DT node found\n",
		__func__);
		return;
		}

		clk_core = of_clk_get_by_name(node, "core");
		if (IS_ERR(clk_core)) {
		pr_warn("%s: no core clock found in DT\n",
		__func__);
		return;
		}

		/*
		* Override the core frequency callback to use
		* this clk.
		*/
		_meta_clock.get_core_freq = get_core_freq_clk;
		}

		/**
		* init_metag_clocks() - Set up clocks from devicetree.
		*
		* Set up important clocks from device tree. In particular any needed for clock
		* sources.
		*/
		void __init init_metag_clocks(void)
		{
		init_metag_core_clock();
		}

		/**
		* setup_meta_clocks() - Set up the Meta clock.
		* setup_meta_clocks() - Early set up of the Meta clock.
		* @desc: Clock descriptor usually provided by machine description
		*
		* Ensures all callbacks are valid.

arch/metag/kernel/time.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -5,11 +5,21 @@
		*
		*/

		#include <linux/init.h>

		#include <clocksource/metag_generic.h>
		#include <linux/clk-provider.h>
		#include <linux/init.h>
		#include <asm/clock.h>

		void __init time_init(void)
		{
		#ifdef CONFIG_COMMON_CLK
		/* Init clocks from device tree */
		of_clk_init(NULL);
		#endif

		/* Init meta clocks, particularly the core clock */
		init_metag_clocks();

		/* Set up the timer clock sources */
		metag_generic_timer_init();
		}

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