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Commit a8b447f2 authored by Heiko Stuebner's avatar Heiko Stuebner
Browse files

clocksource: dw_apb_timer_of: add clock-handling 



Add the possibility to get the clock-frequency from a timer clock instead
of specifying it as dt property. Additionally also add the possibility
to also define a controlling periphal clock for the timer block.

The clock-frequency property is kept to act as fallback if no clocks
are specified.

Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
Acked-by: default avatarJamie Iles <jamie@jamieiles.com>
parent a1198f83

Documentation/devicetree/bindings/rtc/dw-apb.txt

+19 −0
Original line number Original line Diff line number Diff line
@@ -5,9 +5,20 @@ Required properties: 
- reg: physical base address of the controller and length of memory mapped

- reg: physical base address of the controller and length of memory mapped

  region.

  region.

- interrupts: IRQ line for the timer.

- interrupts: IRQ line for the timer.

- either clocks+clock-names or clock-frequency properties



Optional properties:

- clocks	: list of clock specifiers, corresponding to entries in

		  the clock-names property;

- clock-names	: should contain "timer" and "pclk" entries, matching entries

		  in the clocks property.

- clock-frequency: The frequency in HZ of the timer.

- clock-frequency: The frequency in HZ of the timer.

- clock-freq: For backwards compatibility with picoxcell

- clock-freq: For backwards compatibility with picoxcell





If using the clock specifiers, the pclk clock is optional, as not all

systems may use one.





Example:

Example:





		timer1: timer@ffc09000 {

		timer1: timer@ffc09000 {
@@ -23,3 +34,11 @@ Example: 
				clock-frequency = <200000000>;

				clock-frequency = <200000000>;

				reg = <0xffd00000 0x1000>;

				reg = <0xffd00000 0x1000>;

			};

			};



		timer3: timer@ffe00000 {

				compatible = "snps,dw-apb-timer-osc";

				interrupts = <0 170 4>;

				reg = <0xffe00000 0x1000>;

				clocks = <&timer_clk>, <&timer_pclk>;

				clock-names = "timer", "pclk";

			};

drivers/clocksource/dw_apb_timer_of.c

+25 −1
Original line number Original line Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/of.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_address.h>

#include <linux/of_irq.h>

#include <linux/of_irq.h>

#include <linux/clk.h>





#include <asm/mach/time.h>

#include <asm/mach/time.h>

#include <asm/sched_clock.h>

#include <asm/sched_clock.h>
@@ -27,14 +28,37 @@ 
static void timer_get_base_and_rate(struct device_node *np,

static void timer_get_base_and_rate(struct device_node *np,

				    void __iomem **base, u32 *rate)

				    void __iomem **base, u32 *rate)

{

{

	struct clk *timer_clk;

	struct clk *pclk;



	*base = of_iomap(np, 0);

	*base = of_iomap(np, 0);





	if (!*base)

	if (!*base)

		panic("Unable to map regs for %s", np->name);

		panic("Unable to map regs for %s", np->name);





	/*

	 * Not all implementations use a periphal clock, so don't panic

	 * if it's not present

	 */

	pclk = of_clk_get_by_name(np, "pclk");

	if (!IS_ERR(pclk))

		if (clk_prepare_enable(pclk))

			pr_warn("pclk for %s is present, but could not be activated\n",

				np->name);



	timer_clk = of_clk_get_by_name(np, "timer");

	if (IS_ERR(timer_clk))

		goto try_clock_freq;



	if (!clk_prepare_enable(timer_clk)) {

		*rate = clk_get_rate(timer_clk);

		return;

	}



try_clock_freq:

	if (of_property_read_u32(np, "clock-freq", rate) &&

	if (of_property_read_u32(np, "clock-freq", rate) &&

		of_property_read_u32(np, "clock-frequency", rate))

		of_property_read_u32(np, "clock-frequency", rate))

		panic("No clock-frequency property for %s", np->name);

		panic("No clock nor clock-frequency property for %s", np->name);

}

}





static void add_clockevent(struct device_node *event_timer)

static void add_clockevent(struct device_node *event_timer)