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clocksource: dw_apb_timer_of: add clock-handling

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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: Heiko Stuebner <heiko@sntech.de>
Acked-by: Jamie Iles <jamie@jamieiles.com>
This commit is contained in:
Heiko Stuebner 2013-06-04 11:37:36 +02:00
parent a1198f8340
commit a8b447f2bb
2 changed files with 44 additions and 1 deletions
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19
Documentation/devicetree/bindings/rtc/dw-apb.txt
View file

@ -5,9 +5,20 @@ Required properties:
- reg: physical base address of the controller and length of memory mapped
region.
- 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-freq: For backwards compatibility with picoxcell
If using the clock specifiers, the pclk clock is optional, as not all
systems may use one.
Example:
timer1: timer@ffc09000 {
@ -23,3 +34,11 @@ Example:
clock-frequency = <200000000>;
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";
};

26
drivers/clocksource/dw_apb_timer_of.c
View file

@ -20,6 +20,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clk.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
@ -27,14 +28,37 @@
static void timer_get_base_and_rate(struct device_node *np,
void __iomem **base, u32 *rate)
{
struct clk *timer_clk;
struct clk *pclk;
*base = of_iomap(np, 0);
if (!*base)
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) &&
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)