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/**
* @file
* @brief Provide @ref clocksource functionality for OMAP
*
* FileName: arch/arm/mach-omap/s32k_clksource.c
*
* @ref clocksource provides a neat architecture. all we do is
* To loop in with Sync 32Khz clock ticking away at 32768hz on OMAP.
* Sync 32Khz clock is an always ON clock.
*
*/
/*
* (C) Copyright 2008
* Texas Instruments, <www.ti.com>
* Nishanth Menon <x0nishan@ti.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <clock.h>
#include <init.h>
#include <io.h>
#include <mach/silicon.h>
#include <mach/clocks.h>
#include <mach/timers.h>
#include <mach/sys_info.h>
#include <mach/syslib.h>
/**
* @brief Provide a simple clock read
*
* Nothing is simpler.. read direct from clock and provide it
* to the caller.
*
* @return S32K clock counter
*/
static uint64_t s32k_clocksource_read(void)
{
return readl(S32K_CR);
}
/* A bit obvious isn't it? */
static struct clocksource s32k_cs = {
.read = s32k_clocksource_read,
.mask = CLOCKSOURCE_MASK(32),
.shift = 10,
};
/**
* @brief Initialize the Clock
*
* There is nothing to do on OMAP as SYNC32K clock is
* always on, and we do a simple data structure initialization.
* 32K clock gives 32768 ticks a seconds
*
* @return result of @ref init_clock
*/
static int s32k_clocksource_init(void)
{
s32k_cs.mult = clocksource_hz2mult(S32K_FREQUENCY, s32k_cs.shift);
return init_clock(&s32k_cs);
}
/* Run me at boot time */
core_initcall(s32k_clocksource_init);
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