| /** |
| * @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 <asm/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); |