diff options
Diffstat (limited to 'arch/arm/plat-omap/common.c')
-rw-r--r-- | arch/arm/plat-omap/common.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c index 57b7b93..fecd3d6 100644 --- a/arch/arm/plat-omap/common.c +++ b/arch/arm/plat-omap/common.c @@ -156,3 +156,53 @@ static int __init omap_add_serial_console(void) return add_preferred_console("ttyS", line, opt); } console_initcall(omap_add_serial_console); + + +/* + * 32KHz clocksource ... always available, on pretty most chips except + * OMAP 730 and 1510. Other timers could be used as clocksources, with + * higher resolution in free-running counter modes (e.g. 12 MHz xtal), + * but systems won't necessarily want to spend resources that way. + */ + +#if defined(CONFIG_ARCH_OMAP16XX) +#define TIMER_32K_SYNCHRONIZED 0xfffbc410 +#elif defined(CONFIG_ARCH_OMAP24XX) +#define TIMER_32K_SYNCHRONIZED 0x48004010 +#endif + +#ifdef TIMER_32K_SYNCHRONIZED + +#include <linux/clocksource.h> + +static cycle_t omap_32k_read(void) +{ + return omap_readl(TIMER_32K_SYNCHRONIZED); +} + +static struct clocksource clocksource_32k = { + .name = "32k_counter", + .rating = 250, + .read = omap_32k_read, + .mask = CLOCKSOURCE_MASK(32), + .shift = 10, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init omap_init_clocksource_32k(void) +{ + static char err[] __initdata = KERN_ERR + "%s: can't register clocksource!\n"; + + if (cpu_is_omap16xx() || cpu_is_omap24xx()) { + clocksource_32k.mult = clocksource_hz2mult(32768, + clocksource_32k.shift); + + if (clocksource_register(&clocksource_32k)) + printk(err, clocksource_32k.name); + } + return 0; +} +arch_initcall(omap_init_clocksource_32k); + +#endif /* TIMER_32K_SYNCHRONIZED */ |