/* * linux/arch/arm/mach-sa1100/clock.c */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/string.h> #include <linux/clk.h> #include <linux/spinlock.h> #include <asm/hardware.h> #include <asm/semaphore.h> struct clk { struct list_head node; unsigned long rate; struct module *owner; const char *name; unsigned int enabled; void (*enable)(void); void (*disable)(void); }; static LIST_HEAD(clocks); static DECLARE_MUTEX(clocks_sem); static DEFINE_SPINLOCK(clocks_lock); struct clk *clk_get(struct device *dev, const char *id) { struct clk *p, *clk = ERR_PTR(-ENOENT); down(&clocks_sem); list_for_each_entry(p, &clocks, node) { if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) { clk = p; break; } } up(&clocks_sem); return clk; } EXPORT_SYMBOL(clk_get); void clk_put(struct clk *clk) { module_put(clk->owner); } EXPORT_SYMBOL(clk_put); int clk_enable(struct clk *clk) { unsigned long flags; spin_lock_irqsave(&clocks_lock, flags); if (clk->enabled++ == 0) clk->enable(); spin_unlock_irqrestore(&clocks_lock, flags); return 0; } EXPORT_SYMBOL(clk_enable); void clk_disable(struct clk *clk) { unsigned long flags; WARN_ON(clk->enabled == 0); spin_lock_irqsave(&clocks_lock, flags); if (--clk->enabled == 0) clk->disable(); spin_unlock_irqrestore(&clocks_lock, flags); } EXPORT_SYMBOL(clk_disable); unsigned long clk_get_rate(struct clk *clk) { return clk->rate; } EXPORT_SYMBOL(clk_get_rate); static void clk_gpio27_enable(void) { /* * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111: * (SA-1110 Developer's Manual, section 9.1.2.1) */ GAFR |= GPIO_32_768kHz; GPDR |= GPIO_32_768kHz; TUCR = TUCR_3_6864MHz; } static void clk_gpio27_disable(void) { TUCR = 0; GPDR &= ~GPIO_32_768kHz; GAFR &= ~GPIO_32_768kHz; } static struct clk clk_gpio27 = { .name = "GPIO27_CLK", .rate = 3686400, .enable = clk_gpio27_enable, .disable = clk_gpio27_disable, }; int clk_register(struct clk *clk) { down(&clocks_sem); list_add(&clk->node, &clocks); up(&clocks_sem); return 0; } EXPORT_SYMBOL(clk_register); void clk_unregister(struct clk *clk) { down(&clocks_sem); list_del(&clk->node); up(&clocks_sem); } EXPORT_SYMBOL(clk_unregister); static int __init clk_init(void) { clk_register(&clk_gpio27); return 0; } arch_initcall(clk_init);