diff options
Diffstat (limited to 'drivers/misc/atmel_tclib.c')
| -rw-r--r-- | drivers/misc/atmel_tclib.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c new file mode 100644 index 00000000000..05dc8a31f28 --- /dev/null +++ b/drivers/misc/atmel_tclib.c @@ -0,0 +1,161 @@ +#include <linux/atmel_tc.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> + +/* Number of bytes to reserve for the iomem resource */ +#define ATMEL_TC_IOMEM_SIZE 256 + + +/* + * This is a thin library to solve the problem of how to portably allocate + * one of the TC blocks. For simplicity, it doesn't currently expect to + * share individual timers between different drivers. + */ + +#if defined(CONFIG_AVR32) +/* AVR32 has these divide PBB */ +const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, }; +EXPORT_SYMBOL(atmel_tc_divisors); + +#elif defined(CONFIG_ARCH_AT91) +/* AT91 has these divide MCK */ +const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, }; +EXPORT_SYMBOL(atmel_tc_divisors); + +#endif + +static DEFINE_SPINLOCK(tc_list_lock); +static LIST_HEAD(tc_list); + +/** + * atmel_tc_alloc - allocate a specified TC block + * @block: which block to allocate + * @name: name to be associated with the iomem resource + * + * Caller allocates a block. If it is available, a pointer to a + * pre-initialized struct atmel_tc is returned. The caller can access + * the registers directly through the "regs" field. + */ +struct atmel_tc *atmel_tc_alloc(unsigned block, const char *name) +{ + struct atmel_tc *tc; + struct platform_device *pdev = NULL; + struct resource *r; + + spin_lock(&tc_list_lock); + list_for_each_entry(tc, &tc_list, node) { + if (tc->pdev->id == block) { + pdev = tc->pdev; + break; + } + } + + if (!pdev || tc->iomem) + goto fail; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + r = request_mem_region(r->start, ATMEL_TC_IOMEM_SIZE, name); + if (!r) + goto fail; + + tc->regs = ioremap(r->start, ATMEL_TC_IOMEM_SIZE); + if (!tc->regs) + goto fail_ioremap; + + tc->iomem = r; + +out: + spin_unlock(&tc_list_lock); + return tc; + +fail_ioremap: + release_resource(r); +fail: + tc = NULL; + goto out; +} +EXPORT_SYMBOL_GPL(atmel_tc_alloc); + +/** + * atmel_tc_free - release a specified TC block + * @tc: Timer/counter block that was returned by atmel_tc_alloc() + * + * This reverses the effect of atmel_tc_alloc(), unmapping the I/O + * registers, invalidating the resource returned by that routine and + * making the TC available to other drivers. + */ +void atmel_tc_free(struct atmel_tc *tc) +{ + spin_lock(&tc_list_lock); + if (tc->regs) { + iounmap(tc->regs); + release_resource(tc->iomem); + tc->regs = NULL; + tc->iomem = NULL; + } + spin_unlock(&tc_list_lock); +} +EXPORT_SYMBOL_GPL(atmel_tc_free); + +static int __init tc_probe(struct platform_device *pdev) +{ + struct atmel_tc *tc; + struct clk *clk; + int irq; + + if (!platform_get_resource(pdev, IORESOURCE_MEM, 0)) + return -EINVAL; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return -EINVAL; + + tc = kzalloc(sizeof(struct atmel_tc), GFP_KERNEL); + if (!tc) + return -ENOMEM; + + tc->pdev = pdev; + + clk = clk_get(&pdev->dev, "t0_clk"); + if (IS_ERR(clk)) { + kfree(tc); + return -EINVAL; + } + + tc->clk[0] = clk; + tc->clk[1] = clk_get(&pdev->dev, "t1_clk"); + if (IS_ERR(tc->clk[1])) + tc->clk[1] = clk; + tc->clk[2] = clk_get(&pdev->dev, "t2_clk"); + if (IS_ERR(tc->clk[2])) + tc->clk[2] = clk; + + tc->irq[0] = irq; + tc->irq[1] = platform_get_irq(pdev, 1); + if (tc->irq[1] < 0) + tc->irq[1] = irq; + tc->irq[2] = platform_get_irq(pdev, 2); + if (tc->irq[2] < 0) + tc->irq[2] = irq; + + spin_lock(&tc_list_lock); + list_add_tail(&tc->node, &tc_list); + spin_unlock(&tc_list_lock); + + return 0; +} + +static struct platform_driver tc_driver = { + .driver.name = "atmel_tcb", +}; + +static int __init tc_init(void) +{ + return platform_driver_probe(&tc_driver, tc_probe); +} +arch_initcall(tc_init); |