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/drivers/misc/atmel_tclib.c

https://bitbucket.org/ndreys/linux-sunxi
C | 162 lines | 109 code | 28 blank | 25 comment | 15 complexity | c94c1af8caab40b1afffc444dfd526e2 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1#include <linux/atmel_tc.h>
  2#include <linux/clk.h>
  3#include <linux/err.h>
  4#include <linux/init.h>
  5#include <linux/io.h>
  6#include <linux/ioport.h>
  7#include <linux/kernel.h>
  8#include <linux/platform_device.h>
  9#include <linux/slab.h>
 10
 11/* Number of bytes to reserve for the iomem resource */
 12#define ATMEL_TC_IOMEM_SIZE	256
 13
 14
 15/*
 16 * This is a thin library to solve the problem of how to portably allocate
 17 * one of the TC blocks.  For simplicity, it doesn't currently expect to
 18 * share individual timers between different drivers.
 19 */
 20
 21#if defined(CONFIG_AVR32)
 22/* AVR32 has these divide PBB */
 23const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
 24EXPORT_SYMBOL(atmel_tc_divisors);
 25
 26#elif defined(CONFIG_ARCH_AT91)
 27/* AT91 has these divide MCK */
 28const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
 29EXPORT_SYMBOL(atmel_tc_divisors);
 30
 31#endif
 32
 33static DEFINE_SPINLOCK(tc_list_lock);
 34static LIST_HEAD(tc_list);
 35
 36/**
 37 * atmel_tc_alloc - allocate a specified TC block
 38 * @block: which block to allocate
 39 * @name: name to be associated with the iomem resource
 40 *
 41 * Caller allocates a block.  If it is available, a pointer to a
 42 * pre-initialized struct atmel_tc is returned. The caller can access
 43 * the registers directly through the "regs" field.
 44 */
 45struct atmel_tc *atmel_tc_alloc(unsigned block, const char *name)
 46{
 47	struct atmel_tc		*tc;
 48	struct platform_device	*pdev = NULL;
 49	struct resource		*r;
 50
 51	spin_lock(&tc_list_lock);
 52	list_for_each_entry(tc, &tc_list, node) {
 53		if (tc->pdev->id == block) {
 54			pdev = tc->pdev;
 55			break;
 56		}
 57	}
 58
 59	if (!pdev || tc->iomem)
 60		goto fail;
 61
 62	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 63	r = request_mem_region(r->start, ATMEL_TC_IOMEM_SIZE, name);
 64	if (!r)
 65		goto fail;
 66
 67	tc->regs = ioremap(r->start, ATMEL_TC_IOMEM_SIZE);
 68	if (!tc->regs)
 69		goto fail_ioremap;
 70
 71	tc->iomem = r;
 72
 73out:
 74	spin_unlock(&tc_list_lock);
 75	return tc;
 76
 77fail_ioremap:
 78	release_mem_region(r->start, ATMEL_TC_IOMEM_SIZE);
 79fail:
 80	tc = NULL;
 81	goto out;
 82}
 83EXPORT_SYMBOL_GPL(atmel_tc_alloc);
 84
 85/**
 86 * atmel_tc_free - release a specified TC block
 87 * @tc: Timer/counter block that was returned by atmel_tc_alloc()
 88 *
 89 * This reverses the effect of atmel_tc_alloc(), unmapping the I/O
 90 * registers, invalidating the resource returned by that routine and
 91 * making the TC available to other drivers.
 92 */
 93void atmel_tc_free(struct atmel_tc *tc)
 94{
 95	spin_lock(&tc_list_lock);
 96	if (tc->regs) {
 97		iounmap(tc->regs);
 98		release_mem_region(tc->iomem->start, ATMEL_TC_IOMEM_SIZE);
 99		tc->regs = NULL;
100		tc->iomem = NULL;
101	}
102	spin_unlock(&tc_list_lock);
103}
104EXPORT_SYMBOL_GPL(atmel_tc_free);
105
106static int __init tc_probe(struct platform_device *pdev)
107{
108	struct atmel_tc *tc;
109	struct clk	*clk;
110	int		irq;
111
112	if (!platform_get_resource(pdev, IORESOURCE_MEM, 0))
113		return -EINVAL;
114
115	irq = platform_get_irq(pdev, 0);
116	if (irq < 0)
117		return -EINVAL;
118
119	tc = kzalloc(sizeof(struct atmel_tc), GFP_KERNEL);
120	if (!tc)
121		return -ENOMEM;
122
123	tc->pdev = pdev;
124
125	clk = clk_get(&pdev->dev, "t0_clk");
126	if (IS_ERR(clk)) {
127		kfree(tc);
128		return -EINVAL;
129	}
130
131	tc->clk[0] = clk;
132	tc->clk[1] = clk_get(&pdev->dev, "t1_clk");
133	if (IS_ERR(tc->clk[1]))
134		tc->clk[1] = clk;
135	tc->clk[2] = clk_get(&pdev->dev, "t2_clk");
136	if (IS_ERR(tc->clk[2]))
137		tc->clk[2] = clk;
138
139	tc->irq[0] = irq;
140	tc->irq[1] = platform_get_irq(pdev, 1);
141	if (tc->irq[1] < 0)
142		tc->irq[1] = irq;
143	tc->irq[2] = platform_get_irq(pdev, 2);
144	if (tc->irq[2] < 0)
145		tc->irq[2] = irq;
146
147	spin_lock(&tc_list_lock);
148	list_add_tail(&tc->node, &tc_list);
149	spin_unlock(&tc_list_lock);
150
151	return 0;
152}
153
154static struct platform_driver tc_driver = {
155	.driver.name	= "atmel_tcb",
156};
157
158static int __init tc_init(void)
159{
160	return platform_driver_probe(&tc_driver, tc_probe);
161}
162arch_initcall(tc_init);