drivers/misc/atmel_tclib.c

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