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 #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 */
  23 const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
  24 EXPORT_SYMBOL(atmel_tc_divisors);
  25
  26 #elif defined(CONFIG_ARCH_AT91)
  27 /* AT91 has these divide MCK */
  28 const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
  29 EXPORT_SYMBOL(atmel_tc_divisors);
  30
  31 #endif
  32
  33 static DEFINE_SPINLOCK(tc_list_lock);
  34 static 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  */
  45 struct 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
  73 out:
  74         spin_unlock(&tc_list_lock);
  75         return tc;
  76
  77 fail_ioremap:
  78         release_resource(r);
  79 fail:
  80         tc = NULL;
  81         goto out;
  82 }
  83 EXPORT_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  */
  93 void atmel_tc_free(struct atmel_tc *tc)
  94 {
  95         spin_lock(&tc_list_lock);
  96         if (tc->regs) {
  97                 iounmap(tc->regs);
  98                 release_resource(tc->iomem);
  99                 tc->regs = NULL;
 100                 tc->iomem = NULL;
 101         }
 102         spin_unlock(&tc_list_lock);
 103 }
 104 EXPORT_SYMBOL_GPL(atmel_tc_free);
 105
 106 static 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
 154 static struct platform_driver tc_driver = {
 155         .driver.name    = "atmel_tcb",
 156 };
 157
 158 static int __init tc_init(void)
 159 {
 160         return platform_driver_probe(&tc_driver, tc_probe);
 161 }
 162 arch_initcall(tc_init);