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