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