kernel/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/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/export.h>
  12 #include <linux/of.h>
  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  *
  39  * Caller allocates a block.  If it is available, a pointer to a
  40  * pre-initialized struct atmel_tc is returned. The caller can access
  41  * the registers directly through the "regs" field.
  42  */
  43 struct atmel_tc *atmel_tc_alloc(unsigned block)
  44 {
  45         struct atmel_tc         *tc;
  46         struct platform_device  *pdev = NULL;
  47
  48         spin_lock(&tc_list_lock);
  49         list_for_each_entry(tc, &tc_list, node) {
  50                 if (tc->allocated)
  51                         continue;
  52
  53                 if ((tc->pdev->dev.of_node && tc->id == block) ||
  54                     (tc->pdev->id == block)) {
  55                         pdev = tc->pdev;
  56                         tc->allocated = true;
  57                         break;
  58                 }
  59         }
  60         spin_unlock(&tc_list_lock);
  61
  62         return pdev ? tc : NULL;
  63 }
  64 EXPORT_SYMBOL_GPL(atmel_tc_alloc);
  65
  66 /**
  67  * atmel_tc_free - release a specified TC block
  68  * @tc: Timer/counter block that was returned by atmel_tc_alloc()
  69  *
  70  * This reverses the effect of atmel_tc_alloc(), invalidating the resource
  71  * returned by that routine and making the TC available to other drivers.
  72  */
  73 void atmel_tc_free(struct atmel_tc *tc)
  74 {
  75         spin_lock(&tc_list_lock);
  76         if (tc->allocated)
  77                 tc->allocated = false;
  78         spin_unlock(&tc_list_lock);
  79 }
  80 EXPORT_SYMBOL_GPL(atmel_tc_free);
  81
  82 #if defined(CONFIG_OF)
  83 static struct atmel_tcb_config tcb_rm9200_config = {
  84         .counter_width = 16,
  85 };
  86
  87 static struct atmel_tcb_config tcb_sam9x5_config = {
  88         .counter_width = 32,
  89 };
  90
  91 static const struct of_device_id atmel_tcb_dt_ids[] = {
  92         {
  93                 .compatible = "atmel,at91rm9200-tcb",
  94                 .data = &tcb_rm9200_config,
  95         }, {
  96                 .compatible = "atmel,at91sam9x5-tcb",
  97                 .data = &tcb_sam9x5_config,
  98         }, {
  99                 /* sentinel */
 100         }
 101 };
 102
 103 MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
 104 #endif
 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         struct resource *r;
 112         unsigned int    i;
 113
 114         irq = platform_get_irq(pdev, 0);
 115         if (irq < 0)
 116                 return -EINVAL;
 117
 118         tc = devm_kzalloc(&pdev->dev, sizeof(struct atmel_tc), GFP_KERNEL);
 119         if (!tc)
 120                 return -ENOMEM;
 121
 122         tc->pdev = pdev;
 123
 124         clk = devm_clk_get(&pdev->dev, "t0_clk");
 125         if (IS_ERR(clk))
 126                 return PTR_ERR(clk);
 127
 128         tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk");
 129         if (IS_ERR(tc->slow_clk))
 130                 return PTR_ERR(tc->slow_clk);
 131
 132         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 133         tc->regs = devm_ioremap_resource(&pdev->dev, r);
 134         if (IS_ERR(tc->regs))
 135                 return PTR_ERR(tc->regs);
 136
 137         /* Now take SoC information if available */
 138         if (pdev->dev.of_node) {
 139                 const struct of_device_id *match;
 140                 match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node);
 141                 if (match)
 142                         tc->tcb_config = match->data;
 143
 144                 tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb");
 145         } else {
 146                 tc->id = pdev->id;
 147         }
 148
 149         tc->clk[0] = clk;
 150         tc->clk[1] = devm_clk_get(&pdev->dev, "t1_clk");
 151         if (IS_ERR(tc->clk[1]))
 152                 tc->clk[1] = clk;
 153         tc->clk[2] = devm_clk_get(&pdev->dev, "t2_clk");
 154         if (IS_ERR(tc->clk[2]))
 155                 tc->clk[2] = clk;
 156
 157         tc->irq[0] = irq;
 158         tc->irq[1] = platform_get_irq(pdev, 1);
 159         if (tc->irq[1] < 0)
 160                 tc->irq[1] = irq;
 161         tc->irq[2] = platform_get_irq(pdev, 2);
 162         if (tc->irq[2] < 0)
 163                 tc->irq[2] = irq;
 164
 165         for (i = 0; i < 3; i++)
 166                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
 167
 168         spin_lock(&tc_list_lock);
 169         list_add_tail(&tc->node, &tc_list);
 170         spin_unlock(&tc_list_lock);
 171
 172         platform_set_drvdata(pdev, tc);
 173
 174         return 0;
 175 }
 176
 177 static void tc_shutdown(struct platform_device *pdev)
 178 {
 179         int i;
 180         struct atmel_tc *tc = platform_get_drvdata(pdev);
 181
 182         for (i = 0; i < 3; i++)
 183                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
 184 }
 185
 186 static struct platform_driver tc_driver = {
 187         .driver = {
 188                 .name   = "atmel_tcb",
 189                 .of_match_table = of_match_ptr(atmel_tcb_dt_ids),
 190         },
 191         .shutdown = tc_shutdown,
 192 };
 193
 194 static int __init tc_init(void)
 195 {
 196         return platform_driver_probe(&tc_driver, tc_probe);
 197 }
 198 arch_initcall(tc_init);