drivers/misc/atmel_tclib.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   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 #include <soc/at91/atmel_tcb.h>
  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  *
  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)
  45 {
  46         struct atmel_tc         *tc;
  47         struct platform_device  *pdev = NULL;
  48
  49         spin_lock(&tc_list_lock);
  50         list_for_each_entry(tc, &tc_list, node) {
  51                 if (tc->allocated)
  52                         continue;
  53
  54                 if ((tc->pdev->dev.of_node && tc->id == block) ||
  55                     (tc->pdev->id == block)) {
  56                         pdev = tc->pdev;
  57                         tc->allocated = true;
  58                         break;
  59                 }
  60         }
  61         spin_unlock(&tc_list_lock);
  62
  63         return pdev ? tc : NULL;
  64 }
  65 EXPORT_SYMBOL_GPL(atmel_tc_alloc);
  66
  67 /**
  68  * atmel_tc_free - release a specified TC block
  69  * @tc: Timer/counter block that was returned by atmel_tc_alloc()
  70  *
  71  * This reverses the effect of atmel_tc_alloc(), invalidating the resource
  72  * returned by that routine and making the TC available to other drivers.
  73  */
  74 void atmel_tc_free(struct atmel_tc *tc)
  75 {
  76         spin_lock(&tc_list_lock);
  77         if (tc->allocated)
  78                 tc->allocated = false;
  79         spin_unlock(&tc_list_lock);
  80 }
  81 EXPORT_SYMBOL_GPL(atmel_tc_free);
  82
  83 #if defined(CONFIG_OF)
  84 static struct atmel_tcb_config tcb_rm9200_config = {
  85         .counter_width = 16,
  86 };
  87
  88 static struct atmel_tcb_config tcb_sam9x5_config = {
  89         .counter_width = 32,
  90 };
  91
  92 static const struct of_device_id atmel_tcb_dt_ids[] = {
  93         {
  94                 .compatible = "atmel,at91rm9200-tcb",
  95                 .data = &tcb_rm9200_config,
  96         }, {
  97                 .compatible = "atmel,at91sam9x5-tcb",
  98                 .data = &tcb_sam9x5_config,
  99         }, {
 100                 /* sentinel */
 101         }
 102 };
 103
 104 MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
 105 #endif
 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         unsigned int    i;
 113
 114         if (of_get_child_count(pdev->dev.of_node))
 115                 return -EBUSY;
 116
 117         irq = platform_get_irq(pdev, 0);
 118         if (irq < 0)
 119                 return -EINVAL;
 120
 121         tc = devm_kzalloc(&pdev->dev, sizeof(struct atmel_tc), GFP_KERNEL);
 122         if (!tc)
 123                 return -ENOMEM;
 124
 125         tc->pdev = pdev;
 126
 127         clk = devm_clk_get(&pdev->dev, "t0_clk");
 128         if (IS_ERR(clk))
 129                 return PTR_ERR(clk);
 130
 131         tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk");
 132         if (IS_ERR(tc->slow_clk))
 133                 return PTR_ERR(tc->slow_clk);
 134
 135         tc->regs = devm_platform_ioremap_resource(pdev, 0);
 136         if (IS_ERR(tc->regs))
 137                 return PTR_ERR(tc->regs);
 138
 139         /* Now take SoC information if available */
 140         if (pdev->dev.of_node) {
 141                 const struct of_device_id *match;
 142                 match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node);
 143                 if (match)
 144                         tc->tcb_config = match->data;
 145
 146                 tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb");
 147         } else {
 148                 tc->id = pdev->id;
 149         }
 150
 151         tc->clk[0] = clk;
 152         tc->clk[1] = devm_clk_get(&pdev->dev, "t1_clk");
 153         if (IS_ERR(tc->clk[1]))
 154                 tc->clk[1] = clk;
 155         tc->clk[2] = devm_clk_get(&pdev->dev, "t2_clk");
 156         if (IS_ERR(tc->clk[2]))
 157                 tc->clk[2] = clk;
 158
 159         tc->irq[0] = irq;
 160         tc->irq[1] = platform_get_irq(pdev, 1);
 161         if (tc->irq[1] < 0)
 162                 tc->irq[1] = irq;
 163         tc->irq[2] = platform_get_irq(pdev, 2);
 164         if (tc->irq[2] < 0)
 165                 tc->irq[2] = irq;
 166
 167         for (i = 0; i < 3; i++)
 168                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
 169
 170         spin_lock(&tc_list_lock);
 171         list_add_tail(&tc->node, &tc_list);
 172         spin_unlock(&tc_list_lock);
 173
 174         platform_set_drvdata(pdev, tc);
 175
 176         return 0;
 177 }
 178
 179 static void tc_shutdown(struct platform_device *pdev)
 180 {
 181         int i;
 182         struct atmel_tc *tc = platform_get_drvdata(pdev);
 183
 184         for (i = 0; i < 3; i++)
 185                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
 186 }
 187
 188 static struct platform_driver tc_driver = {
 189         .driver = {
 190                 .name   = "atmel_tcb",
 191                 .of_match_table = of_match_ptr(atmel_tcb_dt_ids),
 192         },
 193         .shutdown = tc_shutdown,
 194 };
 195
 196 static int __init tc_init(void)
 197 {
 198         return platform_driver_probe(&tc_driver, tc_probe);
 199 }
 200 arch_initcall(tc_init);