drivers/timer/timer-uclass.c

   1 /*
   2  * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <errno.h>
  10 #include <timer.h>
  11
  12 DECLARE_GLOBAL_DATA_PTR;
  13
  14 /*
  15  * Implement a timer uclass to work with lib/time.c. The timer is usually
  16  * a 32/64 bits free-running up counter. The get_rate() method is used to get
  17  * the input clock frequency of the timer. The get_count() method is used
  18  * to get the current 64 bits count value. If the hardware is counting down,
  19  * the value should be inversed inside the method. There may be no real
  20  * tick, and no timer interrupt.
  21  */
  22
  23 int timer_get_count(struct udevice *dev, u64 *count)
  24 {
  25         const struct timer_ops *ops = device_get_ops(dev);
  26
  27         if (!ops->get_count)
  28                 return -ENOSYS;
  29
  30         return ops->get_count(dev, count);
  31 }
  32
  33 unsigned long timer_get_rate(struct udevice *dev)
  34 {
  35         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  36
  37         return uc_priv->clock_rate;
  38 }
  39
  40 static int timer_pre_probe(struct udevice *dev)
  41 {
  42         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  43
  44         uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
  45                                              "clock-frequency", 0);
  46
  47         return 0;
  48 }
  49
  50 u64 timer_conv_64(u32 count)
  51 {
  52         /* increment tbh if tbl has rolled over */
  53         if (count < gd->timebase_l)
  54                 gd->timebase_h++;
  55         gd->timebase_l = count;
  56         return ((u64)gd->timebase_h << 32) | gd->timebase_l;
  57 }
  58
  59 UCLASS_DRIVER(timer) = {
  60         .id             = UCLASS_TIMER,
  61         .name           = "timer",
  62         .pre_probe      = timer_pre_probe,
  63         .per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
  64 };