drivers/clocksource/timer-versatile.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (C) 2014 ARM Limited
   5  */
   6
   7 #include <linux/clocksource.h>
   8 #include <linux/io.h>
   9 #include <linux/of_address.h>
  10 #include <linux/sched_clock.h>
  11
  12 #define SYS_24MHZ 0x05c
  13
  14 static void __iomem *versatile_sys_24mhz;
  15
  16 static u64 notrace versatile_sys_24mhz_read(void)
  17 {
  18         return readl(versatile_sys_24mhz);
  19 }
  20
  21 static int __init versatile_sched_clock_init(struct device_node *node)
  22 {
  23         void __iomem *base = of_iomap(node, 0);
  24
  25         if (!base)
  26                 return -ENXIO;
  27
  28         versatile_sys_24mhz = base + SYS_24MHZ;
  29
  30         sched_clock_register(versatile_sys_24mhz_read, 32, 24000000);
  31
  32         return 0;
  33 }
  34 TIMER_OF_DECLARE(vexpress, "arm,vexpress-sysreg",
  35                        versatile_sched_clock_init);
  36 TIMER_OF_DECLARE(versatile, "arm,versatile-sysreg",
  37                        versatile_sched_clock_init);