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.h>
  10 #include <linux/of_address.h>
  11 #include <linux/sched_clock.h>
  12
  13 #define SYS_24MHZ 0x05c
  14
  15 static void __iomem *versatile_sys_24mhz;
  16
  17 static u64 notrace versatile_sys_24mhz_read(void)
  18 {
  19         return readl(versatile_sys_24mhz);
  20 }
  21
  22 static int __init versatile_sched_clock_init(struct device_node *node)
  23 {
  24         void __iomem *base = of_iomap(node, 0);
  25
  26         of_node_clear_flag(node, OF_POPULATED);
  27
  28         if (!base)
  29                 return -ENXIO;
  30
  31         versatile_sys_24mhz = base + SYS_24MHZ;
  32
  33         sched_clock_register(versatile_sys_24mhz_read, 32, 24000000);
  34
  35         return 0;
  36 }
  37 TIMER_OF_DECLARE(vexpress, "arm,vexpress-sysreg",
  38                        versatile_sched_clock_init);
  39 TIMER_OF_DECLARE(versatile, "arm,versatile-sysreg",
  40                        versatile_sched_clock_init);