clps711x-timer.c 2.3 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101
  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Cirrus Logic CLPS711X clocksource driver
  4. *
  5. * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
  6. */
  7. #include <linux/clk.h>
  8. #include <linux/clockchips.h>
  9. #include <linux/clocksource.h>
  10. #include <linux/interrupt.h>
  11. #include <linux/io.h>
  12. #include <linux/of_address.h>
  13. #include <linux/of_irq.h>
  14. #include <linux/sched_clock.h>
  15. #include <linux/slab.h>
  16. enum {
  17. CLPS711X_CLKSRC_CLOCKSOURCE,
  18. CLPS711X_CLKSRC_CLOCKEVENT,
  19. };
  20. static void __iomem *tcd;
  21. static u64 notrace clps711x_sched_clock_read(void)
  22. {
  23. return ~readw(tcd);
  24. }
  25. static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base)
  26. {
  27. unsigned long rate = clk_get_rate(clock);
  28. tcd = base;
  29. clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
  30. clocksource_mmio_readw_down);
  31. sched_clock_register(clps711x_sched_clock_read, 16, rate);
  32. }
  33. static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
  34. {
  35. struct clock_event_device *evt = dev_id;
  36. evt->event_handler(evt);
  37. return IRQ_HANDLED;
  38. }
  39. static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
  40. unsigned int irq)
  41. {
  42. struct clock_event_device *clkevt;
  43. unsigned long rate;
  44. clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
  45. if (!clkevt)
  46. return -ENOMEM;
  47. rate = clk_get_rate(clock);
  48. /* Set Timer prescaler */
  49. writew(DIV_ROUND_CLOSEST(rate, HZ), base);
  50. clkevt->name = "clps711x-clockevent";
  51. clkevt->rating = 300;
  52. clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
  53. clkevt->cpumask = cpumask_of(0);
  54. clockevents_config_and_register(clkevt, HZ, 0, 0);
  55. return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
  56. "clps711x-timer", clkevt);
  57. }
  58. static int __init clps711x_timer_init(struct device_node *np)
  59. {
  60. unsigned int irq = irq_of_parse_and_map(np, 0);
  61. struct clk *clock = of_clk_get(np, 0);
  62. void __iomem *base = of_iomap(np, 0);
  63. if (!base)
  64. return -ENOMEM;
  65. if (!irq)
  66. return -EINVAL;
  67. if (IS_ERR(clock))
  68. return PTR_ERR(clock);
  69. switch (of_alias_get_id(np, "timer")) {
  70. case CLPS711X_CLKSRC_CLOCKSOURCE:
  71. clps711x_clksrc_init(clock, base);
  72. break;
  73. case CLPS711X_CLKSRC_CLOCKEVENT:
  74. return _clps711x_clkevt_init(clock, base, irq);
  75. default:
  76. return -EINVAL;
  77. }
  78. return 0;
  79. }
  80. TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);