1/*
  2 *  Cirrus Logic CLPS711X clocksource driver
  3 *
  4 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
 10 */
 11
 12#include <linux/clk.h>
 13#include <linux/clockchips.h>
 14#include <linux/clocksource.h>
 15#include <linux/interrupt.h>
 16#include <linux/io.h>
 17#include <linux/of_address.h>
 18#include <linux/of_irq.h>
 19#include <linux/sched_clock.h>
 20#include <linux/slab.h>
 21
 22enum {
 23	CLPS711X_CLKSRC_CLOCKSOURCE,
 24	CLPS711X_CLKSRC_CLOCKEVENT,
 25};
 26
 27static void __iomem *tcd;
 28
 29static u64 notrace clps711x_sched_clock_read(void)
 30{
 31	return ~readw(tcd);
 32}
 33
 34static int __init _clps711x_clksrc_init(struct clk *clock, void __iomem *base)
 35{
 36	unsigned long rate;
 37
 38	if (!base)
 39		return -ENOMEM;
 40	if (IS_ERR(clock))
 41		return PTR_ERR(clock);
 42
 43	rate = clk_get_rate(clock);
 44
 45	tcd = base;
 46
 47	clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
 48			      clocksource_mmio_readw_down);
 49
 50	sched_clock_register(clps711x_sched_clock_read, 16, rate);
 51
 52	return 0;
 53}
 54
 55static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
 56{
 57	struct clock_event_device *evt = dev_id;
 58
 59	evt->event_handler(evt);
 60
 61	return IRQ_HANDLED;
 62}
 63
 64static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
 65					unsigned int irq)
 66{
 67	struct clock_event_device *clkevt;
 68	unsigned long rate;
 69
 70	if (!irq)
 71		return -EINVAL;
 72	if (!base)
 73		return -ENOMEM;
 74	if (IS_ERR(clock))
 75		return PTR_ERR(clock);
 76
 77	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
 78	if (!clkevt)
 79		return -ENOMEM;
 80
 81	rate = clk_get_rate(clock);
 82
 83	/* Set Timer prescaler */
 84	writew(DIV_ROUND_CLOSEST(rate, HZ), base);
 85
 86	clkevt->name = "clps711x-clockevent";
 87	clkevt->rating = 300;
 88	clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
 89	clkevt->cpumask = cpumask_of(0);
 90	clockevents_config_and_register(clkevt, HZ, 0, 0);
 91
 92	return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
 93			   "clps711x-timer", clkevt);
 94}
 95
 96void __init clps711x_clksrc_init(void __iomem *tc1_base, void __iomem *tc2_base,
 97				 unsigned int irq)
 98{
 99	struct clk *tc1 = clk_get_sys("clps711x-timer.0", NULL);
100	struct clk *tc2 = clk_get_sys("clps711x-timer.1", NULL);
101
102	BUG_ON(_clps711x_clksrc_init(tc1, tc1_base));
103	BUG_ON(_clps711x_clkevt_init(tc2, tc2_base, irq));
104}
105
106#ifdef CONFIG_TIMER_OF
107static int __init clps711x_timer_init(struct device_node *np)
108{
109	unsigned int irq = irq_of_parse_and_map(np, 0);
110	struct clk *clock = of_clk_get(np, 0);
111	void __iomem *base = of_iomap(np, 0);
112
113	switch (of_alias_get_id(np, "timer")) {
114	case CLPS711X_CLKSRC_CLOCKSOURCE:
115		return _clps711x_clksrc_init(clock, base);
116	case CLPS711X_CLKSRC_CLOCKEVENT:
117		return _clps711x_clkevt_init(clock, base, irq);
118	default:
119		return -EINVAL;
120	}
121}
122TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);
123#endif