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 22 enum { 23 CLPS711X_CLKSRC_CLOCKSOURCE, 24 CLPS711X_CLKSRC_CLOCKEVENT, 25 }; 26 27 static void __iomem *tcd; 28 29 static u64 notrace clps711x_sched_clock_read(void) 30 { 31 return ~readw(tcd); 32 } 33 34 static 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 55 static 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 64 static 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 96 void __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_CLKSRC_OF 107 static void __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 BUG_ON(_clps711x_clksrc_init(clock, base)); 116 break; 117 case CLPS711X_CLKSRC_CLOCKEVENT: 118 BUG_ON(_clps711x_clkevt_init(clock, base, irq)); 119 break; 120 default: 121 break; 122 } 123 } 124 CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init); 125 #endif 126