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 8 #include <linux/clk.h> 9 #include <linux/clockchips.h> 10 #include <linux/clocksource.h> 11 #include <linux/interrupt.h> 12 #include <linux/io.h> 13 #include <linux/of_address.h> 14 #include <linux/of_irq.h> 15 #include <linux/sched_clock.h> 16 #include <linux/slab.h> 17 18 enum { 19 CLPS711X_CLKSRC_CLOCKSOURCE, 20 CLPS711X_CLKSRC_CLOCKEVENT, 21 }; 22 23 static void __iomem *tcd; 24 25 static u64 notrace clps711x_sched_clock_read(void) 26 { 27 return ~readw(tcd); 28 } 29 30 static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base) 31 { 32 unsigned long rate = clk_get_rate(clock); 33 34 tcd = base; 35 36 clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16, 37 clocksource_mmio_readw_down); 38 39 sched_clock_register(clps711x_sched_clock_read, 16, rate); 40 } 41 42 static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id) 43 { 44 struct clock_event_device *evt = dev_id; 45 46 evt->event_handler(evt); 47 48 return IRQ_HANDLED; 49 } 50 51 static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base, 52 unsigned int irq) 53 { 54 struct clock_event_device *clkevt; 55 unsigned long rate; 56 57 clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL); 58 if (!clkevt) 59 return -ENOMEM; 60 61 rate = clk_get_rate(clock); 62 63 /* Set Timer prescaler */ 64 writew(DIV_ROUND_CLOSEST(rate, HZ), base); 65 66 clkevt->name = "clps711x-clockevent"; 67 clkevt->rating = 300; 68 clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP; 69 clkevt->cpumask = cpumask_of(0); 70 clockevents_config_and_register(clkevt, HZ, 0, 0); 71 72 return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER, 73 "clps711x-timer", clkevt); 74 } 75 76 static int __init clps711x_timer_init(struct device_node *np) 77 { 78 unsigned int irq = irq_of_parse_and_map(np, 0); 79 struct clk *clock = of_clk_get(np, 0); 80 void __iomem *base = of_iomap(np, 0); 81 82 if (!base) 83 return -ENOMEM; 84 if (!irq) 85 return -EINVAL; 86 if (IS_ERR(clock)) 87 return PTR_ERR(clock); 88 89 switch (of_alias_get_id(np, "timer")) { 90 case CLPS711X_CLKSRC_CLOCKSOURCE: 91 clps711x_clksrc_init(clock, base); 92 break; 93 case CLPS711X_CLKSRC_CLOCKEVENT: 94 return _clps711x_clkevt_init(clock, base, irq); 95 default: 96 return -EINVAL; 97 } 98 99 return 0; 100 } 101 TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init); 102