diff options
Diffstat (limited to 'drivers/clocksource/clps711x-timer.c')
| -rw-r--r-- | drivers/clocksource/clps711x-timer.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c new file mode 100644 index 000000000000..d83ec1f2fddc --- /dev/null +++ b/drivers/clocksource/clps711x-timer.c @@ -0,0 +1,131 @@ +/* + * Cirrus Logic CLPS711X clocksource driver + * + * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> + +enum { + CLPS711X_CLKSRC_CLOCKSOURCE, + CLPS711X_CLKSRC_CLOCKEVENT, +}; + +static void __iomem *tcd; + +static u64 notrace clps711x_sched_clock_read(void) +{ + return ~readw(tcd); +} + +static int __init _clps711x_clksrc_init(struct clk *clock, void __iomem *base) +{ + unsigned long rate; + + if (!base) + return -ENOMEM; + if (IS_ERR(clock)) + return PTR_ERR(clock); + + rate = clk_get_rate(clock); + + tcd = base; + + clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16, + clocksource_mmio_readw_down); + + sched_clock_register(clps711x_sched_clock_read, 16, rate); + + return 0; +} + +static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static void clps711x_clockevent_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ +} + +static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base, + unsigned int irq) +{ + struct clock_event_device *clkevt; + unsigned long rate; + + if (!irq) + return -EINVAL; + if (!base) + return -ENOMEM; + if (IS_ERR(clock)) + return PTR_ERR(clock); + + clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL); + if (!clkevt) + return -ENOMEM; + + rate = clk_get_rate(clock); + + /* Set Timer prescaler */ + writew(DIV_ROUND_CLOSEST(rate, HZ), base); + + clkevt->name = "clps711x-clockevent"; + clkevt->rating = 300; + clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP; + clkevt->set_mode = clps711x_clockevent_set_mode; + clkevt->cpumask = cpumask_of(0); + clockevents_config_and_register(clkevt, HZ, 0, 0); + + return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER, + "clps711x-timer", clkevt); +} + +void __init clps711x_clksrc_init(void __iomem *tc1_base, void __iomem *tc2_base, + unsigned int irq) +{ + struct clk *tc1 = clk_get_sys("clps711x-timer.0", NULL); + struct clk *tc2 = clk_get_sys("clps711x-timer.1", NULL); + + BUG_ON(_clps711x_clksrc_init(tc1, tc1_base)); + BUG_ON(_clps711x_clkevt_init(tc2, tc2_base, irq)); +} + +#ifdef CONFIG_CLKSRC_OF +static void __init clps711x_timer_init(struct device_node *np) +{ + unsigned int irq = irq_of_parse_and_map(np, 0); + struct clk *clock = of_clk_get(np, 0); + void __iomem *base = of_iomap(np, 0); + + switch (of_alias_get_id(np, "timer")) { + case CLPS711X_CLKSRC_CLOCKSOURCE: + BUG_ON(_clps711x_clksrc_init(clock, base)); + break; + case CLPS711X_CLKSRC_CLOCKEVENT: + BUG_ON(_clps711x_clkevt_init(clock, base, irq)); + break; + default: + break; + } +} +CLOCKSOURCE_OF_DECLARE(clps711x, "cirrus,clps711x-timer", clps711x_timer_init); +#endif |