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Release 4.7 drivers/clocksource/moxart_timer.c

/*
 * MOXA ART SoCs timer handling.
 *
 * Copyright (C) 2013 Jonas Jensen
 *
 * Jonas Jensen <jonas.jensen@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/io.h>
#include <linux/clocksource.h>
#include <linux/bitops.h>


#define TIMER1_BASE		0x00

#define TIMER2_BASE		0x10

#define TIMER3_BASE		0x20


#define REG_COUNT		0x0 
/* writable */

#define REG_LOAD		0x4

#define REG_MATCH1		0x8

#define REG_MATCH2		0xC


#define TIMER_CR		0x30

#define TIMER_INTR_STATE	0x34

#define TIMER_INTR_MASK		0x38

/*
 * TIMER_CR flags:
 *
 * TIMEREG_CR_*_CLOCK   0: PCLK, 1: EXT1CLK
 * TIMEREG_CR_*_INT     overflow interrupt enable bit
 */

#define TIMEREG_CR_1_ENABLE	BIT(0)

#define TIMEREG_CR_1_CLOCK	BIT(1)

#define TIMEREG_CR_1_INT	BIT(2)

#define TIMEREG_CR_2_ENABLE	BIT(3)

#define TIMEREG_CR_2_CLOCK	BIT(4)

#define TIMEREG_CR_2_INT	BIT(5)

#define TIMEREG_CR_3_ENABLE	BIT(6)

#define TIMEREG_CR_3_CLOCK	BIT(7)

#define TIMEREG_CR_3_INT	BIT(8)

#define TIMEREG_CR_COUNT_UP	BIT(9)


#define TIMER1_ENABLE		(TIMEREG_CR_2_ENABLE | TIMEREG_CR_1_ENABLE)

#define TIMER1_DISABLE		(TIMEREG_CR_2_ENABLE)


static void __iomem *base;

static unsigned int clock_count_per_tick;


static int moxart_shutdown(struct clock_event_device *evt) { writel(TIMER1_DISABLE, base + TIMER_CR); return 0; }

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static int moxart_set_oneshot(struct clock_event_device *evt) { writel(TIMER1_DISABLE, base + TIMER_CR); writel(~0, base + TIMER1_BASE + REG_LOAD); return 0; }

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static int moxart_set_periodic(struct clock_event_device *evt) { writel(clock_count_per_tick, base + TIMER1_BASE + REG_LOAD); writel(TIMER1_ENABLE, base + TIMER_CR); return 0; }

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static int moxart_clkevt_next_event(unsigned long cycles, struct clock_event_device *unused) { u32 u; writel(TIMER1_DISABLE, base + TIMER_CR); u = readl(base + TIMER1_BASE + REG_COUNT) - cycles; writel(u, base + TIMER1_BASE + REG_MATCH1); writel(TIMER1_ENABLE, base + TIMER_CR); return 0; }

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static struct clock_event_device moxart_clockevent = { .name = "moxart_timer", .rating = 200, .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .set_state_shutdown = moxart_shutdown, .set_state_periodic = moxart_set_periodic, .set_state_oneshot = moxart_set_oneshot, .tick_resume = moxart_set_oneshot, .set_next_event = moxart_clkevt_next_event, };
static irqreturn_t moxart_timer_interrupt(int irq, void *dev_id) { struct clock_event_device *evt = dev_id; evt->event_handler(evt); return IRQ_HANDLED; }

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static struct irqaction moxart_timer_irq = { .name = "moxart-timer", .flags = IRQF_TIMER, .handler = moxart_timer_interrupt, .dev_id = &moxart_clockevent, };
static void __init moxart_timer_init(struct device_node *node) { int ret, irq; unsigned long pclk; struct clk *clk; base = of_iomap(node, 0); if (!base) panic("%s: of_iomap failed\n", node->full_name); irq = irq_of_parse_and_map(node, 0); if (irq <= 0) panic("%s: irq_of_parse_and_map failed\n", node->full_name); ret = setup_irq(irq, &moxart_timer_irq); if (ret) panic("%s: setup_irq failed\n", node->full_name); clk = of_clk_get(node, 0); if (IS_ERR(clk)) panic("%s: of_clk_get failed\n", node->full_name); pclk = clk_get_rate(clk); if (clocksource_mmio_init(base + TIMER2_BASE + REG_COUNT, "moxart_timer", pclk, 200, 32, clocksource_mmio_readl_down)) panic("%s: clocksource_mmio_init failed\n", node->full_name); clock_count_per_tick = DIV_ROUND_CLOSEST(pclk, HZ); writel(~0, base + TIMER2_BASE + REG_LOAD); writel(TIMEREG_CR_2_ENABLE, base + TIMER_CR); moxart_clockevent.cpumask = cpumask_of(0); moxart_clockevent.irq = irq; /* * documentation is not publicly available: * min_delta / max_delta obtained by trial-and-error, * max_delta 0xfffffffe should be ok because count * register size is u32 */ clockevents_config_and_register(&moxart_clockevent, pclk, 0x4, 0xfffffffe); }

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CLOCKSOURCE_OF_DECLARE(moxart, "moxa,moxart-timer", moxart_timer_init);

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