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/*
* Clocksource driver for NXP LPC32xx/18xx/43xx timer
*
* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
*
* Based on:
* time-efm32 Copyright (C) 2013 Pengutronix
* mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors
*
* 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.
*
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#define LPC32XX_TIMER_IR 0x000
#define LPC32XX_TIMER_IR_MR0INT BIT(0)
#define LPC32XX_TIMER_TCR 0x004
#define LPC32XX_TIMER_TCR_CEN BIT(0)
#define LPC32XX_TIMER_TCR_CRST BIT(1)
#define LPC32XX_TIMER_TC 0x008
#define LPC32XX_TIMER_PR 0x00c
#define LPC32XX_TIMER_MCR 0x014
#define LPC32XX_TIMER_MCR_MR0I BIT(0)
#define LPC32XX_TIMER_MCR_MR0R BIT(1)
#define LPC32XX_TIMER_MCR_MR0S BIT(2)
#define LPC32XX_TIMER_MR0 0x018
#define LPC32XX_TIMER_CTCR 0x070
struct lpc32xx_clock_event_ddata {
struct clock_event_device evtdev;
void __iomem *base;
};
/* Needed for the sched clock */
static void __iomem *clocksource_timer_counter;
static u64 notrace lpc32xx_read_sched_clock(void)
{
return readl(clocksource_timer_counter);
}
static int lpc32xx_clkevt_next_event(unsigned long delta,
struct clock_event_device *evtdev)
{
struct lpc32xx_clock_event_ddata *ddata =
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
/*
* Place timer in reset and program the delta in the prescale
* register (PR). When the prescale counter matches the value
* in PR the counter register is incremented and the compare
* match will trigger. After setup the timer is released from
* reset and enabled.
*/
writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR);
writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
return 0;
}
static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
{
struct lpc32xx_clock_event_ddata *ddata =
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
/* Disable the timer */
writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);
return 0;
}
static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
{
/*
* When using oneshot, we must also disable the timer
* to wait for the first call to set_next_event().
*/
return lpc32xx_clkevt_shutdown(evtdev);
}
static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
{
struct lpc32xx_clock_event_ddata *ddata = dev_id;
/* Clear match on channel 0 */
writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR);
ddata->evtdev.event_handler(&ddata->evtdev);
return IRQ_HANDLED;
}
static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
.evtdev = {
.name = "lpc3220 clockevent",
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 300,
.set_next_event = lpc32xx_clkevt_next_event,
.set_state_shutdown = lpc32xx_clkevt_shutdown,
.set_state_oneshot = lpc32xx_clkevt_oneshot,
},
};
static int __init lpc32xx_clocksource_init(struct device_node *np)
{
void __iomem *base;
unsigned long rate;
struct clk *clk;
int ret;
clk = of_clk_get_by_name(np, "timerclk");
if (IS_ERR(clk)) {
pr_err("clock get failed (%lu)\n", PTR_ERR(clk));
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("clock enable failed (%d)\n", ret);
goto err_clk_enable;
}
base = of_iomap(np, 0);
if (!base) {
pr_err("unable to map registers\n");
ret = -EADDRNOTAVAIL;
goto err_iomap;
}
/*
* Disable and reset timer then set it to free running timer
* mode (CTCR) with no prescaler (PR) or match operations (MCR).
* After setup the timer is released from reset and enabled.
*/
writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR);
writel_relaxed(0, base + LPC32XX_TIMER_PR);
writel_relaxed(0, base + LPC32XX_TIMER_MCR);
writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR);
rate = clk_get_rate(clk);
ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer",
rate, 300, 32, clocksource_mmio_readl_up);
if (ret) {
pr_err("failed to init clocksource (%d)\n", ret);
goto err_clocksource_init;
}
clocksource_timer_counter = base + LPC32XX_TIMER_TC;
sched_clock_register(lpc32xx_read_sched_clock, 32, rate);
return 0;
err_clocksource_init:
iounmap(base);
err_iomap:
clk_disable_unprepare(clk);
err_clk_enable:
clk_put(clk);
return ret;
}
static int __init lpc32xx_clockevent_init(struct device_node *np)
{
void __iomem *base;
unsigned long rate;
struct clk *clk;
int ret, irq;
clk = of_clk_get_by_name(np, "timerclk");
if (IS_ERR(clk)) {
pr_err("clock get failed (%lu)\n", PTR_ERR(clk));
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("clock enable failed (%d)\n", ret);
goto err_clk_enable;
}
base = of_iomap(np, 0);
if (!base) {
pr_err("unable to map registers\n");
ret = -EADDRNOTAVAIL;
goto err_iomap;
}
irq = irq_of_parse_and_map(np, 0);
if (!irq) {
pr_err("get irq failed\n");
ret = -ENOENT;
goto err_irq;
}
/*
* Disable timer and clear any pending interrupt (IR) on match
* channel 0 (MR0). Configure a compare match value of 1 on MR0
* and enable interrupt, reset on match and stop on match (MCR).
*/
writel_relaxed(0, base + LPC32XX_TIMER_TCR);
writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);
writel_relaxed(1, base + LPC32XX_TIMER_MR0);
writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR);
rate = clk_get_rate(clk);
lpc32xx_clk_event_ddata.base = base;
clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
rate, 1, -1);
ret = request_irq(irq, lpc32xx_clock_event_handler,
IRQF_TIMER | IRQF_IRQPOLL, "lpc3220 clockevent",
&lpc32xx_clk_event_ddata);
if (ret) {
pr_err("request irq failed\n");
goto err_irq;
}
return 0;
err_irq:
iounmap(base);
err_iomap:
clk_disable_unprepare(clk);
err_clk_enable:
clk_put(clk);
return ret;
}
/*
* This function asserts that we have exactly one clocksource and one
* clock_event_device in the end.
*/
static void __init lpc32xx_timer_init(struct device_node *np)
{
static int has_clocksource, has_clockevent;
int ret;
if (!has_clocksource) {
ret = lpc32xx_clocksource_init(np);
if (!ret) {
has_clocksource = 1;
return;
}
}
if (!has_clockevent) {
ret = lpc32xx_clockevent_init(np);
if (!ret) {
has_clockevent = 1;
return;
}
}
}
CLOCKSOURCE_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init);
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