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/*
* Conexant Digicolor timer driver
*
* Author: Baruch Siach <baruch@tkos.co.il>
*
* Copyright (C) 2014 Paradox Innovation Ltd.
*
* Based on:
* Allwinner SoCs hstimer driver
*
* Copyright (C) 2013 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.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.
*/
/*
* Conexant Digicolor SoCs have 8 configurable timers, named from "Timer A" to
* "Timer H". Timer A is the only one with watchdog support, so it is dedicated
* to the watchdog driver. This driver uses Timer B for sched_clock(), and
* Timer C for clockevents.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/sched/clock.h>
#include <linux/sched_clock.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
enum {
TIMER_A,
TIMER_B,
TIMER_C,
TIMER_D,
TIMER_E,
TIMER_F,
TIMER_G,
TIMER_H,
};
#define CONTROL(t) ((t)*8)
#define COUNT(t) ((t)*8 + 4)
#define CONTROL_DISABLE 0
#define CONTROL_ENABLE BIT(0)
#define CONTROL_MODE(m) ((m) << 4)
#define CONTROL_MODE_ONESHOT CONTROL_MODE(1)
#define CONTROL_MODE_PERIODIC CONTROL_MODE(2)
struct digicolor_timer {
struct clock_event_device ce;
void __iomem *base;
u32 ticks_per_jiffy;
int timer_id; /* one of TIMER_* */
};
static struct digicolor_timer *dc_timer(struct clock_event_device *ce)
{
return container_of(ce, struct digicolor_timer, ce);
}
static inline void dc_timer_disable(struct clock_event_device *ce)
{
struct digicolor_timer *dt = dc_timer(ce);
writeb(CONTROL_DISABLE, dt->base + CONTROL(dt->timer_id));
}
static inline void dc_timer_enable(struct clock_event_device *ce, u32 mode)
{
struct digicolor_timer *dt = dc_timer(ce);
writeb(CONTROL_ENABLE | mode, dt->base + CONTROL(dt->timer_id));
}
static inline void dc_timer_set_count(struct clock_event_device *ce,
unsigned long count)
{
struct digicolor_timer *dt = dc_timer(ce);
writel(count, dt->base + COUNT(dt->timer_id));
}
static int digicolor_clkevt_shutdown(struct clock_event_device *ce)
{
dc_timer_disable(ce);
return 0;
}
static int digicolor_clkevt_set_oneshot(struct clock_event_device *ce)
{
dc_timer_disable(ce);
dc_timer_enable(ce, CONTROL_MODE_ONESHOT);
return 0;
}
static int digicolor_clkevt_set_periodic(struct clock_event_device *ce)
{
struct digicolor_timer *dt = dc_timer(ce);
dc_timer_disable(ce);
dc_timer_set_count(ce, dt->ticks_per_jiffy);
dc_timer_enable(ce, CONTROL_MODE_PERIODIC);
return 0;
}
static int digicolor_clkevt_next_event(unsigned long evt,
struct clock_event_device *ce)
{
dc_timer_disable(ce);
dc_timer_set_count(ce, evt);
dc_timer_enable(ce, CONTROL_MODE_ONESHOT);
return 0;
}
static struct digicolor_timer dc_timer_dev = {
.ce = {
.name = "digicolor_tick",
.rating = 340,
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_state_shutdown = digicolor_clkevt_shutdown,
.set_state_periodic = digicolor_clkevt_set_periodic,
.set_state_oneshot = digicolor_clkevt_set_oneshot,
.tick_resume = digicolor_clkevt_shutdown,
.set_next_event = digicolor_clkevt_next_event,
},
.timer_id = TIMER_C,
};
static irqreturn_t digicolor_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static u64 notrace digicolor_timer_sched_read(void)
{
return ~readl(dc_timer_dev.base + COUNT(TIMER_B));
}
static int __init digicolor_timer_init(struct device_node *node)
{
unsigned long rate;
struct clk *clk;
int ret, irq;
/*
* timer registers are shared with the watchdog timer;
* don't map exclusively
*/
dc_timer_dev.base = of_iomap(node, 0);
if (!dc_timer_dev.base) {
pr_err("Can't map registers\n");
return -ENXIO;
}
irq = irq_of_parse_and_map(node, dc_timer_dev.timer_id);
if (irq <= 0) {
pr_err("Can't parse IRQ\n");
return -EINVAL;
}
clk = of_clk_get(node, 0);
if (IS_ERR(clk)) {
pr_err("Can't get timer clock\n");
return PTR_ERR(clk);
}
clk_prepare_enable(clk);
rate = clk_get_rate(clk);
dc_timer_dev.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
writeb(CONTROL_DISABLE, dc_timer_dev.base + CONTROL(TIMER_B));
writel(UINT_MAX, dc_timer_dev.base + COUNT(TIMER_B));
writeb(CONTROL_ENABLE, dc_timer_dev.base + CONTROL(TIMER_B));
sched_clock_register(digicolor_timer_sched_read, 32, rate);
clocksource_mmio_init(dc_timer_dev.base + COUNT(TIMER_B), node->name,
rate, 340, 32, clocksource_mmio_readl_down);
ret = request_irq(irq, digicolor_timer_interrupt,
IRQF_TIMER | IRQF_IRQPOLL, "digicolor_timerC",
&dc_timer_dev.ce);
if (ret) {
pr_warn("request of timer irq %d failed (%d)\n", irq, ret);
return ret;
}
dc_timer_dev.ce.cpumask = cpu_possible_mask;
dc_timer_dev.ce.irq = irq;
clockevents_config_and_register(&dc_timer_dev.ce, rate, 0, 0xffffffff);
return 0;
}
CLOCKSOURCE_OF_DECLARE(conexant_digicolor, "cnxt,cx92755-timer",
digicolor_timer_init);
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