clocksource: Driver for Conexant Digicolor SoC timer (9b8bb773) · Commits · 戴 / test

drivers/clocksource/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,9 @@ config CLKBLD_I8253
		config CLKSRC_MMIO
		bool

		config DIGICOLOR_TIMER
		bool

		config DW_APB_TIMER
		bool

drivers/clocksource/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -10,6 +10,7 @@ obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
		obj-$(CONFIG_EM_TIMER_STI) += em_sti.o
		obj-$(CONFIG_CLKBLD_I8253) += i8253.o
		obj-$(CONFIG_CLKSRC_MMIO) += mmio.o
		obj-$(CONFIG_DIGICOLOR_TIMER) += timer-digicolor.o
		obj-$(CONFIG_DW_APB_TIMER) += dw_apb_timer.o
		obj-$(CONFIG_DW_APB_TIMER_OF) += dw_apb_timer_of.o
		obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o

drivers/clocksource/timer-digicolor.c

0 → 100644

+199 −0

Original line number	Diff line number	Diff line
		/*
		* 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/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_* */
		};

		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 void digicolor_clkevt_mode(enum clock_event_mode mode,
		struct clock_event_device *ce)
		{
		struct digicolor_timer *dt = dc_timer(ce);

		switch (mode) {
		case CLOCK_EVT_MODE_PERIODIC:
		dc_timer_disable(ce);
		dc_timer_set_count(ce, dt->ticks_per_jiffy);
		dc_timer_enable(ce, CONTROL_MODE_PERIODIC);
		break;
		case CLOCK_EVT_MODE_ONESHOT:
		dc_timer_disable(ce);
		dc_timer_enable(ce, CONTROL_MODE_ONESHOT);
		break;
		case CLOCK_EVT_MODE_UNUSED:
		case CLOCK_EVT_MODE_SHUTDOWN:
		default:
		dc_timer_disable(ce);
		break;
		}
		}

		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_mode = digicolor_clkevt_mode,
		.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 digicolor_timer_sched_read(void)
		{
		return ~readl(dc_timer_dev.base + COUNT(TIMER_B));
		}

		static void __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");
		return;
		}

		irq = irq_of_parse_and_map(node, dc_timer_dev.timer_id);
		if (irq <= 0) {
		pr_err("Can't parse IRQ");
		return;
		}

		clk = of_clk_get(node, 0);
		if (IS_ERR(clk)) {
		pr_err("Can't get timer clock");
		return;
		}
		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);

		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);
		}
		CLOCKSOURCE_OF_DECLARE(conexant_digicolor, "cnxt,cx92755-timer",
		digicolor_timer_init);

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