[mirror_ubuntu-artful-kernel.git] / arch / mips / ralink / timer.c

/*
 * Ralink RT2880 timer
 * Author: John Crispin
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * Copyright (C) 2013 John Crispin <john@phrozen.org>
*/

#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/of_gpio.h>
#include <linux/clk.h>

#include <asm/mach-ralink/ralink_regs.h>

#define TIMER_REG_TMRSTAT		0x00
#define TIMER_REG_TMR0LOAD		0x10
#define TIMER_REG_TMR0CTL		0x18

#define TMRSTAT_TMR0INT			BIT(0)

#define TMR0CTL_ENABLE			BIT(7)
#define TMR0CTL_MODE_PERIODIC		BIT(4)
#define TMR0CTL_PRESCALER		1
#define TMR0CTL_PRESCALE_VAL		(0xf - TMR0CTL_PRESCALER)
#define TMR0CTL_PRESCALE_DIV		(65536 / BIT(TMR0CTL_PRESCALER))

struct rt_timer {
	struct device	*dev;
	void __iomem	*membase;
	int		irq;
	unsigned long	timer_freq;
	unsigned long	timer_div;
};

static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val)
{
	__raw_writel(val, rt->membase + reg);
}

static inline u32 rt_timer_r32(struct rt_timer *rt, u8 reg)
{
	return __raw_readl(rt->membase + reg);
}

static irqreturn_t rt_timer_irq(int irq, void *_rt)
{
	struct rt_timer *rt =  (struct rt_timer *) _rt;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
	rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT);

	return IRQ_HANDLED;
}


static int rt_timer_request(struct rt_timer *rt)
{
	int err = request_irq(rt->irq, rt_timer_irq, 0,
						dev_name(rt->dev), rt);
	if (err) {
		dev_err(rt->dev, "failed to request irq\n");
	} else {
		u32 t = TMR0CTL_MODE_PERIODIC | TMR0CTL_PRESCALE_VAL;
		rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
	}
	return err;
}

static void rt_timer_free(struct rt_timer *rt)
{
	free_irq(rt->irq, rt);
}

static int rt_timer_config(struct rt_timer *rt, unsigned long divisor)
{
	if (rt->timer_freq < divisor)
		rt->timer_div = rt->timer_freq;
	else
		rt->timer_div = divisor;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);

	return 0;
}

static int rt_timer_enable(struct rt_timer *rt)
{
	u32 t;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);

	t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
	t |= TMR0CTL_ENABLE;
	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);

	return 0;
}

static void rt_timer_disable(struct rt_timer *rt)
{
	u32 t;

	t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
	t &= ~TMR0CTL_ENABLE;
	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
}

static int rt_timer_probe(struct platform_device *pdev)
{
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	struct rt_timer *rt;
	struct clk *clk;

	rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL);
	if (!rt) {
		dev_err(&pdev->dev, "failed to allocate memory\n");
		return -ENOMEM;
	}

	rt->irq = platform_get_irq(pdev, 0);
	if (!rt->irq) {
		dev_err(&pdev->dev, "failed to load irq\n");
		return -ENOENT;
	}

	rt->membase = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(rt->membase))
		return PTR_ERR(rt->membase);

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "failed get clock rate\n");
		return PTR_ERR(clk);
	}

	rt->timer_freq = clk_get_rate(clk) / TMR0CTL_PRESCALE_DIV;
	if (!rt->timer_freq)
		return -EINVAL;

	rt->dev = &pdev->dev;
	platform_set_drvdata(pdev, rt);

	rt_timer_request(rt);
	rt_timer_config(rt, 2);
	rt_timer_enable(rt);

	dev_info(&pdev->dev, "maximum frequency is %luHz\n", rt->timer_freq);

	return 0;
}

static const struct of_device_id rt_timer_match[] = {
	{ .compatible = "ralink,rt2880-timer" },
	{},
};

static struct platform_driver rt_timer_driver = {
	.probe = rt_timer_probe,
	.driver = {
		.name			= "rt-timer",
		.of_match_table		= rt_timer_match,
		.suppress_bind_attrs	= true,
	},
};
builtin_platform_driver(rt_timer_driver);
Commit	Line	Data
80ecbd24	1	/*
62ee73d2 PG	2	* Ralink RT2880 timer
	3	* Author: John Crispin
	4	*
80ecbd24 JC	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License version 2 as published
	7	* by the Free Software Foundation.
	8	*
97b92108	9	* Copyright (C) 2013 John Crispin <john@phrozen.org>
80ecbd24 JC	10	*/
80ecbd24 JC	11
80ecbd24 JC	12	#include <linux/platform_device.h>
	13	#include <linux/interrupt.h>
	14	#include <linux/timer.h>
	15	#include <linux/of_gpio.h>
	16	#include <linux/clk.h>
	17
	18	#include <asm/mach-ralink/ralink_regs.h>
	19
	20	#define TIMER_REG_TMRSTAT 0x00
	21	#define TIMER_REG_TMR0LOAD 0x10
	22	#define TIMER_REG_TMR0CTL 0x18
	23
	24	#define TMRSTAT_TMR0INT BIT(0)
	25
	26	#define TMR0CTL_ENABLE BIT(7)
	27	#define TMR0CTL_MODE_PERIODIC BIT(4)
	28	#define TMR0CTL_PRESCALER 1
	29	#define TMR0CTL_PRESCALE_VAL (0xf - TMR0CTL_PRESCALER)
	30	#define TMR0CTL_PRESCALE_DIV (65536 / BIT(TMR0CTL_PRESCALER))
	31
	32	struct rt_timer {
	33	struct device *dev;
	34	void __iomem *membase;
	35	int irq;
	36	unsigned long timer_freq;
	37	unsigned long timer_div;
	38	};
	39
	40	static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val)
	41	{
	42	__raw_writel(val, rt->membase + reg);
	43	}
	44
	45	static inline u32 rt_timer_r32(struct rt_timer *rt, u8 reg)
	46	{
	47	return __raw_readl(rt->membase + reg);
	48	}
	49
	50	static irqreturn_t rt_timer_irq(int irq, void *_rt)
	51	{
	52	struct rt_timer rt = (struct rt_timer ) _rt;
	53
	54	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
	55	rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT);
	56
	57	return IRQ_HANDLED;
	58	}
	59
	60
	61	static int rt_timer_request(struct rt_timer *rt)
	62	{
31d6f57d	63	int err = request_irq(rt->irq, rt_timer_irq, 0,
80ecbd24 JC	64	dev_name(rt->dev), rt);
	65	if (err) {
	66	dev_err(rt->dev, "failed to request irq\n");
	67	} else {
	68	u32 t = TMR0CTL_MODE_PERIODIC \| TMR0CTL_PRESCALE_VAL;
	69	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
	70	}
	71	return err;
	72	}
	73
	74	static void rt_timer_free(struct rt_timer *rt)
	75	{
	76	free_irq(rt->irq, rt);
	77	}
	78
	79	static int rt_timer_config(struct rt_timer *rt, unsigned long divisor)
	80	{
	81	if (rt->timer_freq < divisor)
	82	rt->timer_div = rt->timer_freq;
	83	else
	84	rt->timer_div = divisor;
	85
	86	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
	87
	88	return 0;
	89	}
	90
	91	static int rt_timer_enable(struct rt_timer *rt)
	92	{
	93	u32 t;
	94
	95	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
	96
	97	t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
	98	t \|= TMR0CTL_ENABLE;
	99	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
	100
	101	return 0;
	102	}
	103
	104	static void rt_timer_disable(struct rt_timer *rt)
	105	{
	106	u32 t;
	107
	108	t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
	109	t &= ~TMR0CTL_ENABLE;
	110	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
	111	}
	112
	113	static int rt_timer_probe(struct platform_device *pdev)
	114	{
	115	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	116	struct rt_timer *rt;
	117	struct clk *clk;
	118
	119	rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL);
	120	if (!rt) {
	121	dev_err(&pdev->dev, "failed to allocate memory\n");
	122	return -ENOMEM;
	123	}
	124
	125	rt->irq = platform_get_irq(pdev, 0);
	126	if (!rt->irq) {
	127	dev_err(&pdev->dev, "failed to load irq\n");
128	return -ENOENT;
129	}
130
cd5d5810	131	rt->membase = devm_ioremap_resource(&pdev->dev, res);
80ecbd24 JC	132	if (IS_ERR(rt->membase))
	133	return PTR_ERR(rt->membase);
	134
	135	clk = devm_clk_get(&pdev->dev, NULL);
	136	if (IS_ERR(clk)) {
	137	dev_err(&pdev->dev, "failed get clock rate\n");
	138	return PTR_ERR(clk);
	139	}
	140
	141	rt->timer_freq = clk_get_rate(clk) / TMR0CTL_PRESCALE_DIV;
	142	if (!rt->timer_freq)
	143	return -EINVAL;
	144
	145	rt->dev = &pdev->dev;
	146	platform_set_drvdata(pdev, rt);
	147
	148	rt_timer_request(rt);
	149	rt_timer_config(rt, 2);
	150	rt_timer_enable(rt);
	151
77d84ff8	152	dev_info(&pdev->dev, "maximum frequency is %luHz\n", rt->timer_freq);
80ecbd24 JC	153
	154	return 0;
	155	}
	156
80ecbd24 JC	157	static const struct of_device_id rt_timer_match[] = {
	158	{ .compatible = "ralink,rt2880-timer" },
	159	{},
	160	};
80ecbd24 JC	161
	162	static struct platform_driver rt_timer_driver = {
	163	.probe = rt_timer_probe,
80ecbd24	164	.driver = {
62ee73d2 PG	165	.name = "rt-timer",
	166	.of_match_table = rt_timer_match,
	167	.suppress_bind_attrs = true,
80ecbd24 JC	168	},
80ecbd24 JC	169	};
62ee73d2	170	builtin_platform_driver(rt_timer_driver);