[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / clocksource / tcb_clksrc.c

#include <linux/init.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/atmel_tc.h>


/*
 * We're configured to use a specific TC block, one that's not hooked
 * up to external hardware, to provide a time solution:
 *
 *   - Two channels combine to create a free-running 32 bit counter
 *     with a base rate of 5+ MHz, packaged as a clocksource (with
 *     resolution better than 200 nsec).
 *   - Some chips support 32 bit counter. A single channel is used for
 *     this 32 bit free-running counter. the second channel is not used.
 *
 *   - The third channel may be used to provide a 16-bit clockevent
 *     source, used in either periodic or oneshot mode.  This runs
 *     at 32 KiHZ, and can handle delays of up to two seconds.
 *
 * A boot clocksource and clockevent source are also currently needed,
 * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
 * this code can be used when init_timers() is called, well before most
 * devices are set up.  (Some low end AT91 parts, which can run uClinux,
 * have only the timers in one TC block... they currently don't support
 * the tclib code, because of that initialization issue.)
 *
 * REVISIT behavior during system suspend states... we should disable
 * all clocks and save the power.  Easily done for clockevent devices,
 * but clocksources won't necessarily get the needed notifications.
 * For deeper system sleep states, this will be mandatory...
 */

static void __iomem *tcaddr;

static cycle_t tc_get_cycles(struct clocksource *cs)
{
	unsigned long	flags;
	u32		lower, upper;

	raw_local_irq_save(flags);
	do {
		upper = __raw_readl(tcaddr + ATMEL_TC_REG(1, CV));
		lower = __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
	} while (upper != __raw_readl(tcaddr + ATMEL_TC_REG(1, CV)));

	raw_local_irq_restore(flags);
	return (upper << 16) | lower;
}

static cycle_t tc_get_cycles32(struct clocksource *cs)
{
	return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
}

static struct clocksource clksrc = {
	.name           = "tcb_clksrc",
	.rating         = 200,
	.read           = tc_get_cycles,
	.mask           = CLOCKSOURCE_MASK(32),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

#ifdef CONFIG_GENERIC_CLOCKEVENTS

struct tc_clkevt_device {
	struct clock_event_device	clkevt;
	struct clk			*clk;
	void __iomem			*regs;
};

static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
{
	return container_of(clkevt, struct tc_clkevt_device, clkevt);
}

/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
 * because using one of the divided clocks would usually mean the
 * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
 *
 * A divided clock could be good for high resolution timers, since
 * 30.5 usec resolution can seem "low".
 */
static u32 timer_clock;

static void tc_mode(enum clock_event_mode m, struct clock_event_device *d)
{
	struct tc_clkevt_device *tcd = to_tc_clkevt(d);
	void __iomem		*regs = tcd->regs;

	if (tcd->clkevt.mode == CLOCK_EVT_MODE_PERIODIC
			|| tcd->clkevt.mode == CLOCK_EVT_MODE_ONESHOT) {
		__raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR));
		__raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
		clk_disable(tcd->clk);
	}

	switch (m) {

	/* By not making the gentime core emulate periodic mode on top
	 * of oneshot, we get lower overhead and improved accuracy.
	 */
	case CLOCK_EVT_MODE_PERIODIC:
		clk_enable(tcd->clk);

		/* slow clock, count up to RC, then irq and restart */
		__raw_writel(timer_clock
				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
				regs + ATMEL_TC_REG(2, CMR));
		__raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));

		/* Enable clock and interrupts on RC compare */
		__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));

		/* go go gadget! */
		__raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
				regs + ATMEL_TC_REG(2, CCR));
		break;

	case CLOCK_EVT_MODE_ONESHOT:
		clk_enable(tcd->clk);

		/* slow clock, count up to RC, then irq and stop */
		__raw_writel(timer_clock | ATMEL_TC_CPCSTOP
				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
				regs + ATMEL_TC_REG(2, CMR));
		__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));

		/* set_next_event() configures and starts the timer */
		break;

	default:
		break;
	}
}

static int tc_next_event(unsigned long delta, struct clock_event_device *d)
{
	__raw_writel(delta, tcaddr + ATMEL_TC_REG(2, RC));

	/* go go gadget! */
	__raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
			tcaddr + ATMEL_TC_REG(2, CCR));
	return 0;
}

static struct tc_clkevt_device clkevt = {
	.clkevt	= {
		.name		= "tc_clkevt",
		.features	= CLOCK_EVT_FEAT_PERIODIC
					| CLOCK_EVT_FEAT_ONESHOT,
		/* Should be lower than at91rm9200's system timer */
		.rating		= 125,
		.set_next_event	= tc_next_event,
		.set_mode	= tc_mode,
	},
};

static irqreturn_t ch2_irq(int irq, void *handle)
{
	struct tc_clkevt_device	*dev = handle;
	unsigned int		sr;

	sr = __raw_readl(dev->regs + ATMEL_TC_REG(2, SR));
	if (sr & ATMEL_TC_CPCS) {
		dev->clkevt.event_handler(&dev->clkevt);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static struct irqaction tc_irqaction = {
	.name		= "tc_clkevt",
	.flags		= IRQF_TIMER | IRQF_DISABLED,
	.handler	= ch2_irq,
};

static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
{
	struct clk *t2_clk = tc->clk[2];
	int irq = tc->irq[2];

	clkevt.regs = tc->regs;
	clkevt.clk = t2_clk;
	tc_irqaction.dev_id = &clkevt;

	timer_clock = clk32k_divisor_idx;

	clkevt.clkevt.cpumask = cpumask_of(0);

	clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);

	setup_irq(irq, &tc_irqaction);
}

#else /* !CONFIG_GENERIC_CLOCKEVENTS */

static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
{
	/* NOTHING */
}

#endif

static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
{
	/* channel 0:  waveform mode, input mclk/8, clock TIOA0 on overflow */
	__raw_writel(mck_divisor_idx			/* likely divide-by-8 */
			| ATMEL_TC_WAVE
			| ATMEL_TC_WAVESEL_UP		/* free-run */
			| ATMEL_TC_ACPA_SET		/* TIOA0 rises at 0 */
			| ATMEL_TC_ACPC_CLEAR,		/* (duty cycle 50%) */
			tcaddr + ATMEL_TC_REG(0, CMR));
	__raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
	__raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR));	/* no irqs */
	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));

	/* channel 1:  waveform mode, input TIOA0 */
	__raw_writel(ATMEL_TC_XC1			/* input: TIOA0 */
			| ATMEL_TC_WAVE
			| ATMEL_TC_WAVESEL_UP,		/* free-run */
			tcaddr + ATMEL_TC_REG(1, CMR));
	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR));	/* no irqs */
	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));

	/* chain channel 0 to channel 1*/
	__raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
	/* then reset all the timers */
	__raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
}

static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx)
{
	/* channel 0:  waveform mode, input mclk/8 */
	__raw_writel(mck_divisor_idx			/* likely divide-by-8 */
			| ATMEL_TC_WAVE
			| ATMEL_TC_WAVESEL_UP,		/* free-run */
			tcaddr + ATMEL_TC_REG(0, CMR));
	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR));	/* no irqs */
	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));

	/* then reset all the timers */
	__raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
}

static int __init tcb_clksrc_init(void)
{
	static char bootinfo[] __initdata
		= KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";

	struct platform_device *pdev;
	struct atmel_tc *tc;
	struct clk *t0_clk;
	u32 rate, divided_rate = 0;
	int best_divisor_idx = -1;
	int clk32k_divisor_idx = -1;
	int i;

	tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK, clksrc.name);
	if (!tc) {
		pr_debug("can't alloc TC for clocksource\n");
		return -ENODEV;
	}
	tcaddr = tc->regs;
	pdev = tc->pdev;

	t0_clk = tc->clk[0];
	clk_enable(t0_clk);

	/* How fast will we be counting?  Pick something over 5 MHz.  */
	rate = (u32) clk_get_rate(t0_clk);
	for (i = 0; i < 5; i++) {
		unsigned divisor = atmel_tc_divisors[i];
		unsigned tmp;

		/* remember 32 KiHz clock for later */
		if (!divisor) {
			clk32k_divisor_idx = i;
			continue;
		}

		tmp = rate / divisor;
		pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
		if (best_divisor_idx > 0) {
			if (tmp < 5 * 1000 * 1000)
				continue;
		}
		divided_rate = tmp;
		best_divisor_idx = i;
	}


	printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK,
			divided_rate / 1000000,
			((divided_rate + 500000) % 1000000) / 1000);

	if (tc->tcb_config && tc->tcb_config->counter_width == 32) {
		/* use apropriate function to read 32 bit counter */
		clksrc.read = tc_get_cycles32;
		/* setup ony channel 0 */
		tcb_setup_single_chan(tc, best_divisor_idx);
	} else {
		/* tclib will give us three clocks no matter what the
		 * underlying platform supports.
		 */
		clk_enable(tc->clk[1]);
		/* setup both channel 0 & 1 */
		tcb_setup_dual_chan(tc, best_divisor_idx);
	}

	/* and away we go! */
	clocksource_register_hz(&clksrc, divided_rate);

	/* channel 2:  periodic and oneshot timer support */
	setup_clkevents(tc, clk32k_divisor_idx);

	return 0;
}
arch_initcall(tcb_clksrc_init);
Commit	Line	Data
4d243f92 DB	1	#include <linux/init.h>
	2	#include <linux/clocksource.h>
	3	#include <linux/clockchips.h>
	4	#include <linux/interrupt.h>
	5	#include <linux/irq.h>
	6
	7	#include <linux/clk.h>
	8	#include <linux/err.h>
	9	#include <linux/ioport.h>
	10	#include <linux/io.h>
	11	#include <linux/platform_device.h>
	12	#include <linux/atmel_tc.h>
	13
	14
	15	/*
	16	* We're configured to use a specific TC block, one that's not hooked
	17	* up to external hardware, to provide a time solution:
	18	*
	19	* - Two channels combine to create a free-running 32 bit counter
	20	* with a base rate of 5+ MHz, packaged as a clocksource (with
	21	* resolution better than 200 nsec).
8e315a7b NF	22	* - Some chips support 32 bit counter. A single channel is used for
8e315a7b NF	23	* this 32 bit free-running counter. the second channel is not used.
4d243f92 DB	24	*
	25	* - The third channel may be used to provide a 16-bit clockevent
	26	* source, used in either periodic or oneshot mode. This runs
	27	* at 32 KiHZ, and can handle delays of up to two seconds.
	28	*
	29	* A boot clocksource and clockevent source are also currently needed,
	30	* unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
	31	* this code can be used when init_timers() is called, well before most
	32	* devices are set up. (Some low end AT91 parts, which can run uClinux,
	33	* have only the timers in one TC block... they currently don't support
	34	* the tclib code, because of that initialization issue.)
	35	*
	36	* REVISIT behavior during system suspend states... we should disable
	37	* all clocks and save the power. Easily done for clockevent devices,
	38	* but clocksources won't necessarily get the needed notifications.
	39	* For deeper system sleep states, this will be mandatory...
	40	*/
	41
	42	static void __iomem *tcaddr;
	43
8e19608e	44	static cycle_t tc_get_cycles(struct clocksource *cs)
4d243f92 DB	45	{
	46	unsigned long flags;
	47	u32 lower, upper;
	48
	49	raw_local_irq_save(flags);
	50	do {
	51	upper = __raw_readl(tcaddr + ATMEL_TC_REG(1, CV));
	52	lower = __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
	53	} while (upper != __raw_readl(tcaddr + ATMEL_TC_REG(1, CV)));
	54
	55	raw_local_irq_restore(flags);
	56	return (upper << 16) \| lower;
	57	}
	58
8e315a7b NF	59	static cycle_t tc_get_cycles32(struct clocksource *cs)
	60	{
	61	return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
	62	}
	63
4d243f92 DB	64	static struct clocksource clksrc = {
	65	.name = "tcb_clksrc",
	66	.rating = 200,
	67	.read = tc_get_cycles,
	68	.mask = CLOCKSOURCE_MASK(32),
4d243f92 DB	69	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
	70	};
	71
	72	#ifdef CONFIG_GENERIC_CLOCKEVENTS
	73
	74	struct tc_clkevt_device {
	75	struct clock_event_device clkevt;
	76	struct clk *clk;
	77	void __iomem *regs;
	78	};
	79
	80	static struct tc_clkevt_device to_tc_clkevt(struct clock_event_device clkevt)
	81	{
	82	return container_of(clkevt, struct tc_clkevt_device, clkevt);
	83	}
	84
	85	/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
	86	* because using one of the divided clocks would usually mean the
	87	* tick rate can never be less than several dozen Hz (vs 0.5 Hz).
	88	*
	89	* A divided clock could be good for high resolution timers, since
	90	* 30.5 usec resolution can seem "low".
	91	*/
	92	static u32 timer_clock;
	93
	94	static void tc_mode(enum clock_event_mode m, struct clock_event_device *d)
	95	{
	96	struct tc_clkevt_device *tcd = to_tc_clkevt(d);
	97	void __iomem *regs = tcd->regs;
	98
	99	if (tcd->clkevt.mode == CLOCK_EVT_MODE_PERIODIC
	100	\|\| tcd->clkevt.mode == CLOCK_EVT_MODE_ONESHOT) {
	101	__raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR));
	102	__raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
	103	clk_disable(tcd->clk);
	104	}
	105
	106	switch (m) {
	107
	108	/* By not making the gentime core emulate periodic mode on top
	109	* of oneshot, we get lower overhead and improved accuracy.
	110	*/
	111	case CLOCK_EVT_MODE_PERIODIC:
	112	clk_enable(tcd->clk);
	113
	114	/* slow clock, count up to RC, then irq and restart */
	115	__raw_writel(timer_clock
	116	\| ATMEL_TC_WAVE \| ATMEL_TC_WAVESEL_UP_AUTO,
	117	regs + ATMEL_TC_REG(2, CMR));
	118	__raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
	119
	120	/* Enable clock and interrupts on RC compare */
	121	__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
	122
	123	/* go go gadget! */
	124	__raw_writel(ATMEL_TC_CLKEN \| ATMEL_TC_SWTRG,
	125	regs + ATMEL_TC_REG(2, CCR));
	126	break;
	127
	128	case CLOCK_EVT_MODE_ONESHOT:
	129	clk_enable(tcd->clk);
	130
	131	/* slow clock, count up to RC, then irq and stop */
	132	__raw_writel(timer_clock \| ATMEL_TC_CPCSTOP
133	\| ATMEL_TC_WAVE \| ATMEL_TC_WAVESEL_UP_AUTO,
134	regs + ATMEL_TC_REG(2, CMR));
135	__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
136
137	/* set_next_event() configures and starts the timer */
138	break;
139
140	default:
141	break;
142	}
143	}
144
145	static int tc_next_event(unsigned long delta, struct clock_event_device *d)
146	{
147	__raw_writel(delta, tcaddr + ATMEL_TC_REG(2, RC));
148
149	/* go go gadget! */
150	__raw_writel(ATMEL_TC_CLKEN \| ATMEL_TC_SWTRG,
151	tcaddr + ATMEL_TC_REG(2, CCR));
152	return 0;
153	}
154
155	static struct tc_clkevt_device clkevt = {
156	.clkevt = {
157	.name = "tc_clkevt",
158	.features = CLOCK_EVT_FEAT_PERIODIC
159	\| CLOCK_EVT_FEAT_ONESHOT,
4d243f92 DB	160	/* Should be lower than at91rm9200's system timer */
4d243f92 DB	161	.rating = 125,
4d243f92 DB	162	.set_next_event = tc_next_event,
	163	.set_mode = tc_mode,
	164	},
	165	};
	166
	167	static irqreturn_t ch2_irq(int irq, void *handle)
	168	{
	169	struct tc_clkevt_device *dev = handle;
	170	unsigned int sr;
	171
	172	sr = __raw_readl(dev->regs + ATMEL_TC_REG(2, SR));
	173	if (sr & ATMEL_TC_CPCS) {
	174	dev->clkevt.event_handler(&dev->clkevt);
	175	return IRQ_HANDLED;
	176	}
	177
	178	return IRQ_NONE;
	179	}
	180
	181	static struct irqaction tc_irqaction = {
	182	.name = "tc_clkevt",
	183	.flags = IRQF_TIMER \| IRQF_DISABLED,
	184	.handler = ch2_irq,
	185	};
	186
3ee08aea	187	static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
4d243f92	188	{
4d243f92 DB	189	struct clk *t2_clk = tc->clk[2];
	190	int irq = tc->irq[2];
	191
	192	clkevt.regs = tc->regs;
	193	clkevt.clk = t2_clk;
	194	tc_irqaction.dev_id = &clkevt;
	195
	196	timer_clock = clk32k_divisor_idx;
	197
320ab2b0	198	clkevt.clkevt.cpumask = cpumask_of(0);
4d243f92	199
77cc982f	200	clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
1817dc03 VN	201
1817dc03 VN	202	setup_irq(irq, &tc_irqaction);
4d243f92 DB	203	}
	204
	205	#else /* !CONFIG_GENERIC_CLOCKEVENTS */
	206
3ee08aea	207	static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
4d243f92 DB	208	{
	209	/* NOTHING */
	210	}
	211
	212	#endif
	213
8e315a7b NF	214	static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
	215	{
	216	/* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
	217	__raw_writel(mck_divisor_idx /* likely divide-by-8 */
	218	\| ATMEL_TC_WAVE
	219	\| ATMEL_TC_WAVESEL_UP /* free-run */
	220	\| ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
	221	\| ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
	222	tcaddr + ATMEL_TC_REG(0, CMR));
	223	__raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
	224	__raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
	225	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
	226	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
	227
	228	/* channel 1: waveform mode, input TIOA0 */
	229	__raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */
	230	\| ATMEL_TC_WAVE
	231	\| ATMEL_TC_WAVESEL_UP, /* free-run */
	232	tcaddr + ATMEL_TC_REG(1, CMR));
	233	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
	234	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
	235
	236	/* chain channel 0 to channel 1*/
	237	__raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
	238	/* then reset all the timers */
	239	__raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
	240	}
	241
	242	static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx)
	243	{
	244	/* channel 0: waveform mode, input mclk/8 */
	245	__raw_writel(mck_divisor_idx /* likely divide-by-8 */
	246	\| ATMEL_TC_WAVE
	247	\| ATMEL_TC_WAVESEL_UP, /* free-run */
	248	tcaddr + ATMEL_TC_REG(0, CMR));
	249	__raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
	250	__raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
	251
	252	/* then reset all the timers */
	253	__raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
	254	}
	255
4d243f92 DB	256	static int __init tcb_clksrc_init(void)
	257	{
	258	static char bootinfo[] __initdata
	259	= KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";
	260
	261	struct platform_device *pdev;
	262	struct atmel_tc *tc;
3ee08aea	263	struct clk *t0_clk;
4d243f92 DB	264	u32 rate, divided_rate = 0;
	265	int best_divisor_idx = -1;
	266	int clk32k_divisor_idx = -1;
	267	int i;
	268
	269	tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK, clksrc.name);
	270	if (!tc) {
	271	pr_debug("can't alloc TC for clocksource\n");
	272	return -ENODEV;
	273	}
	274	tcaddr = tc->regs;
	275	pdev = tc->pdev;
	276
	277	t0_clk = tc->clk[0];
	278	clk_enable(t0_clk);
	279
	280	/* How fast will we be counting? Pick something over 5 MHz. */
	281	rate = (u32) clk_get_rate(t0_clk);
	282	for (i = 0; i < 5; i++) {
	283	unsigned divisor = atmel_tc_divisors[i];
	284	unsigned tmp;
	285
	286	/* remember 32 KiHz clock for later */
	287	if (!divisor) {
	288	clk32k_divisor_idx = i;
	289	continue;
	290	}
	291
	292	tmp = rate / divisor;
	293	pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
	294	if (best_divisor_idx > 0) {
	295	if (tmp < 5 * 1000 * 1000)
	296	continue;
	297	}
	298	divided_rate = tmp;
	299	best_divisor_idx = i;
	300	}
	301
4d243f92 DB	302
	303	printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK,
	304	divided_rate / 1000000,
	305	((divided_rate + 500000) % 1000000) / 1000);
	306
8e315a7b NF	307	if (tc->tcb_config && tc->tcb_config->counter_width == 32) {
	308	/* use apropriate function to read 32 bit counter */
	309	clksrc.read = tc_get_cycles32;
	310	/* setup ony channel 0 */
	311	tcb_setup_single_chan(tc, best_divisor_idx);
	312	} else {
	313	/* tclib will give us three clocks no matter what the
	314	* underlying platform supports.
	315	*/
	316	clk_enable(tc->clk[1]);
	317	/* setup both channel 0 & 1 */
	318	tcb_setup_dual_chan(tc, best_divisor_idx);
	319	}
4d243f92 DB	320
4d243f92 DB	321	/* and away we go! */
f5a54dd7	322	clocksource_register_hz(&clksrc, divided_rate);
4d243f92 DB	323
4d243f92 DB	324	/* channel 2: periodic and oneshot timer support */
3ee08aea	325	setup_clkevents(tc, clk32k_divisor_idx);
4d243f92 DB	326
	327	return 0;
	328	}
	329	arch_initcall(tcb_clksrc_init);