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Commit 91f8ed83 authored by Andrew Victor's avatar Andrew Victor Committed by Russell King
Browse files

[ARM] 3578/1: AT91RM9200 Clock update 



Patch from Andrew Victor

Some updates to the clock infrastructure for the AT91RM9200.

1. Hard-coded values replaced with names defined in at91rm9200_sys.h.
2. Added the four PIO clocks, which are enabled at startup.
3. At startup, disable all unused clocks.
4. Minor bugfix for usage counts associated with MCK. [Patch from David
Brownell]
5. Added at91_clock_associate() function to associate device & function
with a particular clock.  [Patch from David Brownell]

Signed-off-by: default avatarAndrew Victor <andrew@sanpeople.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent b7408aff

arch/arm/mach-at91rm9200/clock.c

+101 −20
Original line number Diff line number Diff line
@@ -32,8 +32,6 @@ 


#include "generic.h"



#undef	DEBUG



/*

 * There's a lot more which can be done with clocks, including cpufreq

 * integration, slow clock mode support (for system suspend), letting
@@ -41,7 +39,9 @@ 
 */



struct clk {

	const char	*name;

	const char	*name;		/* unique clock name */

	const char	*function;	/* function of the clock */

	struct device	*dev;		/* device associated with function */

	unsigned long	rate_hz;

	struct clk	*parent;

	u32		pmc_mask;
@@ -71,15 +71,14 @@ static struct clk clk32k = { 
};

static struct clk main_clk = {

	.name		= "main",

	.pmc_mask	= 1 << 0,	/* in PMC_SR */

	.users		= 1,

	.pmc_mask	= AT91_PMC_MOSCS,	/* in PMC_SR */

	.id		= 1,

	.primary	= 1,

};

static struct clk plla = {

	.name		= "plla",

	.parent		= &main_clk,

	.pmc_mask	= 1 << 1,	/* in PMC_SR */

	.pmc_mask	= AT91_PMC_LOCKA,	/* in PMC_SR */

	.id		= 2,

	.primary	= 1,

	.pll		= 1,
@@ -105,7 +104,7 @@ static void pllb_mode(struct clk *clk, int is_on) 
static struct clk pllb = {

	.name		= "pllb",

	.parent		= &main_clk,

	.pmc_mask	= 1 << 2,	/* in PMC_SR */

	.pmc_mask	= AT91_PMC_LOCKB,	/* in PMC_SR */

	.mode		= pllb_mode,

	.id		= 3,

	.primary	= 1,
@@ -177,8 +176,7 @@ static struct clk pck3 = { 
 */

static struct clk mck = {

	.name		= "mck",

	.pmc_mask	= 1 << 3,	/* in PMC_SR */

	.users		= 1,		/* (must be) always on */

	.pmc_mask	= AT91_PMC_MCKRDY,	/* in PMC_SR */

};



static void pmc_periph_mode(struct clk *clk, int is_on)
@@ -249,6 +247,30 @@ static struct clk spi_clk = { 
	.pmc_mask	= 1 << AT91_ID_SPI,

	.mode		= pmc_periph_mode,

};

static struct clk pioA_clk = {

	.name		= "pioA_clk",

	.parent		= &mck,

	.pmc_mask	= 1 << AT91_ID_PIOA,

	.mode		= pmc_periph_mode,

};

static struct clk pioB_clk = {

	.name		= "pioB_clk",

	.parent		= &mck,

	.pmc_mask	= 1 << AT91_ID_PIOB,

	.mode		= pmc_periph_mode,

};

static struct clk pioC_clk = {

	.name		= "pioC_clk",

	.parent		= &mck,

	.pmc_mask	= 1 << AT91_ID_PIOC,

	.mode		= pmc_periph_mode,

};

static struct clk pioD_clk = {

	.name		= "pioD_clk",

	.parent		= &mck,

	.pmc_mask	= 1 << AT91_ID_PIOD,

	.mode		= pmc_periph_mode,

};



static struct clk *const clock_list[] = {

	/* four primary clocks -- MUST BE FIRST! */
@@ -279,21 +301,46 @@ static struct clk *const clock_list[] = { 
	&udc_clk,

	&twi_clk,

	&spi_clk,

	&pioA_clk,

	&pioB_clk,

	&pioC_clk,

	&pioD_clk,

	// ssc0..ssc2

	// tc0..tc5

	// irq0..irq6

	&ohci_clk,

	&ether_clk,

};





/*

 * Associate a particular clock with a function (eg, "uart") and device.

 * The drivers can then request the same 'function' with several different

 * devices and not care about which clock name to use.

 */

void __init at91_clock_associate(const char *id, struct device *dev, const char *func)

{

	struct clk *clk = clk_get(NULL, id);



	if (!dev || !clk || !IS_ERR(clk_get(dev, func)))

		return;



	clk->function = func;

	clk->dev = dev;

}



/* clocks are all static for now; no refcounting necessary */

struct clk *clk_get(struct device *dev, const char *id)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(clock_list); i++) {

		if (strcmp(id, clock_list[i]->name) == 0)

			return clock_list[i];

		struct clk *clk = clock_list[i];



		if (strcmp(id, clk->name) == 0)

			return clk;

		if (clk->function && (dev == clk->dev) && strcmp(id, clk->function) == 0)

			return clk;

	}



	return ERR_PTR(-ENOENT);
@@ -593,6 +640,30 @@ fail: 
	return 0;

}





/*

 * Several unused clocks may be active.  Turn them off.

 */

static void at91_periphclk_reset(void)

{

	unsigned long reg;

	int i;



	reg = at91_sys_read(AT91_PMC_PCSR);



	for (i = 0; i < ARRAY_SIZE(clock_list); i++) {

		struct clk	*clk = clock_list[i];



		if (clk->mode != pmc_periph_mode)

			continue;



		if (clk->users > 0)

			reg &= ~clk->pmc_mask;

	}



	at91_sys_write(AT91_PMC_PCDR, reg);

}



int __init at91_clock_init(unsigned long main_clock)

{

	unsigned tmp, freq, mckr;
@@ -626,7 +697,6 @@ int __init at91_clock_init(unsigned long main_clock) 
	 */

	at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | AT91_PMC_USB96M;

	pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);

	at91_sys_write(AT91_PMC_PCDR, (1 << AT91_ID_UHP) | (1 << AT91_ID_UDP));

	at91_sys_write(AT91_PMC_SCDR, AT91_PMC_UHP | AT91_PMC_UDP);

	at91_sys_write(AT91_CKGR_PLLBR, 0);

	at91_sys_write(AT91_PMC_SCER, AT91_PMC_MCKUDP);
@@ -640,11 +710,13 @@ int __init at91_clock_init(unsigned long main_clock) 
	 */

	mckr = at91_sys_read(AT91_PMC_MCKR);

	mck.parent = clock_list[mckr & AT91_PMC_CSS];

	mck.parent->users++;

	freq = mck.parent->rate_hz;

	freq /= (1 << ((mckr >> 2) & 3));		/* prescale */

	mck.rate_hz = freq / (1 + ((mckr >> 8) & 3));	/* mdiv */



	/* MCK and CPU clock are "always on" */

	clk_enable(&mck);



	printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",

		freq / 1000000, (unsigned) mck.rate_hz / 1000000,

		(unsigned) main_clock / 1000000,
@@ -663,19 +735,28 @@ int __init at91_clock_init(unsigned long main_clock) 
			continue;



		pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));

		parent = clock_list[pckr & 3];

		parent = clock_list[pckr & AT91_PMC_CSS];

		clk->parent = parent;

		clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));



		if (clk->users == 0) {

			/* not being used, so switch it off */

			at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);

		}

	}

#else

	/* disable unused clocks */

	/* disable all programmable clocks */

	at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);

#endif	/* CONFIG_AT91_PROGRAMMABLE_CLOCKS */

#endif



	/* FIXME several unused clocks may still be active...  provide

	 * a CONFIG option to turn off all unused clocks at some point

	 * before driver init starts.

	 */

	/* enable the PIO clocks */

	clk_enable(&pioA_clk);

	clk_enable(&pioB_clk);

	clk_enable(&pioC_clk);

	clk_enable(&pioD_clk);



	/* disable all other unused peripheral clocks */

	at91_periphclk_reset();



	return 0;

}