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Commit 38a41fdf authored by Sascha Hauer's avatar Sascha Hauer Committed by Robert Schwebel
Browse files

IMX: introduce clock API



This patch introduces the clock API for i.MX and converts all
in-Kernel drivers to use it.

Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
parent dbff4e9e
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+1 −1
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@

# Object file lists.

obj-y			+= irq.o time.o dma.o generic.o
obj-y			+= irq.o time.o dma.o generic.o clock.o

obj-$(CONFIG_CPU_FREQ_IMX)	+= cpufreq.o

+205 −0
Original line number Diff line number Diff line
/*
 *  Copyright (C) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/math64.h>
#include <linux/err.h>

#include <asm/io.h>
#include <asm/arch/imx-regs.h>

/*
 * Very simple approach: We can't disable clocks, so we do
 * not need refcounting
 */

struct clk {
	struct list_head node;
	const char *name;
	unsigned long (*get_rate)(void);
};

/*
 *  get the system pll clock in Hz
 *
 *                  mfi + mfn / (mfd +1)
 *  f = 2 * f_ref * --------------------
 *                        pd + 1
 */
static unsigned long imx_decode_pll(unsigned int pll, u32 f_ref)
{
	unsigned long long ll;
	unsigned long quot;

	u32 mfi = (pll >> 10) & 0xf;
	u32 mfn = pll & 0x3ff;
	u32 mfd = (pll >> 16) & 0x3ff;
	u32 pd =  (pll >> 26) & 0xf;

	mfi = mfi <= 5 ? 5 : mfi;

	ll = 2 * (unsigned long long)f_ref *
		((mfi << 16) + (mfn << 16) / (mfd + 1));
	quot = (pd + 1) * (1 << 16);
	ll += quot / 2;
	do_div(ll, quot);
	return (unsigned long)ll;
}

static unsigned long imx_get_system_clk(void)
{
	u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);

	return imx_decode_pll(SPCTL0, f_ref);
}

static unsigned long imx_get_mcu_clk(void)
{
	return imx_decode_pll(MPCTL0, CLK32 * 512);
}

/*
 *  get peripheral clock 1 ( UART[12], Timer[12], PWM )
 */
static unsigned long imx_get_perclk1(void)
{
	return imx_get_system_clk() / (((PCDR) & 0xf)+1);
}

/*
 *  get peripheral clock 2 ( LCD, SD, SPI[12] )
 */
static unsigned long imx_get_perclk2(void)
{
	return imx_get_system_clk() / (((PCDR>>4) & 0xf)+1);
}

/*
 *  get peripheral clock 3 ( SSI )
 */
static unsigned long imx_get_perclk3(void)
{
	return imx_get_system_clk() / (((PCDR>>16) & 0x7f)+1);
}

/*
 *  get hclk ( SDRAM, CSI, Memory Stick, I2C, DMA )
 */
static unsigned long imx_get_hclk(void)
{
	return imx_get_system_clk() / (((CSCR>>10) & 0xf)+1);
}

static struct clk clk_system_clk = {
	.name = "system_clk",
	.get_rate = imx_get_system_clk,
};

static struct clk clk_hclk = {
	.name = "hclk",
	.get_rate = imx_get_hclk,
};

static struct clk clk_mcu_clk = {
	.name = "mcu_clk",
	.get_rate = imx_get_mcu_clk,
};

static struct clk clk_perclk1 = {
	.name = "perclk1",
	.get_rate = imx_get_perclk1,
};

static struct clk clk_uart_clk = {
	.name = "uart_clk",
	.get_rate = imx_get_perclk1,
};

static struct clk clk_perclk2 = {
	.name = "perclk2",
	.get_rate = imx_get_perclk2,
};

static struct clk clk_perclk3 = {
	.name = "perclk3",
	.get_rate = imx_get_perclk3,
};

static struct clk *clks[] = {
	&clk_perclk1,
	&clk_perclk2,
	&clk_perclk3,
	&clk_system_clk,
	&clk_hclk,
	&clk_mcu_clk,
	&clk_uart_clk,
};

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

struct clk *clk_get(struct device *dev, const char *id)
{
	struct clk *p, *clk = ERR_PTR(-ENOENT);

	mutex_lock(&clocks_mutex);
	list_for_each_entry(p, &clocks, node) {
		if (!strcmp(p->name, id)) {
			clk = p;
			goto found;
		}
	}

found:
	mutex_unlock(&clocks_mutex);

	return clk;
}

void clk_put(struct clk *clk)
{
}

int clk_enable(struct clk *clk)
{
	return 0;
}

void clk_disable(struct clk *clk)
{
}

unsigned long clk_get_rate(struct clk *clk)
{
	return clk->get_rate();
}

int imx_clocks_init(void)
{
	int i;

	mutex_lock(&clocks_mutex);
	for (i = 0; i < ARRAY_SIZE(clks); i++)
		list_add(&clks[i]->node, &clocks);
	mutex_unlock(&clocks_mutex);

	return 0;
}
+17 −3
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <asm/system.h>

#include <asm/hardware.h>
@@ -52,6 +54,8 @@
static u32 mpctl0_at_boot;
static u32 bclk_div_at_boot;

static struct clk *system_clk, *mcu_clk;

static void imx_set_async_mode(void)
{
	adjust_cr(CR_920T_CLOCK_MODE, CR_920T_ASYNC_MODE);
@@ -160,10 +164,10 @@ static unsigned int imx_get_speed(unsigned int cpu)
	cr = get_cr();

	if((cr & CR_920T_CLOCK_MODE) == CR_920T_FASTBUS_MODE) {
		freq = imx_get_system_clk();
		freq = clk_get_rate(system_clk);
		freq = (freq + bclk_div/2) / bclk_div;
	} else {
		freq = imx_get_mcu_clk();
		freq = clk_get_rate(mcu_clk);
		if (cscr & CSCR_MPU_PRESC)
			freq /= 2;
	}
@@ -201,7 +205,7 @@ static int imx_set_target(struct cpufreq_policy *policy,
	pr_debug(KERN_DEBUG "imx: requested frequency %ld Hz, mpctl0 at boot 0x%08x\n",
			freq, mpctl0_at_boot);

	sysclk = imx_get_system_clk();
	sysclk = clk_get_rate(system_clk);

	if (freq > sysclk / bclk_div_at_boot + 1000000) {
		freq = imx_compute_mpctl(&mpctl0, mpctl0_at_boot, CLK32 * 512, freq, relation);
@@ -290,6 +294,16 @@ static int __init imx_cpufreq_init(void)
	bclk_div_at_boot = __mfld2val(CSCR_BCLK_DIV, CSCR) + 1;
	mpctl0_at_boot = 0;

	system_clk = clk_get(NULL, "system_clk");
	if (IS_ERR(system_clk))
		return PTR_ERR(system_clk);

	mcu_clk = clk_get(NULL, "mcu_clk");
	if (IS_ERR(mcu_clk)) {
		clk_put(system_clk);
		return PTR_ERR(mcu_clk);
	}

	if((CSCR & CSCR_MPEN) &&
	   ((get_cr() & CR_920T_CLOCK_MODE) != CR_920T_FASTBUS_MODE))
		mpctl0_at_boot = MPCTL0;
+0 −76
Original line number Diff line number Diff line
@@ -214,82 +214,6 @@ int imx_irq_to_gpio(unsigned irq)

EXPORT_SYMBOL(imx_irq_to_gpio);

/*
 *  get the system pll clock in Hz
 *
 *                  mfi + mfn / (mfd +1)
 *  f = 2 * f_ref * --------------------
 *                        pd + 1
 */
static unsigned int imx_decode_pll(unsigned int pll, u32 f_ref)
{
	unsigned long long ll;
	unsigned long quot;

	u32 mfi = (pll >> 10) & 0xf;
	u32 mfn = pll & 0x3ff;
	u32 mfd = (pll >> 16) & 0x3ff;
	u32 pd =  (pll >> 26) & 0xf;

	mfi = mfi <= 5 ? 5 : mfi;

	ll = 2 * (unsigned long long)f_ref * ( (mfi<<16) + (mfn<<16) / (mfd+1) );
	quot = (pd+1) * (1<<16);
	ll += quot / 2;
	do_div(ll, quot);
	return (unsigned int) ll;
}

unsigned int imx_get_system_clk(void)
{
	u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);

	return imx_decode_pll(SPCTL0, f_ref);
}
EXPORT_SYMBOL(imx_get_system_clk);

unsigned int imx_get_mcu_clk(void)
{
	return imx_decode_pll(MPCTL0, CLK32 * 512);
}
EXPORT_SYMBOL(imx_get_mcu_clk);

/*
 *  get peripheral clock 1 ( UART[12], Timer[12], PWM )
 */
unsigned int imx_get_perclk1(void)
{
	return imx_get_system_clk() / (((PCDR) & 0xf)+1);
}
EXPORT_SYMBOL(imx_get_perclk1);

/*
 *  get peripheral clock 2 ( LCD, SD, SPI[12] )
 */
unsigned int imx_get_perclk2(void)
{
	return imx_get_system_clk() / (((PCDR>>4) & 0xf)+1);
}
EXPORT_SYMBOL(imx_get_perclk2);

/*
 *  get peripheral clock 3 ( SSI )
 */
unsigned int imx_get_perclk3(void)
{
	return imx_get_system_clk() / (((PCDR>>16) & 0x7f)+1);
}
EXPORT_SYMBOL(imx_get_perclk3);

/*
 *  get hclk ( SDRAM, CSI, Memory Stick, I2C, DMA )
 */
unsigned int imx_get_hclk(void)
{
	return imx_get_system_clk() / (((CSCR>>10) & 0xf)+1);
}
EXPORT_SYMBOL(imx_get_hclk);

static struct resource imx_mmc_resources[] = {
	[0] = {
		.start	= 0x00214000,
+17 −6
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/clk.h>

#include <asm/hardware.h>
#include <asm/io.h>
@@ -86,10 +87,10 @@ static struct clocksource clocksource_imx = {
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

static int __init imx_clocksource_init(void)
static int __init imx_clocksource_init(unsigned long rate)
{
	clocksource_imx.mult =
		clocksource_hz2mult(imx_get_perclk1(), clocksource_imx.shift);
		clocksource_hz2mult(rate, clocksource_imx.shift);
	clocksource_register(&clocksource_imx);

	return 0;
@@ -174,9 +175,9 @@ static struct clock_event_device clockevent_imx = {
	.rating		= 200,
};

static int __init imx_clockevent_init(void)
static int __init imx_clockevent_init(unsigned long rate)
{
	clockevent_imx.mult = div_sc(imx_get_perclk1(), NSEC_PER_SEC,
	clockevent_imx.mult = div_sc(rate, NSEC_PER_SEC,
					clockevent_imx.shift);
	clockevent_imx.max_delta_ns =
		clockevent_delta2ns(0xfffffffe, &clockevent_imx);
@@ -190,13 +191,23 @@ static int __init imx_clockevent_init(void)
	return 0;
}

extern int imx_clocks_init(void);

static void __init imx_timer_init(void)
{
	struct clk *clk;
	unsigned long rate;

	imx_clocks_init();

	clk = clk_get(NULL, "perclk1");
	clk_enable(clk);
	rate = clk_get_rate(clk);

	imx_timer_hardware_init();
	imx_clocksource_init();
	imx_clocksource_init(rate);

	imx_clockevent_init();
	imx_clockevent_init(rate);

	/*
	 * Make irqs happen for the system timer
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