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Commit a0719f52 authored by Linus Walleij's avatar Linus Walleij Committed by Russell King
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ARM: 6376/1: plat-nomadik: MTU: Change prescaler limit and comment updates 



The prescaler 16 is now used only when the timer runs at 32 MHz
or more. Some comment updates as well.

Acked-by: default avatarAlessandro Rubini <rubini@unipv.it>
Signed-off-by: default avatarJonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 99f76891

arch/arm/plat-nomadik/timer.c

+10 −7
Original line number Original line Diff line number Diff line 
/*

/*

 *  linux/arch/arm/mach-nomadik/timer.c

 *  linux/arch/arm/plat-nomadik/timer.c

 *

 *

 * Copyright (C) 2008 STMicroelectronics

 * Copyright (C) 2008 STMicroelectronics

 * Copyright (C) 2010 Alessandro Rubini

 * Copyright (C) 2010 Alessandro Rubini
@@ -75,7 +75,7 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode, 
		cr = readl(mtu_base + MTU_CR(1));

		cr = readl(mtu_base + MTU_CR(1));

		writel(0, mtu_base + MTU_LR(1));

		writel(0, mtu_base + MTU_LR(1));

		writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1));

		writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1));

		writel(0x2, mtu_base + MTU_IMSC);

		writel(1 << 1, mtu_base + MTU_IMSC);

		break;

		break;

	case CLOCK_EVT_MODE_SHUTDOWN:

	case CLOCK_EVT_MODE_SHUTDOWN:

	case CLOCK_EVT_MODE_UNUSED:

	case CLOCK_EVT_MODE_UNUSED:
@@ -131,7 +131,7 @@ void __init nmdk_timer_init(void) 
{

{

	unsigned long rate;

	unsigned long rate;

	struct clk *clk0;

	struct clk *clk0;

	u32 cr;

	u32 cr = MTU_CRn_32BITS;





	clk0 = clk_get_sys("mtu0", NULL);

	clk0 = clk_get_sys("mtu0", NULL);

	BUG_ON(IS_ERR(clk0));

	BUG_ON(IS_ERR(clk0));
@@ -139,12 +139,15 @@ void __init nmdk_timer_init(void) 
	clk_enable(clk0);

	clk_enable(clk0);





	/*

	/*

	 * Tick rate is 2.4MHz for Nomadik and 110MHz for ux500:

	 * Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz

	 * use a divide-by-16 counter if it's more than 16MHz

	 * for ux500.

	 * Use a divide-by-16 counter if the tick rate is more than 32MHz.

	 * At 32 MHz, the timer (with 32 bit counter) can be programmed

	 * to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer

	 * with 16 gives too low timer resolution.

	 */

	 */

	cr = MTU_CRn_32BITS;;

	rate = clk_get_rate(clk0);

	rate = clk_get_rate(clk0);

	if (rate > 16 << 20) {

	if (rate > 32000000) {

		rate /= 16;

		rate /= 16;

		cr |= MTU_CRn_PRESCALE_16;

		cr |= MTU_CRn_PRESCALE_16;

	} else {

	} else {